Dissociation of extrastriate body and biological-motion selective areas by manipulation of visual-motor congruency

Maternal Interaction Relates to Neural Processing of Self-Related Multisensory Information in 5-Month-Olds

The ontogenetic origin of the self in infancy is a topic of ongoing debate. Although influential developmental and neurocognitive theories propose that caregiver-infant interactions play an important role in infants' self-development, little is known about the specific mechanisms involved. Some theories highlight the importance of caregiver sensitivity and touch, while others propose that caregiver contingency plays a central role. The study aimed to investigate infants' self-perception by measuring brain activation in the posterior superior temporal sulcus (pSTS), a region previously associated with self-related processing. A total of 118 mother-infant dyads participated in a free-play interaction, during which maternal sensitivity and touch were measured. Additionally, a face-to-face interaction was conducted to measure maternal contingency. Infants' brain activation was measured using functional near-infrared spectroscopy (fNIRS). They watched a video of their own face while being stroked by a brush on the cheek. The video was either live and the stroking was synchronous to the video (contingent) or the video was delayed by 3 s, which made the stroking asynchronous (non-contingent). The results showed that infants exhibited more HbO-activation in the right pSTS in the non-contingent condition. Importantly, the more sensitive the mothers were and the more they touched infants during free play, the less differential activation the infants showed in response to both conditions. This effect was driven by infants showing less activation to the non-contingent condition when their mothers exhibited more care, maybe because of a smaller prediction error for non-contingent self-related multisensory information. Overall, the study deepens our knowledge of how early social interactions relate to the emergence of the self in infancy.

Effects of acute stress on biological motion perception

Biological motion perception is an essential part of the cognitive process. Stress can affect the cognitive process. The present study explored the intrinsic ERP features of the effects of acute psychological stress on biological motion perception. The results contributed scientific evidence for the adaptive behavior changes under acute stress. After a mental arithmetic task was used to induce stress, the paradigm of point-light displays was used to evaluate biological motion perception. Longer reaction time and lower accuracy were found in the inverted walking condition than in the upright walking condition, which was called the "inversion effect". The P2 peak amplitude and the LPP mean amplitude were significantly higher in the local inverted perception than in the local upright walking condition. Compared to the control condition, the stress condition induced lower RT, shorter P1 peak latency of biological motion perception, lower P2 peak amplitude and LPP mean amplitude, and higher N330 peak amplitude. There was an "inversion effect" in biological motion perception. This effect was related to the structural characteristics of biological motion perception but unrelated to the state of acute psychological stress. Acute psychological stress accelerated the reaction time and enhanced attention control of biological motion perception. Attention resources were used earlier, and less attentional investment was made in the early stage of biological motion perception processing. In the late stage, a continuous weakening of inhibition was shown in the parieto-occipital area.

Reduced body-image disturbance by body-image interventions is associated with neural-response changes in visual and social processing regions: a preliminary study

Introduction

Body-image disturbance is a major factor in the development of eating disorders, especially among young women. There are two main components: perceptual disturbance, characterized by a discrepancy between perceived and actual body size, and affective disturbance, characterized by a discrepancy between perceived and ideal body size. Interventions targeting body-image disturbance ask individuals to describe their own body without using negative expressions when either viewing it in a mirror or imagining it. Despite the importance of reducing body-image disturbance, its neural mechanisms remain unclear. Here we investigated the changes in neural responses before and after an intervention. We hypothesized that neural responses correlated with the degree of body-image disturbance would also be related to its reduction, i.e., a reduction in perceptual and affective disturbances would be related to changes in attentional and socio-cognitive processing, respectively.

Methods

Twenty-eight young adult women without known psychiatric disorders underwent a single 40-min intervention. Participants completed tasks before and after the intervention, in which they estimated their perceived and ideal body sizes using distorted silhouette images to measure body-image disturbance. We analyzed the behavioral and neural responses of participants during the tasks.

Results

The intervention did not significantly reduce body-image disturbance. Analysis of individual differences showed distinct changes in neural responses for each type of disturbance. A decrease in perceptual disturbance was associated with bodily visuospatial processing: increased activation in the left superior parietal lobule, bilateral occipital gyri, and right cuneus. Reduced affective disturbance was associated with socio-cognitive processing; decreased activation in the right temporoparietal junction, and increased functional connectivity between the left extrastriate body area and the right precuneus.

Discussion

We identified distinct neural mechanisms (bodily visuospatial and socio-cognitive processing) associated with the reduction in each component of body-image disturbance. Our results imply that different neural mechanisms are related to reduced perceptual disturbance and the expression thereof, whereas similar neural mechanisms are related to the reduction and expression of affective disturbance. Considering the small sample size of this study, our results should be regarded as preliminary.

Grasping with a Twist: Dissociating Action Goals from Motor Actions in Human Frontoparietal Circuits

In daily life, prehension is typically not the end goal of hand-object interactions but a precursor for manipulation. Nevertheless, functional MRI (fMRI) studies investigating manual manipulation have primarily relied on prehension as the end goal of an action. Here, we used slow event-related fMRI to investigate differences in neural activation patterns between prehension in isolation and prehension for object manipulation. Sixteen (seven males and nine females) participants were instructed either to simply grasp the handle of a rotatable dial (isolated prehension) or to grasp and turn it (prehension for object manipulation). We used representational similarity analysis (RSA) to investigate whether the experimental conditions could be discriminated from each other based on differences in task-related brain activation patterns. We also used temporal multivoxel pattern analysis (tMVPA) to examine the evolution of regional activation patterns over time. Importantly, we were able to differentiate isolated prehension and prehension for manipulation from activation patterns in the early visual cortex, the caudal intraparietal sulcus (cIPS), and the superior parietal lobule (SPL). Our findings indicate that object manipulation extends beyond the putative cortical grasping network (anterior intraparietal sulcus, premotor and motor cortices) to include the superior parietal lobule and early visual cortex.SIGNIFICANCE STATEMENT A simple act such as turning an oven dial requires not only that the CNS encode the initial state (starting dial orientation) of the object but also the appropriate posture to grasp it to achieve the desired end state (final dial orientation) and the motor commands to achieve that state. Using advanced temporal neuroimaging analysis techniques, we reveal how such actions unfold over time and how they differ between object manipulation (turning a dial) versus grasping alone. We find that a combination of brain areas implicated in visual processing and sensorimotor integration can distinguish between the complex and simple tasks during planning, with neural patterns that approximate those during the actual execution of the action.

