The mirror neuron system and the consequences of its dysfunction

Exploring empathic space: correlates of perspective transformation ability and biases in spatial attention

Separate lines of research have noted recruitment of parietal cortex during tasks involving visuo-spatial processes and empathy. To explore the relationship between these two functions, a self-other perspective transformation task and a task of spatial attention (line bisection) were administered to 40 healthy participants (19 women). Performance on these tasks was examined in relation to self-reported empathy. Rightward biases in line bisection correlated positively with trait-level self-reported empathic concern, suggesting a left hemisphere mediation of this prosocial personality trait. Unexpectedly, speed of perspective taking in the self-other transformation task correlated negatively with empathic concern, but only in women, which we interpret in light of gender differences in empathy and strategies for egocentric mental transformations. Together, the findings partially support the commonalities in visuo-spatial attention, perspective-taking and empathy. More broadly, they shed additional light on the relationship between basic cognitive functions and complex social constructs.

Neuromagnetic response to body motion and brain connectivity

Visual detection of body motion is of immense importance for daily-life activities and social nonverbal interaction. Although neurobiological mechanisms underlying visual processing of human locomotion are being explored extensively by brain imaging, the role of structural brain connectivity is not well understood. Here we investigate cortical evoked neuromagnetic response to point-light body motion in healthy adolescents and in patients with early periventricular lesions, periventricular leukomalacia (PVL), that disrupt brain connectivity. In a simultaneous masking paradigm, participants detected the presence of a point-light walker embedded in a few sets of spatially scrambled dots on the joints of a walker. The visual sensitivity to camouflaged human locomotion was lower in PVL patients. In accord with behavioral data, root-mean-square (RMS) amplitude of neuromagnetic trace in response to human locomotion was lower in PVL patients at latencies of 180-244 msec over the right temporal cortex. In this time window, the visual sensitivity to body motion in controls, but not in PVL patients, was inversely linked to the right temporal activation. At later latencies of 276-340 msec, we found reduction in RMS amplitude in PVL patients for body motion stimuli over the right frontal cortex. The findings indicate that disturbances in brain connectivity with the right temporal cortex, a key node of the social brain, and with the right frontal cortex lead to disintegration of the neural network engaged in visual processing of body motion. We suspect that reduced cortical response to body motion over the right temporal and frontal cortices might underlie deficits in visual social cognition.

Brain basis of human social interaction: from concepts to brain imaging

Modern neuroimaging provides a common platform for neuroscience and related disciplines to explore the human brain, mind, and behavior. We base our review on the social shaping of the human mind and discuss various aspects of brain function related to social interaction. Despite private mental contents, people can share their understanding of the world using, beyond verbal communication, nonverbal cues such as gestures, facial expressions, and postures. The understanding of nonverbal messages is supported by the brain's mirroring systems that are shaped by individual experience. Within the organism-environment system, tight links exist between action and perception, both within an individual and between several individuals. Therefore, any comprehensive brain imaging study of the neuronal basis of social cognition requires appreciation of the situated and embodied nature of human cognition, motivating simultaneous monitoring of brain and bodily functions within a socially relevant environment. Because single-person studies alone cannot unravel the dynamic aspects of interpersonal interactions, it seems both necessary and beneficial to move towards "two-person neuroscience"; technological shortcomings and a limited conceptual framework have so far hampered such a leap. We conclude by discussing some major disorders of social interaction.

Right hemisphere dominance for understanding the intentions of others: evidence from a split-brain patient

Understanding the actions performed by other people is a key aspect of social interaction, including in clinical settings where patients are learning from therapists and caregivers. While lesions of the left cerebral hemisphere induce praxic disorders, the hemispheric specialisation of intention understanding remains unclear. Do patients with a right hemispheric lesion understand the intentions of other people properly? The present study investigates how a split-brain patient understands the means (what) and intentions (why) of the actions of other people. Results show a significant left hemispheric dominance for understanding what is done, and a significant right hemispheric dominance for understanding why an action is carried out. This discovery might have important clinical implications in neurological patients, especially when those with right hemisphere lesions are faced with important decisions related to the interpretation of other's intentions.

