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The polyvagal hypothesis: Common mechanisms mediating autonomic regulation, vocalizations and listening
Abstract
AbstractThis chapter applies hypotheses and principles derived from the polyvagal theory (Porges, 1995, 2001, 2007) to interpret mammalian vocalizations. The theory emphasizes the parallel phylogenetic shift in both the neural regulation of the autonomic nervous system and the evolutionary emergence of an integrated social engagement system that includes features optimizing conspecific mammalian vocal communication. The chapter presents the polyvagal hypothesis as a new way to interpret adaptive functions and acoustic features of mammalian vocalizations. The chapter emphasizes both the neural mechanisms involved in social communication, including the reciprocal relationship between production and reception of vocalizations, and the perceptual advantage that mammals have by vocalizing within a frequency band optimized by the physics of the middle ear.
... From this observation stems the idea that the functional output of the NA vagus on the heart can be tracked by respiratory sinus arrhythmia (RSA). This implies that the concept of vagal tone may not be generalized to all vagal efferent pathways, but may need to be limited to a specific branch or subsystem of the vagus being evaluated (Porges and Lewis, 2010;Porges, 2011). Therefore, the vagal system is not monolithic, but rather comprises different components, including general visceral efferent fibers controlling smooth and cardiac muscle, and special visceral efferent fibers that regulate the somatic muscles of the larynx, pharynx, and esophagus. ...
... This contraction reduces the compliance of the ossicular chain, damping the amplitude of low-frequency sounds reaching the inner ear from the environment: a tightened ossicular chain reduces eardrum movement, and only higher frequencies impacting the eardrum are conveyed to the inner ear and brain's auditory processing areas (Fournier et al., 2022). This results in a significant reduction in the perception of low-frequency sounds, which facilitates the extraction of higher frequency sounds associated with human voice and other mammalian vocalizations (Porges, 2004(Porges, , 2011Porges and Lewis, 2010). ...
... Conversely, during safe social engagement states, acoustic stimuli prioritization is based on pitch. In these safe states, the amplification of frequencies linked to conspecific vocalizations is selective, leading to the attenuation of other frequencies (Porges, 2004(Porges, , 2011Porges and Lewis, 2010). ...
This systematic review explores the influence of silence on the autonomic nervous system. The Polyvagal Theory has been used as a reference model to describe the autonomic nervous system by explaining its role in emotional regulation, social engagement, and adaptive physiological responses. PubMed, Scopus, PsycInfo, EMBASE, and Google Scholar were systematically searched up until July 2023 for relevant studies. The literature search yielded 511 results, and 37 studies were eventually included in this review. Silence affects the autonomic nervous system differently based on whether it is inner or outer silence. Inner silence enhances activity of the ventral vagus, favoring social engagement, and reducing sympathetic nervous system activity and physiological stress. Outer silence, conversely, can induce a heightened state of alertness, potentially triggering vagal brake removal and sympathetic nervous system activation, though with training, it can foster inner silence, preventing such activation. The autonomic nervous system response to silence can also be influenced by other factors such as context, familiarity with silence, presence and quality of outer noise, and empathy.
... The hypothesis that the USVs of MS pups may reflect increased distress is consistent with the perceptual advantage framework of the polyvagal hypothesis. This theory postulates that non-threatening social cues between mammalian conspecifics occur in the range of frequencies for which they have heightened sensitivity 29 . Rat audiogram studies reflect heightened sensitivity to calls near 40 kHz, which overlap with the low frequency call type described here [30][31][32] . ...
... This would indicate that control pups communicate in a more adaptive fashion, as the majority of their USVs fall in the frequency band of perceptual advantage. The polyvagal hypothesis further proposes that acoustic information not only serves a communicatory function, but also as a window into the physiological state of the sender 29 . Slow exhalation, the respiratory process associated with expressive social vocalizations, enhances the impact of the vagus on the heart, promoting calm states 29 . ...
... The polyvagal hypothesis further proposes that acoustic information not only serves a communicatory function, but also as a window into the physiological state of the sender 29 . Slow exhalation, the respiratory process associated with expressive social vocalizations, enhances the impact of the vagus on the heart, promoting calm states 29 . Rat USVs occur during the expiratory phase of respiration, so low frequency vocalizations are associated with lower rates of respiration as a result of their longer duration 9 . ...
Early separation of preterm infants from their mothers has adverse, long-term neurodevelopmental consequences. We investigated the effects of daily maternal separation (MS) of rat pups from postnatal days 2–10 (PND2–10) on neurobehavioural responses to brief isolation at PND12 compared with pups receiving controlled handling without MS. Ultrasonic vocalizations (USV) were measured at PND12 during two, 3-minute isolations occurring immediately before and after a 3-minute maternal reunion. There were no significant differences in acoustic characteristics between MS and control animals in the first isolation. However, in the second isolation, MS pups produced a greater proportion of high (~60 kHz) vs low (~40 kHz) frequency calls. During this isolation, control pups made longer and louder low frequency calls compared to the first isolation, whereas MS pups did the opposite. Maternal behaviour of control and MS mothers modulated pup acoustic characteristics in opposite directions; higher maternal care was associated with more low frequency calls in control pups but more high frequency calls in MS pups. We hypothesize that MS results in USV emission patterns reflective of a greater stress response to isolation. This translational model can be used to identify mechanisms and interventions that may be exploited to overcome the negative, long-term effects of MS.
... First, performing aikido exercises and movements involves the soma, one's own body in ancient Greek. Individual training and somatic exercises, such as breathing and movement techniques, change the individual's physiological and mental processes (Swinnen 2021;Laureys and Matthieu 2020;Hanna 1988;Porges and Lewis 2010). Second, performing aikido exercises and techniques with a partner promotes social touch. ...
Aikido, a Japanese martial art, typically transforms interactions where interlocutors may feel unsafe into safe interactions for all involved. To explore how the physical and psychological safety of aikido can benefit intercultural communication training, we conducted a benchmark study and triangulated the study’s findings. First, we collected information about the principles of aikido through semi-structured interviews with 20 aikido experts worldwide. A qualitative content analysis revealed three significant groups of aikido principles: tranquillity (i), connection (ii) and ecology (iii). They form the basis for an interaction model. Second, we triangulated the interview findings with biobehavioural studies. Understanding the body’s self- and co-regulation processes explains how aikido can produce physical, physiological and mental changes that inhibit defensive reactions and positively influence behaviour. We conclude that aikido’s interaction, transferability, and regulation properties offer the opportunity to use aikido as an embodied pedagogy in intercultural communication training.
... The ventral vagal complex also involves the nerves that regulate the middle ear muscles linking the extraction of prosodic vocalizations with the calming of autonomic state and social accessibility. In contrast, the low frequency roars of predators can trigger fight/flight reactions, while high-pitched screams trigger concern (see Refs. [24,25]). ...
Although there is a consistent literature documenting that vagal cardioinhibitory pathways support homeostatic functions, another less frequently cited literature implicates vagal cardioinhibitory pathways in compromises to survival in humans and other mammals. The latter is usually associated with threat reactions, chronic stress, and potentially lethal clinical conditions such as hypoxia. Solving this ‘vagal paradox’ in studies conducted in the neonatal intensive care unit served as the motivator for the Polyvagal Theory (PVT). The paradox is resolved when the different functions of vagal cardioinhibitory fibers originating in two anatomically distinguishable brainstem areas are recognized. One pathway originates in a dorsal area known as the dorsal motor nucleus of the vagus and the other in a ventral area of the brainstem known as nucleus ambiguus. Unlike mammals, in all ancestral vertebrates from which mammals evolved, cardioinhibitory vagal fibers primarily originate in the dorsal motor nucleus of the vagus. Thus, in mammals the vagus nerve is ‘poly’ vagal because it contains two distinct efferent pathways. Developmental and evolutionary biology identify a ventral migration of vagal cardioinhibitory fibers that culminate in an integrated circuit that has been labeled the ventral vagal complex. This complex consists of the interneuronal communication of the ventral vagus with the source nuclei involved in regulating the striated muscles of the head and face via special visceral efferent pathways. This integrated system enables the coordination of vagal regulation of the heart with sucking, swallowing, breathing, and vocalizing and forms the basis of a social engagement system that allows sociality to be a potent neuromodulator resulting in calm states that promote homeostatic function. These biobehavioral features, dependent on the maturation of the ventral vagal complex, can be compromised in preterm infants. Developmental biology informs us that in the immature mammal (e.g., fetus, preterm infant) the ventral vagus is not fully functional and myelinization is not complete; this neuroanatomical profile may potentiate the impact of vagal cardioinhibitory pathways originating in the dorsal motor nucleus of the vagus. This vulnerability is confirmed clinically in the life-threatening reactions of apnea and bradycardia in human preterm newborns, which are hypothetically mediated through chronotropic dorsal vagal pathways. Neuroanatomical research documents that the distribution of cardioinhibitory neurons representing these two distinct vagal source nuclei varies among mammals and changes during early development. By explaining the solution of the ‘vagal paradox’ in the preterm human, the paper highlights the functional cardioinhibitory functions of the two vagal source nuclei and provides the scientific foundation for the testing of hypotheses generated by PVT.
... One example is that those whose nervous systems have been sensitized through adverse experiences hear differently. According to Porges (2018;Porges & Lewis, 2010) when the sympathetic nervous system is activated, inner ear muscles relax, a survival response that makes it easier to hear distant sounds that could signal a threat. In modern life, this renders a person in a chronically defensive state overly sensitive to the background sounds, less able to discern human voices, and generally more sensitive to their environment. ...
