Article

Exploration of the Neural Correlates of Ticklish Laughter by Functional Magnetic Resonance Imaging

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Abstract

The burst of laughter that is evoked by tickling is a primitive form of vocalization. It evolves during an early phase of postnatal life and appears to be independent of higher cortical circuits. Clinicopathological observations have led to suspicions that the hypothalamus is directly involved in the production of laughter. In this functional magnetic resonance imaging investigation, healthy participants were 1) tickled on the sole of the right foot with permission to laugh, 2) tickled but asked to stifle laughter, and 3) requested to laugh voluntarily. Tickling that was accompanied by involuntary laughter activated regions in the lateral hypothalamus, parietal operculum, amygdala, and right cerebellum to a consistently greater degree than did the 2 other conditions. Activation of the periaqueductal gray matter was observed during voluntary and involuntary laughter but not when laughter was inhibited. The present findings indicate that hypothalamic activity plays a crucial role in evoking ticklish laughter in healthy individuals. The hypothalamus promotes innate behavioral reactions to stimuli and sends projections to the periaqueductal gray matter, which is itself an important integrative center for the control of vocalization. A comparison of our findings with published data relating to humorous laughter revealed the involvement of a common set of subcortical centers.

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... The analysis of the neuronal control of overt speech and laughter by functional magnetic resonance imaging (fMRI) is problematical, owing to the occurrence of unavoidable motional artefacts. Although available data pertaining to the neuronal processes that govern overt speech [10][11][12] and laughter [13][14][15][16][17] are thus scarce, they nevertheless extend and complement those derived from pathological [18,19], stimulation [20,21] and tractography studies [22]. They are of particular relevance in distinguishing between the motor control of a postulated voluntary and involuntary pathway of vocalization. ...
... On the basis of available data in humans, a separation of these two pathways is less apparent. It has been postulated that during laughter the two pathways interact at the level of either the ( pre)-supplementary motor area [7,22], the anterior cingulate gyrus [30,31] or the primary motor cortex [15,31], possibly via inhibitory or modulatory processes [7,15]. However, subcortical regions have not been discussed concerning their interaction. ...
... On the basis of available data in humans, a separation of these two pathways is less apparent. It has been postulated that during laughter the two pathways interact at the level of either the ( pre)-supplementary motor area [7,22], the anterior cingulate gyrus [30,31] or the primary motor cortex [15,31], possibly via inhibitory or modulatory processes [7,15]. However, subcortical regions have not been discussed concerning their interaction. ...
Article
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Who has not experienced that sensation of losing the power of speech owing to an involuntary bout of laughter? An investigation of this phenomenon affords an insight into the neuronal processes that underlie laughter. In our functional magnetic resonance imaging study, participants were made to laugh by tickling in a first condition; in a second one they were requested to produce vocal utterances under the provocation of laughter by tickling. This investigation reveals increased neuronal activity in the sensorimotor cortex, the anterior cingulate gyrus, the insula, the nucleus accumbens, the hypothalamus and the periaqueductal grey for both conditions, thereby replicating the results of previous studies on ticklish laughter. However, further analysis indicates the activity in the emotion-associated regions to be lower when tickling is accompanied by voluntary vocalization. Here, a typical pattern of activation is identified, including the primary sensory cortex, a ventral area of the anterior insula and the ventral tegmental field, to which belongs to the nucleus ambiguus, namely, the common effector organ for voluntary and involuntary vocalizations. During the conflictual voluntary-vocalization versus laughter experience, the laughter-triggering network appears to rely heavily on a sensory and a deep interoceptive analysis, as well as on motor effectors in the brainstem. This article is part of the theme issue ‘Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience’.
... This spontaneous production of voice signals mainly concerns the expression of simple social information, such as vocal affect, stress, trustworthiness, and authenticity. The expression of spontaneous laughter in humans comprise areas of the amygdala, hypothalamus, and PAG (Wattendorf et al., 2013), and a negative association between the ventral PFC and the limbic system (i.e. ACC and amygdala) during vocal stress (Laukka et al., 2011) (see Fig. 6A for recent studies on functional brain connectivity during voice signal production). ...
... ACC and amygdala) during vocal stress (Laukka et al., 2011) (see Fig. 6A for recent studies on functional brain connectivity during voice signal production). Voluntary laughter additionally activates Heschl's gyrus of the auditory cortical system (Wattendorf et al., 2013), highlighting the relevance of auditory feedback processing. A combined involvement of the paramotor, auditory, and limbic system was also observed for the voluntary expression of vocal anger (Frühholz et al., 2015c;Klaas et al., 2015) as well as for other expressions of affect (Pichon and Kell, 2013). ...
... A common observation is that produced vocalizations that meet the requirements of the predicted vocal intention stored as efference copy lead to a decreased signal in the auditory system indicating a successful vocal expression (Creutzfeldt et al., 1989;Toyomura et al., 2007). While this observation has been mainly made with verbal signaling (Hickok, 2012) and signaling physical attributes of senders, such as vocal pitch (Behroozmand et al., 2009;Toyomura et al., 2007), studies on signaling basic and complex social information observed rather increased auditory system activity for successful voice signaling (Frühholz et al., 2015c;Wattendorf et al., 2013). It seems like the increasing social relevance of voice signaling attract auditory processing resources even for successful vocalizations. ...
Article
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While humans have developed a sophisticated and unique system of verbal auditory communication, they also share a more common and evolutionarily important nonverbal channel of voice signaling with many other mammalian and vertebrate species. This nonverbal communication is mediated and modulated by the acoustic properties of a voice signal, and is a powerful – yet often neglected – means of sending and perceiving socially relevant information. From the viewpoint of dyadic (involving a sender and a signal receiver) voice signal communication, we discuss the integrated neural dynamics in primate nonverbal voice signal production and perception. Most previous neurobiological models of voice communication modelled these neural dynamics from the limited perspective of either voice production or perception, largely disregarding the neural and cognitive commonalities of both functions. Taking a dyadic perspective on nonverbal communication, however, it turns out that the neural systems for voice production and perception are surprisingly similar. Based on the interdependence of both production and perception functions in communication, we first propose a re-grouping of the neural mechanisms of communication into auditory, limbic, and paramotor systems, with special consideration for a subsidiary basal-ganglia-centered system. Second, we propose that the similarity in the neural systems involved in voice signal production and perception is the result of the co-evolution of nonverbal voice production and perception systems promoted by their strong interdependence in dyadic interactions.
... Only a few studies have investigated neural correlates underlying the production of laughter, and yet no studies to our knowledge have investigated the neural activations during the production of crying by healthy adults. For the investigation of producing laughter, Wattendorf et al. (2013) conducted a functional imaging study while participants laughed in the scanner. During tickling conditions, the participants were either instructed to inhibit laughter or to allow laughter during tickling. ...
... In the neural correlates of laughter production demonstrated by Wattendorf et al. (2013), the lateral hypothalamus, parietal operculum, the amygdala, and right cerebellum increased activity during producing tickling laughter compared with producing voluntary laughter. Furthermore, activation of the periaqueductal gray matter (PAG) was observed during voluntary and tickling laughter but was absent during the condition of inhibiting laughter, thus the PAG area is proposed to act as a coordinating centre in the process of producing laughter. ...
... crying, yet only little empirical research has focused on the production of laughing and crying with normal participants. One study investigated the production of laughter and revealed involvements of the lateral sensorimotor areas identified in the conditions of producing voluntary laughter and producing tickling laughter, however, the area increased activations when the participants were asked to inhibit the tickling laughter (Wattendorf et al., 2013). It can indicate that the role of the lateral sensorimotor system is not limited to supressing uncontrolled laughter, but rather it can also be involved in a general underlying neural mechanism of producing laughter. ...
Conference Paper
This PhD investigates the perception of laughter and crying, two non verbal expressions of emotion, and how this perception is affected by the authenticity of the expressed emotions. Three separate approaches were used to address the perception of these stimuli by healthy participants: behavioural rating tasks, physiological responses recordings, and functional magnetic resonance imaging (fMRI) techniques. A series of behavioural ratings established that naïve listeners can reliably differentiate involuntary laughter from voluntary laughter, however, their performance was poorer when discriminating between involuntary crying and voluntary crying. In a larger set of behavioural ratings collected at the Science Museum (n=1723, age range = 3-76 years old), the ratings accuracy of voluntary and involuntary emotional vocalizations were both found to improve over age, however, the developmental trajectories of the voluntary expressions were shown to have a steeper slope throughout early adulthood than involuntary expressions. This difference may reflect a developmental learning process of perceiving voluntary emotional expressions through social interactions. The results of behavioural and developmental experiments consistently show that the involuntary crying was perceived as moe similar to voluntary crying than voluntary and involuntary laughter However the physiological responses (pupil size) shows a different pattern: listeners’ pupils were significantly more dilated for involuntary vocalizations than for voluntary ones, regardless of emotions. This discrepancy between physiological responses and behavioural ratings on crying suggests that social learning processes influence the perceivers’ judgments of involuntary crying, other than pure perceptual processes. In the fMRI study, we found that perceiving laughter and crying requires activation of similar areas in an emotional motor task as well as in a theory-of-mind task, suggesting that a shared interactive neural network of perceiving and interpreting emotions is involved. However, the cortical areas involved in differentiating voluntary and involuntary vocalizations are partly distinct for laughter and for crying, implying different neural networks may be responsible for the authenticity differentiation of different emotions. In summary, this thesis demonstrates the existence of emotion-specific differences in perception of non-verbal emotional vocalizations and these differences may be due to developmental factors. Moreover, multiple neural networks were shown to play important roles in perceiving and differentiating positive and negative emotions.
... In the rat, the lateral hypothalamus is involved in vocalizations that are related to the expression of positive emotions (Burgdorf et al., 2007), notably to those that occur in the context of tickling and play (Roccaro-Waldmeyer et al., 2016). In humans, the lateral hypothalamus is activated during the processing of humor (Watson et al., 2007;Schwartz et al., 2008) and of ticklish laughter (Wattendorf et al., 2013). Both the hypothalamus and the PAG receive projections from the insula (Reep and Winans, 1982); the latter represents a primary cortical relay for tactile afferents that mediate affective information (Olausson et al., 2002). ...
... However, a possible involvement of downstream regions, such as the hypothalamus and the PAG, has not been considered thus far. Our own investigations have permitted us to demonstrate activity that is associated with ticklish laughter in the AI/hypothalamic/PAG axis (Wattendorf et al., 2013;Wattendorf et al., 2016). However, in these former studies, no attempt was made to locate the sites of activity that are associated with the preceding anticipatory processes. ...
... We investigated the selected brain volume in the framework of an event-related paradigm with the following three conditions: (i) tickling of the right foot (T) by a friend or his/her partner. In this condition, the participant was encouraged not to suppress the audible vocalizations (Wattendorf et al., 2013). (ii) Monotonous foot contacts (C). ...
Article
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In analogy to the appreciation of humor, that of tickling is based upon the re-interpretation of an anticipated emotional situation. Hence, the anticipation of tickling contributes to the final outburst of ticklish laughter. To localize the neuronal substrates of this process, fMRI was conducted on 31 healthy volunteers. The state of anticipation was simulated by generating an uncertainty respecting the onset of manual foot tickling. Anticipation was characterized by an augmented fMRI- signal in the anterior insula, the hypothalamus, the nucleus accumbens and the ventral tegmental area, as well as by an attenuated one in the internal globus pallidus. Furthermore, anticipatory activity in the anterior insula correlated positively with the degree of laughter that was produced during tickling. These findings are consistent with an encoding of the expected emotional consequences of tickling and suggest that early regulatory mechanisms influence, automatically, the laughter circuitry at the level of affective and sensory processing. Tickling activated not only those regions of the brain that were involved during anticipation, but also the posterior insula, the anterior cingulate cortex and the periaqueductal gray matter. Sequential or combined anticipatory and tickling-related neuronal activities may adjust emotional- and sensorimotor pathways in preparation for the impending laughter response.
... Several sources of evidence point to the PAG as a possible substrate for play. First, the analysis of immediate early gene expression in animals after play-enriched social interaction 4 and the circuit analysis of tickling and laughter in humans 5,6 have shown to implicate the PAG. Second, the PAG has a decisive role in controlling vocalizations [7][8][9] and positive affect vocalizations are of paramount importance in orchestrating play. ...