Intention understanding in autism

When we observe a motor act (e.g. grasping a cup) done by another individual, we extract, according to how the motor act is performed and its context, two types of information: the goal (grasping) and the intention underlying it (e.g. grasping for drinking). Here we examined whether children with autistic spectrum disorder (ASD) are able to understand these two aspects of motor acts. Two experiments were carried out. In the first, one group of high-functioning children with ASD and one of typically developing (TD) children were presented with pictures showing hand-object interactions and asked what the individual was doing and why. In half of the "why" trials the observed grip was congruent with the function of the object ("why-use" trials), in the other half it corresponded to the grip typically used to move that object ("why-place" trials). The results showed that children with ASD have no difficulties in reporting the goals of individual motor acts. In contrast they made several errors in the why task with all errors occurring in the "why-place" trials. In the second experiment the same two groups of children saw pictures showing a hand-grip congruent with the object use, but within a context suggesting either the use of the object or its placement into a container. Here children with ASD performed as TD children, correctly indicating the agent's intention. In conclusion, our data show that understanding others' intentions can occur in two ways: by relying on motor information derived from the hand-object interaction, and by using functional information derived from the object's standard use. Children with ASD have no deficit in the second type of understanding, while they have difficulties in understanding others' intentions when they have to rely exclusively on motor cues.

Audiovisual integration of speech is disturbed in schizophrenia: an fMRI study

Speech perception is an essential part of social interaction. Visual information (lip movements, facial expression) may supplement auditory information in particular under inadvertent listening situations. Schizophrenia patients have been shown to have a deficit in integrating articulatory motions with the auditory speech input. The goal of this study was to investigate the neural basis of this deficit in audiovisual speech processing in schizophrenia patients by using fMRI. Disyllabic nouns were presented in congruent (audio matches visual information) and incongruent conditions in a slow event related fMRI design. Schizophrenia patients (n=15) were compared to age and gender matched control participants. The statistical examination was conducted by analysis of variance with main factors: audiovisual congruency and group membership. The patients' brain activity differed from the control group as evidenced by congruency by group interaction effects. The pertinent brain sites were located predominantly in the right hemisphere and comprised the pars opercularis, middle frontal sulcus, and superior temporal gyrus. In addition, we observed interactions bilaterally in the fusiform gyrus and the nucleus accumbens. We suggest that schizophrenia patients' deficits in audiovisual integration during speech perception are due to a dysfunction of the speech motor system in the right hemisphere. Furthermore the results can be also seen as a reflection of reduced lateralization of language functions to the left hemisphere in schizophrenia.

The performance and observation of action shape future behaviour

The observation of other people's actions plays an important role in shaping the perceptual, cognitive, and motor processes of the observer. It has been suggested that these social influences occur because the observation of action evokes a representation of that response in the observer and that these codes are subsequently accessed by other cognitive systems to modify future behaviour. In the case of social search and movement tasks, the observation-evoked response code is thought to activate the same mechanisms that are activated following internally-generated response codes. In support of this hypothesis, the present study revealed that the magnitudes of the between-person inhibition of return (IOR) effects were correlated with within-person IOR effects. These findings provide substantial support for the link between observation-evoked response codes and social cognitive effects.

Nonlinear phase-phase cross-frequency coupling mediates communication between distant sites in human neocortex

Human cognition is thought to be mediated by large-scale interactions between distant sites in the neocortex. Synchronization between different cortical areas has been suggested as one possible mechanism for corticocortical interaction. Here, we report robust, directional cross-frequency synchronization between distant sensorimotor sites in human neocortex during a movement task. In four subjects, electrocorticographic recordings from the cortical surface revealed a low-frequency rhythm (10-13 Hz) that combined with a higher frequency (77-82 Hz) in a ventral region of the premotor cortex to produce a third rhythm at the sum of these two frequencies in a distant motor site. Such cross-frequency coupling implies a nonlinear interaction between these cortical sites. These findings demonstrate that task-specific, phase-phase coupling can support communication between distant areas of the human neocortex.