Current theories about the aetiology of nightmares and mechanisms of action that account for their successful treatment have not yet taken the polyvagal theory (Porges, 2011) into consideration. While the polyvagal theory’s updated and multifaceted view of the autonomic nervous system’s (ANS) response to threat has begun to transform the field of trauma treatment, most of these ideas have not yet been applied to nightmares and their treatment. This article outlines how the theory may provide a missing link in understanding specific ways that trauma and adversity lead to chronic nightmares, and it offers a way to make sense of the heterogeneity of trauma-related symptoms and concomitant responses to nightmare treatments. A review of the literature demonstrates evidence of links between measures of ANS and physiological responses to nightmares. Content similarities between threat responses described by polyvagal theory and common nightmare themes provides an additional avenue for assessment and intervention. Theories of nightmare aetiology and treatment are evaluated with respect to polyvagal theory, and lastly, a proposed treatment protocol, nightmare relief, offers a polyvagal-informed, process-experiential approach to treating nightmares, with links to clinical examples.
... In all mammalian species, based on the physics of their middle ear structures, there is a frequency band of perceptual advantage that is expressed when the middle ear muscles contract (see . It is within this frequency band that social communication occurs, while the low frequencies that through evolution have been associated with predators are attenuated (see Porges and Lewis, 2010). ...
Contemporary strategies for health and wellbeing fail our biological needs by not acknowledging that feelings of safety emerge from internal physiological states regulated by the autonomic nervous system. The study of feelings of safety has been an elusive construct that has historically been dependent upon subjectivity. Acknowledging that feelings of safety have a measurable underlying neurophysiological substrate would shift investigations of feelings of safety from a subjective to an objective science. Polyvagal Theory provides an innovative scientific perspective to study feelings of safety that incorporates an understanding of neuroanatomy and neurophysiology. This perspective identifies neural circuits that downregulate neural regulation of threat reactions and functionally neutralize defensive strategies via neural circuits communicating cues of safety that enable feelings of safety to support interpersonal accessibility and homeostatic functions. Basically, when humans feel safe, their nervous systems support the homeostatic functions of health, growth, and restoration, while they simultaneously become accessible to others without feeling or expressing threat and vulnerability. Feelings of safety reflect a core fundamental process that has enabled humans to survive through the opportunistic features of trusting social engagements that have co-regulatory capacities to mitigate metabolically costly defense reactions. Through the study of neural development and phylogeny, we can extract foundational principles and their underlying mechanisms through which the autonomic nervous system leads to feelings of safety and opportunities to co-regulate. Several principles highlight the validity of a science of safety that when implemented in societal institutions, ranging from healthcare to education, would enhance health, sociality, and lead to greater productivity, creativity, and a sense of wellbeing. By respecting our need to feel safe as a biological imperative linked to survival, we respect our phylogenetic heritage and elevate sociality as a neuromodulator that functionally provides the scientific validation for a societal focus on promoting opportunities to experience feelings of safety and co-regulation.
... The HRV parameters, for example the root mean square of successive differences (RMSSD), percentage of successive NN intervals that differ by more than 50 ms (pNN50), high frequency spectrum (HF, HF%, HFnu) and standard deviation of point plot to the transverse diameter (SD1) are established markers of vagal function [18]. In vagal tone (activity of the vagus nerve), the parasympathetic nervous system predominates and this is proposed as a novel index of stress and stress vulnerability [25]. In contrast, other parameters (e.g., LF, LF/HF) are without clear assignment and can be influence from the sympathetic and parasympathetic nervous systems. ...
Background
The workloads of emergency physicians are severe. The prevalence of burnout among emergency physicians is higher than with other physicians or compared to the general population. The analysis of heart rate variability (HRV) is a valid method for objective monitoring of workload. The aim of this paper is to systematically evaluate the literature on heart rate variability as an objective indicator for mental stress of emergency physicians.
Methods
A systematic literature review examining heart rate variability of emergency physicians in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement for reporting systematic reviews was performed. PubMed, Ovid, Cochrane Libary, Scopus, and Web of Science electronic databases were used. The methodological quality was evaluated by using a modified STARD for HRV.
Results
Two studies matched the inclusion criteria by using HRV between alert intervention and two other studies were considered that used HRV in other question areas. It showed an adaptation of HRV under stress. The studies were not comparable.
Conclusions
There is a need for occupational health studies that examine strains and stress of emergency physicians. The well-established parasympathetic mediated HRV parameters seem to be suitable parameters to objectify the stress.
Sound and movement are entangled in animal communication. This is obviously true in the case of sound-constituting vibratory movements of biological structures which generate acoustic waves. A little less obvious is that other moving structures produce the energy required to sustain these vibrations. In many species, the respiratory system moves to generate the expiratory flow which powers the sound-constituting movements (sound-powering movements). The sound may acquire additional structure via upper tract movements, such as articulatory movements or head raising (sound-filtering movements). Some movements are not necessary for sound production, but when produced, impinge on the sound-producing process due to weak biomechanical coupling with body parts (e.g., respiratory system) that are necessary for sound production (sound-impinging movements). Animals also produce sounds contingent with movement, requiring neuro-physiological control regimes allowing to flexibly couple movements to a produced sound, or coupling movements to a perceived external sound (sound-contingent movement). Here, we compare and classify the variety of ways sound and movements are coupled in animal communication; our proposed framework should help structure previous and future studies on this topic.
Sensory impairments are common features of autism spectrum disorder (ASD) and are associated with its social impairments. However, there is no established treatment for these impairments in adults with ASD. The Safe & Sound Protocol (SSP) is a listening program designed to improve social communication skills by reducing auditory hypersensitivity. We investigated the effectiveness of the SSP for adults with ASD. We administered the SSP to six participants with ASD aged 21–44 years old, and the effects were assessed using the Social Responsiveness Scale, Second Edition (SRS-2). Secondary outcomes were assessed using the Center for Epidemiological Studies Depression Scale (CES-D), State-Trait Anxiety Inventory (STAI), WHO Quality of Life 26 (WHOQOL-BREF), and Adolescent/Adult Sensory Profile (A/ASP). In this study, only the Social Awareness scale of the SRS-2 Family-Report showed a significant improvement after the intervention. In addition, it was significantly correlated with physical health of WHOQOL-BREF (r = −0.577, p = 0.012), state and trait anxiety of STAI (r = 0.576, p = 0.012; r = 0.708, p = 0.00009, respectively), and CES-D (r = 0.465, p = 0.05). In conclusion, the SSP has a partial effect on social impairments in adults with ASD, specifically on the Social Awareness subscale of the SRS-2.
Artificial Intelligence (AI) is supporting decisions in ways that increasingly affect humans in many aspects of their lives. Both autonomous and decision-support systems applying AI algorithms and data-driven models are used for decisions about justice, education, physical and psychological health, and to provide or deny access to credit, healthcare, and other essential resources, in all aspects of daily life, in increasingly ubiquitous and sometimes ambiguous ways. Too often systems are built without considering human factors associated with their use, such as gender bias. The need for clarity about the correct way to employ such systems is an an increasingly critical aspect of design, implementation, and presentation. Models and systems provide results that are difficult to interpret and are blamed for being good or bad, whereas only the design of such tools is good or bad, and the necessary training for them to be integrated into human values. This chapter aims at discussing the most evident issues about gender bias in AI and exploring possible solutions for the impact on humans of AI and decision support algorithms, with a focus on how to integrate gender balance principles into data sets, AI agents, and in general in scientific research.
Communication, specifically the elements crucial for typical social interaction, can be significantly affected in psychiatric illness, especially depression. Of specific importance to conversational competence are familiar expressions (prefabricated expressions known to the language community) including formulaic expressions (conversational speech formulas and idioms; these are high in nuance) and lexical bundles (fixed linguistic segments that are prevalent in naturalistic conversation; low in nuance). The goals of this study were to examine familiar language production in the naturalistic, conversational speech of individuals with treatment-resistant depression before and after receiving surgical deep brain stimulation of the subcallosal cingulate white matter pathways and to compare their performance to healthy adults’ familiar language use. Results revealed fewer conversational speech formulas (typically nuanced) produced by those with depression pre- and post-operatively as compared to healthy controls. There was an increase in the production of non-nuanced familiar expressions (largely lexical bundles) and a decrease in nuanced expressions (formulaic expressions) post-operatively when compared to the pre-operative condition for those with depression. These results conform to a recent model that distinguishes three distinct classes of familiar language, based on linguistic and neurological criteria. This study offers a first look at familiar language in depression and provides a foundation for further study into the pragmatic components of communication to help address the often-reported diminished social connectedness experienced by those with depression.
Ancient rituals and contemplative practices are conceptualized as methods that function as neural exercises enhancing vagal regulation of the autonomic nervous system. The model proposes that specific voluntary behaviours (e.g., breath, vocalisations, and posture), which characterise these rituals and practices, have the potential to trigger a physiological state mediated by vagal pathways that fosters health and optimises subjective experiences. In order for these positive benefits to be experienced, the rituals associated with contemplative practices (e.g., chants, prayers, meditation, and dance) must be performed in a context defined by physical features that are calming and soothing and promote feelings of safety.KeywordsAncient ritualsAutonomic nervous systemPolyvagal theoryVagal brakeSocial engagement systemNeuroceptionContemplative neuroscience
Stage models have been influential in characterizing infant vocalizations in the first year of life. These models are basically descriptive and do not explain why certain types of vocal behaviors occur within a particular stage or why successive patterns of vocalization occur. This review paper summarizes and elaborates a theory of Developmental Functional Modules (DFMs) and discusses how maturational gradients in the DFMs explain age typical vocalizations as well as the transitions between successive stages or other static forms. Maturational gradients are based on biological processes that effect the reconfiguration and remodeling of the respiratory, laryngeal, and craniofacial systems during infancy. From a dynamic systems perspective, DFMs are part of a complex system with multiple degrees of freedom that can achieve stable performance with relatively few control variables by relying on principles such as synergies, self-organization, nonlinear performance, and movement variability.