The neural signature of reality-monitoring: A meta-analysis of functional neuroimaging studies

Distinguishing imagination and thoughts from information we perceived from the environment, a process called reality-monitoring, is important in everyday situations. Although reality monitoring seems to overlap with the concept of self-monitoring, which allows one to distinguish self-generated actions or thoughts from those generated by others, the two concepts remain largely separate cognitive domains and their common brain substrates have received little attention. We investigated the brain regions involved in these two cognitive processes and explored the common brain regions they share. To do this, we conducted two separate coordinate-based meta-analyses of functional magnetic resonance imaging studies assessing the brain regions involved in reality- and self-monitoring. Few brain regions survived threshold-free cluster enhancement family-wise multiple comparison correction (p < .05), likely owing to the small number of studies identified. Using uncorrected statistical thresholds recommended by Signed Differential Mapping with Permutation of Subject Images, the meta-analysis of reality-monitoring studies (k = 9 studies including 172 healthy subjects) revealed clusters in the lobule VI of the cerebellum, the right anterior medial prefrontal cortex and anterior thalamic projections. The meta-analysis of self-monitoring studies (k = 12 studies including 192 healthy subjects) highlighted the involvement of a set of brain regions including the lobule VI of the left cerebellum and fronto-temporo-parietal regions. We showed with a conjunction analysis that the lobule VI of the cerebellum was consistently engaged in both reality- and self-monitoring. The current findings offer new insights into the common brain regions underlying reality-monitoring and self-monitoring, and suggest that the neural signature of the self that may occur during self-production should persist in memories.

The cross-domain functional organization of posterior lateral temporal cortex: insights from ALE meta-analyses of 7 cognitive domains spanning 12,000 participants

The posterior lateral temporal cortex is implicated in many verbal, nonverbal, and social cognitive domains and processes. Yet without directly comparing these disparate domains, the region's organization remains unclear; do distinct processes engage discrete subregions, or could different domains engage shared neural correlates and processes? Here, using activation likelihood estimation meta-analyses, the bilateral posterior lateral temporal cortex subregions engaged in 7 domains were directly compared. These domains comprised semantics, semantic control, phonology, biological motion, face processing, theory of mind, and representation of tools. Although phonology and biological motion were predominantly associated with distinct regions, other domains implicated overlapping areas, perhaps due to shared underlying processes. Theory of mind recruited regions implicated in semantic representation, tools engaged semantic control areas, and faces engaged subregions for biological motion and theory of mind. This cross-domain approach provides insight into how posterior lateral temporal cortex is organized and why.

More Than the Face: Representations of Bodies in the Inferior Temporal Cortex

Visual representations of bodies, in addition to those of faces, contribute to the recognition of con- and heterospecifics, to action recognition, and to nonverbal communication. Despite its importance, the neural basis of the visual analysis of bodies has been less studied than that of faces. In this article, I review what is known about the neural processing of bodies, focusing on the macaque temporal visual cortex. Early single-unit recording work suggested that the temporal visual cortex contains representations of body parts and bodies, with the dorsal bank of the superior temporal sulcus representing bodily actions. Subsequent functional magnetic resonance imaging studies in both humans and monkeys showed several temporal cortical regions that are strongly activated by bodies. Single-unit recordings in the macaque body patches suggest that these represent mainly body shape features. More anterior patches show a greater viewpoint-tolerant selectivity for body features, which may reflect a processing principle shared with other object categories, including faces. Expected final online publication date for the Annual Review of Vision Science, Volume 8 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Sense of agency as synecdoche: Multiple neurobiological mechanisms may underlie the phenomenon summarized as sense of agency

Functional magnetic resonance imaging (fMRI) studies on the sense of agency (SoA) have yielded heterogeneous findings identifying regional brain activity during tasks that probed SoA. In this review, we argue that the reason behind this between-study heterogeneity is a "synecdochic" way the field conceptualizes and studies SoA. Typically, a single feature is experimentally manipulated and then this is interpreted as covering all aspects of SoA. The purpose of this paper is to give an overview of the fMRI studies of SoA and attempt to provide meaningful categories whereby the heterogeneous findings may be classified. This classification is based on a separation of the experimental paradigms (Feedback Manipulations of ongoing movements, Action-Effect, and Sensory Attenuation) and type of report employed (implicit, explicit reports of graded or dichotic nature, and whether these concern self-other distinctions or sense of control). We only find that Feedback Manipulation and Action-Effect share common activation in supplementary motor area, insula and cerebellum in positive SoA and inferior frontal gyrus in the negative SoA, but observe large networks related to SoA only in Feedback Manipulation studies. To illustrate the advantages of this approach, we discuss the findings from an fMRI study which we conducted, within this framework.

Parieto-Occipital Alpha and Low-Beta EEG Power Reflect Sense of Agency

The sense of agency (SoA) is part of psychophysiological modules related to the self. Disturbed SoA is found in several clinical conditions, hence understanding the neural correlates of the SoA is useful for the diagnosis and determining the proper treatment strategies. Although there are several neuroimaging studies on SoA, it is desirable to translate the knowledge to more accessible and inexpensive EEG-based biomarkers for the sake of applicability. However, SoA has not been widely investigated using EEG. To address this issue, we designed an EEG experiment on healthy adults (n = 15) to determine the sensitivity of EEG on the SoA paradigm using hand movement with parametrically delayed visual feedback. We calculated the power spectral density over the traditional EEG frequency bands for ten delay conditions relative to no delay condition. Independent component analysis and equivalent current dipole modeling were applied to address artifact rejection, volume conduction, and source localization to determine the effect of interest. The results revealed that the alpha and low-beta EEG power increased in the parieto-occipital regions in proportion to the reduced SoA reported by the subjects. We conclude that the parieto-occipital alpha and low-beta EEG power reflect the sense of agency.