The mirror neuron system: new frontiers

Since the discovery of mirror neurons, much effort has been invested into studying their location and properties in the human brain. Here we review these original findings and introduce the main topics of this special issue of Social Neuroscience. What does the mirror system code? How is the mirror system embedded into the mosaic of circuits that compose our brain? How does the mirror system contribute to communication, language and social interaction? Can the principle of mirror neurons be extended to emotions, sensations and thoughts? Papers using a wide range of methods, including single cell recordings, fMRI, TMS, EEG and psychophysics, collected in this special issue, start to give us some impressive answers.

Application of neuroscience to technology in stroke rehabilitation

The past decade has seen remarkable advances in our understanding of mechanisms that drive functional neuroplastic change after brain injury and the mirror neuron system that appears essential for language learning and communicative interaction. This article describes five neuroscience-based interventions available for clinical practice, with a discussion of the potential value of mirror neurons in stroke rehabilitation. Case-study data on three adults with aphasia who received various combinations of neuroscience-derived technological interventions are provided to inform the clinician of the potential advantages of technology as an adjunct to, not a substitution for, conventional therapeutic intervention.

Befunde zum menschlichen Spiegelneuronensystem bei Autismus: Eine kritische Übersicht funktioneller Bildgebungsstudien

Es mehren sich Hinweise, dass Menschen über ein Spiegelneuronensystem verfügen, das für das Verständnis von Handlungen, für Imitation und für Empathie von großer Bedeutung sein könnte. Autistische Störungen gehen mit Beeinträchtigungen in der Imitation und Empathie einher. Die Annahme, dass diesen Beeinträchtigungen defizitäre Spiegelneuronenmechanismen zugrunde liegen könnten, hat eine Reihe von Untersuchungen angeregt, die mittels bildgebender Methoden die Funktion des Spiegelneuronensystems bei Personen mit Autismus überprüft haben. Basierend auf Annahmen und Erkenntnissen zu Spiegelneuronenmechanismen bei gesunden Kindern und Erwachsenen werden in der vorliegenden Arbeit die Ergebnisse dieser Studien zusammengefasst und kritisch diskutiert. Zudem werden mögliche klinische Implikationen der Befunde dargestellt.

Embodied and Disembodied Emotion Processing: Learning From and About Typical and Autistic Individuals

Successful social functioning requires quick and accurate processing of emotion and generation of appropriate reactions. In typical individuals, these skills are supported by embodied processing, recruiting central and peripheral mechanisms. However, emotional processing is atypical in individuals with autism spectrum disorder (ASD). Individuals with ASD show deficits in recognition of briefly presented emotional expressions. They tend to recognize expressions using rule-based, rather than template, strategies. Individuals with ASD also do not spontaneously and quickly mimic emotional expressions, unless the task encourages engagement. When processing emotional scenes, ASD individuals show atypical basic motivational responses, despite intact ability to verbally determine stimulus valence. We discuss how these findings highlight the contribution of both embodied and disembodied mechanisms to typical and atypical emotional functioning.