Most children will experience some type of trauma during childhood, and many children suffer from significant adversities. Research in genetics, neuroscience, and epidemiology all provide evidence that these experiences have effects at the molecular, cellular, and organ level, with consequences on physical, emotional, developmental, and behavioral health across the life span. Trauma-informed care translates that science to inform and improve pediatric care and outcomes. To practically address trauma and promote resilience, pediatric clinicians need tools to assess childhood trauma and adversity experiences as well as practical guidance, resources, and interventions. In this clinical report, we summarize current, practical advice for rendering trauma-informed care across varied medical settings.
A polyvagal perspective clarifies the neurobiological and biobehavioral shifts that occurred during evolutionary transition from asocial reptiles to social mammals. This transition enabled mammals, unlike their reptilian ancestors, to derive a biological benefit from social interactions. This innovation enabled social behavior to function as a neuromodulator that could efficiently regulate and optimize autonomic function to support homeostatic processes. This journey is highlighted by the phylogenetic transition during which the autonomic nervous system was repurposed to suppress defensive strategies to support and express sociality. The product of this transition was an autonomic nervous system with capacities to self-calm, to spontaneous socially engage others, and to mitigate threat reactions in ourselves and others through social cues. Thus, social behavior became embedded with specific neurobiological processes that had capabilities to support homeostatic functions leading to optimized health, growth, and restoration. Polyvagal Theory emphasizes sociality as the core process in mitigating threat reactions and supporting mental and physical health.
Personal identity can be discerned from fleeting instances of speech, and, remains recognizable after temporal displacements of years. The science of voice, including the nature of the voice as social object, the auditory‐acoustic cues that are accountable for the recognition or discrimination of individual voice patterns, information carried in the voice, and cerebral functions underlying the perception and production of unique vocal patterns are now receiving much attention. Partitioning voices into unfamiliar and personally familiar sets, with respect to the role of the listener, leads to consideration of the respective roles of featural analysis and gestalt apperception. Due to the limited temporal resolution of neuroimaging techniques, some researchers have used electroencephalography or magnetoencephalography to determine the exact time course of voice‐identity processing. The voice perception model must accommodate both featural analysis and pattern recognition. Lesion and functional imaging studies have identified areas on cortical regions of the temporal lobes as important for voice recognition.
Background:
Dyads receiving palliative care for advanced heart failure are at risk for the loss of feeling safe, experienced as a fractured sense of coherence, discontinuity in sense of self and relationships, and strained social connections and altered roles. However, few theory-based interventions have addressed feeling safe in this vulnerable population.
Purpose:
The purpose of this article is to describe the development of the Nostalgic Remembering Intervention to strengthen feeling safe and promote adaptive physiological and psychological regulation in dyads receiving palliative care for heart failure.
Conclusions:
Systematic intervention development is essential to understand what, for whom, why, and how an intervention works in producing outcomes. Program theory provided a systematic approach to the development of the Nostalgic Remembering Intervention, including conceptualization of the problem targeted by the intervention, specification of critical inputs and conditions that operationalize the intervention, and understanding the mediating processes leading to expected outcomes.
Clinical implications:
Creating a foundation for cardiovascular nursing research and practice requires continued, systematic development of theory-based interventions to best meet the needs of dyads receiving palliative care for heart failure. The development of the Nostalgic Remembering Intervention to strengthen feeling safe in dyads provides a novel and relevant approach.
Research suggests that music has a powerful effect on the human mind and body. This article explores the impact of music as an intervention. For this purpose, the X-System technology is used to curate relaxing and enlivening music playlists designed to positively impact wellbeing and emotional state during the COVID-19 pandemic. A wellbeing model grounded in autopoietic theory of self-organisation in living systems is developed to inform the evaluation of the impact of the intervention and ensure the reliability of the data. More specifically, data quality is enhanced by focusing the participants’ awareness on their immediate embodied experience of physical, emotional and relational wellbeing and sense of pleasure/displeasure prior to and after listening to a preferred playlist. The statistical analysis shows significant positive changes in emotional wellbeing, valence and sense of meaning (
) with a medium effect size. It also reveals a statistically significant change for physical wellbeing (
p=0.009
) with a small effect size. With the relaxing playlists leading to decrease in arousal levels and the enlivening playlists to an increase in activation, it is also concluded that appropriately curated playlists may be able to lead the listener to positive relaxation or activation states or indeed to positive mood change that may have health benefits.
Emotions guide behavioural decisions in response to events or stimuli of importance for the organism, and thus, are an important component of an animal’s life. Communicating emotions to conspecifics allows, in turn, the regulation of social interactions (e.g. approach and avoidance). The existence of common rules governing vocal expression of affective states across species has been proposed as a function of the motivational state (i.e. intention of behaviour) of the emitter (‘motivation-structural rules’) and as a function the two main dimensions of emotions, valence (positive versus negative) and arousal (bodily activation). In this chapter, I review the potential for vocalisations to serve as universal non-invasive indicators of animal emotions, by considering the latest evidence for common rules existing across species according to the two dimensions of emotions (‘emotional-dimension rules’). Vocal indicators of emotional arousal have been relatively well studied. Cross-species comparison shows that, when arousal increases, vocalisations tend to be louder and are produced at faster rates, with higher frequencies (both source- and filter-related) and a more variable fundamental frequency (F0). In contrast, indicators of valence have only been investigated in a few species. The evidence so far indicates that, compared with negative vocalisations, positive vocalisations tend to be shorter, with a lower and less variable F0. Yet, comparison of vocal indicators of valence between closely related species suggests that these indicators are more species specific than indicators of arousal, which have clearly been conserved throughout evolution. To conclude, I further suggest a new set of rules that could explain the acoustic structure of vocalisations across species, which combine features predicted by the motivation-structural rules, the emotional-dimension rules, and characteristics of the social relationship involving the emitter and receiver.
Individuals with autism spectrum disorder (ASD)may exhibit chronic autonomic nervous system (ANS)hyperarousal (e.g., lower respiratory sinus arrhythmia and higher heart rate)compared to their typically developing peers, reflecting a chronic biological threat response. The sustained nature of this cardiac threat suggests tonic nervous system perception of threat in safe contexts. Herein, the cardiac literature in adult and child populations with ASD is reviewed and placed within a continuum of functioning in order to inform the relationship between cardiac response and functioning in ASD. Findings from this review support the relationship between chronic autonomic hyperarousal and emotional and behavioral difficulties observed in individuals with ASD.
A range of psychiatric disorders such as anxiety, depression, and post‐traumatic stress disorder frequently co‐occur with functional gastrointestinal (GI) disorders. Risk of these pathologies is particularly high in those with a history of trauma, abuse, and chronic stress. These scientific findings and rising awareness within the healthcare profession give rise to a need for an integrative framework to understand the developmental mechanisms that give rise to these observations. In this paper, we introduce a plausible explanatory framework, based on the Polyvagal Theory (Porges, Psychophysiology, 32, 301–318, 1995; Porges, International Journal of Psychophysiology, 42, 123–146, 2001; Porges, Biological Psychology, 74, 116–143, 2007), which describes how evolution impacted the structure and function of the autonomic nervous system (ANS). The Polyvagal Theory provides organizing principles for understanding the development of adaptive diversity in homeostatic, threat‐response, and psychosocial functions that contribute to pathology. Using these principles, we outline possible mechanisms that promote and maintain socioemotional and GI dysfunction and review their implications for therapeutic targets.
Chronic diffuse pain disorders, such as fibromyalgia, and functional gastrointestinal disorders (FGIDs), such as irritable bowel syndrome, place substantial burden on those affected and on the medical system. Despite their sizable impact, their pathophysiology is poorly understood. In contrast to an approach that focuses on the correlation between heart rate variability (HRV) and a specific organ or symptom, we propose that a bio-evolutionary threat-related autonomic response—as outlined in the Polyvagal Theory—may serve as a plausible explanation of how HRV, particularly respiratory sinus arrhythmia (RSA), would index the pathophysiology of these disorders. Evidence comes from: (1) the well-documented atypical autonomic regulation of the heart common to fibromyalgia and irritable bowel syndrome reflected in dampened RSA, (2) the neural architecture that integrates the heart, pain pathways, and the gastrointestinal tract, (3) the common physical co-morbidities shared by chronic diffuse pain and FGIDs, many of which are functionally regulated by the autonomic nervous system, (4) the elevated risk of chronic diffuse pain and FGIDs following traumatic stress or abuse, (5) and the elevated risk of chronic diffuse pain and FGIDs in individuals with anxiety and panic disorders. This novel conceptualization points to a pathogenesis rooted in changes to brain-body autonomic feedback loops in response to evolutionarily-salient threat cues, providing an integrated biopsychosocial model of chronic diffuse pain and FGIDs and suggesting new, non-pharmacological treatment strategies.
Music is much more than a simple stimulus bringing individual pleasure; it also facilitates interpersonal synchrony. In this chapter, evidence from various disciplines is brought together to provide a new perspective on how music stimulates social engagement and learning and further affects cognitive reserve and the way we age. Music and musical elements affect listeners differently but seem to regulate our body and brain at a much deeper level than we are aware of. When music touches and engages us, a release of the neurotransmitter norepinephrine follows. This process involves the brain stem (more precisely the locus coeruleus), and a compensatory effect is observed. By engaging in music from early childhood, preventive mechanisms add to healthy aging and may even slow down the development of dementia symptoms, although it cannot prevent dementia. In addition, through musical interaction, meaningful expression of psychosocial needs may indirectly lead to a reduction of behavioural and psychological symptoms of dementia. For the person with severe dementia, with sensory and cognitive decline, this offers a healthy means of remaining active, autonomous and integrated.