... (4) Does the play-related activity map onto the PAG columnar organization? (5) How do PAG play-related neurons respond to anxiogenic conditions and vocalizations? (6) Are specific PAG columns required for play ? ...
Article
The persistence of play after decortication points to a subcortical mechanism of play control. We found that global blockade of the rat periaqueductal gray with either muscimol or lidocaine interfered with ticklishness and play. We recorded vocalizations and neural activity from the periaqueductal gray of young, playful rats during interspecific touch, play, and tickling. Rats vocalized weakly to touch and more strongly to play and tickling. Periaqueductal gray units showed diverse but strong modulation to tickling and play. Hierarchical clustering based on neuronal responses to play and tickling revealed functional clusters mapping to different periaqueductal gray columns. Specifically, we observed play-neutral/tickling-inhibited and tickling/play-neutral units in dorsolateral and dorsomedial periaqueductal gray columns. In contrast, strongly play/tickling-excited units mapped to the lateral columns and were suppressed by anxiogenic conditions. Optogenetic inactivation of lateral periaqueductal columns disrupted ticklishness and play. We conclude that the lateral periaqueductal gray columns are decisive for play and laughter.
... Tickling-induced laughter is a quite old and conserved form of social physicality and communication allowing preverbal interaction between mother and infant and nonverbal communication between family, peers, and sexual partners. Tickling has been shown to induce positive affective responses [95] and to be significantly mediated by hypothalamic activity [41,96]. In healthy individuals, ticklish laughter induced by skin stimulation executed by a partner or a friend was associated with bilateral activation of the lateral hypothalamus along with other limbic areas such as the substantia nigra, amygdala, hippocampus, anterior insula, anterior cingulate gyrus, periaqueductal gray, and ventral tegmental area [41,96]. ...
... Tickling has been shown to induce positive affective responses [95] and to be significantly mediated by hypothalamic activity [41,96]. In healthy individuals, ticklish laughter induced by skin stimulation executed by a partner or a friend was associated with bilateral activation of the lateral hypothalamus along with other limbic areas such as the substantia nigra, amygdala, hippocampus, anterior insula, anterior cingulate gyrus, periaqueductal gray, and ventral tegmental area [41,96]. Activity in the lateral hypothalamus, the nucleus accumbens, and the ventral tegmental area was also observed in relation to anticipation of tickling, suggesting that these regions might support anticipatory mechanisms promoting social physicality [41]. ...
Article
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There exist extensive animal research and lesion studies in humans demonstrating a tight association between the hypothalamus and socioemotional behavior. However, human neuroimaging literature in this direction is still rather limited. In order to reexamine the functional role of this region in regulating human social behavior, we here provided a synthesis of neuroimaging studies showing hypothalamic activation during affiliative, cooperative interactions, and in relation to ticklish laughter and humor. In addition, studies reporting involvement of the hypothalamus during aggressive and antisocial interactions were also considered. Our systematic review revealed a growing number of investigations demonstrating that the evolutionary conserved hypothalamic neural circuity is involved in multiple and diverse aspects of human socioemotional behavior. On the basis of the observed heterogeneity of hypothalamus-mediated socioemotional responses, we concluded that the hypothalamus might play an extended functional role for species survival and preservation, ranging from exploratory and approaching behaviors promoting social interactions to aggressive and avoidance responses protecting and defending the established social bonds.
... Vocal folds also prevent any object to enter into the larynx. 6 Humans use their voices to express emotions, both as nonverbal bursts of emotional sounds, such as laughter, yells, screams 7,8 pride, guilt or boredom, 9 and as modification of the intonation of speech. Poetry is a good example of the latter one. ...
... 10 Vocal emotions, such as anger, fear, surprise, sexual pleasure, happiness, 7 sadness and disgust, are processed in the limbic system. 8 Voice disorders may arise due to problems being encountered upon movement of air through respiratory passages that is lungs, vocal cords, throat, nose, mouth and lips. There may be damage to nerves supplying the muscles of vocal cords, laryngeal webs or clefts, polyps, nodules, cysts, granulomas, papillomas, or ulcers on the vocal cord, cancer of the throat, cleft palate or other palate problems. ...
Article
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Sound is an important communication tool for humans that contain information about the surrounding environment. It may signify a danger or a reward for an organism. In humans, the mechanism of sound production and perception is complex and sophisticated. Sound is produced by vibrating body in a medium that contains molecules in the surrounding space. The sound perception starts in human foetus at around the third trimester where it plays a vital role in organising the foetal brain. This process continues after birth and can be exploited by various endogenous and exogenous factors. Many mechanisms that can modulate hearing process at different levels lead to subclinical or clinical presentation of hearing-related problems. It is important to contemplate the mechanisms underlying sound production, perception and pathogenesis of hearing loss. This will facilitate prescribing a relevant treatment option according to the cause and its underlying mechanism. --Continue
... contributes to the suppression of movements such as spontaneous laughter vocalizations 4,44 or laughter with tickling. 47 The roles of the cerebellum and primary somatosensory cortex will be discussed in the unresolved questions section, the parietal and occipital regions are addressed in the limitations. ...
... Unfortunately, the neural correlates of ticklishness in humans are not yet well defined, but tickling and its inhibition activate the sensorimotor cortex. 47 Moreover, recent experiments in rats prove the sensory cortices' role in the control of rat ticklish 'laughter'. Tickling activates the somatosensory cortex, deep cortical layer microstimulation there can trigger laughter-like vocalizations and self-touch suppression of these vocalizations is mediated via cortical inhibition in the somatosensory cortex. ...
Article
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The study of pathological laughter and crying (PLC) allows insights into the neural basis of laughter and crying, two hallmarks of human nature. PLC is defined by brief, intense and frequent episodes of uncontrollable laughter or crying provoked by trivial stimuli. It occurs secondary to CNS disorders such as stroke, tumours or neurodegenerative diseases. Based on case studies reporting various lesions locations, PLC has been conceptualized as dysfunction in a cortico-limbic-subcortico-thalamo-ponto-cerebellar network. To test whether the heterogeneous lesion locations are indeed linked in a common network, we applied ‘lesion network-symptom-mapping’ to 70 focal lesions identified in a systematic literature search for case reports of PLC. In lesion network-symptom-mapping normative connectome data (resting state functional MRI, n = 100) is used to identify the brain regions that are likely affected by diaschisis based on the lesion locations. With lesion network-symptom-mapping we were able to identify a common network specific for PLC when compared with a control cohort (n = 270). This bilateral network is characterized by positive connectivity to the cingulate and temporomesial cortices, striatum, hypothalamus, mesencephalon and pons, and negative connectivity to the primary motor and sensory cortices. In the most influential pathophysiological model of PLC, a centre for the control and coordination of facial expressions, respiration and vocalization in the periaqueductal grey is assumed, which is controlled via two pathways: an emotional system that exerts excitatory control of the periaqueductal grey descending from the temporal and frontal lobes, basal ganglia and hypothalamus; and a volitional system descending from the lateral premotor cortices that can suppress laughter or crying. To test whether the positive and negative PLC subnetworks identified in our analyses can indeed be related to an emotional system and a volitional system, we identified lesions causing emotional (n = 15) or volitional facial paresis (n = 46) in a second literature search. Patients with emotional facial paresis show preserved volitional movements but cannot trigger emotional movements in the affected hemiface, while the reverse is true for volitional facial paresis. Importantly, these lesions map differentially onto the PLC subnetworks: the ‘positive PLC subnetwork’ is part of the emotional system and the ‘negative PLC subnetwork’ overlaps with the volitional system for the control of facial movements. Based on this network analysis we propose a two-hit model of PLC: a combination of direct lesion and indirect diaschisis effects cause PLC through the loss of inhibitory cortical control of a dysfunctional emotional system.
... It should be acknowledged that neuroscientific research on genuine, emotional, laughter is particularly difficult to conduct, because standard imaging techniques can hardly tackle the issue of its spontaneous and social nature. Accordingly, only few functional magnetic resonance studies investigated the neural correlates of laughter, mainly by Meletti and colleagues (Meletti et al. 2015;Talami et al. 2019;Vaudano et al. 2019) and Wattendorf and colleagues (Wattendorf et al. 2013(Wattendorf et al. , 2016(Wattendorf et al. , 2019. In contrast, insights concerning the precise identification of the regions involved in laughter production can be provided by intracerebral electrical stimulation studies mostly conducted on patients during presurgical evaluations. ...
... Most importantly, a recent stimulation study reporting the results of stimulation in 252 sites from a group of 31 patients (Mȃlîia et al. 2018) showed that the most frequent effects evoked by FO stimulation are speech-related or oropharyngeal sensations. Finally, the hypothesis that the FO plays a key role in the voluntary control of facial expressions is supported by brain imaging (Leslie et al. 2004;van der Gaag et al. 2007;Lee et al. 2008;Wattendorf et al. 2013) and clinical (Salas et al. 2016) studies as well as by electrophysiology investigation of the homolog region of FO in the monkey (Coudé et al. 2011;Ferrari et al. 2017). ...
Article
Laughter is a complex motor behavior occurring in both emotional and nonemotional contexts. Here, we investigated whether the different functions of laughter are mediated by distinct networks and, if this is the case, which are the white matter tracts sustaining them. We performed a multifiber tractography investigation placing seeds in regions involved in laughter production, as identified by previous intracerebral electrical stimulation studies in humans: the pregenual anterior cingulate (pACC), ventral temporal pole (TPv), frontal operculum (FO), presupplementary motor cortex, and ventral striatum/nucleus accumbens (VS/NAcc). The primary motor cortex (M1) and two subcortical territories were also studied to trace the descending projections. Results provided evidence for the existence of two relatively distinct networks. A first network, including pACC, TPv, and VS/NAcc, is interconnected through the anterior cingulate bundle, the accumbofrontal tract, and the uncinate fasciculus, reaching the brainstem throughout the mamillo-tegmental tract. This network is likely involved in the production of emotional laughter. A second network, anchored to FO and M1, projects to the brainstem motor nuclei through the internal capsule. It is most likely the neural basis of nonemotional and conversational laughter. The two networks interact throughout the pre-SMA that is connected to both pACC and FO.
... Because of the known susceptibility of functional magnetic resonance imaging to motion artifacts, spontaneous laughter has never become a topic of particular relevance in neuroimaging research, and the current knowledge about the neural networks involved in emotion expression rely on cortical electrical stimulation studies carried out in epileptic patients (Fried et al. 1998;Schmit et al. 2006;Sperli et al. 2006;Caruana et al. 2011Caruana et al. , 2015Caruana et al. , 2016Fernandez-Baca Vaca et al. 2011;Yamao et al. 2014;Yan et al. 2019). Thus far, functional magnetic resonance imaging (fMRI) studies investigating laughter and humor have been concentrating on the brain correlates of passive listening of laughter produced by other individuals (Meyer et al. 2007;Szameitaat et al. 2010;Wildgruber et al. 2013), verbal-like humor detection and appreciation (Goel and Dolan 2001;Mobbs et al. 2003;Moran et al. 2004;Bartolo et al. 2006;Watson et al. 2007;Vrticka et al. 2013), and tickling laughter (Wattendorf et al. 2013(Wattendorf et al. , 2016. ...
... However, despite this schematic subdivision, our findings support the theory of a complex inter-relationship between the two systems. The FO, while playing a crucial role in the voluntary control of facial expression (Wattendorf et al. 2013), has been suggested to be the interface between the voluntary and involuntary network, gating limbic information to the motor system (Caruana et al. 2016;Caruana 2017). The FO, together with the ACC, was found to be connected with the affiliative field of the ventral insula in macaque monkey and therefore identified as the main hub linking the involuntary network and the premotor cortex (Jezzini et al. 2015;Caruana et al. 2016). ...