Oxytocin, sexually dimorphic features of the social brain, and autism

The common features of autism spectrum disorder, a highly heritable representative pervasive developmental disorder with significant heterogeneity and multiple-genetic factors, are severe dysfunction in social reciprocity, abnormalities in social brain regions, and disproportionately low probability in the female gender. Concomitantly, certain domains of mental function, such as emotional memory and social reciprocity, show a significant sex difference. In addition, recent neuroimaging studies have shown significant sexual dimorphisms in neuroanatomical correlates of social cognition. Recently, some sexually dimorphic factors, including oxytocin, vasopressin, and genes linked with the x-chromosome, have received attention because of their possible contribution to mental development especially in the social cognitive domain. Taking this evidence together, it is hypothesized that a sexually dimorphic factor associated with social reciprocity could affect characteristics of autism spectrum disorder including dysfunction in social reciprocity, abnormalities in social brain regions, and disproportionately low probability in female gender. This review article overviews sexual dimorphisms in clinical features of autism spectrum disorder, in normal social cognition, and in social brain function and structure. The association of oxytocin with sexual dimorphisms, social reciprocity, neural correlates of social cognition, and the pathogenesis of autism spectrum disorder were further summarized. Recent studies have suggested that oxytocin plays a role in social attachment in experimental animals, in enhancing social interactive ability in human adults, and in the pathogenesis of autism spectrum disorder. Thus, the ongoing accumulated evidence suggests that oxytocin deserves to be examined as a candidate that causes the sexually dimorphic aspect of human social reciprocity, social brain development and the pathogenesis of autism spectrum disorder.

Walking on a line: a motor paradigm using rotation and reflection symmetry to study mental body transformations

Researchers have recently reintroduced the own-body in the center of the social interaction theory. From the discovery of the mirror neurons in the ventral premotor cortex of the monkey's brain, a human embodied model of interindividual relationship based on simulation processes has been advanced, according to which we tend to embody spontaneously the other individuals' behavior when interacting. Although the neurocognitive mechanisms of the embodiment process have started being described, the mechanisms of self-location during embodiment are still less known. Here, we designed a motor paradigm which allows investigating in ecologically more valid conditions whether we embody another person's intransitive action with an embodied or disembodied self-location. Accordingly, we propose a phenomenological model of self-other interaction showing how perspective-taking mechanisms may relate on mental body transformation and offering a promising way to investigate the different sorts of intersubjectivity.

Hand preference influences neural correlates of action observation

It has been argued that we map observed actions onto our own motor system. Here we added to this issue by investigating whether hand preference influences the neural correlates of action observation of simple, essentially meaningless hand actions. Such an influence would argue for an intricate neural coupling between action production and action observation, which goes beyond effects of motor repertoire or explicit motor training, as has been suggested before. Indeed, parts of the human motor system exhibited a close coupling between action production and action observation. Ventral premotor and inferior and superior parietal cortices showed differential activation for left- and right-handers that was similar during action production as well as during action observation. This suggests that mapping observed actions onto the observer's own motor system is a core feature of action observation - at least for actions that do not have a clear goal or meaning. Basic differences in the way we act upon the world are not only reflected in neural correlates of action production, but can also influence the brain basis of action observation.

Neurobiology of empathy and callousness: implications for the development of antisocial behavior

Information on the neurobiology of empathy and callousness provides clinicians with an opportunity to develop sophisticated understanding of mechanisms underpinning antisocial behavior and its counterpart, moral decision-making. This article provides an integrated in-depth review of hormones (e.g. peripheral steroid hormones such as cortisol) and brain structures (e.g. insula, anterior cingulate cortex, and amygdala) implicated in empathy, callousness, and psychopathic-like behavior. The overarching goal of this article is to relate these hormones and brain structures to moral decision-making. This review will begin in the brain, but will then integrate information about biological functioning in the body, specifically stress-reactivity. Our aim is to integrate understanding of neural processes with hormones such as cortisol, both of which have demonstrated relationships to empathy, psychopathy, and antisocial behavior. The review proposes that neurobiological impairments in individuals who display little empathy are not necessarily due to a reduced ability to understand the emotions of others. Instead, evidence suggests that individuals who show little arousal to the distress of others likewise show decreased physiological arousal to their own distress; one manifestation of reduced stress reactivity may be a dysfunction in empathy, which supports psychopathic-like constructs (e.g. callousness). This integration will assist in the development of objective methodologies that can inform and monitor treatment interventions focused on decreasing antisocial behavior.