The production of emotional tears appears to be uniquely present in Homo sapiens. Despite the ubiquity of this human behavior, research is only just beginning to uncover the neurobiologic underpinnings of human emotional crying. In this article, we review the current state of the literature investigating the neurobiologic aspects of this uniquely human behavior, including the neuroanatomical, neurochemical, and psychophysiologic findings. To set the context for this review, we first provide a brief overview of the evolutionary background and functions of tearful crying. Despite an accumulating understanding of the neurobiology of human emotional crying, the primary sources of information are currently from animal studies and observations in neurologic patients suffering from pathologic crying. Currently, most of the research on the neurobiology of crying in humans has focused on autonomic physiologic processes underlying tearful crying, which may yield essential clues regarding the neural substrates of the production of crying behavior and its effects on the crier. Further challenges in elucidating the neurobiology of crying involve the complexity of crying behavior, which includes vocalizations, tear production, the involvement of facial musculature, subjective emotional experience, emotion regulatory behaviors, and social behaviors. Future research is needed to comprehensively characterize the neurobiology of this intriguing and complex human behavior.
La teoría polivagal aporta una explicación neurofisiológica de cómo el cuerpo y el cerebro se interrelacionan con el contexto social en el que ambos tienen lugar. Su aplicación al ámbito de mindfulness y compasión puede contribuir a optimizar la eficacia de estas intervenciones, integrar los resultados obtenidos en los estudios de eficacia y guiar la investigación futura.
Nuestro propósito con el presente artículo es ofrecer un marco integrador que pueda explicar las bases neurofisiológicas subyacentes a la práctica de mindfulness y compasión.
Tras presentar los fundamentos de la teoría polivagal, se exploran sus posibles aportaciones al ámbito de mindfulness y compasión. Mediante la revisión de constructos como el apego, el embodiment o la presencia terapéutica, se ofrecen recomendaciones prácticas para el instructor. Para finalizar se plantea la importancia de tener en cuenta el estado fisiológico para la práctica de compasión y se proponen sugerencias de investigación futura.
During infancy, cardiac vagal modulation has been associated with attentional and social engagement behaviors. While studies have shown that infants display a behavioral repertoire that enables them to interact with others by being able to regulate themselves in order to attend to and to discriminate emotional and social cues, vagal modulation to sensory stimuli and its association with behavioral outcomes at early ages remains to be addressed. In this study, we analyzed the cardiac vagal response of 1-month-old infants to two auditory stimuli intensities and whether vagal response was associated with social interactive and self-regulatory abilities. Therefore, we recorded cardiac and respiratory physiological responses in 28 infants using a Biopac System. Neurobehavioral assessment was performed using the Neonatal Behavioral Assessment Scale. We observed increased respiratory sinus arrhythmia (RSA) amplitude to both auditory stimuli intensities when compared to baseline. No intensity effect was found for the RSA response. Additionally, we observed that higher RSA amplitude to both auditory stimuli was positively correlated with adjusted self-regulatory behaviors, suggesting a convergence between multiple measures assessing infants' state regulation. Results are discussed in light of 1-month-old infants' auditory stimuli processing and its implications for regulatory behaviors and the emergent social-like behaviors.
Conversational voice and speech—which are enlarged and refined in theatrical performance—evolved from the social sounds and gestures of animals. A recent and influential theory in psychophysiology links this evolution to specific changes in the vagus nerve, which is also the parent of the nerves that control the larynx. This “polyvagal theory,” developed by Stephen W. Porges through decades of objective research, offers powerful insights into the nature of stage presence in general and vocal communication in particular, including the visceral impact of voice on the listener. The polyvagal theory is presented here following background on the autonomic nervous system, how vagus nerve activity is measured, and how this nerve impacts communication ability. Strong parallels emerge between the objectively based polyvagal theory and artists’ subjective descriptions of vocal performance. The discussion concludes with implications for theater–voice pedagogy and suggestions for future research linking neuroscience to the vocal arts.
This study investigated the role of basal cardiac activity and inhibitory control at the beginning of the school year in predicting oral comprehension at the end of the year in pre-schoolers. Forty-three, 4-year-olds participated in the study. At the beginning of the school year children's electrocardiogram at rest was registered followed by the assessment of inhibitory control as well as verbal working memory and verbal ability. At the end of the year all children were administered a listening comprehension ability measure. A stepwise regression showed a significant effect of basal cardiac vagal tone in predicting listening comprehension together with inhibitory control and verbal ability. These results are among the first to show the predictive role of basal cardiac vagal tone and inhibitory control in pre-schoolers' oral text comprehension, and offer new insight into the association between autonomic regulation of the heart, inhibitory control, and cognitive activity at a young age.
This paper reviews some recent advances in our understanding of the effects of sham or dummy interventions on pain and other symptoms in osteoarthritis, and outlines two new approaches to the investigation of placebo and nocebo effects. We argue that the placebo effect provides us with a valuable way of investigating the nature of conditions like osteoarthritis (OA). For example, by examining which symptoms, biochemical markers or imaging features do or do not respond to placebo, we might learn more about the relationships between pathology and symptoms in OA. Placebo and nocebo effects are positive or negative outcomes resulting from the human interactions and contexts in which healthcare consultations take place. Subtle changes in behaviours and the environments in which consultations take place can have major effects on pain and other symptoms being experienced by people with OA. Nocebo effects are particularly powerful, leading to many health-care professionals causing unintended harm to their clients. Based on our own research, we conclude that beneficial outcomes are most likely to occur when both the health-care professional and the client feel safe and relaxed, and when the experiences of the client are validated by the health-care professional. These findings have important implications for clinical practice. We believe that research in this field needs to be 'trans-disciplinary', escaping from the constraints of the purely biomedical, deterministic, positivist paradigm of most medical research. We provide the example of our own work which combines performance studies and scholarship, with psychology and medicine.
Measuring well-being may benefit from increasingly sophisticated methodologies such as autonomic markers. Psychology provides data and tools related to the emotional factor in well-being processes. This chapter depicts the importance of affective and sensorial pain on the basis of 25 years of Mexican experience on the clinical study of pain.
Why do we believe to understand animal voices such as whining or aggressive barking of our dogs, the longing meows of our cats? Why do we frequently assess deep voices as dominant and high voices as submissive. Are there universal principles governing our own communication system? Can we even see how close animals are related to us by constructing an evolutionary tree based on similarities and dissimilarities in acoustic signaling? Research on the role of emotions in acoustic communication and its evolution was neglected for a long time. When we infect others with our laugh, soothe a crying baby with a lullaby or get goose bumps listening to classical music, we are barely aware of the complex processes upon which this behavior is based. It is not facial expressions or body language that is affecting us, but sound. They are present in music and speech as “emotional prosody” and allow us to communicate not only verbally but also emotionally. In this book we will demonstrate new and surprising insights how acoustically conveyed emotions are generated and processed in animal and man. We will demonstrate why acoustic communication of emotions are of paramount importance and essential for communication across all mammal species and human cultures.
Communicative and social capacities are known to be of primary developmental importance to all children and often present a particular difficulty for children with neurodevelopmental disorders. A recurring challenge for teachers is achieving effective communication with children who span developmental diversity (e.g. inclusive settings or those with a range of special needs) while using practical strategies that feel manageable to the teachers themselves. Music, a powerful affective medium, is appealing to all children and has the inherent flexibility to reach differing individuals. Thus, it is especially valuable for children with autism and other special needs. However, teachers without musical training may miss a great deal of music’s potential benefits. The author describes an affective singing technique that, while grounded in vocal practice and music theory, uses an overt focus upon vowels—vowels being known conveyors of emotion in sounded communication. This natural port of entry offers non-musician teachers a simple and accessible way to incorporate live singing into daily activities that opens space for two-way affective communication, a crucial component of social development. Key concepts in this paper are elucidated by childhood instructional and play scenarios and graphics. The discussion is supported by published behavioral and imaging research.
Auditory hypersensitivities are a common feature of autism spectrum disorder (ASD). In the present study, the effectiveness of a novel intervention, the listening project protocol (LPP), was evaluated in two trials conducted with children diagnosed with ASD. LPP was developed to reduce auditory hypersensitivities. LPP is based on a theoretical "neural exercise" model that uses computer altered acoustic stimulation to recruit the neural regulation of middle ear muscles. Features of the intervention stimuli were informed by basic research in speech and hearing sciences that has identified the specific acoustic frequencies necessary to understand speech, which must pass through middle ear structures before being processed by other components of the auditory system. LPP was hypothesized to reduce auditory hypersensitivities by increasing the neural tone to the middle ear muscles to functionally dampen competing sounds in frequencies lower than human speech. The trials demonstrated that LPP, when contrasted to control conditions, selectively reduced auditory hypersensitivities. These findings are consistent with the polyvagal theory, which emphasizes the role of the middle ear muscles in social communication.
This study examined the effect of HIV on visceromotor (i.e., heart rate and heart rate variability) and somatomotor (i.e., auditory processing and affect recognition) components of a social engagement system defined by the Polyvagal Theory (Porges, 1995) that links vagal regulation of the heart with brainstem regulation of the striated muscles of the face and head. Relative to at risk HIV- seronegative women, HIV-seropositive women had less heart rate variability (i.e., respiratory sinus arrhythmia) and had poorer performance on auditory processing and affect recognition tasks. CD4 was negatively correlated with the accuracy to detect specific emotions. The observed indices of atypical autonomic and behavioral regulation may contribute to greater difficulties in social behavior and social communication between HIV- infected women and other individuals in their social network.