Computation-Based Feature Representation of Body Expressions in the Human Brain

Humans and other primate species are experts at recognizing body expressions. To understand the underlying perceptual mechanisms, we computed postural and kinematic features from affective whole-body movement videos and related them to brain processes. Using representational similarity and multivoxel pattern analyses, we showed systematic relations between computation-based body features and brain activity. Our results revealed that postural rather than kinematic features reflect the affective category of the body movements. The feature limb contraction showed a central contribution in fearful body expression perception, differentially represented in action observation, motor preparation, and affect coding regions, including the amygdala. The posterior superior temporal sulcus differentiated fearful from other affective categories using limb contraction rather than kinematics. The extrastriate body area and fusiform body area also showed greater tuning to postural features. The discovery of midlevel body feature encoding in the brain moves affective neuroscience beyond research on high-level emotion representations and provides insights in the perceptual features that possibly drive automatic emotion perception.

Transcranial magnetic stimulation over the right temporoparietal junction influences the sense of agency in healthy humans

Background

The sense of agency is an important aspect of motor control. Impaired sense of agency has been linked to several medical conditions, including schizophrenia and functional neurological disorders. A complex brain network subserves the sense of agency, and the right temporoparietal junction is one of its main nodes. In this paper, we tested whether transcranial magnetic stimulation over the right temporoparietal junction elicited behavioural changes in the sense of agency.

Methods

In experiment 1, 15 healthy participants performed a behavioural task during functional MRI, with the goal of localizing the area relevant for the sense of agency in the right temporoparietal junction. In the task, the movement of a cursor (controlled by the participants) was artificially manipulated, and the sense of agency was either diminished (turbulence) or enhanced (magic). In experiment 2, we applied transcranial magnetic stimulation in 20 healthy participants in a sham-controlled, crossover trial with excitatory, inhibitory or sham (vertex) stimulation. We measured the summary agency score, an indicator of the sense of agency (lower values correspond to diminished sense of agency).

Results

Experiment 1 revealed a peak of activation during agency manipulation in the right temporoparietal junction (Montreal Neurological Institute coordinates x, y, z: 68, -26, 34). Experiment 2 showed that inhibition of the right temporoparietal junction significantly reduced the summary agency score in both turbulence (from -14.4 ± 11.4% to -22.5 ± 8.9%), and magic (from -0.7 ± 5.8% to -4.4 ± 4.4%).

Limitations

We found no excitatory effects, possibly because of a ceiling effect (because healthy participants have a normal sense of agency) or noneffectiveness of the excitatory protocol.

Conclusion

Our experiments showed that the network subserving the sense of agency was amenable to neuromodulation in healthy participants. This sets the ground for further research in patients with impaired sense of agency. Clinical trial identification: DRKS00012992 (German clinical trials registry).

How the effects of actions become our own

Every day, we do things that cause effects in the outside world with little doubt about who caused what. To some, this sense of agency derives from a post hoc reconstruction of a likely causal relationship between an event and our preceding movements; others propose that the sense of agency originates from prospective comparisons of motor programs and their effects. Using functional magnetic resonance imaging, we found that the sense of agency is associated with a brain network including the pre-supplementary motor area (SMA) and dorsal parietal cortex. Transcranial magnetic stimulation affected the sense of agency only when delivered over the pre-SMA and specifically when time-locked to action planning, rather than when the physical consequences of the actions appeared. These findings make a prospective theory of the sense of agency more likely.

Neural correlates of sense of agency in motor control: A neuroimaging meta-analysis

The sense of agency (SoA) refers to the perception that an action is the consequence of one’s own intention. Studies exploring the SoA with neuroimaging techniques summarized the available data and confirmed a role of fronto-parietal areas and subcortical structures. However, these studies focused on specific regions of interest. We thus conducted a whole-brain meta-analysis to verify which regions emerge as significant for the SoA, specifically during motor execution. We performed a systematic search on PubMed, PsycINFO and Cochrane databases with the following inclusion criteria: studies investigating SoA with a visuo-motor task by means of neuroimaging in healthy subjects. We performed a quantitative, whole-brain, meta-analysis of neural correlates of the SoA based on the activation likelihood estimation. Of the 785 articles identified by our search, 22 studies met our inclusion criteria (169 foci, 295 subjects for decreased agency, and 58 foci, 165 subjects for normal agency). Neural correlates of decreased agency were the bilateral temporo-parietal junction (MNI: 50,-54,14; -44,-52,42; -48,-56,8). Normal agency showed no significant clusters of activation. This meta-analysis confirmed the key role of areas responsible for decreased SoA during motor control, whereas normal agency did not show a specific neural signature. This study sets the ground for future regions-of-interest analyses of neural correlates of SoA, as well as potential neuromodulation studies, which might be relevant in medical conditions presenting with abnormal SoA.

The representational space of observed actions

Categorizing and understanding other people’s actions is a key human capability. Whereas there exists a growing literature regarding the organization of objects, the representational space underlying the organization of observed actions remains largely unexplored. Here we examined the organizing principles of a large set of actions and the corresponding neural representations. Using multiple regression representational similarity analysis of fMRI data, in which we accounted for variability due to major action components (body parts, scenes, movements, objects, sociality, transitivity) and three control models (distance between observer and actor, number of people, HMAX-C1), we found that the semantic dissimilarity structure was best captured by patterns of activation in the lateral occipitotemporal cortex (LOTC). Together, our results demonstrate that the organization of observed actions in the LOTC resembles the organizing principles used by participants to classify actions behaviorally, in line with the view that this region is crucial for accessing the meaning of actions.

