[show abstract][hide abstract] ABSTRACT: Traditionally, the lateral premotor cortex (PM) is assigned a role in stimulus-driven rather than memory-driven motor control, whereas the opposite holds for the mesial premotor cortex (supplementary motor area, SMA). Consistently, patients with Parkinson's Disease (PD), in which a specific functional degradation of the mesial loop (i.e. SMA-Striatum) occurs, show impaired memory-driven but relatively preserved stimulus-driven motor control. However, both parts of the premotor cortex are involved in perceptual prediction tasks as well. Here we tested whether the functional bias described on the motor level (i.e., memory-driven/mesial versus stimulus-driven/lateral) can also be detected in perceptual prediction tasks thereby suggesting that PD patients exhibit the same pattern of impaired memory-driven and preserved stimulus-driven control in the cognitive domain. To this end, we investigated 20 male PD-patients "on" and "off" dopaminergic medication while performing a serial prediction task (SPT). A specific modification was implemented to the classical SPT (SPT0) that caused shifts from stimulus- to memory-based prediction (SPT+). As a result, PD patients showed a significantly impaired performance "off" compared to "on" medication for SPT+, whereas no significant "on"/"off"-effects were found for SPT0. Descriptively, the "off"-performance decreased gradually with increasing demands on memory-based prediction. Further, the severity of motor deficits according to the UPDRS III correlated significantly with impaired performance in SPT0 "on" medication. Importantly, an even stronger dependency was found for UPDRS III and SPT+. These findings point to a role of the SMA-striatal loop in memory-driven serial prediction beyond the motor domain.
[show abstract][hide abstract] ABSTRACT: Context has been found to have a profound effect on the recognition of social stimuli and correlated brain activation. The present study was designed to determine whether knowledge about emotional authenticity influences emotion recognition expressed through speech intonation. Participants classified emotionally expressive speech in an fMRI experimental design as sad, happy, angry, or fearful. For some trials, stimuli were cued as either authentic or play-acted in order to manipulate participant top-down belief about authenticity, and these labels were presented both congruently and incongruently to the emotional authenticity of the stimulus. Contrasting authentic versus play-acted stimuli during uncued trials indicated that play-acted stimuli spontaneously up-regulate activity in the auditory cortex and regions associated with emotional speech processing. In addition, a clear interaction effect of cue and stimulus authenticity showed up-regulation in the posterior superior temporal sulcus and the anterior cingulate cortex, indicating that cueing had an impact on the perception of authenticity. In particular, when a cue indicating an authentic stimulus was followed by a play-acted stimulus, additional activation occurred in the temporoparietal junction, probably pointing to increased load on perspective taking in such trials. While actual authenticity has a significant impact on brain activation, individual belief about stimulus authenticity can additionally modulate the brain response to differences in emotionally expressive speech.
[show abstract][hide abstract] ABSTRACT: Abstract: Not only committing errors, but also observing errors has been shown to activate the dorsal
medial prefrontal cortex, particularly BA 8 and adjacent rostral cingulate zone (RCZ). Currently, there
is a debate on whether this activity reflects a response to the incorrectness of the committed action or
to its unexpectedness. This article reports two studies investigating whether activity in BA 8/RCZ is
due to the unexpectedness of observed errors or the incorrectness of the specific observed action. Both
studies employed an action observation paradigm reliant on the observation of an actor tying sailing
knots. The reported behavioral experiment delivered evidence that the paradigm successfully induced
the expectation of incorrect actions as well as the expectation of correct actions. The functional magnetic
resonance imaging study revealed that unexpectedly correct as well as unexpectedly incorrect
actions activate the BA 8/RCZ. The same result was confirmed for a coordinate in the vicinity that has
been previously reported to be activated in separate studies either by the error observation or by the
unexpectedness of committed errors, and has been associated with the error-related negativity. The
present results suggest that unexpectedness has an impact on the medial prefrontal correlate of
[show abstract][hide abstract] ABSTRACT: When we observe an action, we recognize meaningful action steps that help us to predict probable upcoming action steps. This segmentation of observed actions, or more generally events, has been proposed to rely in part on changes in motion features. However, segmentation of actions, in contrast to meaningless movements, may exploit additional information such as action knowledge. The present fMRI study sought to tear apart the neural signatures of processing two sources of information that observers may exploit at action boundaries: change in motion dynamics and action knowledge. To this end, subjects performed a segmentation task on both actions (that can be segmented based on motion and action knowledge) as well as tai chi movements (that can be segmented only based on motion) and two further control conditions that implemented point-light walker like displays of the same videos. Behavioral tests showed that motion features played a critical role in boundary detection in all conditions. Consistent with this finding, activity in area MT was enhanced during boundary detection in all conditions, but importantly, this effect was not stronger for actions. In contrast, only action boundary detection was reflected by specific activation in the superior frontal sulcus, parietal angular gyrus and the parahippocampal cortex. Based on these findings, we propose that during action observation, motion features trigger a top-down modulation of the attentional focus and the incitement of retrieving long-term memory place-action associations. While action perception entails activity common to processing of all motion stimuli, it is at the same time unique as it allows long-term memory based predictions of succeeding steps.