Automatic responses play a central role in many areas of psychology. Counter to views that such responses are relatively rigid and inflexible, a large body of research has shown that they are highly context-sensitive. Research on animal learning and animal behavior has a strong potential to provide a deeper understanding of such context effects by revealing remarkable parallels between the functional properties of automatic responses in human and nonhuman animals. These parallels involve the contextual modulation of attitude formation and change (automatic evaluation), and the role of contextual contingencies in shaping the particular action tendencies in response to a stimulus (automatic behavior). Theoretical concepts of animal research not only provide novel insights into the processes and representations underlying context effects on automatic responses in humans; they also offer new perspectives on the interface between affect, cognition, and motivation.
The present longitudinal study examined relations between respiratory sinus arrhythmia (RSA) development and social responsiveness characteristics associated with autism spectrum disorders. Group-based developmental trajectory modeling was used to characterize RSA development patterns in 106 typically developing children across 5, 10, 24, 36, and 48 months of age. A two-group model fit of RSA development was found: a "typically" and "atypically" developing group. The typical group gradually increased in RSA across 5-48 months of age. The atypical group, however, increased in RSA from 5 to 24 months and demonstrated a plateau or "delay" in RSA development from 24 to 48 months. The atypical RSA development group also demonstrated more difficulties in parent-reported social responsiveness at 48 months. The results support current literature that identifies RSA as a marker of social functioning level. © 2013 Wiley Periodicals, Inc. Dev Psychobiol.
While variations in neonatal distress vocalizations have long been shown to reflect the integrity of nervous system development following a wide range of prenatal and perinatal insults, a paucity of research has explored the neurobiological basis of these variations. To address this, virgin Sprague-Dawley rats were bred and divided into three groups: [1] untreated, [2] chronic-cocaine treated (30mg/kg/day, gestation days (GDs) 1-20); or [3] chronic saline treated (2mg/kg/day, GDs 1-20). Pregnant dams were injected with Bromodeoxyuridine (10mg/kg) on GDs 13-15 to label proliferating cells in limbic regions of interest. Ultrasonic vocalizations (USVs) were recorded on postnatal days (PNDs) 1, 14, and 21, from one male and female pup per litter. Variations in acoustic properties of USVs following cocaine-exposure were age and sex-dependent including measures of total number, total duration and amplitude of USVs, and percent of USVs with at least one harmonic. Following USV testing brains were stained with standard fluorescent immunohistochemistry protocols and examined for variations in neuronal development and if variations were associated with acoustic characteristics. Limbic region developmental differences following cocaine-exposure were sex- and age-dependent with variations in the ventral medial hypothalamus and central amygdala correlating with variations in vocalizations on PND 14 and 21. Results suggest maturation of the ventral medial hypothalamus and central amygdala may provide the basis for variations in the sound and production of USVs. As vocalizations may serve as a neurobehavioral marker for nervous system integrity, understanding the neurobiological basis of neonatal vocalizations may provide the basis for early intervention strategies in high-risk infant populations.
Emotional systems are central to the behavior of many animals, either as part of the impetus to behavioral action, or as an important accompaniment to it. In this chapter, we consider the role of the emotions, or affective systems construed more broadly, in vocal communication. We focus not on the role that affective systems might play in motivating calling, nor on the related issue of how vocal signals might then serve as indicators of caller emotional state. Instead, we focus on how vocal signals influence the affective systems of listeners in ways that steer and impel behavioral responding in them. We emphasize: (1) that affective systems can be important functional targets of signaling in animals, including humans; (2) that they include phylogenetically widespread neuro-affective sensitivity to some sounds; (3) that such sensitivity can impel responses from listeners in quite direct fashion, or combine with general processes of conditioning and learning to steer listener behavior more indirectly; and (4) that the effect that signals have on core affective processes and behavior in listeners can also serve to scaffold more complex communicative processes and outcomes.
The current study builds on the emerging autism spectrum disorder (ASD) literature that associates autonomic nervous system activity with social function, and examines the link between respiratory sinus arrhythmia (RSA) and both social behavior and cognitive function. The RSA response pattern was assessed in 23 4- to 7-year-old children diagnosed with an ASD. Higher baseline RSA amplitudes were associated with better social behavior (i.e., more conventional gestures, more instances of joint attention) and receptive language abilities. Similar to reports of typically developing children, ASD children with higher RSA amplitude at baseline showed greater RSA and HP reactivity during an attention-demanding task. These results highlight the importance of studying RSA as a marker of positive function in children with ASD. © 2011 Wiley Periodicals, Inc. Dev Psychobiol.
The purpose of this article is to describe the development of translational methods by which spectrum analysis of human infant crying and rat pup ultrasonic vocalizations (USVs) can be used to assess potentially adverse effects of various prenatal conditions on early neurobehavioral development. The study of human infant crying has resulted in a rich set of measures that has long been used to assess early neurobehavioral insult due to non-optimal prenatal environments, even among seemingly healthy newborn and young infants. In another domain of study, the analysis of rat put USVs has been conducted via paradigms that allow for better experimental control over correlated prenatal conditions that may confound findings and conclusions regarding the effects of specific prenatal experiences. The development of translational methods by which cry vocalizations of both species can be analyzed may provide the opportunity for findings from the two approaches of inquiry to inform one another through their respective strengths. To this end, we present an enhanced taxonomy of a novel set of common measures of cry vocalizations of both human infants and rat pups based on a conceptual framework that emphasizes infant crying as a graded and dynamic acoustic signal. This set includes latency to vocalization onset, duration and repetition rate of expiratory components, duration of inter-vocalization-intervals and spectral features of the sound, including the frequency and amplitude of the fundamental and dominant frequencies. We also present a new set of classifications of rat pup USV waveforms that include qualitative shifts in fundamental frequency, similar to the presence of qualitative shifts in fundamental frequency that have previously been related to insults to neurobehavioral integrity in human infants. Challenges to the development of translational analyses, including the use of different terminologies, methods of recording, and spectral analyses are discussed, as well as descriptions of automated processes, software solutions, and pitfalls.
A fossil from the Early Jurassic (Sinemurian, ∼195 million years ago) represents a new lineage of mammaliaforms, the extinct groups more closely related to the living mammals than to nonmammaliaform cynodonts. It has an enlarged cranial cavity, but no postdentary trough on the mandible, indicating separation of the middle ear bones from the mandible. This extends the earliest record of these crucial mammalian features by some 45 million years and suggests that separation of the middle ear bones from the mandible and the expanded brain vault could be correlated. It shows that several key mammalian evolutionary innovations in the ear region, the temporomandibular joint, and the brain vault evolved incrementally through mammaliaform evolution and long before the differentiation of the living mammal groups. With an estimated body weight of only 2 grams, its coexistence with other larger mammaliaforms with similar “triconodont-like” teeth for insectivory within the same fauna suggests a great trophic diversity within the mammaliaform insectivore feeding guild, as inferred from the range of body sizes.
Phylogenetic analysis with x-ray computed tomography of fossilized and recent crania implicates differential growth of the
neocortex in the evolution and development of the mammalian middle ear. In premammalian tetrapods, the middle ear evolved
as a chain of bones attached to the mandible and cranium, but in adult mammals the chain is detached from the mandible and
lies behind it. The neocortex evolved concurrently with detachment of the chain. In mammalian development the auditory chain
arises connected to the mandible but later detaches, recapitulating the phylogenetic transformation. In modern didelphid development,
the auditory chain reaches mature size by the third week after birth and is then separated from the jaw and displaced caudally
as the neocortex grows for another 9 weeks.
Since sounds may induce physiological and behavioural changes in animals, it is necessary to assess and define the acoustic environment in laboratory animal facilities. Sound studies usually express sound levels as unweighted linear sound pressure levels. However, because a linear scale does not take account of hearing sensitivity-which may differ widely both between and within species at various frequencies-the results may be spurious. In this study a novel sound pressure level weighting for rats, R-weighting, was calculated according to a rat's hearing sensitivity. The sound level of a white noise signal was assessed using R-weighting, with H-weighting tailored for humans, A-weighting and linear sound pressure level combined with the response curves of two different loudspeakers. The sound signal resulted in different sound levels depending on the weighting and the type of loudspeaker. With a tweeter speaker reproducing sounds at high frequencies audible to a rat, R- and A-weightings gave similar results, but the H-weighted sound levels were lower. With a middle-range loudspeaker, unable to reproduce high frequencies, R-weighted sound showed the lowest sound levels. In conclusion, without a correct weighting system and proper equipment, the final sound level of an exposure stimulus can differ by several decibels from that intended. To achieve reliable and comparable results, standardization of sound experiments and assessment of the environment in animal facilities is a necessity. Hence, the use of appropriate species-specific sound pressure level weighting is essential. R-weighting for rats in sound studies is recommended.
A fossil from the Early Jurassic (Sinemurian, approximately 195 million years ago) represents a new lineage of mammaliaforms, the extinct groups more closely related to the living mammals than to nonmammaliaform cynodonts. It has an enlarged cranial cavity, but no postdentary trough on the mandible, indicating separation of the middle ear bones from the mandible. This extends the earliest record of these crucial mammalian features by some 45 million years and suggests that separation of the middle ear bones from the mandible and the expanded brain vault could be correlated. It shows that several key mammalian evolutionary innovations in the ear region, the temporomandibular joint, and the brain vault evolved incrementally through mammaliaform evolution and long before the differentiation of the living mammal groups. With an estimated body weight of only 2 grams, its coexistence with other larger mammaliaforms with similar "triconodont-like" teeth for insectivory within the same fauna suggests a great trophic diversity within the mammaliaform insectivore feeding guild, as inferred from the range of body sizes.