Article
Laughter is a universal human behavior generated by the cooperation of different systems toward the construction of an expressive vocal pattern. Given the sensitivity of neuroimaging techniques to movements, the neural mechanisms underlying laughter expression remain unclear. Herein, we characterized the neural correlates of emotional laughter using the onsets and the duration of laughter bursts to inform functional magnetic resonance imaging. Laughter-related blood oxygen level-dependent (BOLD) increases involved both the motor (motor cortex, supplementary motor area, frontal operculum) and the emotional/limbic (anterior cingulate cortex, amygdala, n. accumbens, hippocampus) systems, as well as modulatory circuitries encompassing the basal ganglia, thalamus, and cerebellum. BOLD changes related to the 2 s preceding the laughter outbreak were selectively observed at the temporo-occipital junction and the periaqueductal gray matter, supporting the role of the former in the detection of incongruity and the gating role of the latter in the initiation of spontaneous laughter. Moreover, developmental changes were identified in laughter processing, consisting in a greater engagement of the reward circuitry in younger subjects; conversely, the default mode network appears more activated in older participants. Our findings contribute valuable information about the processing of real-life humorous materials and suggest a close link between laughter-related motor, affective, and cognitive elements, confirming its complex and multi-faceted nature.
... Recent studies suggest that networks involved with laughter perception may vary depending on the laughter's nature (11)(12)(13). Researchers have characterized laughter in various ways, sometimes demonstrating that different types of laughter have distinctive acoustic properties (9,11,(14)(15)(16)(17)(18). One of the more common distinctions is between "voluntary" and "involuntary" laughter (9,14,18), with the former being more internally driven, and the latter being more stimulus driven and externally provoked. ...
... Researchers have characterized laughter in various ways, sometimes demonstrating that different types of laughter have distinctive acoustic properties (9,11,(14)(15)(16)(17)(18). One of the more common distinctions is between "voluntary" and "involuntary" laughter (9,14,18), with the former being more internally driven, and the latter being more stimulus driven and externally provoked. The neural substrate supporting perception of voluntary, controlled laughter (as is commonly associated with social interaction) may differ from that supporting perception of involuntary laughter (commonly elicited by tickling). ...
Article
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Perceiving another person's emotional expression often sparks a corresponding signal in the observer. Shared conversational laughter is a familiar example. Prior studies of shared laughter have made use of task-based functional neuroimaging. While these methods offer insight in a controlled setting, the ecological validity of such controlled tasks has limitations. Here, we investigate the neural correlates of shared laughter in patients with one of a variety of neurodegenerative disease syndromes (N = 75), including Alzheimer's disease (AD), behavioral variant frontotemporal dementia (bvFTD), right and left temporal variants of semantic dementia (rtvFTD, svPPA), nonfluent/agrammatic primary progressive aphasia (nfvPPA), corticobasal syndrome (CBS), and progressive supranuclear palsy (PSP). Patients were recorded in a brief unrehearsed conversation with a partner (e.g., a friend or family member). Laughter was manually labeled, and an automated system was used to assess the timing of that laughter relative to the partner's laughter. The probability of each participant with neurodegenerative disease laughing during or shortly after his or her partners' laughter was compared to differences in brain morphology using voxel-based morphometry, thresholded based on cluster size and a permutation method and including age, sex, magnet strength, disease-specific atrophy and total intracranial volumes as covariates. While no significant correlations were found at the critical T value, at a corrected voxelwise threshold of p < 0.005, a cluster in the left posterior cingulate gyrus demonstrated a trend at p = 0.08 (T = 4.54). Exploratory analysis with a voxelwise threshold of p = 0.001 also suggests involvement of the left precuneus (T = 3.91) and right fusiform gyrus (T = 3.86). The precuneus has been previously implicated in the detection of socially complex laughter, and the fusiform gyrus has a well-described role in the recognition and processing of others' emotional cues. This study is limited by a relatively small sample size given the number of covariates. While further investigation is needed, these results support our understanding of the neural underpinnings of shared conversational laughter.
... Laughter contributed to maintaining and enhancing personal relationships, thereby acting as a means to alleviate stress. Studies on laughter can be classi ed into several categories [9,10]; however, de ning these clearly is di cult. Therefore, we focused on "hearing laughter," a type of behavior related to laughter, and investigated whether the effect of hearing laughter alleviated stress to the same degree as laughing itself. ...
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Background : Studies have recognized the beneficial effects of hearing laughter. However, its mechanism has not been sufficiently investigated. Therefore, we examined how laughter influenced affect and emotions and evaluated brain activity upon hearing laughter via near-infrared spectroscopy (NIRS). Method s: An experiment was conducted with seven healthy university students and used a block design with laughter and relaxing music as interventions. A portable brain activity measurement device (HOT-2000; NeU Corporation) was used to capture neural activity in the lateral prefrontal cortex, based on the degree of changes in total hemoglobin (Hb). Results : Comparison of the blood flow volume between the right and left prefrontal lateral cortices after each intervention revealed a significant difference in total Hb; however, this was only at rest. No differences were observed during either the laughter or music intervention. Furthermore, comparison of the cerebral blood flow volume between the three experimental conditions (rest period, laughter, music) revealed a significant difference ( p = 0.016) between rest period and laughter. However, no significant difference was observed between the other factors. Discussion : The results did not provide substantial insights into the affect and emotions during laughter interventions based on the degree of change in total Hb between the right and left lateral prefrontal cortices. However, hearing laughter brought about changes in mental states, such as feelings of pleasure and calm, which suggested that hearing laughter relaxed brain activity.
... 31 Among these structures, PAG attracts special attention because it is the output, decision-making structure of neural networks determining many social behaviors. 32 Moreover, neural activity is increased in the PAG during laughter or tickling in humans 33 and hand chasing play in rats. 4 This study presents evidence for the necessity of PAG for social play behavior. ...
... Nevertheless, there are some notable studies of tickling in the field of psychology often exploring the neural and psychological mechanisms underlying tickling sensations, as well as its relationship to laughter, playfulness, and bonding (Hall and Allin, 1897;Harris and Christenfeld, 1999;Verónica Juárez-Ramos et al., 2014;Ishijima and Negayama, 2017;Elise Wattendorf et al., 2019;Hammond et al., 2019). Neuroscientists have explored the processing of touch within the nervous system, as well as the brain regions and nerve pathways implicated in the tickling response (Zotterman, 1939;Ruggieri et al., 1985;Carlsson et al., 2000;Wattendorf et al., 2013Wattendorf et al., , 2016Ishiyama and Brecht, 2016;Leavens and Bard, 2016;Elise Wattendorf et al., 2019;Ishiyama et al., 2019). In the field of physiology, researchers have examined the physiological responses to tickling and touch (Drescher et al., 1985;Weiss, 1992), such as changes in heart rate (Drescher et al., 1980), hormones (Hori et al., 2013), facial expressions (Davila-Ross et al., 2015;Proelss et al., 2022) and muscle tone . ...
Article
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Tickling is commonly perceived as juvenile play associated with laughter. However, its potential connection to adult sexual behavior has largely remained unexplored. Our online survey, primarily distributed among individuals interested in tickle fetishism, explored tickling and its association with sexual behavior. Ticklishness types, tools, preferred body parts, and partner preferences, were examined. Results revealed diverse patterns of ticklishness changes over time and distinct body-part preferences for different types of tickling. Childhood experiences and exposure to tickling content in television were found to shape individuals’ affinity for tickle fetishism. A quarter of respondents reported experiencing orgasms exclusively from tickling, while around 88% expressed sexual satisfaction through tickling alone, indicating its sufficiency as a sexual stimulus among fetishists. Tickling desire decreased after orgasm, indicating an association between tickling and sexual activity. Moreover, ticklishness degree predicted preferences for being tickled rather than tickling others. Exploratory factor analysis identified three factors underlying tickling and sexual experiences: enjoyment and frequency of tickling during sexual activity; preference for intense sexual experiences; age of becoming sexually active. In conclusion, this study provides unique insights into tickling and its connections to sexual context, enhancing our understanding of diverse human sexual behavior and tickle fetishism as a distinct preference.
... Until now studies investigating the neural correlates of laughter have been mainly restrained to the study of laughs produced or perceived in isolation, produced in response to isolated humorous stimuli, or in response to electrical brain stimulation (e.g. [8,9,10,11,12,13,14]). Yet, very little is known as to the production and processing of laughter in interaction. ...
Conference Paper
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The current study analyses laughter distribution, pragmatic use, and acoustic features in a multimodal conversation corpus, where one of the interlocutor had brain activity recorded with functional MRI. Particular focus is on the analysis of mimicking and non-mimicking laughter, as we hypothesized that the former might involve different neural pathways in comparison to latter, and a spectrotemporal modulation analysis was selected to evaluate the acoustic differences between them. The goals of our investigation are (1) to validate the corpus as ecological in terms of laughter production prior to evaluating neurophysiological correlates of laughter production and perception in conversational interactions, (2) to compare mimicking and non-mimicking laughter in terms of acoustic features, and (3) to evaluate which features need to be taken in account for our forthcoming analysis of fMRI data. Despite the unconventional recording conditions, laughter production and use results are comparable to those observed in face-to-face interactions. Mimicking laughter has significantly increased temporal modulations in comparison to non-mimicking laughter, however, no differences are observed in the spectral modulation domain. Our findings suggest that mimicking laughter might be related to different underpinning neuro-psychological processes on which we plan on gaining insight through future neural-correlate analysis.
... It is also important to note that Antonio's presession pairing and reinforcement during DTT involved tickling while he was on the hammock chair. As laughter is considered an automatic emotional response to being tickled (Wattendorf et al., 2013), this could have inadvertently increased his happiness indices during DTT sessions. A final limitation was potential researcher bias. ...
Article
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Objectives Happiness is paramount to an improved quality of life (QoL), but there are barriers to assessing the happiness and overall QoL of autistic children using traditional measures. To address this, Study 1 aimed to identify and validate the idiosyncratic mood indices of three autistic children. In Study 2, these indices were measured as QoL indicators during discrete trial teaching (DTT) sessions that followed presession pairing. Task engagement was recorded as a secondary measure. Methods Three preschool boys on the autism spectrum participated in both studies. Their individualized indices of happiness and unhappiness were first identified and validated using an abbreviated procedure that extended previous research. The effects of presession pairing were then examined using a concurrent multiple baseline design across participants. The idiosyncratic mood indices were measured using 10-s partial interval recording, while task engagement was measured using 15-s whole interval recording. Results Study 1 demonstrated that the abbreviated procedure was efficient for identifying and validating the idiosyncratic mood indices of the participants. Study 2 found that presession pairing improved the mood of all three children during DTT, but there were minimal increases in task engagement. Percentage of nonoverlapping data (PND) scores initially revealed no effects for indices of happiness (M = 43.2%), large effects for indices of unhappiness (M = 76.4%), and no effects for task engagement (M = 37.6%). Contrary to this, omnibus Tau-U scores suggested large effects for indices of happiness (Tau-U = 0.7), very large effects for indices of unhappiness (Tau-U = 0.9), and moderate effects for task engagement (Tau-U = 0.5). Conclusions Individualized indices of happiness and unhappiness can and should be used as QoL indicators during behavioral interventions for autistic children.
... Darwin (1872) and Hecker (1873) proposed a close parallelism and equivalence between tickling and humour, relying on a common underlying mechanism (the Darwin-Hecker Hypothesis). 7 Panksepp (2000) and Wattendorf et al. (2012) proposed that laughter in response to tickling and to humour might share the same neurological activation. This hypothesis found support also in a study by Harris and Christenfeld (1997) showing a positive correlation between the amount of laughs produced by their participants in response to tickling and in response to humorous stimuli. ...
... According to the "dual pathway" account of the neural control of the human voice, laughter production is also controlled by a voluntary network, originating from the ventral part of the motor system (housing the motor representations of mouth actions) and controlling the volitional production and modulation of laughter (Lauterbach et al., 2013;Scott et al., 2014;Gerbella et al., 2021). Imaging studies showed that this region is active during the observation (Jabbi et al., 2008) and the voluntary imitation of smiles (Leslie et al., 2004;Hennenlotter et al., 2005;van der Gaag et al., 2007) and during the production of voluntary, involuntary, and inhibited laughter (Wattendorf et al., 2013). While electrical stimulation of the motor system may also elicit smiling and laughter, the elicited response is rarely accompanied by a positive affect . ...
