Neural Circuits Underlying Imitation Learning of Hand Actions

Mirrored high gamma cortical activity during finger tap imitation

The discovery of mirror neuron system in the macaque study in the 1990s explored a new way to investigate motor imitation. By using the electrocorticographic (ECoG) with high resolution in both spatial and temporal domains, this paper studies brain function during both observation and execution of a simple finger tapping task. Four epilepsy patients were asked to watch simple finger tapping video clips and then imitate the same action themselves. A significant mirrored power increase in the high gamma (HG) band (> 60Hz) have been observed over the superior parietal cortex in the right hemisphere. Furthermore, the power changes in the frequency range 75-95Hz were phase locked to the finger tapping trajectory. The temporal patterns of ECoG power varied during observation and execution, and were similar with the neuronal firing histogram recorded in the macaque imitation study.

Anterior intraparietal cortex codes complexity of observed hand movements

Human and monkey studies clearly show that the anterior intraparietal area (AIP) is crucial for hand-related visuomotor transformations. Human AIP activates also during observation of hand actions, involving it in the mirror system. It is not known, however, whether its activation can also reflect a difference in the complexity of the observed action. In the present study we used functional magnetic resonance imaging (fMRI) to explore the activation of human area AIP during the observation of complex object-manipulation tasks (e.g. inserting a key in a lock and turning it) as compared to simple tasks (whole hand grasping of an object) executed with the left and the right hand in a first person perspective. The results show that, in general, both complex and simple tasks produced an activation of the fronto-parietal mirror system and that the activity of AIP in each hemisphere was higher during observation of the contralateral hand (hand identity effect). A Region-Of-Interest (ROI) analysis of the parietal activations responding to hand identity showed that each AIP was more active during the observation of complex with respect to simple tasks. In the right AIP this effect was stronger during observation of the contralateral hand, in the left AIP was strong during observation of both hands. This complexity-related property was not observed in the other activated areas. These findings support the concept that the observation of motor acts retrieves the internal representation of those same acts in the observer's motor system (direct-matching hypothesis based on the mirror neuron mechanism).

Dissociating networks of imitation

The investigation of imitation, which consists of observation and later reproduction of voluntary actions, promises insights into the complex processes of human actions. Although several aspects concerning the component neural processes necessary for action execution are known, our current understanding of the neural networks underlying these remains sparse. The present study applies independent component analysis (ICA) to functional magnetic resonance imaging (fMRI) data acquired during imitation of abstract gestures and object-related actions. This enables identification of neural networks underlying the production of these imitations. The explorative approach of ICA is complemented by an analysis of time courses from the maxima of each component. Four independent networks were active during delayed imitation. These can be assigned to the aspects of (1) action perception, (2) motor preparation and action execution, (3) encoding and retrieval into and from working memory, as well as (4) the dynamic integration of object affordances into the action. At least two of these networks participate in action preparation, one contains areas involved with motor working memory and one includes areas which are connected to the true action execution. The fourth network only shows activity shortly before an object-related action is imitated. This indicates a late integration of object affordances into the movement as the time course of activity in this network pertains to action rather than perception of the object.

Neurobiology of imitation

Recent research on the neurobiology of imitation has gone beyond the study of its 'core' mechanisms, focus of investigation of the past years.. The current trends can be grouped into four main categories: (1) non 'core' neural mechanisms that are also important for imitation; (2) mechanisms of control, in both imitative learning and inhibition of imitation; (3) the developmental trajectory of neural mechanisms of imitation and their relation with the development of social cognition; (4) neurobiological mechanisms of imitation in non-primates, in particular vocal learning in songbirds, and their relations with similar mechanisms of vocal learning in humans. The existing data suggest that both perceptual and motor aspects of imitation follow organizing principles that originally belonged to the motor system.