An ossified Meckel's cartilage has been recovered from two early Cretaceous mammals from China. This element is similar to
Meckel's cartilage in prenatal and some postnatal extant mammals and indicates the relationship of Meckel's cartilage with
the middle ear in early mammals. The evidence shows that brain expansion may not be the initial factor that caused the separation
of postdentary bones from the dentary as middle ear ossicles during mammalian evolution. The failure of the dentary to seize
reduced postdentary elements during ontogeny of early mammals is postulated as an alternative mechanism for the separation.
Modifications of both feeding and hearing apparatuses in early mammals may have led to the development of the definitive mammalian
middle ear.
Evolution of the earliest mammals shows successive episodes of diversification. Lineage-splitting in Mesozoic mammals is coupled with many independent evolutionary experiments and ecological specializations. Classic scenarios of mammalian morphological evolution tend to posit an orderly acquisition of key evolutionary innovations leading to adaptive diversification, but newly discovered fossils show that evolution of such key characters as the middle ear and the tribosphenic teeth is far more labile among Mesozoic mammals. Successive diversifications of Mesozoic mammal groups multiplied the opportunities for many dead-end lineages to iteratively evolve developmental homoplasies and convergent ecological specializations, parallel to those in modern mammal groups.
Book on noise effects on man covering audiometry, aural reflex, hearing damage risk, physiological responses, motor performance and speech communication
Chapter I. Introduction - p.1 Chapter II. Critical Survey of Some Previous Investigations - p.6 Investigations with Classical Methods - p.6 Modern Methods of Testing Bone Conduction - p.17 Investigations with Modern Methods - p.20 Chapter III. Present State of Knowledge. Plan of Own Investigations - p.27 Chapter IV. General Theory of Bone Conduction Receiver - p.30 Summary - p.41 Appendix - p.42 Chapter V. The Tuned Bone Conduction Receiver - p.44 Summary - p.48 Appendix - p.48 Chapter VI. A Moving Coil Bone Conduction Receiver with Measurable Amplitude, Phase and External Force - p.50 Summary - p.45 Appendix - p.45 Chapter VII. The Behaviour of the Soft Tissues - p.56 Summary - p.62 Appendix - p.62 Chapter VIII. The Oscillations of the Skull - p.65 Summary - p.71 Chapter IX. The Restraint of the Skull. The Contribution of Bone Conduction to the Hearing of Air Sound - p.72 Summary - p.80 Appendix - p.81 Chapter X. "Inertia Bone Conduction" and "Compression Bone Conduction" - p.84 Summary - p.88 Chapter XI. The Vector Method in Oscillation Problems. The Locus Curve - p.89 Summary - p.95 Chapter XII. Inertia Movements of the Chain of Ossicles and of the Liquid in the Labyrinth when the Skull is Translated. A New Theory of the Function of the Chain of Ossicles - p.96 Summary - p.111 Appendix - p.112 Chapter XIII. Inertia Movements of the Chain of Ossicles and the Liquid in the Labyrinth, when the Skull is Rotated - p.114 Summary - p.120 Chapter XIV. The Compression of the Labyringh and its Relevance to Bone Conduction - p.121 Summary - p.129 Chapter XV. Bone Conduction Composed of Several Components - p.130 Summary - p.132 Chapter XVI. The Measurement of Relative Amplitude and Phase of Bone Conduction - p.133 The Principle of the Method - p.133 Description of the Experimental Arrangement - p.136 The Measurements - p.142 The Unwanted Air Sound. Apparent and Real Bone Conduction - p.144 Sources of Error - p.148 Summary - p.154 Appendix - p.154 Chapter XVII. The Variations of Amplitude and Phase of Bone Conduction in Normal Ears when the Bone Conduction Receiver is Applied to Different Points of the Head - p.157 Summary - p.166 Appendix - p.167 Chapter XVIII. Bone Conduction in Conduction Deafness - p.170 Bone Conduction with Retracted Ear-Drum - p.170 Bone Conduction with Obturated Meatus - p.179 Summary - p.182 Chapter XIX. The Exceptional Position of the Mastoid Process in Bone Conduction. "Cartilage Conduction" - p.183 Summary - p.187 Chapter XX. Experimental Proof of the Existence of Inertia Bone Conduction Generated by Rotations of the Head around a Horizontal Axis - p.189 Summary - p.195 Chapter XXI. The Degree of Balance Attained by the Ossicular Chain. The Vertial Distance Between its Mass-Centre and Axis of Rotation - p.196 Summary - p.201 Appendix - p.201 Chapter XXII. Bone Conduction with Loaded Ear Drum - p.202 Summary - p.208 Chapter XXIII. The Determination of Bone Conduciton Thresholds in Absolute Units - p.209 Summary - p.212 Chapter XXIV. Applications to Clinical Audiometry - p.213 Summary - p.217 Results - p.218 Bibliography - p.221
Speech‐intelligibility testing is an expensive and time‐consuming operation that requires laboratory test conditions. In an attempt to short‐cut or make unnecessary this type of testing, a procedure was developed by French and Steinberg [J. Acoust. Soc. Am. 19, 90–119 (1949)] for calculating from physical and acoustical measurements made on a communication system a measure that is indicative of the intelligibility scores that would be obtained for that system under actual test conditions. This measure is called the “Articulation Index” (AI). Methods of calculating AI have been improved and elaborated to the point where several methods for its calculation, herein reported, can be proposed for use in the evaluation of most speech communication systems.
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The central role of crying in early infancy has been discussed by parents, pediatricians, and theorists. In Western cultures crying is the primary mode of communication through which the young infant’s needs and wants are expressed. The affective messages transmitted by the cry tell the caregivers that the infant needs attention, and in most cases crying is terminated when the infant’s needs are met. There are times, however, when the immediate cause of crying is not clear—socalled “unexplained fussiness”—when the infant cannot be easily soothed.
"Oral speech intelligibility tests were conducted with, and without, supplementary visual observation of the speaker's facial and lip movements. The difference between these two conditions was examined as a function of the speech-to-noise ratio and of the size of the vocabulary under test. The visual contribution to oral speech intelligibility (relative to its possible contribution) is, to a first approximation, independent of the speech-to-noise ratio under test. However, since there is a much greater opportunity for the visual contribution at low speech-to-noise ratios, its absolute contribution can be exploited most profitably under these conditions." (PsycINFO Database Record (c) 2012 APA, all rights reserved)
In this laboratory experiment it is shown that, like four North American soricid shrew species, the European common shrew Sorex araneus L. is able to use echolocation to identify open and closed tubes at a distance of 200 mm.
Three common shrews captured in Sweden were used for the experiments, which were carried out in darkness and within a sound-proof box. The experimental set-up eliminated orientation using sight, sound or scent from outside the experimental cage. Echolocation calls consisted of broadband ultrasonic clicks at low sound pressure. These were recorded using an ultrasound detector.
The ecological significance of echolocation in shrews is discussed. It is proposed that common shrews use echolocation to locate protective cover, thus minimizing the risk to be taken by, e.g. owls.
Echolocation may also be used for detecting obstacles in subterranean tunnels. Hence, echolocation could be of certain importance when abandoned burrows in the periphery of the tunnel system are restored during periods of increasing population densities. Since density peaks in most populations occur regularly each summer, and may reach extreme magnitudes in cyclic populations, the ecological significance of echolocation in shrews may be considerabl.
MOST verbal communication occurs in contexts where the listener can see
the speaker as well as hear him. However, speech perception is normally
regarded as a purely auditory process. The study reported here
demonstrates a previously unrecognised influence of vision upon speech
perception. It stems from an observation that, on being shown a film of
a young woman's talking head, in which repeated utterances of the
syllable [ba] had been dubbed on to lip movements for [ga], normal
adults reported hearing [da]. With the reverse dubbing process, a
majority reported hearing [bagba] or [gaba]. When these subjects
listened to the soundtrack from the film, without visual input, or when
they watched untreated film, they reported the syllables accurately as
repetitions of [ba] or [ga]. Subsequent replications confirm the
reliability of these findings; they have important implications for the
understanding of speech perception.
Previous studies showed that when socially isolated at 22 degrees C, postnatal day 14 rats, but not younger day 7 rats, reduce their emission of ultrasonic vocalizations when exposed to an unfamiliar adult male rat, a naturalistic threat. Because ultrasound production is associated with factors such as age and body temperature, this study examined in age-appropriate thermoneutral temperature ranges whether preweanling rats of different ages are equally capable of inhibiting their emission of ultrasounds when threatened. In Experiment 1, 7- and 14-day-old rats were socially isolated and exposed to unfamiliar anesthetized adult male rats in a thermoneutral environment. Only 14-day-old rats significantly reduced their emission of ultrasounds. This reduction in ultrasound production was accompanied by freezing. In Experiment 2, additional ages were examined under identical test conditions. At 3, 6, and 9 days of age, pups frequently emitted ultrasounds when exposed to the anesthetized male rat. However, at 12 days of age, rat pups responded to the anesthetized male rat by freezing and significantly reducing their emission of ultrasounds. Results indicate clearly that under the present testing conditions the ability of rat pups to inhibit ultrasounds and freeze when threatened is not present at birth but emerges by the end of the second postnatal week.