Chapter
Here it will be advanced the hypothesis that the ability to interact with the emotions displayed by co-specifics depends on two distinct simulationist systems, i.e., “motor simulation” and “emotional mirroring.” Although these systems are typically conceived as alternative and mutually exclusive models, the first aim of this chapter is to present empirical evidence demonstrating that they are coexisting systems that differ in terms of input, output, neural circuitry, and cognitive function. The former exploits motor knowledge to assist the visual system during the identification of potentially ambiguous emotional stimuli, while the latter conveys emotional contagion and social bonding. To clarify the functional difference between the two systems, it will be made reference to the notion of automatic abduction, as it has been originally described in the Peircean semiotic tradition. It will be argued that only “motor simulation” – but not “emotional mirroring” – can be thought of as part of an automatic sensorimotor abduction, that is, a sensorimotor inferential process which allows the exploitation of motor knowledge to assist the visual system during the identification of potentially ambiguous emotional stimuli. Instances of simulations triggered by “motor simulation” and “emotional mirroring” will be considered, respectively, in terms of motor and affective habits. The former will be characterized as ignorance-based kind of habits, whereas the latter will be defined as knowledge-based habits. Finally, the mechanism of “motor simulation” will be discussed in the light of the predictive processing framework.
... Imaging studies showed that the frontal operculum was activated during voluntary and involuntary laughter. [36][37][38][39] The frontal operculum and the premotor cortex are located near each other. Jabbi et al 40 suggested that the frontal operculum was part of a premotor network and participated in the voluntary control of emotional facial expressions. ...
Article
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Objective The cortical representation of emotions is complex, and cortical mapping of emotional experience is incomplete. We aimed to contribute to cortical mapping of emotional experience. Methods Clinical data from 400 patients with medically refractory epilepsy who underwent stereo‐electroencephalography implantation for localization of the epileptogenic zone at the Beijing Institute of Functional Neurosurgery between October 2015 and June 2021 were collected retrospectively. Furthermore, we reviewed studies that described cortical mapping of emotional experience through electrical cortical stimulation (ECS). Affective responses similar to ictal aura and electrode contacts located in the SOZ were excluded to investigate emotional experiences in normal brain regions. Results Emotional experiences were evoked by stimulation at 10 electrode contacts in the seven patients, including five contacts that evoked mirth and excitement, one contact that evoked calmness, three contacts that evoked fear, and one contact that evoked sadness. In addition, 21 studies that evaluated emotional experiences in response to cortical electrical stimulation were reviewed. Emotions were distributed in the amygdala, hippocampus, temporal lobe, frontal lobe, insula, frontal operculum, parietal operculum, and cingulate cortex. Significance We provided additional evidence that brain regions including the amygdala, hippocampus, temporal lobe, frontal lobe, insula, frontal operculum, parietal operculum, and cingulate cortex were associated with emotional experience.
... According to the "dual pathway" account of the neural control of the human voice, laughter production is also controlled by a voluntary network, originating from the ventral part of the motor system (housing the motor representations of mouth actions) and controlling the volitional production and modulation of laughter (Lauterbach et al., 2013;Scott et al., 2014;Gerbella et al., 2021). Imaging studies showed that this region is active during the observation (Jabbi et al., 2008) and the voluntary imitation of smiles (Leslie et al., 2004;Hennenlotter et al., 2005;van der Gaag et al., 2007) and during the production of voluntary, involuntary, and inhibited laughter (Wattendorf et al., 2013). While electrical stimulation of the motor system may also elicit smiling and laughter, the elicited response is rarely accompanied by a positive affect . ...
Chapter
Full-text available
Here it will be advanced the hypothesis that the ability to interact with the emotions displayed by co-specifics depends on two distinct simulationist systems, i.e., “motor simulation” and “emotional mirroring.” Although these systems are typically conceived as alternative and mutually exclusive models, the first aim of this chapter is to present empirical evidence demonstrating that they are coexisting systems that differ in terms of input, output, neural circuitry, and cognitive function. The former exploits motor knowledge to assist the visual system during the identification of potentially ambiguous emotional stimuli, while the latter conveys emotional contagion and social bonding. To clarify the functional difference between the two systems, it will be made reference to the notion of automatic abduction, as it has been originally described in the Peircean semiotic tradition. It will be argued that only “motor simulation” – but not “emotional mirroring” – can be thought of as part of an automatic sensorimotor abduction, that is, a sensorimotor inferential process which allows the exploitation of motor knowledge to assist the visual system during the identification of potentially ambiguous emotional stimuli. Instances of simulations triggered by “motor simulation” and “emotional mirroring” will be considered, respectively, in terms of motor and affective habits. The former will be characterized as ignorance-based kind of habits, whereas the latter will be defined as knowledge-based habits. Finally, the mechanism of “motor simulation” will be discussed in the light of the predictive processing framework.
... In addition, widespread cortical and subcortical processing during ticklish laughter may further contribute to delayed vocalizations. Greater involvement of the limbic pathway was identified during ticklish laughter compared to voluntary initiated laughter, and ticklish laughter suppression using functional imaging [30]. Observationally, we further note that ticklish vocal latencies were more variable than vocal latencies in the cued speech paradigm. ...
Article
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A tickle is a complex sensation: it occurs in response to touch but not unequivocally so, and makes us laugh albeit not when we self-tickle. We quantified human ticklishness by means of physiological, visual and acoustic measures alongside subjective reports, and assessed mechanisms of self-tickle suppression. Tickle responses arose faster than previously reported as changes in thoracic circumference and joyous facial expressions co-emerge approximately 300 ms after tickle onset and are followed by vocalizations starting after an additional 200 ms. The timing and acoustic properties of vocalizations tightly correlated with subjective reports: the faster, louder and higher-pitched participants laughed, the stronger they rated the experienced ticklishness. Externally evoked ticklishness is reduced by simultaneous self-tickling, whereby self-touch evokes stronger suppression than sole self-tickle movement without touch. We suggest that self-tickle suppression can be understood as broad attenuation of sensory temporally coincident inputs. Our study provides new insight on the nature of human ticklishness and the attenuating effects of self-tickling. This article is part of the theme issue ‘Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience’.
... Finally, OP3 seems to be involved in oral somatosensory stimulation, comprising the gustatory network [69], and laryngeal cortical network involved in swallowing [70,71]. Its involvement was also described in laughing and tickling [72], in the central representation of the tympanic membrane and middle-ear muscles in response to 1 Hz mechanical pressure variation [19] and in relation to temporomandibular joint disorder [73]. Taken together, the stimuli involving orofacial muscles thus seem to be represented in the cortical region OP3. ...
Article
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In tinnitus literature, researchers have increasingly been advocating for a clearer distinction between tinnitus perception and tinnitus-related distress. In non-bothersome tinnitus, the perception itself can be more specifically investigated: this has provided a body of evidence, based on resting-state and activation fMRI protocols, highlighting the involvement of regions outside the conventional auditory areas, such as the right parietal operculum. Here, we aim to conduct a review of available investigations of the human parietal operculo–insular subregions conducted at the microscopic, mesoscopic, and macroscopic scales arguing in favor of an auditory–somatosensory cross-talk. Both the previous literature and new results on functional connectivity derived from cortico–cortical evoked potentials show that these subregions present a dense tissue of interconnections and a strong connectivity with auditory and somatosensory areas in the healthy brain. Disrupted integration processes between these modalities may thus result in erroneous perceptions, such as tinnitus. More precisely, we highlight the role of a subregion of the right parietal operculum, known as OP3 according to the Jülich atlas, in the integration of auditory and somatosensory representation of the orofacial muscles in the healthy population. We further discuss how a dysfunction of these muscles could induce hyperactivity in the OP3. The evidence of direct electrical stimulation of this area eliciting auditory hallucinations further suggests its involvement in tinnitus perception. Finally, a small number of neuroimaging studies of therapeutic interventions for tinnitus provide additional evidence of right parietal operculum involvement.
... Finally, the interplay of lower and higher brain areas in production and perception of laughter and the role of the auditory mirror-neuron system in its contagion support its social-emotional-communicative role: laughter production involves brain stem centers for emotional vocalizations (PAG, upper reticular formation) that receive input from cortex and hypothalamus (Wild et al., 2003;Wattendorf et al., 2013). Laughter perception on the other hand recruits perimotor areas (PMC, SMA, pre-SMA) and prefrontal regions in amPFC which are also involved in mirroring and mentalizing (McGettigan et al., 2015;Billing et al., 2021). ...
Article
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Laughter and yawning can both occur spontaneously and are highly contagious forms of social behavior. When occurring contagiously, laughter and yawning are usually confounded with a social situation and it is difficult to determine to which degree the social situation or stimulus itself contribute to its contagion. While contagious yawning can be reliably elicited in lab when no other individuals are present, such studies are more sparse for laughter. Moreover, laughter and yawning are multimodal stimuli with both an auditory and a visual component: laughter is primarily characterized as a stereotyped vocalization whereas yawning is a predominantly visual signal and it is not known to which degree the visual and auditory modalities affect the contagion of laughter and yawning. We investigated how these two sensory modalities contribute to the contagion of laughter and yawning under controlled laboratory conditions in the absence of a social situation that might confound their contagion. Subjects were presented with naturally produced laughter and yawning in three sensory modalities (audio, visual, audio-visual), and we recorded their reaction to these stimuli. Contagious responses differed for laughter and yawning: overall, laughter elicited more contagious responses than yawning, albeit mostly smiling rather than overt laughter. While the audio-visual condition elicited most contagious responses overall, laughter was more contagious in the auditory modality, and yawning was more contagious in the visual modality. Furthermore, laughter became decreasingly contagious over time, while yawning remained steadily contagious. We discuss these results based on the ontogenetic and phylogenetic trajectories of laughter and yawning.
... The human larynx motor cortices (LMCs), which control the muscles of the larynx, differ markedly in humans from the homologous system in other primates 50 . Among other functions, the LMCs are involved in raising or lowering the larynx 51 and participate in broader brain networks 52 involved in characteristically human modes of communication such as speaking and singing 53,54 , as well as expressing emotions 55,56 . Vocal trait modulation similarly engages this system, alongside a broader network of brain areas associated with social reasoning 57 . ...
Article
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The human voice carries socially relevant information such as how authoritative, dominant, and attractive the speaker sounds. However, some speakers may be able to manipulate listeners by modulating the shape and size of their vocal tract to exaggerate certain characteristics of their voice. We analysed the veridical size of speakers’ vocal tracts using real-time magnetic resonance imaging as they volitionally modulated their voice to sound larger or smaller, corresponding changes to the size implied by the acoustics of their voice, and their influence over the perceptions of listeners. Individual differences in this ability were marked, spanning from nearly incapable to nearly perfect vocal modulation, and was consistent across modalities of measurement. Further research is needed to determine whether speakers who are effective at vocal size exaggeration are better able to manipulate their social environment, and whether this variation is an inherited quality of the individual, or the result of life experiences such as vocal training.
... Flexibility in vocal production has also been observed in other great ape species, including wild bonobos (Clay et al. 2015;Cornec et al. 2022) and both wild and enculturated orangutans (Lameira et al. 2013a(Lameira et al. , 2013b. Research emerging in the past decade is also challenging the traditional dual-pathway model of vocal control in mammals, pointing to a greater degree of cross-talk between the cortical and limbic pathways typically thought to be respectively involved in volitional and spontaneous vocal production (e.g., Wattendorf et al. 2013;Ludlow 2015;reviewed in Ackermann et al. 2014;Pisanski et al. 2016;Scott 2021). ...
Article
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Until recently, human nonverbal vocalisations such as cries, laughs, screams, moans, and groans have received relatively little attention in the human behavioural sciences. Yet these vocal signals are ubiquitous in human social interactions across diverse cultures and may represent a missing link between relatively fixed nonhuman animal vocalisations and highly flexible human speech. Here, we review converging empirical evidence that the acoustic structure (“forms”) of these affective vocal sounds in humans reflect their evolved biological and social “functions”. Human nonverbal vocalisations thus largely parallel the form-function mapping found in the affective calls of other animals, such as play vocalisations, distress cries, and aggressive roars, pointing to a homologous nonverbal vocal communication system shared across mammals, including humans. We aim to illustrate how this form-function approach can provide a solid framework for making predictions, including about cross-species and cross-cultural universals or variations in the production and perception of nonverbal vocalisations. Despite preliminary evidence that key features of human vocalisations may indeed be universal and develop reliably across distinct cultures, including small-scale societies, we emphasise the important role of vocal control in their production among humans. Unlike most other terrestrial mammals including nonhuman primates, people can flexibly manipulate vocalisations, from conversational laughter and fake pleasure moans to exaggerated roar-like threat displays. We discuss how human vocalisations may thus represent the cradle of vocal control, a precursor of human speech articulation, providing important insight into the origins of speech. Finally, we describe how ground-breaking parametric synthesis technologies are now allowing researchers to create highly naturalistic, yet fully experimentally controlled vocal stimuli to directly test hypotheses about form and function in nonverbal vocalisations, opening the way for a new era of voice sciences.