[show abstract][hide abstract] ABSTRACT: To recognize an action, an observer exploits information about the applied manipulation, the involved objects, and the context where the action occurs. Context, object, and manipulation information are hence expected to be tightly coupled in a triadic relationship (the COM triad hereafter). The current fMRI study investigated the hemodynamic signatures of reciprocal modulation in the COM triad. Participants watched short video clips of pantomime actions, that is, actions performed with inappropriate objects, taking place at compatible or incompatible contexts. The usage of pantomime actions enabled the disentanglement of the neural substrates of context-manipulation (CM) and context-object (CO) associations. There were trials in which (1) both manipulation and objects, (2) only manipulation, (3) only objects, or (4) neither manipulation nor objects were compatible with the context. CM compatibility effects were found in an action-related network comprising ventral premotor cortex, SMA, left anterior intraparietal sulcus, and bilateral occipito-temporal cortex. Conversely, CO compatibility effects were found bilaterally in lateral occipital complex. These effects interacted in subregions of the lateral occipital complex. An overlap of CM and CO effects was observed in the occipito-temporal cortex and the dorsal attention network, that is, superior frontal sulcus/dorsal premotor cortex and superior parietal lobe. Results indicate that contextual information is integrated into the analysis of actions. Manipulation and object information is linked by contextual associations as a function of co-occurrence in specific contexts. Activation of either CM or CO associations shifts attention to either action- or object-related relevant information.
Journal of Cognitive Neuroscience 03/2012; 24(7):1548-59. · 4.49 Impact Factor
[show abstract][hide abstract] ABSTRACT: The aim of the present study was to determine how authenticity of emotion expression in speech modulates activity in the neuronal substrates involved in emotion recognition. Within an fMRI paradigm, participants judged either the authenticity (authentic or play acted) or emotional content (anger, fear, joy, or sadness) of recordings of spontaneous emotions and reenactments by professional actors. When contrasting between task types, active judgment of authenticity, more than active judgment of emotion, indicated potential involvement of the theory of mind (ToM) network (medial prefrontal cortex, temporoparietal cortex, retrosplenium) as well as areas involved in working memory and decision making (BA 47). Subsequently, trials with authentic recordings were contrasted with those of reenactments to determine the modulatory effects of authenticity. Authentic recordings were found to enhance activity in part of the ToM network (medial prefrontal cortex). This effect of authenticity suggests that individuals integrate recollections of their own experiences more for judgments involving authentic stimuli than for those involving play-acted stimuli. The behavioral and functional results show that authenticity of emotional prosody is an important property influencing human responses to such stimuli, with implications for studies using play-acted emotions.
[show abstract][hide abstract] ABSTRACT: Predicting the actions of other individuals is crucial for our daily interactions. Recent evidence suggests that the prediction of object-directed arm and full-body actions employs the dorsal premotor cortex (PMd). Thus, the neural substrate involved in action control may also be essential for action prediction. Here, we aimed to address this issue and hypothesized that disrupting the PMd impairs action prediction. Using fMRI-guided coil navigation, rTMS (five pulses, 10 Hz) was applied over the left PMd and over the vertex (control region) while participants observed everyday actions in video clips that were transiently occluded for 1 s. The participants detected manipulations in the time course of occluded actions, which required them to internally predict the actions during occlusion. To differentiate between functional roles that the PMd could play in prediction, rTMS was either delivered at occluder-onset (TMS-early), affecting the initiation of action prediction, or 300 ms later during occlusion (TMS-late), affecting the maintenance of an ongoing prediction. TMS-early over the left PMd produced more prediction errors than TMS-early over the vertex. TMS-late had no effect on prediction performance, suggesting that the left PMd might be involved particularly during the initiation of internally guided action prediction but may play a subordinate role in maintaining ongoing prediction. These findings open a new perspective on the role of the left PMd in action prediction which is in line with its functions in action control and in cognitive tasks. In the discussion, the relevance of the left PMd for integrating external action parameters with the observer's motor repertoire is emphasized. Overall, the results are in line with the notion that premotor functions are employed in both action control and action observation.