The effects of oral vs. iv administration of kappa- and mu-opioid agonists on plasma cortisol release induced by acoustic stress (AS) were evaluated in fasted dogs with an implanted jugular catheter. AS was induced by 1 h of music (less than or equal to 86 decibels) played through earphones and was accompanied by a 382% maximal rise in plasma cortisol after 15-30 min. Administered orally 30 min before the AS session, both U-50488 (0.1 mg/kg) and PD 117-302 (0.05 mg/kg) significantly (P less than or equal to 0.01) decreased (by 71.2% and 80.9%, respectively) the maximal increase in plasma cortisol induced by AS, while bremazocine, morphine, as well as iv administration of U-50488 at similar doses were ineffective. The effects of U-50488 and PD 117-302 orally administered (0.1 mg/kg) on the hypercortisolemia induced by AS were abolished by pretreatment with iv naloxone (0.1 mg/kg) or MR 2266 (0.1 mg/kg). Naloxone given alone significantly (P less than 0.01) increased basal plasma cortisol, without affecting cortisol increase induced by AS. Vagotomy abolished the effects of orally administered U-50488 on the AS-induced increase in plasma cortisol. Neither U-50488 nor PD 117302 (0.1 mg/kg, orally) reduced the increase in plasma cortisol induced by intracerebroventricular administration of ovine CRF (100 ng/kg). It is concluded that kappa- but not mu-opioid agonists are able to inhibit the stimulation of the hypothalamo-pituitary-adrenocortical axis induced by AS by acting selectively on peripheral kappa-receptors located in the wall of the proximal gut. This action is neurally mediated through afferent vagal fibers affecting central nervous system release of CRF induced by a centrally acting stressor.
Measurement of the middle ear muscle reflex is an important tool in audiologic examination; however, the precise function of the tensor tympani and stapedius muscle is not fully understood. The function of the middle ear muscles in speech discrimination and noise-induced hearing loss is the main object of our study. Morphologic and enzyme-histochemical properties of the middle ear muscles of the rat indicate a complex, fine-tuned function of the middle ear muscles. Both middle ear muscles are merely composed of relatively small fast-twitch fibers. Almost all fibers possess an enzymatic profile that allows aerobic as well as anaerobic metabolism. The innervation of the muscles is extensive, and motor end plates are well developed. In a parallel study, middle ear muscle contraction (to be analyzed by electromyography) will be correlated with a change of the sound transmission characteristics of the middle ear (measured by the electrocochlear and brainstem auditory evoked responses). Preliminary results of the electrophysiologic measurements (electrocochleogram and brainstem auditory evoked response) are presented.
Psychophysical data on unspecialized mammals commonly used in auditory research were compiled from the literature, and an attempt was made to compare the hearing capacities of these species with man. Binaural hearing and sound localization were not considered. The most complete psychoacoustic data exist for chinchilla, cat, various primates, and the mouse. The existing data include audiograms, frequency and intensity discrimination thresholds, critical masking ratios, critical bandwidths, temporal summation functions at threshold, psychophysical tuning curves, gap detection thresholds, temporal modulation transfer functions, temporal discriminations, and auditory filter shapes. In general, the qualitative forms of most all psychoacoustic functions for these mammals are similar to those for man, and there is little reason to believe that the mechanisms underlying these capacities are different across mammals. Although the discriminative capacities of humans are generally more acute than those of non-humans, the database on the capacities of non-humans is not yet sufficient for systematic comparisons across species to be made with confidence.
Clinical studies have demonstrated that the cries of chronically stressed, medically compromised infants are characteristically higher and more variable in pitch than those of healthy infants. Other studies have indicated that the vagal tone of chronically stressed infants is significantly reduced in comparison to that of normal infants. A neural model of cry production has been proposed which suggests that decreased vagal tone among infants at risk may, in fact, be related to these increases in cry pitch. Using routine, unanesthetized circumcision as a model of stress, we were able to examine the relation between cry acoustics and vagal tone in normal, healthy newborns undergoing an acutely stressful event. Vocalizations, heart, and respiratory waveforms were continuously recorded from 49 (32 experimental; 17 control) 1-2-day-old, full-term infants during preoperative, surgical, and postoperative periods. Vagal tone, as measured by the amplitude of respiratory sinus arrhythmia extracted from heart period data, was significantly reduced during the severe stress of circumcision, and these reductions were paralleled by significant increases in the pitch of the infants' cries. In addition, individual differences in vagal tone measured prior to circumcision surgery were predictive of physiological and acoustic reactivity to subsequent stress. These results emphasize the potential role of vagal control of the autonomic nervous system during stress.
Heart period, heart period variability, and respiration frequency were observed and compared longitudinally in rats from birth to 24 days of age. In addition, V, a quantification of respiratory sinus arrhythmia derived via spectral analysis of the heart period pattern, was observed. It was hypothesized that these heart period parameters would be differentially sensitive to the neural control of the heart and would, therefore, reflect different developmental patterns. Heart period and heart period variability indicated developmental patterns consistent with the literature. The ontogeny of V suggests that it may represent the developmental pattern of tonic vagal influences on the heart.
Acoustic energy enters the mammalian cochlea aided by an anatomical impedance matching performed by the middle ear. The purpose of this paper is to analyse the functional consequences of changes in scale of the middle ear when going from the smallest mammals to the largest. Our anatomical measurements in mammals of different sizes ranging from bats to elephants indicate that middle ear proportions are largely isometric. Thus the calculated transformer ratio is basically independent of animal size, a typical value lying between 30 and 80. Similarly, the calculated specific acoustic input impedance of the inner ear is independent of animal size, the average value being about 140 kPa s/m. We show that if the high frequency hearing limit of isometric ears is limited by ossicle inertia, it should be inversely proportional to the cubic root of the ossicular mass. This prediction is in reasonable agreement with published audiogram data. We then present a three-parameter model of the middle ear where some obvious deviations from perfect isometry are taken into account. The high frequency hearing limits of different species generally agree well with the predictions of this simple model. However, the hearing limits of small rodents clearly deviate from the model calculation. We interpret this observation as indicating that the hearing limit towards very high frequencies may be set by cochlear transduction mechanisms. Further we discuss the exceptional high frequency hearing of the cat and the amphibious hearing of seals.
The vagus, the 10th cranial nerve, contains pathways that contribute to the regulation of the internal viscera, including the heart. Vagal efferent fibers do not originate in a common brainstem structure. The Polyvagal Theory is introduced to explain the different functions of the two primary medullary source nuclei of the vagus: the nucleus ambiguus (NA) and the dorsal motor nucleus (DMNX). Although vagal pathways from both nuclei terminate on the sinoatrial node, it is argued that the fibers originating in NA are uniquely responsible for respiratory sinus arrhythmia (RSA). Divergent shifts in RSA and heart rate are explained by independent actions of DMNX and NA. The theory emphasizes a phylogenetic perspective and speculates that mammalian, but not reptilian, brainstem organization is characterized by a ventral vagal complex (including NA) related to processes associated with attention, motion, emotion, and communication. Various clinical disorders, such as sudden infant death syndrome and asthma, may be related to the competition between DMNX and NA.
The effect of the acoustic middle ear reflex (MER) was quantified using electrodes chronically implanted in the middle ears of rats. Cochlear microphonics (CM) and middle ear muscle EMG were measured under light Ketamin anesthesia after stimulation with tone pulses of 5-20 kHz ranging between 75 and 120 dB SPL. With increasing intensity, the CM measured before the onset of the MER increased to a maximum amplitude and then decreased with higher SPLs. At 10 kHz this maximum was reached at 95 dB SPL, for other stimulus frequencies at higher SPLs. After a latency of 10-20 ms, CM to 10 kHz stimuli of 80-95 dB SPL were decreased by the attenuating action of the MER. The lowest threshold of the MER was also measured at 10 kHz (77 dB SPL in the mean). To stimuli greater than 100 dB SPL after a latency of 6-10 ms, the CM amplitude was increased. That this CM increase to intense stimuli is caused by the action of the MER was confirmed by control experiments such as cutting the tendons of the middle ear muscles. The CM decrease to stimuli below 100 dB SPL, as well as the increase to very intense stimuli, can be explained by sound attenuation caused by the MER, together with the nonlinear dependence of CM amplitude on stimulus level. The observed shift of the maxima of the CM input-output function by the MER to higher stimulus levels probably indicates an increase of the dynamic range of the ear.
There has been little exploration of the mechanisms by which stapedius muscle contractions reduce the masking of responses to high-frequency sounds by low-frequency sounds. To fill this gap in knowledge, controlled stapedius contractions were elicited with direct shocks in anesthetized cats, and measurements were made of the effects of these contractions on the masking of single auditory-nerve fibers and on the attenuation of middle-ear transmission. The results show that the stapedius-induced reductions of masking can be much larger than the attenuations of low-frequency sound. With a 300-Hz band of masking noise centered at 500 Hz, and signal tones at 6 or 8 kHz, unmasking effects over 40 dB were observed for sounds 100 dB SPL or less. The data suggest that much larger unmasking might occur. The observed unmasking can be explained completely by a linear stapedius-induced attenuation of sound transmission through the middle ear and a nonlinear growth rate of masking for auditory-nerve fibers. No central effects are required. It is argued that the reduction of the upward spread of masking is probably one of the most important functions of the stapedius muscle.
This review explores the fundamental neuranatomical and functional bases for integration of the respiratory and cardiovascular systems in vertebrates and traces their evolution through the vertebrate groups, from primarily water-breathing fish and larval amphibians to facultative air-breathers such as lungfish and some adult amphibians and finally obligate air-breathers among the reptiles, birds, and mammals. A comparative account of respiratory rhythm generation leads to consideration of the changing roles in cardiorespiratory integration for central and peripheral chemoreceptors and mechanoreceptors and their central projections. We review evidence of a developing role in the control of cardiorespiratory interactions for the partial relocation from the dorsal motor nucleus of the vagus into the nucleus ambiguus of vagal preganglionic neurons, and in particular those innervating the heart, and for the existence of a functional topography of specific groups of sympathetic preganglionic neurons in the spinal cord. Finally, we consider the mechanisms generating temporal modulation of heart rate, vasomotor tone, and control of the airways in mammals; cardiorespiratory synchrony in fish; and integration of the cardiorespiratory system during intermittent breathing in amphibians, reptiles, and diving birds. Concluding comments suggest areas for further productive research.