Imitation, empathy, and mirror neurons

There is a convergence between cognitive models of imitation, constructs derived from social psychology studies on mimicry and empathy, and recent empirical findings from the neurosciences. The ideomotor framework of human actions assumes a common representational format for action and perception that facilitates imitation. Furthermore, the associative sequence learning model of imitation proposes that experience-based Hebbian learning forms links between sensory processing of the actions of others and motor plans. Social psychology studies have demonstrated that imitation and mimicry are pervasive, automatic, and facilitate empathy. Neuroscience investigations have demonstrated physiological mechanisms of mirroring at single-cell and neural-system levels that support the cognitive and social psychology constructs. Why were these neural mechanisms selected, and what is their adaptive advantage? Neural mirroring solves the "problem of other minds" (how we can access and understand the minds of others) and makes intersubjectivity possible, thus facilitating social behavior.

Mental state references in psychosis: a pilot study of prompted implicit mentalising during dialogue and its relationship with social functioning

INTRODUCTION

Few studies of psychosis have examined dialogue-based implicit mentalising even though this is likely to reflect the skills required in everyday life better than more typical mentalising tasks. Using a semistructured dialogue task, we predicted that a psychosis sample would be impaired in "prompted" online mentalising (i.e., the frequency and variety of mental and emotional state words as well as references to own mental state) and that performance would relate to social functioning.

METHODS

Eighteen adults with psychosis and nine healthy adults were each recorded during four semistructured dialogues, which were transcribed, coded, scored, and quantitatively analysed. The patients also completed a measure of social functioning.

RESULTS

Compared to controls, the psychosis participants referred to others' mental and emotional states significantly less and with a lower variety of words. These findings were all large effects with sufficient observed power. There was no significant difference in references to own mental state. The relationships between mentalising and social functioning were mostly modest.

CONCLUSIONS

Although prompted implicit mentalising is impoverished in psychosis, self-knowledge appears to be intact. Simulation-based mentalising may be spared in the context of impoverished theory-based mentalising. Also, implicit mentalising contributes to social functioning, corroborating the results of previous work.

Reduced spontaneous facial mimicry in women with autistic traits

Deficits in empathizing and perspective taking are defining characteristics of autism-spectrum disorders. Converging evidence suggests that these socio-emotional abilities are rooted in basic mechanisms that subserve imitative behavior, and may vary with autistic traits across the population as a whole. We investigated this notion by assessing spontaneous and instructed mimicry of facial expressions in healthy male and female volunteers scoring extremely high or low on the autism-spectrum quotient questionnaire. Mimicry was recorded using electromyography of the corrugator supercilii and zygomaticus major. Results show that spontaneous mimicry in the corrugator supercilii was strongest in female participants with low AQ-scores. Mimicry in the zygomaticus major, and in the instructed facial mimicry condition, did not differ between groups. These findings indicate that the degree to which individuals exhibit spontaneous mimicry may vary as a function of both gender and autistic traits.

Mirror neuron system as the joint from action to language

Mirror neuron system (MNS) represents one of the most important discoveries of cognitive neuroscience in the past decade, and it has been found to involve in multiple aspects of brain functions including action understanding, imitation, language understanding, empathy, action prediction and speech evolution. This manuscript reviewed the function of MNS in action understanding as well as language evolution, and specifically assessed its roles as the bridge from body language to fluent speeches. Then we discussed the speech defects of autism patients due to the disruption of MNS. Finally, given that MNS is plastic in adult brain, we proposed MNS targeted therapy provides an efficient rehabilitation approach for brain damages conditions as well as autism patients.