... Ventral premotor/motor regions are typically involved in the voluntary production or the imitation of smile and laughter (Leslie et al., 2004;Wattendorf et al., 2013) and its electrical stimulation may produce the motor pattern of laughter, devoid of emotional valence (Caruana et al., 2016(Caruana et al., , 2020. Following Billing et al., the activation of premotor/ motor regions is unrelated to emotional contagion, rather suggesting a possible link between volitional laughter and speech e a phenomenon referred to as "laughspeak" by Provine (2012). ...
... Lesions to the cingulate cortex prevent the initiation of operantly conditioned vocalizations, but spare responses to stimuli that would normally elicit an innate vocalisation ( Aitken, 1981 ;Sutton et al., 1981Sutton et al., , 1974. The homologous pathway in humans is activated during verbal expressions of emotion ( Barrett et al., 2004 ;Wattendorf et al., 2013 ). This cingulate-PAG axis provides a mechanism for coordinated laryngeal-respiratory control of innate species-typical vocalisations, which is conserved across primates. ...
Article
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Vocal flexibility is a hallmark of the human species, most particularly the capacity to speak and sing. This ability is supported in part by the evolution of a direct neural pathway linking the motor cortex to the brainstem nucleus that controls the larynx - the primary sound source for communication. Early brain imaging studies demonstrated that larynx motor cortex at the dorsal end of the orofacial division of motor cortex (dLMC) integrated laryngeal and respiratory control, thereby coordinating two major muscular systems that are necessary for vocalization. Neurosurgical studies have since demonstrated the existence of a second larynx motor area at the ventral extent of the orofacial motor division (vLMC) of motor cortex. The vLMC has been presumed to be less relevant to speech motor control, but its functional role remains unknown. We employed a novel ultra-high field (7T) magnetic resonance imaging paradigm that combined singing and whistling simple melodies to localise the larynx motor cortices and test their involvement in respiratory motor control. Surprisingly, whistling activated both 'larynx areas' more strongly than singing despite the reduced involvement of the larynx during whistling. We provide further evidence for the existence of two larynx motor areas in the human brain, and the first evidence that laryngeal-respiratory integration is a shared property of both larynx motor areas. We outline explicit predictions about the descending motor pathways that give these cortical areas access to both the laryngeal and respiratory systems and discuss the implications for the evolution of speech.
... Moreover, although argued to play an evolutionary role in social play and bonding (Meyer et al., 2007;Panksepp & Burgdorf, 2003;Provine, 2004), the experience of being tickled has a "tipping point", during which the reported subjective experience changes from being something pleasant to something unpleasant, or socially aversive (Alter & Wildgruber, 2019). In line with this, tickling is associated with defensive behavior, and tickling laughter with increased activation of brain regions involved in pain perception and fight or flight responses (Wattendorf et al., 2013). Due to these contrary responses, tickling laughter was implemented here as a signal with ambiguous social intention. ...
Article
Human laughter is a powerful means of communicating social intention, ranging from welcoming and friendly to hostile and ridiculing. To be communicated accurately, the recipient must correctly identify the laugher’s underlying social intention. Regular misattribution of the social intention of others has been associated with maladaptive psychosocial development, in particular with aggressive behavior. We investigated the relationship between self-reported aggressive behavior and the neural correlates of social intention attributions to different audiovisual laughter types in 50 healthy children and adolescents (29 female, 10-18 years, M 15.5, SD 2.2) using functional magnetic resonance imaging. Trial-by-trial associations of neural response and behavioral attributions were distinctly modulated by aggression for benevolent versus taunting and tickling laughter. With increasing aggression, hostile misattributions of benevolent laughter were associated with decreased dorsolateral prefrontal and anterior insular cortex activation. In contrast, hostile attributions of taunting and tickling laughter were associated with increased superior frontal, superior temporal, medial prefrontal, supplementary motor, and anterior and mid-cingulate cortex activation. We argue that aggression may be associated with down-regulated emotional saliency of benevolent laughter, whereas up-regulated neural responses to taunting laughter may underlie a heightened sensitivity to hostility or acceptance of taunting behavior in more aggressive individuals.
... Darwin (1872) in his pioneering work collected in The Expression of emotions in men and animals and Hecker (1873), proposed a close parallelism and equivalence between tickling and humour, relying on a common underlying mechanism (the Darwin-Hecker Hypothesis). (Darwin, 1872, p.199) Along the same lines, Panksepp (2000) and Wattendorf et al. (2012) proposed that laughter in response to tickling and laughter in response to humour might share the same neurological activation. Some research using different experimental approaches seems to support the hypothesis. ...
Thesis
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Laughter is a social vocalization universal across cultures and languages. It is ubiquitous in our dialogues and able to serve a wide range of functions. Laughter has been studied from several perspectives, but the classifications proposed are hard to integrate. Despite being crucial in our daily interaction, relatively little attention has been devoted to the study of laughter in conversation, attempting to model its sophisticated pragmatic use, neuro-correlates in perception and development in children. In the current thesis a new comprehensive framework for laughter analysis is proposed, crucially grounded in the assumption that laughter has propositional content, arguing for the need to distinguish different layers of analysis, similarly to the study of speech: form, positioning, semantics and pragmatics. A formal representation of laughter meaning is proposed and a multilingual corpus study (French, Chinese and English) is conducted in order to test the proposed framework and to deepen our understanding of laughter use in adult conversation. Preliminary investigations are conducted on the viability of a laughter form-function mapping based on acoustic features and on the neuro-correlates involved in the perception of laughter serving different functions in natural dialogue. Our results give rise to novel generalizations about the placement, alignment, semantics and function of laughter, stressing the high pragmatic skills involved in its production and perception. The development of the semantic and pragmatic use of laughter is observed in a longitudinal corpus study of 4 American-English child-mother pairs from 12 to 36 months of age. Results show that laughter use undergoes important development at each level analysed, which complies with what could be hypothesised on the base of phylogenetic data, and that laughter can be an effective means to track cognitive/communicative development, and potential difficulties or delays at a very early stage.
... Involuntary laughter sounds more "animalistic", genuine, and emotive, and is difficult to control or produce on demand . It involves the subcortical brain structures associated with the basic emotions (Wattendorf, Westermann, Fiedler, Kaza, Lotze, & Celio, 2013;Wild, Rodden, Grodd, & Ruch, 2003) that humans share with other mammals (Panksepp, 2005a). ...
Preprint
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This is a draft of a chapter that has been accepted for publication by Oxford University Press in the forthcoming book The Oxford Handbook of Emotional Development edited by Dr. Daniel Dukes, Prof. Andrea C. Samson, and Prof. Eric A. Walle, and due for publication in 2021. ABSTRACT Within 6 weeks after birth, the endogenous smile comes under infants’ voluntary control, serving as strong social currency between infants and others within their environment. Shortly after, by just 4 months, infants laugh. But why? And what, if anything, does laughter tell us about infants’ understanding of the world? For example, by 5 months, infants appear to perceive the difference between absurd and ordinary events, and seemingly interpret absurd events as comical all by themselves without relying on cues from others. By six months, infants give the impression of employing fake laughter that can goad others into play, and by 8-months, they appear capable of simple acts of deception that underlie teasing. This chapter investigates what early humor creation and perception reveal about infants’ knowledge of the social and physical world, and explores the social, emotional and cognitive power of humor in infancy.
... The most frequent effects evoked by stimulation of the frontal operculum were speech related, and the peri-rolandic opercular area produced most often oropharyngeal symptoms. An amount of imaging (Lee, Dolan, & Critchley, 2008;Leslie, Johnson-Frey, & Grafton, 2004;van der Gaag, Minderaa, & Keysers, 2007;Wattendorf et al., 2013) and clinical (Salas et al., 2016) evidence suggests that FO plays a key role in the voluntary control of facial expressions, and neurological evidences suggest that lesions inducing voluntary facial paresis typically involve the operculum (Wild et al., 2003). Also considering the vicinity of the FO to the Broca's area and to the voluntary motor system, it is tempting to speculate that FO is mostly involved in conversational, voluntary laughter. ...
... While it is argued to play an evolutionary role in social play and bonding (Provine, 2004), the experience of being tickled has a "tipping point" with a reported change of experience from pleasantness to unpleasantness or even social aversion (Alter & Wildgruber, 2019). Consequently, tickling can be associated with defensive behavior and lead to increased activation of brain regions involved in pain perception as well as fight and flight responses (Wattendorf et al., 2013). Due to these contrary responses, tickling laughter is seen as ambiguous social stimulus. ...
Article
Full-text available
Laughter is a multifaceted signal, which can convey social acceptance facilitating social bonding as well as social rejection inflicting social pain. In the current study, we addressed the neural correlates of social intent attribution to auditory or visual laughter within an fMRI study to identify brain areas showing linear increases of activation with social intent ratings. Negative social intent attributions were associated with activation increases within the medial prefrontal cortex/anterior cingulate cortex (mPFC/ACC). Interestingly, negative social intent attributions of auditory laughter were represented more rostral than visual laughter within this area. Our findings corroborate the role of the mPFC/ACC as key node for processing “social pain” with distinct modality‐specific subregions. Other brain areas that showed an increase of activation included bilateral inferior frontal gyrus and right superior/middle temporal gyrus (STG/MTG) for visually presented laughter and bilateral STG for auditory presented laughter with no overlap across modalities. Similarly, positive social intent attributions were linked to hemodynamic responses within the right inferior parietal lobe and right middle frontal gyrus, but there was no overlap of activity for visual and auditory laughter. Our findings demonstrate that social intent attribution to auditory and visual laughter is located in neighboring, but spatially distinct neural structures.
... In fact, while personal relations in the workplace have been reported to increase the incidence of psychiatric disorders [12], it has been suggested that encouraging laughing may be an effective means of reducing such stress, as it can contribute to maintaining and improving personal relations in the workplace. Studies on laughter have, however, reported that laughing can be divided into several categories (e.g., Duchenne laughter, non-Duchenne laughter, requested laughter, tickling laughter) [13,14] and is difficult to define as a specific activity. In addition, individuals' subjectivity may influence the effect of laughing, even when individuals are participating in the same intervention. ...
Article
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Background It has become necessary to develop mental health management methods that do not require specialized skills or tools to implement. With this in mind, we performed a subjective and objective investigation of the stress-reducing effect of hearing laughter. Methods Ninety healthy students were randomly assigned to a laughter (n = 45) or rest (n = 45) group. Both groups were then administered the Uchida-Kraepelin test for 15 min, which served as a stress-loading method. The laughter group listened to a specially prepared CD for five minutes, while the rest group rested for five minutes. The participants’ subjective stress level was assessed using a visual analogue scale and their physiological status was assessed by measuring blood pressure and monitoring heart rate variability. Results The visual analogue scale score for subjective stress was found to decrease significantly in both the laughter and rest groups after the intervention. However, a two-way repeated-measures analysis of variance revealed significant interaction and main effects for the change in heart rate and the natural logarithm of the high-frequency component of heart rate variability (lnHF). A post-hoc analysis using Dunnett’s test showed that hearing laughter caused the lnHF to significantly increase compared to that recorded during the Uchida-Kraepelin test and the rest period. Conclusions These results suggest that hearing laughter might produce a relaxing effect by increasing parasympathetic nervous activity. This would make it an easily accessible method for improving the recovery process of the autonomic nervous system after a stress-loading task that does not require specialized skills or tools. Trial registration UMIN000016422. Retrospectively registered on 2 February 2015. Electronic supplementary material The online version of this article (10.1186/s13030-018-0141-0) contains supplementary material, which is available to authorized users.
... A similar mechanism is that of index signals, which are reliable because they are structurally tied to a fitness relevant quality (Maynard Smith & Harper, 1995;Vehrencamp, 2000). Applying these concepts to human emotional communication, one might expect that the production of natural expressions either imposes certain costs (Mehu & Scherer, 2012) or else is linked compulsorily to underlying states (Ruch & Ekman, 2001;Wattendorf et al., 2013), rendering them difficult or impossible to imitate faithfully (Dezecache, Mercier, & Scott-Phillips, 2013). ...