Distinct neural response to visual perspective and body size in the extrastriate body area

Neuroimaging research has independently implicated the extrastriate body area (EBA) in distinguishing between different visual perspectives and morphologies of bodies within visual processing. However, the combined processing of these physical attributes towards neural EBA response remains unclear, and may be crucial in influencing higher-order, aesthetic evaluation of bodies. Indeed, EBA alterations amongst eating disorder patients have been associated with disturbances in body image, and disruption to EBA activity amongst healthy individuals has been shown to influence aesthetic evaluations made towards bodies. Therefore, the present study used images of slim and large female bodies viewed from egocentric and allocentric perspectives, to investigate neural EBA response amongst healthy females (N = 30). In addition, participants provided behavioural aesthetic and weight evaluations of all model stimuli. Results revealed an interaction, bilaterally, between visual perspective and body size towards EBA activity, with multi-voxel pattern analysis revealing distinct neural patterns between the four conditions. However, EBA activity did not relate to non-clinical eating disorder psychopathology. No direct relationship was found between EBA activity and behavioural evaluations of model stimuli; however, a whole brain analysis revealed that higher-order, prefrontal regions were associated with cognitive evaluations of large bodies. Taken together, our results suggest that the EBA is an integral core region in discriminating between multiple physical attributes of the body, which is likely to provide important information to higher-order brain regions which make aesthetic evaluations towards bodies.

A functional dissociation of face-, body- and scene-selective brain areas based on their response to moving and static stimuli

The human brain contains areas that respond selectively to faces, bodies and scenes. Neuroimaging studies have shown that a subset of these areas preferentially respond more to moving than static stimuli, but the reasons for this functional dissociation remain unclear. In the present study, we simultaneously mapped the responses to motion in face-, body- and scene-selective areas in the right hemisphere using moving and static stimuli. Participants (N = 22) were scanned using functional magnetic resonance imaging (fMRI) while viewing videos containing bodies, faces, objects, scenes or scrambled objects, and static pictures from the beginning, middle and end of each video. Results demonstrated that lateral areas, including face-selective areas in the posterior and anterior superior temporal sulcus (STS), the extrastriate body area (EBA) and the occipital place area (OPA) responded more to moving than static stimuli. By contrast, there was no difference between the response to moving and static stimuli in ventral and medial category-selective areas, including the fusiform face area (FFA), occipital face area (OFA), amygdala, fusiform body area (FBA), retrosplenial complex (RSC) and parahippocampal place area (PPA). This functional dissociation between lateral and ventral/medial brain areas that respond selectively to different visual categories suggests that face-, body- and scene-selective networks may be functionally organized along a common dimension.

Action sharpens sensory representations of expected outcomes

When we produce actions we predict their likely consequences. Dominant models of action control suggest that these predictions are used to ‘cancel’ perceptual processing of expected outcomes. However, normative Bayesian models of sensory cognition developed outside of action propose that rather than being cancelled, expected sensory signals are represented with greater fidelity (sharpened). Here, we distinguished between these models in an fMRI experiment where participants executed hand actions (index vs little finger movement) while observing movements of an avatar hand. Consistent with the sharpening account, visual representations of hand movements (index vs little finger) could be read out more accurately when they were congruent with action and these decoding enhancements were accompanied by suppressed activity in voxels tuned away from, not towards, the expected stimulus. Therefore, inconsistent with dominant action control models, these data show that sensorimotor prediction sharpens expected sensory representations, facilitating veridical perception of action outcomes.

Our brains predict the likely sensory consequences of actions we take; one theory is that these sensory responses are suppressed, but another theory is that they are sharpened. Here, the authors show using fMRI evidence consistent with the sharpening account for sensory consequences of hand movements.

Distinct sensitivities of the lateral prefrontal cortex and extrastriate body area to contingency between executed and observed actions

Detecting relationships between our own actions and the subsequent actions of others is critical for our social behavior. Self-actions differ from those of others in terms of action kinematics, body identity, and feedback timing. Thus, the detection of social contingency between self-actions and those of others requires comparison and integration of these three dimensions. Neuroimaging studies have highlighted the role of the frontotemporal network in action representation, but the role of each node and their relationships are still controversial. Here, we conducted a functional MRI experiment to test the hypothesis that the lateral prefrontal cortex and lateral occipito-temporal cortex are critical for the integration processes for social contingency. Twenty-four adults performed right finger gestures and then observed them as feedback. We manipulated three parameters of visual feedback: action kinematics (same or different gestures), body identity (self or other), and feedback timing (simultaneous or delayed). Three-way interactions of these factors were observed in the left inferior and middle frontal gyrus (IFG/MFG). These areas were active when self-actions were directly fed back in real-time (i.e., the condition causing a sense of agency), and when participants observed gestures performed by others after a short delay (i.e., the condition causing social contingency). In contrast, the left extrastriate body area (EBA) was sensitive to the concordance of action kinematics regardless of body identity or feedback timing. Body identity × feedback timing interactions were observed in regions including the superior parietal lobule (SPL). An effective connectivity analysis supported the model wherein experimental parameters modulated connections from the occipital cortex to the IFG/MFG via the EBA and SPL. These results suggest that both social contingency and the sense of agency are achieved by hierarchical processing that begins with simple concordance coding in the left EBA, leading to the complex coding of social relevance in the left IFG/MFG.

The Action Imitation network and motor imitation in children and adolescents with autism

While deficits in imitation had been reported in children with autism spectrum disorder (ASD), its exact nature remains unclear. A dysfunction in mirroring mechanisms (through action imitation) has been proposed by some studies to explain this, although some recent evidence points against this hypothesis. The current study used behavior and functional MRI to examine the integrated functioning of the regions that are considered part of the Action Imitation network (AIN) in children and adolescents with ASD during a motor imitation task. Fourteen ASD and 15 age-and-IQ-matched typically developing (TD) children were asked to imitate a series of hand gestures in the MRI scanner. Intact performance on imitation (accurate imitation of hand gestures outside the scanner) in both ASD and TD groups was accompanied by significantly lower activity in ASD participants, relative to TD, in right angular gyrus, precentral gyrus, and left middle cingulate. In addition, autism traits were found to be significantly correlated with activation in the right angular gyrus. Overall, the findings of this study support the role of AIN in imitation and a potential difference in the recruitment of this network in ASD children.