Mirror neuron system differentially activated by facial expressions and social hand gestures: a functional magnetic resonance imaging study

Facial expressions and hand gestures are utilized in nonverbal communication to convey socially relevant information. One key process that mediates nonverbal communication is simulation. The mirror neuron system (MNS), which maps observed actions onto the motor representations used when producing those actions, likely plays a role in simulation. Previous neuroimaging experiments have identified a putative human MNS that includes the inferior parietal lobule (IPL) and the frontal operculum. Although understanding nonverbal communication presumably involves the MNS, it is unknown whether these two forms of nonverbal social communication have distinct representations within that system. Here we report the results of a functional magnetic resonance imaging experiment in which participants viewed, imitated, and produced facial expressions and social hand gestures. The observation and execution of facial expressions and social hand gestures activated the MNS, but the magnitude of response differed. Activation in the IPL was greater for social hand gestures, whereas activation in the frontal operculum was greater for viewing facial expressions. The locations of neural activity evoked by viewing facial expressions and social hand gestures in the frontal operculum were significantly different. These data argue that there are distinct representations of different types of social nonverbal communication in the MNS.

Update on apraxia

Apraxia is classically defined as difficulty performing learned, skilled gestures. In this review, we describe the range of motor impairments classified as apraxia, focusing on ideomotor limb apraxia. We present several prominent models of praxis to explain the variety of difficulties seen in patients with apraxia. We also discuss the large-scale frontal-parietal-basal ganglia network thought to underlie praxis. In this context, we highlight the common occurrence of limb apraxia in corticobasal degeneration, a neurodegenerative condition characterized by frontal, parietal, and basal ganglia disease.

Dopaminergic-neuropeptide interactions in the social brain

A well-mapped set of brain regions is dedicated to social cognition. It is responsive to social cues, engaged in moral decision-making and makes predictions about the likely behaviour of other people. Recent studies of affiliation, using animal models, have revealed that specific neurotransmitters and hormones influence the neural circuits of 'the social brain'. There is converging evidence that the interface between the neuropeptides oxytocin and vasopressin and dopaminergic reward circuits is of particular importance. In the context of recent research, we discuss emerging evidence for the impact of these neuropeptides on the regulation of the social brain. We also examine the putative role of allelic variation in candidate genes on individual differences in social cognitive processing and associated social behaviour.

fMRI adaptation reveals mirror neurons in human inferior parietal cortex

Mirror neurons, as originally described in the macaque, have two defining properties [1, 2]: They respond specifically to a particular action (e.g., bringing an object to the mouth), and they produce their action-specific responses independent of whether the monkey executes the action or passively observes a conspecific performing the same action. In humans, action observation and action execution engage a network of frontal, parietal, and temporal areas. However, it is unclear whether these responses reflect the activity of a single population that represents both observed and executed actions in a common neural code or the activity of distinct but overlapping populations of exclusively perceptual and motor neurons [3]. Here, we used fMRI adaptation to show that the right inferior parietal lobe (IPL) responds independently to specific actions regardless of whether they are observed or executed. Specifically, responses in the right IPL were attenuated when participants observed a recently executed action relative to one that had not previously been performed. This adaptation across action and perception demonstrates that the right IPL responds selectively to the motoric and perceptual representations of actions and is the first evidence for a neural response in humans that shows both defining properties of mirror neurons.

Observation-based learning for brain-machine interfaces

Canonically, 'mirror neurons' are cells in area F5 of the ventral premotor cortex that are active during both observation and execution of goal-directed movements. Recently, cells with similar properties have been observed in a number of other areas in the motor system, including the primary motor cortex. Mirror neurons are a part of a system whose function is thought to involve the prediction and interpretation of the sensory consequences of our own actions as well as the actions of others. Mirror-like responses are relevant to the development of brain-machine interfaces (BMIs) because they provide a robust way to map neural activity to behavior, and because they represent high-level information about goals and intentions that may have utility in future BMI applications.