Article
Researchers have long relied on acted material to study emotional expression and perception in humans. It has been suggested, however, that certain aspects of natural expressions are difficult or impossible to produce voluntarily outside of their associated emotional contexts, and that acted expressions tend to be overly intense caricatures. From an evolutionary perspective, listeners’ abilities to distinguish acted from natural expressions likely depend on the type of expression in question, the costs entailed in its production, and elements of receiver psychology. Here, we investigated these issues as they relate to human screams. We also examined whether listeners’ abilities to distinguish acted from natural screams might vary as a function of individual differences in emotional processing and empathy. Using a forced-choice categorization task, we found that listeners could not distinguish acted from natural exemplars, suggesting that actors can produce dramatisations of screams resembling natural vocalisations. Intensity ratings did not differ between acted and natural screams, nor did individual differences in emotional processing significantly predict performance. Scream duration predicted both the probability that an exemplar was categorised as acted and the probability that participants classified that scream accurately. These findings are discussed with respect to potential evolutionary implications and their practical relevance to future research using acted screams.
... Furthermore, this pathway is responsible for maintaining the persistent increase in synaptic strength induced by anxiety following traumatic stress (Adamec, 1997). The PAG and the amygdala have been found to reliably co-activate in investigations of affect and emotion (Kober et al., 2008); thus, consideration of the integral role the amygdalo-PAG pathway plays in regulating behavioral and psychological manifestations of different emotions or affective states (Adamec, 1997;Graeff et al., 1993;Bandler and Shipley, 1994;Bandler and Carrive, 1988;Davis, 1998;Davis et al., 1996;Dietrich et al., 2012;Wattendorf et al., 2013;Wild et al., 2003) is important and supports the idea that the processing of positive or negative emotions or reacting to stressful situations can affect the PAG's ability to also mediate movement patterns during voicing. We speculate this may be due to the PAG's inefficiency in simultaneously regulating heightened states as well as coordinated movements necessary for human phonation. ...
Article
Previous studies in animals and humans suggest the periaqueductal grey region (PAG) is a final integration station between the brain and laryngeal musculature during phonation. To date, a limited number of functional magnetic neuroimaging (fMRI) studies have examined the functional connectivity of the PAG during volitional human phonation. An event-related, stimulus-induced, volitional movement paradigm was used to examine neural activity during sustained vocalization in neurologically healthy adults and was compared to controlled exhalation through the nose. The contrast of vocalization greater than controlled expiration revealed activation of bilateral auditory cortex, dorsal and ventral laryngeal motor areas (dLMA and vLMA) (p < 0.05, corrected), and suggested activation of the cerbellum, insula, dorsomedial prefrontal cortex (dmPFC), amygdala, and PAG. The functionally defined PAG cluster was used as a seed region for psychophysiological interaction analysis (PPI) to identify regions with greater functional connectivity with PAG during volitional vocalization, while the above functionally defined amygdala cluster was used in an ROI PPI analysis. Whole-brain results revealed increased functional connectivity of the PAG with left vLMA during voicing, relative to controlled expiration, while trend-level evidence was observed for increased PAG/amygdala coupling during voicing (p = 0.07, uncorrected). Diffusion tensor imaging (DTI) analysis confirmed structural connectivity between PAG and vLMA. The present study sheds further light on neural mechanisms of volitional vocalization that include multiple inputs from both limbic and motor structures to PAG. Future studies should include investigation of how these neural mechanisms are affected in individuals with voice disorders during volitional vocalization.
... The insular cortex is related to a variety of functions, such as interoception (Craig & Craig, 2009), attention (Sridharan, Levitin, & Menon, 2008), and arousal (Brooks et al., 2012). However, previous studies in the field of humor processing (Goel & Dolan, 2001;Mobbs et al., 2003;Moran et al., 2004) and laughter (Wattendorf et al., 2013;Wattendorf, Westermann, Lotze, Fiedler, & Celio, 2015) were able to show that insular function is fundamentally associated with the processing of positive emotions. During humor processing, the insular cortex is thought to be associated to reward-mechanisms that follow the recognition and appreciation of humorous content (Watson et al., 2007), as supported by studies reporting an association of pathological laughter with lesions in the anterior insula (Carel, Albucher, Manelfe, Guiraud-Chaumeil, & Chollet, 1997). ...
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We, here, provide a personal review article on the development of a functional MRI in the radiology departments of two German university medicine units. Although the international community for human brain mapping has met since 1995, the researchers fascinated by human brain function are still young and innovative. However, the impact of functional magnetic resonance imaging (fMRI) on prognosis and treatment decisions is restricted, even though standardized methods have been developed. The tradeoff between the groundbreaking studies on brain function and the attempt to provide reliable biomarkers for clinical decisions is large. By describing some historical developments in the field of fMRI, from a personal view, the rise of this method in clinical neuroscience during the last 25 years might be understandable. We aim to provide some background for (a) the historical developments of fMRI, (b) the establishment of two research units for fMRI in the departments of radiology in Germany, and (c) a description of some contributions within the selected fields of systems neuroscience, clinical neurology, and behavioral psychology.
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A substantial body of acoustic and behavioural evidence points to the existence of two broad categories of laughter in humans: spontaneous laughter that is emotionally genuine and somewhat involuntary, and volitional laughter that is produced on demand. In this study, we tested the hypothesis that these are also physiologically distinct vocalizations, by measuring and comparing them using real-time magnetic resonance imaging (rtMRI) of the vocal tract. Following Ruch and Ekman (Ruch and Ekman 2001 In Emotions, qualia, and consciousness (ed. A Kaszniak), pp. 426–443), we further predicted that spontaneous laughter should be relatively less speech-like (i.e. less articulate) than volitional laughter. We collected rtMRI data from five adult human participants during spontaneous laughter, volitional laughter and spoken vowels. We report distinguishable vocal tract shapes during the vocalic portions of these three vocalization types, where volitional laughs were intermediate between spontaneous laughs and vowels. Inspection of local features within the vocal tract across the different vocalization types offers some additional support for Ruch and Ekman's predictions. We discuss our findings in light of a dual pathway hypothesis for the neural control of human volitional and spontaneous vocal behaviours, identifying tongue shape and velum lowering as potential biomarkers of spontaneous laughter to be investigated in future research. This article is part of the theme issue ‘Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience’.
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The dual pathway model posits that spontaneous and volitional laughter are voiced using distinct production systems, and perceivers rely upon these system-related cues to make accurate judgments about relationship status. Yet, to our knowledge, no empirical work has examined whether raters can differentiate laughter directed at friends and romantic partners and the cues driving this accuracy. In Study 1, raters (N = 50), who listened to 52 segments of laughter, identified conversational partner (friend versus romantic partner) with greater than chance accuracy (M = 0.57) and rated laughs directed at friends to be more pleasant-sounding than laughs directed at romantic partners. Study 2, which involved 58 raters, revealed that prototypical friendship laughter sounded more spontaneous (e.g., natural) and less “vulnerable” (e.g., submissive) than prototypical romantic laughter. Study 3 replicated the findings of the first two studies using a large cross-cultural sample (N = 252). Implications for the importance of laughter as a subtle relational signal of affiliation are discussed.
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Research in the neuroscience of pain perception and visual perception has taken contrasting paths. The contextual and the social aspects of pain judgements predisposed pain researchers to develop computational and functional accounts early, while vision researchers tended to simple localizationist or descriptive approaches first. Evolutionary thought was applied to distinct domains, such as game-theoretic approaches to cheater detection in pain research, versus vision scientists' studies of comparative visual ecologies. Both fields now contemplate current motor or decision-based accounts of perception, particularly predictive coding. Vision researchers do so without the benefit of earlier attention to social and motivational aspects of vision, while pain researchers lack a comparative behavioural ecology of pain, the normal incidence and utility of responses to tissue damage. Hybrid hypotheses arising from predictive coding as used in both domains are applied to some perplexing phenomena in pain perception to suggest future directions. The contingent and predictive interpretation of complex sensations, in such domains as ‘runner's high’, multiple cosmetic procedures, self-harm and circadian rhythms in pain sensitivity is one example. The second, in an evolutionary time frame, considers enhancement of primary perception and expression of pain in social species, when expressions of pain might reliably elicit useful help. This article is part of the Theo Murphy meeting issue ‘Evolution of mechanisms and behaviour important for pain’.
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This review article was written for people like Paul McGhee when he was 20 years old: curious and interested in the neurology and psychiatry of humor, smiling and laughter but neither physicians nor experts in cognitive science. It begins with necessary reflections on what it even means to consider humor, smiling and laughter from within these disciplines. These frames of reference, useful as they are, are far from neutral. The reader is encouraged to be sensitive to some logical and linguistic pitfalls that can fatally endanger meaningful discussions of these subjects. The results of empirical studies of humor, smiling and laughter which have employed the tools of neurology and psychiatry are then reviewed, roughly in the order in which the techniques have emerged historically, beginning with clinical studies (Part I) and continuing with current studies employing functional imaging methods in Part II. Therapeutic approaches using humor, smiling and laughter, particularly with respect to neurological and psychiatric diseases – but also including other diseases – are discussed. Finally, a short synopsis of what is known about the neurology and psychiatry of humor, smiling and laughter is presented.
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This is a continuation of Part I. Section 2 of that part (“Humor and the Body”) should be read before reading reports of the studies described below. Understanding the methods and experiments in this part is, perhaps, easier than making sense of them. As mentioned at the outset of Part 1, the relationship of the brain to humor, smiling, and laugher is but one tiny aspect of the vastly larger mind-body problem that has yet to be fruitfully addressed. What follows is a listing of technical findings that are probably mostly true, but the deeper sense of which remains largely mysterious.
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Darwin (1872) and Hecker (1873) suggested that laughter induced by tickle and by humour share common underlying mechanisms. Seventy-two undergraduate students participated in a study designed to explore the relationship between the two phenomena. Subjects were tickled before and after viewing comedy and control videotapes. Subjects exhibiting more pronounced laughter to comedy also laughed more vigorously to tickle, extending and validating self-report findings of Fridlund and Loftis (1990). However, there was no evidence that comedy-induced laughter increased subsequent laughter to tickle nor that ticklish laughter increased laughter to comedy. We suggest that humour and tickle may be related only in that they share a final threshold for elicitation of their common behavioural response (smiling and laughter).
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It is well known that you cannot tickle yourself. Here, we discuss the proposal that such attenuation of self-produced tactile stimulation is due to the sensory predictions made by an internal forward model of the motor system. A forward model predicts the sensory consequences of a movement based on the motor command. When a movement is self-produced, its sensory consequences can be accurately predicted, and this prediction can be used to attenuate the sensory effects of the movement. Studies are reviewed that demonstrate that as the discrepancy between predicted and actual sensory feedback increases during self-produced tactile stimulation there is a concomitant decrease in the level of sensory attenuation and an increase in tickliness. Functional neuroimaging studies have demonstrated that this sensory attenuation might be mediated by somatosensory cortex and anterior cingulate cortex: these areas are activated less by a self-produced tactile stimulus than by the same stimulus when it is externally produced. Furthermore, evidence suggests that the cerebellum might be involved in generating the prediction of the sensory consequences of movement. Finally, recent evidence suggests that this predictive mechanism is abnormal in patients with auditory hallucinations and/or passivity experiences. NeuroReport 11:11-16 (C) 2000 Lippincott Williams & Wilkins.
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Most explanations for humor neglect important types of humor, such as tickling and word play; or raise difficult evolutionary theoretical problems, such as group selection, dubious fitness benefits, and excessive complexity of design; or ignore the data on humor and laughter. The present theory was based on the following observations. Tickling entails a mock attack at vulnerable body spots, and may provide youngsters with practice in defending themselves. The child's laughter is pleasant and encourages the tickler to persist. Similarly, juvenile primates including children encourage roughhousing by laughter and other emotional expressions. We also laugh at humorous content that provides striking counter-examples (incongruities), as in word play, or that informs us about fitness-relevant topics such as sexual, aggressive, and social poise scenarios. The present theory is that the pleasure of humor motivates us to seek out poignant, fitness- enhancing input of this sort. Laughter evolved to allow us to continue to recieve amusement. Laughter is a pleasant social signal that prompts the humorist to persist in providing this edifying stimulation. In response to true wit, laughter conveys appreciation and gratitude—an intention to reciprocate for having received a stimulating idea. Thus, humor benefits both humorist and laughter. This theory and others are evaluated in the light of evolutionary principles and relevant data.