Frontiers in Human Neuroscience 01/2012; 6:20. · 2.91 Impact Factor
[show abstract][hide abstract] ABSTRACT: Influential concepts in neuroscientific research cast the brain a predictive machine that revises its predictions when they are violated by sensory input. This relates to the predictive coding account of perception, but also to learning. Learning from prediction errors has been suggested for take place in the hippocampal memory system as well as in the basal ganglia. The present fMRI study used an action-observation paradigm to investigate the contributions of the hippocampus, caudate nucleus and midbrain dopaminergic system to different types of learning: learning in the absence of prediction errors, learning from prediction errors, and responding to the accumulation of prediction errors in unpredictable stimulus configurations. We conducted analyses of the regions of interests' BOLD response towards these different types of learning, implementing a bootstrapping procedure to correct for false positives. We found both, caudate nucleus and the hippocampus to be activated by perceptual prediction errors. The hippocampal responses seemed to relate to the associative mismatch between a stored representation and current sensory input. Moreover, its response was significantly influenced by the average information, or Shannon entropy of the stimulus material. In accordance with earlier results, the habenula was activated by perceptual prediction errors. Lastly, we found that the substantia nigra was activated by the novelty of sensory input. In sum, we established that the midbrain dopaminergic system, the hippocampus, and the caudate nucleus were to different degrees significantly involved in the three different types of learning: acquisition of new information, learning from prediction errors and responding to unpredictable stimulus developments. We relate learning from perceptual prediction errors to the concept of predictive coding and related information theoretic accounts.
PLoS ONE 01/2012; 7(5):e36445. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Most every day actions take place in domestic rooms that are specific for certain classes of actions. Contextual information derived from domestic settings may therefore influence the efficiency of action recognition. The present studies investigated whether action recognition is modulated by compatibility of the context an action is embedded in. To this end, subjects watched video clips of actions performed in compatible, incompatible, and neutral contexts. Recognition was significantly slower when actions took place in an incompatible as compared to a compatible or a neutral context (Experiment 1). Functional MRI revealed increased activation for incompatible context in Brodmann Areas (BA) 44, 45, and 47 of the left ventrolateral prefrontal cortex (vlPFC; Experiment 2). Results suggest that contextual information - even when task-irrelevant - informs a high processing level of action analysis. In particular, the functional profiles assigned to these prefrontal regions suggest that contextual information activates associated action representations as a function of (in-)compatibility. Thus, incompatibility effects may reflect the attempt to resolve the conflict between action and context by embedding the presented action step into an overarching action that is again compatible with the provided context.
[show abstract][hide abstract] ABSTRACT: Behavioral studies suggest that preference for a beat rate (tempo) in auditory sequences is tightly linked to the motor system. However, from a neuroscientific perspective the contribution of motor-related brain regions to tempo preference in the auditory domain remains unclear. A recent fMRI study (Kornysheva et al. : Hum Brain Mapp 31:48-64) revealed that the activity increase in the left ventral premotor cortex (PMv) is associated with the preference for a tempo of a musical rhythm. The activity increase correlated with how strongly the subjects preferred a tempo. Despite this evidence, it remains uncertain whether an interference with activity in the left PMv affects tempo preference strength. Consequently, we conducted an offline repetitive transcranial magnetic stimulation (rTMS) study, in which the cortical excitability in the left PMv was temporarily reduced. As hypothesized, 0.9 Hz rTMS over the left PMv temporarily affected individual tempo preference strength depending on the individual strength of tempo preference in the control session. Moreover, PMv stimulation temporarily interfered with the stability of individual tempo preference strength within and across sessions. These effects were specific to the preference for tempo in contrast to the preference for timbre, bound to the first half of the experiment following PMv stimulation and could not be explained by an impairment of tempo recognition. Our results corroborate preceding fMRI findings and suggest that activity in the left PMv is part of a network that affects the strength of beat rate preference.