The sense of touch: embodied simulation in a visuotactile mirroring mechanism for observed animate or inanimate touch

Previous studies have shown a shared neural circuitry in the somatosensory cortices for the experience of one's own body being touched and the sight of intentional touch. Using functional magnetic resonance imaging (fMRI), the present study aimed to elucidate whether the activation of a visuotactile mirroring mechanism during touch observation applies to the sight of any touch, that is, whether it is independent of the intentionality of observed touching agent. During fMRI scanning, healthy participants viewed video clips depicting a touch that was intentional or accidental, and occurring between animate or inanimate objects. Analyses showed equal overlapping activation for all the touch observation conditions and the experience of one's own body being touched in the bilateral secondary somatosensory cortex (SII), left inferior parietal lobule (IPL)/supramarginal gyrus, bilateral temporal-occipital junction, and left precentral gyrus. A significant difference between the sight of an intentional touch, compared to an accidental touch, was found in the left primary somatosensory cortex (SI/Brodmann's area [BA] 2). Interestingly, activation in SI/BA 2 significantly correlated with the degree of intentionality of the observed touch stimuli as rated by participants. Our findings show that activation of a visuotactile mirroring mechanism for touch observation might underpin an abstract notion of touch, whereas activation in SI might reflect a human tendency to "resonate" more with a present or assumed intentional touching agent.

Action Co-representation is Tuned to Other Humans

The present study attempts to explore the process by which knowledge of another's intentional behavior in a joint-action scenario is represented through the action observation and execution network—also known as the common coding system. Participants (n = 18) were instructed to perform the complementary social Simon task under the implemented belief of interaction with either an unseen human (biological agent) or a computer program, where in fact, all response sequences from either “partner” were generated by computer. Results provide behavioral and neurophysiological evidence (P3 and S-LRP) that the believed intentionality of another person's actions is sufficient to facilitate a strong-enough agency-dependent social Simon effect to modulate action planning and anticipation. We suggest that the co-representation of human action may be an evolved biologically tuned default of the human motor system.

Frontal contributions to face processing differences in autism: evidence from fMRI of inverted face processing

Functional neuroimaging studies of face processing deficits in autism have typically focused on visual processing regions, such as the fusiform face area (FFA), which have shown reduced activity in autism spectrum disorders (ASD), though inconsistently. We recently reported reduced activity in the inferior frontal region in ASD, implicating impaired mirror-neuron systems during face processing. In the present study, we used fMRI during a face processing task in which subjects had to match faces presented in the upright versus inverted position. Typically developing (TD) children showed a classic behavioral inversion effect, increased reaction time for inverted faces, while this effect was significantly reduced in ASD subjects. The fMRI data showed similar responses in the fusiform face area for ASD and TD children, with both groups demonstrating increased activation for inverted faces. However, the groups did differ in several brain regions implicated in social cognition, particularly prefrontal cortex and amygdala. These data suggest that the behavioral differences in processing upright versus inverted faces for TD children are related not to visual information processing but to the social significance of the stimuli. Our results are consistent with other recent studies implicating frontal and limbic dysfunction during face processing in autism.

Virtual Neurorobotics (VNR) to Accelerate Development of Plausible Neuromorphic Brain Architectures

Traditional research in artificial intelligence and machine learning has viewed the brain as a specially adapted information-processing system. More recently the field of social robotics has been advanced to capture the important dynamics of human cognition and interaction. An overarching societal goal of this research is to incorporate the resultant knowledge about intelligence into technology for prosthetic, assistive, security, and decision support applications. However, despite many decades of investment in learning and classification systems, this paradigm has yet to yield truly “intelligent” systems. For this reason, many investigators are now attempting to incorporate more realistic neuromorphic properties into machine learning systems, encouraged by over two decades of neuroscience research that has provided parameters that characterize the brain's interdependent genomic, proteomic, metabolomic, anatomic, and electrophysiological networks. Given the complexity of neural systems, developing tenable models to capture the essence of natural intelligence for real-time application requires that we discriminate features underlying information processing and intrinsic motivation from those reflecting biological constraints (such as maintaining structural integrity and transporting metabolic products). We propose herein a conceptual framework and an iterative method of virtual neurorobotics (VNR) intended to rapidly forward-engineer and test progressively more complex putative neuromorphic brain prototypes for their ability to support intrinsically intelligent, intentional interaction with humans. The VNR system is based on the viewpoint that a truly intelligent system must be driven by emotion rather than programmed tasking, incorporating intrinsic motivation and intentionality. We report pilot results of a closed-loop, real-time interactive VNR system with a spiking neural brain, and provide a video demonstration as online supplemental material.