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In the lateral hypothalamus, groups of functionally related cells tend to be widely scattered rather than confined to discrete, anatomically distinct units. However, by using parvalbumin (PV)-specific antibodies, a solitary, compact cord of PV-immunoreactive cells (the PV1-nucleus) has been identified in the ventrolateral tuberal hypothalamus in various species. Here we describe the topography, the chemo-, cyto-, and myeloarchitectonics, and the ultrastructure of this PV1-nucleus in rodents. The PV1-nucleus is located within the ventrolateral division of the medial forebrain bundle. In the horizontal plane, it has a length of 1 mm in mice and 2 mm in rats. PV-immunoreactive perikarya fall into two distinct size categories and number (~800 in rats and ~400 in mice). They are intermingled with PV-negative neurons and coarse axons of the medial forebrain bundle, some of which are PV-positive. Symmetric and asymmetric synapses, as well as PV-positive and PV-negative fiber endings, terminate on the perikarya of both PV-positive and PV-negative neurons. PV-positive neurons of the PV1-nucleus express glutamate, not γ-aminobutyric acid (GABA), the neurotransmitter that is usually associated with PV-containing nerve cells. Although we could not find evidence that PV1 neurons express either catecholamines or known neuropeptides, they sometimes are interspersed with the fibers and terminals of such cells. From its analogous topographical situation, the PV1-nucleus could correspond to the lateral tuberal nucleus in humans. We anticipate that the presence of the marker protein PV in the PV1-nucleus of the rodent hypothalamus will facilitate future studies relating to the connectivity, transcriptomics, and function of this entity.
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Although recent fMRI studies on humor have begun to elucidate cognitive and affective neural correlates, they weren't able to distinguish between different logical mechanisms or steps of humor processing, i.e., the detection of an incongruity and its resolution. This fMRI study aimed to focus in more detail on cognitive humor processing. In order to investigate pure incongruity resolution without preprocessing steps, nonverbal cartoons differing in their logical mechanisms were contrasted with nonhumorous pictures containing an irresolvable incongruity. The logical mechanisms were: (1) visual puns (visual resemblance, PUNs); (2) semantic cartoons (pure semantic relationships, SEMs); and (3) Theory of Mind cartoons (which require additionally mentalizing abilities, TOMs). Thirty cartoons from each condition were presented to 17 healthy subjects while acquiring fMR images. The results reveal a left-sided network involved in pure incongruity resolution: e.g., temporo-parietal junction, inferior frontal gyrus and ventromedian prefrontal cortex. These areas are also involved in processing of SEMs, whereas PUNs show more activation in the extrastriate cortex and TOMs show more activation in so-called mentalizing areas. Processing of pictures containing an irresolvable incongruity evokes activation in the rostral cingulate zone, which might reflect error processing. We conclude that cognitive processing of different logical mechanisms depends on separate neural networks.
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Although laughter plays an essential part in emotional vocal communication, little is known about the acoustical correlates that encode different emotional dimensions. In this study we examined the acoustical structure of laughter sounds differing along four emotional dimensions: arousal, dominance, sender's valence, and receiver-directed valence. Correlation of 43 acoustic parameters with individual emotional dimensions revealed that each emotional dimension was associated with a number of vocal cues. Common patterns of cues were found with emotional expression in speech, supporting the hypothesis of a common underlying mechanism for the vocal expression of emotions.
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The origin and termination of prefrontal cortical projections to the periaqueductal gray (PAG) were defined with retrograde axonal tracers injected into the PAG and anterograde axonal tracers injected into the prefrontal cortex (PFC). The retrograde tracer experiments demonstrate projections to the PAG that arise primarily from the medial prefrontal areas 25, 32, and 10m, anterior cingulate, and dorsomedial areas 24b and 9, select orbital areas 14c, 13a, Iai, 12o, and caudal 12l, and ventrolateral area 6v. Only scattered cells were retrogradely labeled in other areas in the PFC. Caudal to the PFC, projections to the PAG also arise from the posterior cingulate cortex, the dorsal dysgranular, and granular parts of the temporal polar cortex, the ventral insula, and the dorsal bank of the superior temporal sulcus. Cells were also labeled in subcortical structures, including the central nucleus and ventrolateral part of the basal nucleus of the amygdala. The anterograde tracer experiments indicate that projections from distinct cortical areas terminate primarily in individual longitudinal PAG columns. The projections from medial prefrontal areas 10m, 25, and 32 end predominantly in the dorsolateral columns, bilaterally. Fibers from orbital areas 13a, Iai, 12o, and caudal 12l terminate primarily in the ventrolateral column, whereas fibers from dorsomedial areas 9 and 24b terminate mainly in the lateral column. The PFC areas that project to the PAG include most of the areas previously defined as the “medial prefrontal network.” The areas that comprise this network represent a visceromotor system, distinct from the sensory related “orbital network.” J. Comp. Neurol. 401:455–479, 1998.
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The occurrence of affective responses, such as involuntary laughing or crying, associated with lesions of the nervous system has been the topic of several contributions. By pathologic laughing and crying we mean involuntary and uncontrollable attacks of emotional expressions as a result of a cerebral lesion or lesions. The few attempts at correlation of these emotional expressions on a neuroanatomic and physiologic basis in man have led to various interpretations. The problem is beset by many difficulties because in most instances the lesions are neither isolated nor limited to specific areas of the nervous system. This is especially true in the cases of cerebrovascular disease and multiple sclerosis with multiple and bilateral lesions, in which pathologic laughing and crying commonly occur. At times, however, these affective responses appear in case of cerebrovascular disease at the same time as, or soon after, the ictus. In such cases, with utilization of the
Chapter
This chapter reviews and discusses the anatomical and functional aspects of the human Periaqueductal Gray (PAG). The PAG or central gray of the midbrain is the midline structure that encircles the mesencephalic aqueduct. It is a large structure made of poorly differentiated gray matter. It is rich in neuropeptides, and it forms an interface between the forebrain and the lower brain stem. There has been considerable attention focused on the PAG because of its role in putative analgesic mechanisms. The chapter further presents anatomical evidences that the human PAG is not a homogeneous structure. Behind a deceiving cytoarchitecture lies a chemical organization that suggests the existence of four longitudinal columns located dorsomedial, dorsolateral, lateral, and ventrolateral to the aqueduct. The columns appear to be important features as they are conserved across mammalian species. It is noted that the human PAG is involved in antinociception and aversive emotional responses. Although functional and anatomical data suggest the PAG is an important integrating center for coordinated emotional responses, the contribution of the various columns to these responses in human remains largely unknown.
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This chapter focuses on the functional organization of the hypothalamus. The functions of the hypothalamus are so basic that its plan and organizational patterns have been, to a great degree, conserved throughout the mammalian spectrum. As a result, even when data in humans or monkeys are still sketchy, it is useful to view in a functional context that is derived in large part from other sources. The functional knowledge about the hypothalamus has relied on morphological approaches because of the extraordinarily small size and functional complexity of this region. The hypothalamus contains the integrative systems that support life, including such activities as fluid and electrolyte balance, food ingestion and energy metabolism, thermoregulation and immune response, and, of course, emotional expression and reproduction. Furthermore, the chapter reviews the overall plan of the cytoarchitecture and the major fiber pathways of the hypothalamus. This is followed by the functional organization of the hypothalamus.
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THIS STUDY PRESENTS six patients with hypothalamic hamartomas diagnosed on the basis of magnetic resonance imaging. Histological confirmation was performed in three patients who underwent surgery. Immunohistological assays were used to determine the neurosecretory pattern. Four patients presented with epilepsy, including gelastic seizures. Other symptoms included behavioral abnormalities in four patients and precocious puberty and visual impairment in two patients. One patient presented associated developmental defects. Good results without morbidity were achieved with surgical resectioning in two patients with large hamartomas associated with behavioral abnormalities and gelastic epilepsy that was unresponsive to conventional medical treatment and in one patient with visual impairment. We propose a classification of the hypothalamic hamartomas based on topographical and clinical data obtained from 36 selected cases in the literature and six of our own cases. This classification should help to classify the various treatment methods and the surgical risks into four subgroups (Types Ia, Ib, IIa, and IIb). We conclude that the surgical approach is a realistic alternative in certain cases, including large and broad-based Type IIb hamartomas associated with gelastic epilepsy and behavioral disorders.
Article
: In his writing Darwin emphasized direct veridical links between vocal acoustics and vocalizer emotional state. Yet he also recognized that acoustics influence the emotional state of listeners. This duality—that particular vocal expressions are likely linked to particular internal states, yet may specifically function to influence others—lies at the heart of contemporary efforts aimed at understanding affect-related vocal acoustics. That work has focused most on speech acoustics and laughter, where the most common approach has been to argue that these signals reflect the occurrence of discrete emotional states in the vocalizer. An alternative view is that the underlying states can be better characterized using a small number of continuous dimensions such as arousal (or activation) and a valenced dimension such as pleasantness. A brief review of the evidence suggests, however, that neither approach is correct. Data from speech-related research provides little support for a discrete-emotions view, with emotion-related aspects of the acoustics seeming more to reflect to vocalizer arousal. However, links to a corresponding emotional valence dimension have also been difficult to demonstrate, suggesting a need for interpretations outside this traditional dichotomy. We therefore suggest a different perspective in which the primary function of signaling is not to express signaler emotion, but rather to impact listener affect and thereby influence the behavior of these individuals. In this view, it is not expected that nuances of signaler states will be highly correlated with particular features of the sounds produced, but rather that vocalizers will be using acoustics that readily affect listener arousal and emotion. Attributions concerning signaler states thus become a secondary outcome, reflecting inferences that listeners base on their own affective responses to the sounds, their past experience with such signals, and the context in which signaling is occurring. This approach has found recent support in laughter research, with the bigger picture being that the sounds of emotion—be they carried in speech, laughter, or other species-typical signals—are not informative, veridical beacons on vocalizer states so much as tools of social influence used to capitalize on listener sensitivities.
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Cognitive capacity of non-human primates has become a popular topic in recent years. Humor is an important indicator of mental function. For the four stages of humor development in children: 1.) inappropriate action. 2.) incongruous labels. 3.) incongruous features. and 4.) multiple word meanings, examples are presented from ape behavior. Apes appreciate and produce humor in a manner comparable to humans.
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An overview is presented of important issues having to do with relationships between humor and biology, including those having to do with the genetic origin of the sense of humor, physiology of mirthful response to humor, impacts on health of humor physiology. Discussion is provided on theoretical implications derived from the complex relationship between humor and biology.
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This article argues for a parallelism between the foundations of the General Theory of Verbal Humor and the incongruity-resolution models. The incongruity phase is found to correspond to the script opposition knowledge resource and the resolution phase is argued to be identical to the logical mechanism. The necessity of a setup phase, preceding the other two in the incongruity-resolution models, is argued for; this phase is matched to the script overlap. Revisions of the definition of the script opposition and logical mechanism are presented. The consequences of these redefinitions for the theory and humor research at large are examined.
Article
As a behavioral and physiological phenomenon, tickling is a bag of riddles. Most young children instinctively giggle when tickled; yet prolonged tickling was one of the worst Medieval tortures. Aristotle raised the question of why one cannot tickle oneself. Surely, Christine Harris says, science should be able to explain tickling and the laughter it induces. And with some ingenious experiments, she is beginning to assemble answers. She finds, for instance, that when people believe they are being tickled by a machine, they laugh just as hard---suggesting that the laughter does not require an interpersonal context. In the article she explores the physiology of tickle (both annoying "light tickle" and laughter-inducing "heavy tickle") and its possible evolutionary function.