Human Brain Mapping 08/2011; 32(8):1300-10. · 6.88 Impact Factor
[show abstract][hide abstract] ABSTRACT: While neural signatures of breaches of expectancy and their immediate effects have been investigated, thus far, temporally more remote effects have been neglected. The present fMRI study explored neural correlates of temporally remote destabilization of prediction following rare breaches of expectancy with a mean delay of 14 s. We hypothesized temporally remote destabilization to be reflected either in an attenuation of areas related to long-term memory or in an increase of lateral fronto-parietal loops related to the encoding of new stimuli. Monitoring a deterministic 24-digit sequence, subjects were asked to indicate occasional sequential omissions by key press. Temporally remote destabilization of prediction was expected to be revealed by contrasting sequential events whose equivalent was omitted in the preceding sequential run n-1 (destabilized events) with sequential events without such history (nondestabilized events). Temporally remote destabilization of prediction was reflected in an attenuation of activity in the dorsal frontomedian cortex (Brodmann Area (BA) 9) bilaterally. Moreover, activation of the left medial BA 9 was enhanced by contrasting nondestabilized events with breaches. The decrease of dorsal frontomedian activation in the case of destabilized events might be interpreted as a top-down modulation on perception causing a less expectation-restricted encoding of the current stimulus and hence enabling the adaptation of expectation and prediction in the long run.
Human Brain Mapping 06/2011; 33(8):1812-20. · 6.88 Impact Factor
[show abstract][hide abstract] ABSTRACT: Identifying and evaluating events which are novel in a particular environment is crucially important for adaptive behavior. These events are often not just novel, as they typically violate expectations which may be formulated based on numerous features of our surroundings, one of which includes the ordinal structure (temporal order) of relevant stimuli. Events which violate such expectations, namely sequential deviants, constitute one category of associatively novel stimuli. The present event-related fMRI study investigated the detection of sequential deviants presented within three types of equivalently organized, attended visual sequences which differed in stimulus dimensions relevant for defining the sequential structure (position, rhythm, and object identity). Presenting deviants within perceptual sequences defined by position and rhythm stimulus properties triggered comparable patterns of activations within the lateral parietal, premotor, and prefrontal regions. However, the activations identified in the context of position sequences showed a more dorsal distribution when compared to those in rhythm sequences. In contrast, detection of deviants within object sequences was supported by right-lateralized parietal and temporal cortices. Thus, although the obtained results indicate similarities and partial overlap in activations triggered by specific pairs of deviants, differences in their processing were also revealed. This suggests that the general task context and specific stimulus features which define the deviant itself influence which brain regions within a widespread network incorporating lateral prefrontal, anterior premotor, and posterior (mainly lateral parietal) areas will become engaged in its processing.
Human Brain Mapping 03/2011; 32(3):370-81. · 6.88 Impact Factor
[show abstract][hide abstract] ABSTRACT: The striatum has been established as a carrier of reward-related prediction errors. This prediction error signal concerns the difference between how much reward was predicted and how much reward is gained. However, it remains to be established whether general breaches of expectation, i.e., perceptual prediction errors, are also implemented in the striatum. The current study used functional magnetic resonance imaging (fMRI) to investigate the role of caudate nucleus in breaches of expectation. Importantly, breaches were not related to the occurrence or absence of reward. Preceding the fMRI study, participants were trained to produce a sequence of whole-body movements according to auditory cues. In the fMRI session, they watched movies of a dancer producing the same sequences either according to the cue (88%) or not (12%). Caudate nucleus was activated for the prediction-violating movements. This activation was flanked by activity in posterior superior temporal sulcus, the temporo-parietal junction and adjacent angular gyrus, a network that may convey the deviating movement to caudate nucleus, while frontal areas may reflect adaptive adjustments of the current prediction. Alternative interpretations of caudate activity relating either to the saliency of breaches of expectation or to behavioral adaptation could be excluded by two control contrasts. The results foster the notion that neurons in the caudate nucleus code for a breach in expectation, and point toward a distributed network involved in detecting, signaling and adjusting behavior and expectations toward violated prediction.
Frontiers in Human Neuroscience 01/2011; 5:38. · 2.91 Impact Factor