Neural basis of self and other representation in autism: an FMRI study of self-face recognition

BACKGROUND

Autism is a developmental disorder characterized by decreased interest and engagement in social interactions and by enhanced self-focus. While previous theoretical approaches to understanding autism have emphasized social impairments and altered interpersonal interactions, there is a recent shift towards understanding the nature of the representation of the self in individuals with autism spectrum disorders (ASD). Still, the neural mechanisms subserving self-representations in ASD are relatively unexplored.

METHODOLOGY/PRINCIPAL FINDINGS

We used event-related fMRI to investigate brain responsiveness to images of the subjects' own face and to faces of others. Children with ASD and typically developing (TD) children viewed randomly presented digital morphs between their own face and a gender-matched other face, and made "self/other" judgments. Both groups of children activated a right premotor/prefrontal system when identifying images containing a greater percentage of the self face. However, while TD children showed activation of this system during both self- and other-processing, children with ASD only recruited this system while viewing images containing mostly their own face.

CONCLUSIONS/SIGNIFICANCE

This functional dissociation between the representation of self versus others points to a potential neural substrate for the characteristic self-focus and decreased social understanding exhibited by these individuals, and suggests that individuals with ASD lack the shared neural representations for self and others that TD children and adults possess and may use to understand others.

The pathogenesis of autism

Autism is well known as a complex developmental disorder with a seemingly confusing and uncertain pathogenesis. The definitive mechanisms that promote autism are poorly understood and mostly unknown, yet available theories do appear to focus on the disruption of normal cerebral development and its subsequent implications on the functional brain unit. This mini-review aims solely to discuss and evaluate the most prominent current theories regarding the pathogenesis of autism. The main conclusion is that although there is not a clear pathway of mechanisms directed towards a simple pathogenesis and an established link to autism on the symptomatic level; there are however several important theories (neural connectivity, neural migration, excitatory-inhibitory neural activity, dendritic morphology, neuroimmune; calcium signalling and mirror neurone) which appear to offer an explanation to how autism develops. It seems probable that autism's neurodevelopmental defect is 'multi-domain' in origin (rather than a single anomaly) and is hence distributed across numerous levels of study (genetic, immunopathogenic, etc.). A more definitive understanding of the pathogenesis could facilitate the development of better treatments for this complex psychiatric disorder.

The purpose and neurobiology of theory of mind functions

Theory of Mind (ToM) refers to a cognitive process which allows an individual to "place him/herself" in the other person's "mind," so as to comprehend the latter's cognitive and emotional status, so as to predict his/her behavior and emotional response to a particular situation. ToM is necessary for everyday interaction among individuals and accounts for such human traits as empathy, compassion, and deceit. It is also particularly important in the relationship between a healer and his or her client, as well as in the God-human relationship. Recent research in the area of neurosciences has identified a specific brain "system" responsible for ToM, as well as described how these functions may be affected in certain neuropsychiatric conditions. In this article, we discuss the definition and neurobiological substrate of ToM. In addition, we discuss the cognitive steps important to achieve an "accurate" theory of mind, its relevance to "self-knowledge," and its limitations. We also review some of the data concerning abnormalities and "distortion" of ToM in neuropsychiatric disorders and aberrant human behavior.