Left extrastriate body area is sensitive to the meaning of symbolic gesture: evidence from fMRI repetition suppression

Functional magnetic resonance imaging (fMRI) adaptation (a.k.a. repetition suppression) paradigm was used to test if semantic information contained in object-related (transitive) pantomimes and communicative (intransitive) gestures is represented differently in the occipito-temporal cortex. Participants watched 2.75 s back-to-back videos where the meaning of gesture was either repeated or changed. The just observed (typically second) gesture was then imitated. To maintain participants’ attention, some trials contained a single video. fMRI adaptation –signal decreases– for watching both movement categories were observed particularly in the lateral occipital cortex, including the extrastriate body area (EBA). Yet, intransitive (vs. transitive) gesture specific repetition suppression was found mainly in the left rostral EBA and caudal middle temporal gyrus- the rEBA/cMTG complex. Repetition enhancement (signal increase) was revealed in the precuneus. While the whole brain and region-of-interest analyses indicate that the precuneus is involved only in visuospatial action processing for later imitation, the common EBA repetition suppression discloses sensitivity to the meaning of symbolic gesture, namely the “semantic what” of actions. Moreover, the rEBA/cMTG suppression reveals greater selectivity for conventionalized communicative gesture. Thus, fMRI adaptation shows higher-order functions of EBA, its role in the semantic network, and indicates that its functional repertoire is wider than previously thought.

Lateral occipitotemporal cortex (LOTC) activity is greatest while viewing dance compared to visualization and movement: learning and expertise effects

The lateral occipitotemporal cortex (LOTC) is comprised of subregions selectively activated by images of human bodies (extrastriate body area, EBA), objects (lateral occipital complex, LO), and motion (MT+). However, their role in motor imagery and movement processing is unclear, as are the influences of learning and expertise on its recruitment. The purpose of our study was to examine putative changes in LOTC activation during action processing following motor learning of novel choreography in professional ballet dancers. Subjects were scanned with functional magnetic resonance imaging up to four times over 34 weeks and performed four tasks: viewing and visualizing a newly learned ballet dance, visualizing a dance that was not being learned, and movement of the foot. EBA, LO, and MT+ were activated most while viewing dance compared to visualization and movement. Significant increases in activation were observed over time in left LO only during visualization of the unlearned dance, and all subregions were activated bilaterally during the viewing task after 34 weeks of performance, suggesting learning-induced plasticity. Finally, we provide novel evidence for modulation of EBA with dance experience during the motor task, with significant activation elicited in a comparison group of novice dancers only. These results provide a composite of LOTC activation during action processing of newly learned ballet choreography and movement of the foot. The role of these areas is confirmed as primarily subserving observation of complex sequences of whole-body movement, with new evidence for modification by experience and over the course of real world ballet learning.

The lateral occipitotemporal cortex in action

Understanding and responding to other people's actions is fundamental for social interactions. Whereas many studies emphasize the importance of parietal and frontal regions for these abilities, several lines of recent research show that the human lateral occipitotemporal cortex (LOTC) represents varied aspects of action, ranging from perception of tools and bodies and the way they typically move, to understanding the meaning of actions, to performing overt actions. Here, we highlight common themes across these lines of work, which have informed theories related to high-level vision, concepts, social cognition, and apraxia. We propose that patterns of activity in LOTC form representational spaces, the dimensions of which capture perceptual, semantic, and motor knowledge of how actions change the state of the world.

Concept Representation Reflects Multimodal Abstraction: A Framework for Embodied Semantics

Recent research indicates that sensory and motor cortical areas play a significant role in the neural representation of concepts. However, little is known about the overall architecture of this representational system, including the role played by higher level areas that integrate different types of sensory and motor information. The present study addressed this issue by investigating the simultaneous contributions of multiple sensory-motor modalities to semantic word processing. With a multivariate fMRI design, we examined activation associated with 5 sensory-motor attributes--color, shape, visual motion, sound, and manipulation--for 900 words. Regions responsive to each attribute were identified using independent ratings of the attributes' relevance to the meaning of each word. The results indicate that these aspects of conceptual knowledge are encoded in multimodal and higher level unimodal areas involved in processing the corresponding types of information during perception and action, in agreement with embodied theories of semantics. They also reveal a hierarchical system of abstracted sensory-motor representations incorporating a major division between object interaction and object perception processes.

Neural Mechanisms of Body Awareness in Infants

The ability to differentiate one's body from others is a fundamental aspect of social perception and has been shown to involve the integration of sense modalities attributable to the self. Though behavioral studies in infancy have investigated infants' discrimination of body-related multisensory stimuli, whether they attribute this information as belonging to the self is still unknown. In human adults, neuroimaging studies have demonstrated the recruitment of a specific set of brain regions in response to body-related multisensory integration. To test whether the infant brain integrates this information similarly to adults, in a first functional near-infrared spectroscopy study we investigated the role of visual–proprioceptive feedback when temporal cues are manipulated by showing 5-month-old infants an online video of their own face while the infant was performing movements. To explore the role of body-related contingency further, in a second study we investigated whether cortical activation in response to self-initiated movements and external tactile stimulation was similar to that found in the first study. Our results indicate that infants' specialized cortical activation in response to body-related contingencies is similar to brain activation seen in response to body awareness in adults.

Loss of agency in apraxia

The feeling of acting voluntarily is a fundamental component of human behavior and social life and is usually accompanied by a sense of agency. However, this ability can be impaired in a number of diseases and disorders. An important example is apraxia, a disturbance traditionally defined as a disorder of voluntary skillful movements that often results from frontal-parietal brain damage. The first part of this article focuses on direct evidence of some core symptoms of apraxia, emphasizing those with connections to agency and free will. The loss of agency in apraxia is reflected in the monitoring of internally driven action, in the perception of specifically self-intended movements and in the neural intention to act. The second part presents an outline of the evidences supporting the functional and anatomical link between apraxia and agency. The available structural and functional results converge to reveal that the frontal-parietal network contributes to the sense of agency and its impairment in disorders such as apraxia. The current knowledge on the generation of motor intentions and action monitoring could potentially be applied to develop therapeutic strategies for the clinical rehabilitation of voluntary action.