Abnormalities in the integration of auditory and visual language inputs could underlie many core psychotic features. Perceptual confusion may arise because of the normal propensity of visual speech perception to evoke auditory percepts. Recent functional neuroimaging studies of normal subjects have demonstrated activation in auditory-linguistic brain areas in response to silent lip-reading. Three functional magnetic resonance imaging experiments were carried out on seven normal volunteers, and 14 schizophrenia patients, half of whom were actively psychotic. The tasks involved listening to auditory speech, silent lip-reading (visual speech), and perception of meaningless lip movements (visual non-speech). Subjects also undertook a behavioural study of audio-visual word identification designed to evoke perceptual fusions. Patients and controls both showed susceptibility to audio-visual fusions on the behavioural task. The patient group as a whole showed less activation relative to controls in superior and inferior posterior temporal areas while performing the silent lip-reading task. Attending to visual non-speech, the patients activated less posterior (occipito-temporal) and more anterior (frontal, insular and striatal) brain areas than controls. This difference was accounted for largely by the psychotic subgroup. Insular and striatal areas were also activated in both subject groups in the auditory speech perception condition, thus demonstrating the bimodal sensitivity of these regions. The results suggest that schizophrenia patients with psychotic symptoms respond to visually ambiguous stimuli (non-speech) by activation of polysensory structures. This could reflect particular processing strategies and may increase susceptibility to certain paranoid and hallucinatory symptoms.
The evolution of the autonomic nervous system provides an organizing principle to interpret the adaptive significance of physiological responses in promoting social behavior. According to the polyvagal theory, the well-documented phylogenetic shift in neural regulation of the autonomic nervous system passes through three global stages, each with an associated behavioral strategy. The first stage is characterized by a primitive unmyelinated visceral vagus that fosters digestion and responds to threat by depressing metabolic activity. Behaviorally, the first stage is associated with immobilization behaviors. The second stage is characterized by the sympathetic nervous system that is capable of increasing metabolic output and inhibiting the visceral vagus to foster mobilization behaviors necessary for 'fight or flight'. The third stage, unique to mammals, is characterized by a myelinated vagus that can rapidly regulate cardiac output to foster engagement and disengagement with the environment. The mammalian vagus is neuroanatomically linked to the cranial nerves that regulate social engagement via facial expression and vocalization. As the autonomic nervous system changed through the process of evolution, so did the interplay between the autonomic nervous system and the other physiological systems that respond to stress, including the cortex, the hypothalamic-pituitary-adrenal axis, the neuropeptides of oxytocin and vasopressin, and the immune system. From this phylogenetic orientation, the polyvagal theory proposes a biological basis for social behavior and an intervention strategy to enhance positive social behavior.
Human stapedius-muscle contractions in response to 3-kHz, 20-msec tone bursts were determined indirectly by measuring the associated acoustic-impedance changes at the tympanic membrane with an acoustic bridge. The measurement was possible because the bridge practically eliminates the effect of the ear-canal air volume interposed between the tympanic membrane and the tip of the measuring tube. By using burst pairs, temporal additivity of the muscle responses was demonstrated both when the stimulus bursts were presented contralaterally to the measured impedance changes and when the first burst was presented ipsilaterally. The summation time constant was on the order of 200 msec, much longer than the twitch time constant of the muscle fibers. Therefore, the summation had to take place in a nucleus preceding the stapedius muscle. The magnitude of the muscle response obeyed a compressive function paralleling the loudness function up to sound pressure levels of at least 120 dB.
Résumé L'étude de l'orientation latérale dans l'audition binaurale a déjà montré une interaction binaurale dans les réponses électrophysiologiques de l'écorce cérébrale et des tubercules quadrijumeaux inférieurs. Nous avons cherché le niveau le plus bas d'une telle interaction. S'il existe une interaction binaurale aux tubercules acoustiques, elle doit être très faible. Par contre, nous avons trouvé une interaction réelle dans le corps trapezoïde, l'olive supérieure et le lemniscus latéral. Une base anatomique de l'interaction binaurale a été découverte récemment au noyau médial de l'olive supérieure où se trouve une convergence des fibres des deux noyaux cochléaires.
The strong predominance of right-handedness appears to be a uniquely human characteristic, whereas the left-cerebral dominance for vocalization occurs in many species, including frogs, birds, and mammals. Right-handedness may have arisen because of an association between manual gestures and vocalization in the evolution of language. I argue that language evolved from manual gestures, gradually incorporating vocal elements. The transition may be traced through changes in the function of Broca's area. Its homologue in monkeys has nothing to do with vocal control, but contains the so-called "mirror neurons," the code for both the production of manual reaching movements and the perception of the same movements performed by others. This system is bilateral in monkeys, but predominantly left-hemispheric in humans, and in humans is involved with vocalization as well as manual actions. There is evidence that Broca's area is enlarged on the left side in Homo habilis, suggesting that a link between gesture and vocalization may go back at least two million years, although other evidence suggests that speech may not have become fully autonomous until Homo sapiens appeared some 170,000 years ago, or perhaps even later. The removal of manual gesture as a necessary component of language may explain the rapid advance of technology, allowing late migrations of Homo sapiens from Africa to replace all other hominids in other parts of the world, including the Neanderthals in Europe and Homo erectus in Asia. Nevertheless, the long association of vocalization with manual gesture left us a legacy of right-handedness.
People naturally move their heads when they speak, and our study shows that this rhythmic head motion conveys linguistic information. Three-dimensional head and face motion and the acoustics of a talker producing Japanese sentences were recorded and analyzed. The head movement correlated strongly with the pitch (fundamental frequency) and amplitude of the talker's voice. In a perception study, Japanese subjects viewed realistic talking-head animations based on these movement recordings in a speech-in-noise task. The animations allowed the head motion to be manipulated without changing other characteristics of the visual or acoustic speech. Subjects correctly identified more syllables when natural head motion was present in the animation than when it was eliminated or distorted. These results suggest that nonverbal gestures such as head movements play a more direct role in the perception of speech than previously known.
The polyvagal theory introduced a new perspective relating autonomic function to behavior, that included an appreciation of the autonomic nervous system as a "system," the identification of neural circuits involved in the regulation of autonomic state, and an interpretation of autonomic reactivity as adaptive within the context of the phylogeny of the vertebrate autonomic nervous system. The paper has two objectives: first, to provide an explicit statement of the theory; and second, to introduce the features of a polyvagal perspective. The polyvagal perspective emphasizes how an understanding of neurophysiological mechanisms and phylogenetic shifts in neural regulation leads to different questions, paradigms, explanations, and conclusions regarding autonomic function in biobehavioral processes than peripheral models. Foremost, the polyvagal perspective emphasizes the importance of phylogenetic changes in the neural structures regulating the autonomic nervous system and how these phylogenetic shifts provide insights into the adaptive function and the neural regulation of the two vagal systems.
Adult rats produce two distinct types of ultrasonic vocalizations referred to as 22- and 50-kHz calls, respectively. Emission of the respective calls represents signaling a negative or positive state of the rat organism. The signaling has an adaptive value for survival and/or well-being of rats and their social groups. Literature is reviewed from studies on cats and rats, which indicates that the positive or negative states constitute a complex and integrated set of somatic, autonomic, endocrine, affective, and cognitive correlates. The basic states and their correlates are initiated, integrated, and maintained by activity of the subsets of the ascending cholinergic and dopaminergic systems originating from the reticular brainstem core. The cholinergic and dopaminergic systems interact mutually to form a dynamic balance, which is involved in a decision-making process of initiating and maintaining one or the other of these states. Activation of the relevant portion of the ascending cholinergic system invariably induces the negative state and releases 22-kHz calls while activation of the ascending dopaminergic system induces the positive state with 50-kHz calls. The 22- and 50-kHz calls have distinct and mostly non-overlapping acoustic parameters, which ensure unambiguous recognition of the calls and thus, the state of the emitter. The animal may only signal one of the states at any given time and emission of 22- or 50-kHz calls is mutually exclusive. It is postulated, therefore, that these two main types of ultrasonic calls are reliable indicator variables of two opposing states of the adult rat organism: negative or positive.
In skeletal muscle, interventions that unload the muscle cause slow-to-fast myosin heavy chain (MHC) conversions, whereas fast-to-slow conversions are seen when the muscles are engaged in resistance training and endurance exercise. The stapedius muscle (SM) is reported to prevent cochlear damage by noise. This theory may be supported by showing comparable changes of muscle fibre composition when ears are exposed to longstanding noise (SM training). Comparable changes after sound deprivation (SM unloading) would suggest that the SM needs a certain degree of daily activity evoked by environmental sound to sustain its normal composition.
We review recent research that examines audio-visual integration
in multimodal communication. The topics include bimodality in human
speech, human and automated lip reading, facial animation, lip
synchronization, joint audio-video coding, and bimodal speaker
verification. We also study the enabling technologies for these research
topics, including automatic facial-feature tracking and audio-to-visual
mapping. Recent progress in audio-visual research shows that joint
processing of audio and video provides advantages that are not available
when the audio and video are processed independently
Comparative Physiology and Evolution of the Autonomic Nervous System
- J L Morris
- S Nilsson
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The polyvagal perspective
- S W Porges
Porges, S.W., 2007. The polyvagal perspective. Biol.
Psychol. 74, 116 -143.
The circulatory system
- Morris
Newborn pain cries and vagal tone: parallel changes in response to circumcision
- Porter