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This review emphasizes 2 major points. First, the organization of cerebellar (CB) systems and the physiological characteristics of the neuronal interactions in the CB cortex strongly suggest that CB function involves a characteristic operation that is performed across its various components. Second, this operation includes integrating sensory information about execution space, the target, peripheral inputs, and the body scheme with inputs reflecting the properties of the movements being executed. Although the fundamental characteristics of this operation are likely to be similar across the subdivisions of the cerebellum, the organization of CB afferent and efferent systems will result in differences in the behavioral consequences of the processing in various CB regions. 12 commentaries on this article appear at the end of the journal. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
A solitary, elongated cluster of parvalbumin-immunoreactive neurons has been previously observed in the rodent ventrolateral hypothalamus. However, the function of this so-called PV1 nucleus is unknown. In this article, we report the results of an unbiased, broad and in-depth molecular characterization of this small, compact group of neurons. The Allen Brain Atlas database of in situ hybridization was screened in order to identify genes expressed in the PV1-nucleus-containing area of the hypothalamus, and those that might be co-expressed with parvalbumin. Although GABA is the principal neurotransmitter in parvalbumin-expressing cells in various other brain areas, we found that PV1 neurons express the vesicular glutamate transporter (VGlut) VGlut2-encoding gene Slc17a6 and are negative for the glutamic acid decarboxylase 1 (GAD1) gene. These cells also express the mRNA for the neuropeptides Adcyap1 and possibly Nxph4, express several types of potassium and sodium channels, are under the control of the neurotransmitter acetylcholine, bear receptors for the glial-derived neurotrophic factor, and produce an extracellular matrix rich in osteopontin. The PV1 nucleus is thus composed of glutamatergic nerve cells, expressing some typical markers of long-axon, projecting neurons (e.g. VGlut2), but also co-expressing genes typical of short-axon GABA neurons (e.g. a variety of potassium channels). Hence, neurons of the PV1 nucleus combine physiological characteristics of interneurons with those of projection neurons.
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In the present study we utilised functional magnetic resonance imaging (fMRI) to examine cerebral activation during performance of a classic motor task in which response suppression load was parametrically varied. Linear increases in activity were observed in a distributed network of regions across both cerebral hemispheres, although with more extensive involvement of the right prefrontal cortex. Activated regions included prefrontal, parietal and occipitotemporal cortices. Decreasing activation was similarly observed in a distributed network of regions. These response forms are discussed in terms of an increasing requirement for visual cue discrimination and suppression/selection of motor responses, and a decreasing probability of the occurrence of non-target stimuli and attenuation of a prepotent tendency to respond. The results support recent proposals for a dominant role for the right-hemisphere in performance of motor response suppression tasks that emphasise the importance of the right prefrontal cortex.
Article
The present study investigated the neural overlap and dissociation underlying overt word production in the first language (L1) and second language (L2). Twenty-four Chinese-English bilinguals named pictures in either L1 or L2 while being scanned with functional magnetic resonance imaging (fMRI). When comparing picture naming in L2 to naming in L1, increased activity in the left inferior frontal gyrus, bilateral supplementary motor areas (SMA), left precentral gyrus, left lingual gyrus, left cuneus, bilateral putamen, bilateral globus pallidus, bilateral caudate and bilateral cerebellum were observed. This suggested that word production in L2 is less automatic and needs to recruit more neural resources for lexical retrieval, articulatory processing and cognitive control than in L1. In contrast, picture naming in L1 relative to picture naming in L2 revealed increased activity in the right putamen and right globus pallidus probably due to different phonological features between Chinese and English. In addition, the conjunction analysis, for the first time, revealed the common neural correlates underlying picture naming in L1 and L2.
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Several studies have investigated the neural correlates of self-reflection. In the paradigm most commonly used to address this concept, a subject is presented with trait adjectives or sentences and asked whether they describe him or her. Functional neuroimaging research has revealed a set of regions known as Cortical Midline Structures (CMS) appearing to be critically involved in self-reflection processes. Furthermore, it has been shown that patients suffering damage to the CMS, have difficulties in properly evaluating the problems they encounter and often overestimate their capacities and performance. Building on previous work, a meta-analysis of published fMRI and PET studies on self-reflection was conducted. The results showed that two areas within the medial prefrontal cortex (MPFC) are important in reflective processing, namely the ventral (v) and dorsal (d) MPFC. In this paper a model is proposed in which the vMPFC is responsible for tagging information relevant for 'self', whereas the dMPFC is responsible for evaluation and decision-making processes in self- and other-referential processing. Finally, implications of the model for schizophrenia and lack of insight are noted.
Article
A sizable literature on the neuroimaging of speech production has reliably shown activations in the orofacial region of the primary motor cortex. These activations have invariably been interpreted as reflecting "mouth" functioning and thus articulation. We used functional magnetic resonance imaging to compare an overt speech task with tongue movement, lip movement, and vowel phonation. The results showed that the strongest motor activation for speech was the somatotopic larynx area of the motor cortex, thus reflecting the significant contribution of phonation to speech production. In order to analyze further the phonatory component of speech, we performed a voxel-based meta-analysis of neuroimaging studies of syllable-singing (11 studies) and compared the results with a previously-published meta-analysis of oral reading (11 studies), showing again a strong overlap in the larynx motor area. Overall, these findings highlight the under-recognized presence of phonation in imaging studies of speech production, and support the role of the larynx motor cortex in mediating the "melodicity" of speech.
Article
By means of functional magnetic resonance imaging the present paper analyzes the neural correlates of processing and appreciating incongruity-resolution and nonsense cartoons. Furthermore, the relation between experience seeking and these neural substrates was investigated as this personality characteristic is known to influence humor appreciation. In the processing of incongruity-resolution stimuli the incongruity of the joke is largely resolvable, whereas in nonsense stimuli it is only partially resolvable and more incongruity remains. The anterior medial prefrontal cortex, bilateral superior frontal gyri and temporo-parietal junctions (TPJ) show more activation during processing of incongruity-resolution than of nonsense cartoons. These differences indicate that processing of incongruity-resolution cartoons requires more integration of multi-sensory information and coherence building, as well as more mental manipulation and organization of information. In addition, less self-reference might be established in nonsense cartoons as it is more absurd and more often deals with impossible situations. Higher experience-seeking scores correlate with increased activation in prefrontal, posterior temporal regions and the hippocampus. This might be due to a more intense exploration of the humorous stimuli as experience seekers tend to search novel mental stimulation. Furthermore, experience seeking was positively associated with brain reactivity towards processing nonsense in contrast to incongruity-resolution stimuli, which is in line with behavioral studies that showed a preference for nonsense humor by experience seekers.
Article
In 39 squirrel monkeys (Saimiri sciureus), the effects of various brain lesions on vocalizations elicited from the precallosal cingulate gyrus were tested. It was found that lesions abolishing the “cingular vocalization” completely can be traced from the stimulation site continuously down to the laryngeal motoneurons in the nucleus ambiguus. The pathway thus determined (Fig. 4) travels from the precallosal cingulate gyrus through the frontal white matter and enters the internal capsule from a dorsolateral position. The pathway then follows this structure in a medio-caudal direction down to the caudal diencephalon. Here, the effective lesions leave the corticospinal tract and ascend dorsally into the periaqueductal grey. The pathway follows this structure to its end where it sweeps lateral through the parabrachial area and then descends through the lateral pons and ventrolateral medulla to the nucleus ambiguus. In nine of the animals, in addition, the effects of bilateral anterior cingular lesions on vocalizations elicited in other brain areas were tested. It was found that the only vocalization-eliciting area which becomes ineffective after destruction of the anterior cingulate gyrus is the postero-medial orbital cortex.
Article
1. The spino-olivocerebellar paths ascending through the ventral funiculus (VF-SOCPs) and projecting to the cerebellar anteior lobe were investigated in cats with the spinal cord transected in the third cervical segment sparing only the ventral funiculus on one side. The climbing fibre responses evoked in Purkinje cells by limb nerve stimulation were studied by recording the mass activity at the cerebellar surface or in the molecular layer. 2. Five VF-SOCPs were distinguished on the basis of their receptive fields, response latencies, and projection areas. 3. The projection areas consist of narrow sagittal zones. Three zones (a, b1 and b2) lie in the vermis and extend throughout lobules II--V. Two zones (c1 and c3) lie in the pars intermedia and are restricted to the classical hindlimb area, lobules II--IV. The VF-SOCPs are labelled according to their termination zones: a-VF-SOCP, b1-VF-SOCP, etc. 4. The a-, c1- and c3-paths are activated from the ipsilateral hindlimb, whereas the b1- and b2-paths are activated bilaterally from the forelimbs and hindlimbs, respectively. The latencies of the responses evoked from the ipsilateral hindlimb are relatively short for the c1-path and successively longer for the c3-, b2- and a-paths. 5. The olivary transmission showed fluctuations in efficacy independent for the different VF-SOCPs. The effect of anaesthetics on this transmission also differed between the paths. 6. It is concluded that the five VF-SOCPs relay in different compartments of the inferior olive which are tentatively identified.
Article
Two right-handed patients with clinical evidence of major infarction in the territory of the left anterior cerebral artery developed a profound but transient aphasia characterized by (1) a striking dissociation between intact repetition and grossly disturbed spontaneous conversational speech, (2) an absence of phonemic paraphasia, (3) a lack of speech inhibition and (4) relative preservation of conformation naming and comprehension. Despite the initially profound motor aphasia, servicable spontaneous conversational speech returned in two to three months. However, more subtle changes in the form of lack of speech initiative and difficulties in narrating stories and describing complex pictures, remained many months after the onset. In these patients the major features of the disturbance could not be explained only on the basis of an interruption of the downgoing pathway from the dominant motor speech area, and in fact, may have been due to damage to the superior and mesial pre-motor area (particularly the supplementary motor region), an area that has been shown to play a role in processes which govern the initiation, continuation and inhibition of speech.
Article
Projections of neurones in the rostral hypothalamus to the periaqueductal grey matter (PAG) of the rat were investigated using retrograde tracing of red and green fluorescent latex microspheres. Microspheres were injected into one of 4 PAG sub-divisions, namely the dorsal, dorsolateral, ventral and ventrolateral parts. The patterns of retrogradely labelled neurones in the hypothalamus from each of the 4 PAG sub-divisions were found to differ and these are described. The precise nature of projections of neurones in the anterior hypothalamic area (AHA) was investigated and it was found that neurones within a circumscribed area of AHA, the lateral area of the anterior hypothalamus (LAAH), projected predominantly to the dorsolateral PAG while neurones in immediately adjacent areas projected to either dorsolateral or ventrolateral aspects of the PAG. Double retrograde tracing studies, where the two different colour beads were injected into different subdivisions of the PAG, gave rise to very few double labelled hypothalamic neurones, indicating that neurones in the hypothalamus project to only one sub-division of the PAG. The functional significance of these pathways is discussed in relation to mechanisms of autonomic and sensory control.
Article
Sensory perception thresholds were assessed by clinical testing and by quantitative instrumental testing before and after operation in 16 subjects for whom unilateral percutaneous cervical cordotomy was performed for the relief of pain due to malignant disease, and compared with clinical assessments of sensory function. We were able to confirm the association between deficit in pin-prick sensation and pain relief in the majority of instances, though the completeness or otherwise of pain relief does not correspond to absence of pin-prick sensation. There is no objective interference with low threshold mechanical sensation as measured instrumentally, although cordotomised subjects do not experience startle, tickle, or cutaneous erotic sensation when subjected to appropriate low intensity tactile sensation. Quantitative instrumental testing shows that the greatest deficits produced by cordotomy are in the sensations of skinfold pinch (? = tissue-damage pain) and skin cooling. The latter is transduced in the periphery by A delta fibres; sensations of warmth and hot pain, transduced by primary afferent C fibres, are much less significantly affected. Our findings thus fail to resolve the question as to whether chronic clinical pain is mainly an A delta- or a C fibre-mediated phenomenon.
Article
1. Transcranial magnetic stimulation was performed using a figure-of-eight-shaped coil over the right motor cortex with the aim of identifying those areas involved with activation of the diaphragm. 2. The response of the right and left hemi-diaphragms was recorded using surface electrodes in either the 7th or 8th intercostal spaces 3 cm lateral to the anterior costal margin on either side. 3. The compound muscle action potentials recorded over the left diaphragm in response to transcranial magnetic stimulation were maximal when the centre of the figure-of-eight coil was placed approximately 3 cm to the right of the mid-line and 2-3 cm anterior to the auricular plane. 4. The amplitude of the response recorded from the diaphragm depended upon the angulation of the figure-of-eight coil and hence the direction of the stimulating current. 5. The response of the inspiratory muscles to magnetic stimulation of one side of the brain was predominantly contralateral but a small response was seen on the ipsilateral side. Ultrasonic techniques confirmed that the diaphragm was responding contralaterally and not ipsilaterally.