Disintegration of multisensory signals from the real hand reduces default limb self-attribution: an fMRI study

The perception of our limbs in space is built upon the integration of visual, tactile, and proprioceptive signals. Accumulating evidence suggests that these signals are combined in areas of premotor, parietal, and cerebellar cortices. However, it remains to be determined whether neuronal populations in these areas integrate hand signals according to basic temporal and spatial congruence principles of multisensory integration. Here, we developed a setup based on advanced 3D video technology that allowed us to manipulate the spatiotemporal relationships of visuotactile (VT) stimuli delivered on a healthy human participant's real hand during fMRI and investigate the ensuing neural and perceptual correlates. Our experiments revealed two novel findings. First, we found responses in premotor, parietal, and cerebellar regions that were dependent upon the spatial and temporal congruence of VT stimuli. This multisensory integration effect required a simultaneous match between the seen and felt postures of the hand, which suggests that congruent visuoproprioceptive signals from the upper limb are essential for successful VT integration. Second, we observed that multisensory conflicts significantly disrupted the default feeling of ownership of the seen real limb, as indexed by complementary subjective, psychophysiological, and BOLD measures. The degree to which self-attribution was impaired could be predicted from the attenuation of neural responses in key multisensory areas. These results elucidate the neural bases of the integration of multisensory hand signals according to basic spatiotemporal principles and demonstrate that the disintegration of these signals leads to "disownership" of the seen real hand.

A causal role for the extrastriate body area in detecting people in real-world scenes

People are extremely efficient at detecting relevant objects in complex natural scenes. In three experiments, we used functional magnetic resonance imaging-guided transcranial magnetic stimulation (TMS) to investigate the role of the extrastriate body area (EBA) in the detection of people in scenes. In Experiment 1, participants reported, in different blocks, whether people or cars were present in a briefly presented scene. Detection (d-prime) of people, but not of cars, was impaired after TMS over right EBA (rEBA; five pulses at -200, -100, 0, 100, 200 ms) compared with sham stimulation. In Experiment 2, we applied TMS either before (-200, -100 ms) or after (+100, +200) the scene onset. Poststimulus EBA stimulation impaired people detection relative to prestimulus EBA stimulation, while timing had no effect during sham stimulation. In Experiment 3, we examined anatomical specificity by comparing TMS over EBA with TMS over scene-selective transverse occipital sulcus (TOS). Two scenes were presented side by side, and response times to detect which scene contained people (or cars) were measured. For people detection, but not for car detection, response times during EBA stimulation were significantly slower than during TOS stimulation. Furthermore, rEBA stimulation led to an equivalent slowing of response times to left and right lateralized targets. These findings are the first to demonstrate the causal involvement of a category-selective human brain region in detecting its preferred stimulus category in natural scenes. They shed light on the nature of such regions, and help us understand how we efficiently extract socially relevant information from a complex input.

Visuomotor discordance during visually-guided hand movement in virtual reality modulates sensorimotor cortical activity in healthy and hemiparetic subjects

We investigated neural effects of visuomotor discordances during visually-guided finger movements. A functional magnetic resonance imaging (fMRI)-compatible data glove was used to actuate (in real-time) virtual hand models shown on a display in first person perspective. In Experiment 1, we manipulated virtual hand motion to simulate either hypometric or unintentional (actuation of a mismatched finger) feedback of sequential finger flexion in healthy subjects. Analysis of finger motion revealed no significant differences in movement behavior across conditions, suggesting that between-condition differences in brain activity could only be attributed to varying modes of visual feedback rather than motor output. Hypometric feedback and mismatched finger feedback (relative to veridical) were associated with distinct activation. Hypometric feedback was associated with activation in the contralateral motor cortex. Mismatched feedback was associated with activation in bilateral ventral premotor, left dorsal premotor, and left occipitotemporal cortex. The time it took the subject to evaluate visuomotor discordance was positively correlated with activation in bilateral supplementary motor area, bilateral insula, right postcentral gyrus, bilateral dorsal premotor areas, and bilateral posterior parietal lobe. In Experiment 2, we investigated the effects of hypo- and hypermetric visual feedback in three stroke subjects. We observed increased activation of ipsilesional motor cortex in both hypometric and hypermetric feedback conditions. Our data indicate that manipulation of visual feedback of one's own hand movement may be used to facilitate activity in select brain networks. We suggest that these effects can be exploited in neurorehabilition to enhance the processes of brain reorganization after injury and, specifically, might be useful in aiding recovery of hand function in patients during virtual reality-based training.

The overlap of the EBA and the MT/V5 cluster

The extrastriate body area (EBA) is located in the lateral occipito-temporal cortex, in the vicinity of the motion-sensitive region hMT/V5+. To investigate the relationship of EBA to the recently mapped retinotopic areas of the MT/V5 cluster (Kolster et al., 2010), we evaluated the proportion of voxels responsive to the presentation of static human bodies (EBA voxels) in each of the four areas of the MT/V5 cluster and neighboring LO and phPIT areas. We evaluated this proportion as both a function of the number of voxels in a given area and the total number of voxels in a broader lateral occipito-temporal cortex (LOTC) ROI. We observed that each of the four retinotopic areas of the MT/V5 cluster includes substantial fractions of EBA voxels, in contrast to the LO and phPIT areas. This proportion was slightly greater in the right than left hemisphere, and did not depend on the control condition. While most EBA voxels in MT/V5 were only body-sensitive, those in pMSTv and pFST were also motion-sensitive. The main locus of EBA voxels outside the MT/V5 cluster was in the LOTC cortex just rostral to the MT/V5 cluster. Although this region contained more EBA voxels than the MT/V5 cluster, the proportion as a function of areal size was much reduced compared to the MT/V5 cluster. Our results show that EBA is not a single cortical area as EBA voxels are located in all four areas of the MT/V5 cluster, and that body-sensitivity is a key feature of the MT/V5 cluster, in keeping with its exquisite sensitivity to observed actions of others.

Articulatory movements modulate auditory responses to speech

Production of actions is highly dependent on concurrent sensory information. In speech production, for example, movement of the articulators is guided by both auditory and somatosensory input. It has been demonstrated in non-human primates that self-produced vocalizations and those of others are differentially processed in the temporal cortex. The aim of the current study was to investigate how auditory and motor responses differ for self-produced and externally produced speech. Using functional neuroimaging, subjects were asked to produce sentences aloud, to silently mouth while listening to a different speaker producing the same sentence, to passively listen to sentences being read aloud, or to read sentences silently.

We show that that separate regions of the superior temporal cortex display distinct response profiles to speaking aloud, mouthing while listening, and passive listening. Responses in anterior superior temporal cortices in both hemispheres are greater for passive listening compared with both mouthing while listening, and speaking aloud. This is the first demonstration that articulation, whether or not it has auditory consequences, modulates responses of the dorsolateral temporal cortex. In contrast posterior regions of the superior temporal cortex are recruited during both articulation conditions. In dorsal regions of the posterior superior temporal gyrus, responses to mouthing and reading aloud were equivalent, and in more ventral posterior superior temporal sulcus, responses were greater for reading aloud compared with mouthing while listening. These data demonstrate an anterior–posterior division of superior temporal regions where anterior fields are suppressed during motor output, potentially for the purpose of enhanced detection of the speech of others. We suggest posterior fields are engaged in auditory processing for the guidance of articulation by auditory information.

The responsiveness of biological motion processing areas to selective attention towards goals

A growing literature indicates that visual cortex areas viewed as primarily responsive to exogenous stimuli are susceptible to top-down modulation by selective attention. The present study examines whether brain areas involved in biological motion perception are among these areas-particularly with respect to selective attention towards human movement goals. Fifteen participants completed a point-light biological motion study following a two-by-two factorial design, with one factor representing an exogenous manipulation of human movement goals (goal-directed versus random movement), and the other an endogenous manipulation (a goal identification task versus an ancillary color-change task). Both manipulations yielded increased activation in the human homologue of motion-sensitive area MT+ (hMT+) as well as the extrastriate body area (EBA). The endogenous manipulation was associated with increased right posterior superior temporal sulcus (STS) activation, whereas the exogenous manipulation was associated with increased activation in left posterior STS. Selective attention towards goals activated a portion of left hMT+/EBA only during the perception of purposeful movement-consistent with emerging theories associating this area with the matching of visual motion input to known goal-directed actions. The overall pattern of results indicates that attention towards the goals of human movement activates biological motion areas. Ultimately, selective attention may explain why some studies examining biological motion show activation in hMT+ and EBA, even when using control stimuli with comparable motion properties.

Imagined tool-use in near and far space modulates the extra-striate body area

Active tool-use can result in the incorporation of the tool into the body schema, e.g., the representation of the arm is enlarged according to tool length. This modification even influences the processing of space: using a long tool leads to a remapping of far space as near space. We here further investigate the interaction of the neural representations of the human body, tool use, and spatial domain. Functional magnetic resonance imaging (fMRI) was performed in twelve right-handed healthy individuals while they imagined moving a cylinder towards a target position in far or near space by mentally using either pliers or a joystick. The fMRI data revealed that already the imagined use of preferred tools in near and far space (i.e., pliers in far space, joystick in near space) modulated the neural activity in the extra-striate body area (EBA) located in the occipito-temporal cortex. Moreover, psycho-physical interaction analysis showed that during imagined tool-use the functional connectivity of left EBA to a network representing the near-personal space around the hand was strengthened. This increased functional connectivity is likely to reflect the neural processes underlying the incorporation of the tool into the body schema. Thus, the current data suggest that simulating tool-use modulates the representation of the human body in extra-striate cortex.

Am I seeing my hand? Visual appearance and knowledge of controllability both contribute to the visual capture of a person's own body

When confronted with complex visual scenes in daily life, how do we know which visual information represents our own hand? We investigated the cues used to assign visual information to one's own hand. Wrist tendon vibration elicits an illusory sensation of wrist movement. The intensity of this illusion attenuates when the actual motionless hand is visually presented. Testing what kind of visual stimuli attenuate this illusion will elucidate factors contributing to visual detection of one's own hand. The illusion was reduced when a stationary object was shown, but only when participants knew it was controllable with their hands. In contrast, the visual image of their own hand attenuated the illusion even when participants knew that it was not controllable. We suggest that long-term knowledge about the appearance of the body and short-term knowledge about controllability of a visual object are combined to robustly extract our own body from a visual scene.

Acting alters visual processing: flexible recruitment of visual areas by one's own actions

Using functional magnetic resonance imaging, we investigated the effect of motor preparation/execution on the activation of visual cortical areas by action observation. We presented videos of human actors performing several fine manipulative actions (e.g., grasping) with the hand or foot, together with appropriate control stimuli. Subjects either responded in a central fixation task with the hand (A) or foot (B) or viewed the stimuli passively (C). Experimental conditions were arranged according to a 2 × 2 × 3 factorial design with action, effector, and response as factors. Bilateral posterior parietal cortex was more strongly activated for action videos compared with controls during active runs (A or B) contrasted with passive runs (C). Two neighboring regions in the right fusiform gyrus (FG) were activated when the effector employed to respond in the task matched that displayed in the videos (A or B), independently of whether the stimulus was an action or a control. Neighboring regions in the right posterior middle temporal gyrus (MTG) were also activated when the effector observed and that used to respond matched (A or B), but only for action videos, not controls. Our results indicate flexible modulation of visual areas during concurrent action observation and action execution/preparation, which was effector specific in the FG and MTG.

The posterior superior temporal sulcus is sensitive to the outcome of human and non-human goal-directed actions

Prior studies have demonstrated that the posterior superior temporal sulcus (pSTS) is involved in analyzing the intentions underlying actions and is sensitive to the context within which actions occur. However, it is debated whether the pSTS is actually sensitive to goals underlying actions, or whether previous studies can be interpreted to suggest that the pSTS is instead involved in the allocation of visual attention towards unexpected events. In addition, little is known about whether the pSTS is specialized for reasoning about the actions of social agents or whether the pSTS is sensitive to the actions of both animate and inanimate entities. Here, using functional magnetic resonance imaging, we investigated activation in response to passive viewing of successful and unsuccessful animate and inanimate goal-directed actions. Activation in the right pSTS was stronger in response to failed actions compared to successful actions, suggesting that the pSTS plays a role in encoding the goals underlying actions. Activation in the pSTS did not differentiate between animate and inanimate actions, suggesting that the pSTS is sensitive to the goal-directed actions of both animate and inanimate entities.

Dealing with individual variability: when telling what is real depends on telling who is acting

You are queuing at the bus stop, and notice that someone suddenly turns her walk into a run: typically, you assume that she wants to catch the bus and may want to tell the driver to wait. Faced with a sudden speed change, rather than considering it bizarre or unnatural, observers attach a meaning to it, and act consequently. In a social context, speed of a movement often bears as much significance as its form, and can be adapted to vehicle precise meanings. This pragmatic rule facilitates decoding of non-verbal messages from other individuals, but may not necessarily apply when observing one's own movements, for which intentions should be informative enough. Hence, the range of motion speeds labeled as 'natural' could be broader for other people's actions compared to one's own. We explored this possibility through a task in which human observers decided whether speed of a gesture had been artificially modified. A virtual hand was presented, which - unbeknownst to participants - moved according to the kinematics of either the observer, or another individual. Although a self/other distinction was never required, participants applied different criteria when dealing with self compared to other people's gestures, suggesting that the brain implicitly extracts identity information before any overt judgment is produced. Interestingly, observers were reluctant to labeling movements of another individual as artificial, in keeping with the hypothesis that large variations in movements' speed can vehicle social messages, and therefore are not regarded a priori as unnatural.

Different brain structures related to self- and external-agency attribution: a brief review and meta-analysis

Several neuroimaging studies have consistently shown activations of areas surrounding the temporo-parietal junction (TPJ) during tasks exploring the sense of agency. Beyond TPJ, activations in different structures, such as the dorsolateral prefrontal cortex (dLPFC), the pre-supplementary motor area (pre-SMA), the insula and the precuneus have been reported. Moreover, a possible dissociation between self- and external-agency attribution has been suggested. To test the hypothesis of distinct neural correlates for self- and external-agency attribution a quantitative meta-analysis, based on activation likelihood estimation (ALE) method, across 15 PET and fMRI studies (228 subjects) was conducted. Results show converging activations including the TPJ, pre-SMA, precuneus and dorsomedial prefrontal cortex (dMPFC) in external-agency, while insula activation was related to self-agency. We discuss these findings, highlighting the role of the insula, and calling for the use of alternative paradigms such as intentional binding and interactive imitation to study agency.

Representation of action in occipito-temporal cortex

A fundamental question for social cognitive neuroscience is how and where in the brain the identities and actions of others are represented. Here we present a replication and extension of a study by Kable and Chatterjee [Kable, J. W., & Chatterjee, A. Specificity of action representations in the lateral occipito-temporal cortex. Journal of Cognitive Neuroscience, 18, 1498-1517, 2006] examining the role of occipito-temporal cortex in these processes. We presented full-cue movies of actors performing whole-body actions and used fMRI to test for action- and identity-specific adaptation effects. We examined a series of functionally defined regions, including the extrastriate and fusiform body areas, the fusiform face area, the parahippocampal place area, the lateral occipital complex, the right posterior superior temporal sulcus, and motion-selective area hMT+. These regions were analyzed with both standard univariate measures as well as multivoxel pattern analyses. Additionally, we performed whole-brain tests for significant adaptation effects. We found significant action-specific adaptation in many areas, but no evidence for identity-specific adaptation. We argue that this finding could be explained by differences in the familiarity of the stimuli presented: The actions shown were familiar but the actors performing the actions were unfamiliar. However, in contrast to previous findings, we found that the action adaptation effect could not be conclusively tied to specific functionally defined regions. Instead, our results suggest that the adaptation to previously seen actions across identities is a widespread effect, evident across lateral and ventral occipito-temporal cortex.

Surface-based information mapping reveals crossmodal vision-action representations in human parietal and occipitotemporal cortex

Many lines of evidence point to a tight linkage between the perceptual and motoric representations of actions. Numerous demonstrations show how the visual perception of an action engages compatible activity in the observer's motor system. This is seen for both intransitive actions (e.g., in the case of unconscious postural imitation) and transitive actions (e.g., grasping an object). Although the discovery of "mirror neurons" in macaques has inspired explanations of these processes in human action behaviors, the evidence for areas in the human brain that similarly form a crossmodal visual/motor representation of actions remains incomplete. To address this, in the present study, participants performed and observed hand actions while being scanned with functional MRI. We took a data-driven approach by applying whole-brain information mapping using a multivoxel pattern analysis (MVPA) classifier, performed on reconstructed representations of the cortical surface. The aim was to identify regions in which local voxelwise patterns of activity can distinguish among different actions, across the visual and motor domains. Experiment 1 tested intransitive, meaningless hand movements, whereas experiment 2 tested object-directed actions (all right-handed). Our analyses of both experiments revealed crossmodal action regions in the lateral occipitotemporal cortex (bilaterally) and in the left postcentral gyrus/anterior parietal cortex. Furthermore, in experiment 2 we identified a gradient of bias in the patterns of information in the left hemisphere postcentral/parietal region. The postcentral gyrus carried more information about the effectors used to carry out the action (fingers vs. whole hand), whereas anterior parietal regions carried more information about the goal of the action (lift vs. punch). Taken together, these results provide evidence for common neural coding in these areas of the visual and motor aspects of actions, and demonstrate further how MVPA can contribute to our understanding of the nature of distributed neural representations.

Attentional networks and biological motion

Our ability to see meaningful actions when presented with point-light traces of human movement is commonly referred to as the perception of biological motion. While traditional explanations have emphasized the spontaneous and automatic nature of this ability, more recent findings suggest that attention may play a larger role than is typically assumed. In two studies we show that the speed and accuracy of responding to point-light stimuli is highly correlated with the ability to control selective attention. In our first experiment we measured thresholds for determining the walking direction of a masked point-light figure, and performance on a range of attention-related tasks in the same set of observers. Mask-density thresholds for the direction discrimination task varied quite considerably from observer to observer and this variation was highly correlated with performance on both Stroop and flanker interference tasks. Other components of attention, such as orienting, alerting and visual search efficiency, showed no such relationship. In a second experiment, we examined the relationship between the ability to determine the orientation of unmasked point-light actions and Stroop interference, again finding a strong correlation. Our results are consistent with previous research suggesting that biological motion processing may requite attention, and specifically implicate networks of attention related to executive control and selection.