From monkey mirror neurons to primate behaviours: possible 'direct' and 'indirect' pathways

The discovery of mirror neurons (MNs), deemed to be at the basis of action understanding, could constitute the potential solution to the 'correspondence problem' between one's own and others' action that is crucial for of imitative behaviours. However, it is still to be clarified whether, and how, several imitative phenomena, differing in terms of complexity and cognitive effort, could be explained within a unified framework based on MNs. Here we propose that MNs could differently contribute to distinct imitative behaviours by means of two anatomo-functional pathways, subjected to changes during development. A 'direct mirror pathway', directly influencing the descending motor output, would be responsible for neonatal and automatic imitation. This proposal is corroborated by some new behavioural evidences provided here. During development, the increased control of voluntary movements and the capacity to efficiently suppress automatic motor activation during action observation assign to the core MNs regions essentially perceptuo-cognitive functions. These functions would be exploited by an 'indirect mirror pathway' from the core regions of the MN system to prefrontal cortex. This latter would play a key role in parsing, storing and organizing motor representations, allowing the emergence of more efficient and complex imitative behaviours such as response facilitation and true imitation.

Comparison of error-amplification and haptic-guidance training techniques for learning of a timing-based motor task by healthy individuals

Performance errors drive motor learning for many tasks. Some researchers have suggested that reducing performance errors with haptic guidance can benefit learning by demonstrating correct movements, while others have suggested that artificially increasing errors will force faster and more complete learning. This study compared the effect of these two techniques--haptic guidance and error amplification--as healthy subjects learned to play a computerized pinball-like game. The game required learning to press a button using wrist movement at the correct time to make a flipper hit a falling ball to a randomly positioned target. Errors were decreased or increased using a robotic device that retarded or accelerated wrist movement, based on sensed movement initiation timing errors. After training with either error amplification or haptic guidance, subjects significantly reduced their timing errors and generalized learning to untrained targets. However, for a subset of more skilled subjects, training with amplified errors produced significantly greater learning than training with the reduced errors associated with haptic guidance, while for a subset of less skilled subjects, training with haptic guidance seemed to benefit learning more. These results suggest that both techniques help enhanced performance of a timing task, but learning is optimized if training subjects with the appropriate technique based on their baseline skill level.

The human mirror neuron system in a population with deficient self-awareness: an fMRI study in alexithymia

The mirror neuron system (MNS) is considered crucial for human imitation and language learning and provides the basis for the development of empathy and mentalizing. Alexithymia (ALEX), which refers to deficiencies in the self-awareness of emotional states, has been reported to be associated with poor ability in various aspects of social cognition such as mentalizing, cognitive empathy, and perspective-taking. Using functional magnetic resonance imaging (fMRI), we measured the hemodynamic signal to examine whether there are functional differences in the MNS activity between participants with ALEX (n = 16) and without ALEX (n = 13), in response to a classic MNS task (i.e., the observation of video clips depicting goal-directed hand movements). Both groups showed increased neural activity in the premotor and the parietal cortices during observation of hand actions. However, activation was greater for the ALEX group than the non-ALEX group. Furthermore, activation in the left premotor area was negatively correlated with perspective-taking ability as assessed with the interpersonal reactivity index. The signal in parietal cortices was negatively correlated with cognitive facets assessed by the stress coping inventory and positively correlated with the neuroticism scale from the NEO five factor personality scale. In addition, in the ALEX group, activation in the right superior parietal region showed a positive correlation with the severity of ALEX as measured by a structured interview. These results suggest that the stronger MNS-related neural response in individuals scoring high on ALEX is associated with their insufficient self-other differentiation.

Evidence for mirror systems in emotions

Why do we feel tears well up when we see a loved one cry? Why do we wince when we see other people hurt themselves? This review addresses these questions from the perspective of embodied simulation: observing the actions and tactile sensations of others activates premotor, posterior parietal and somatosensory regions in the brain of the observer which are also active when performing similar movements and feeling similar sensations. We will show that seeing the emotions of others also recruits regions involved in experiencing similar emotions, although there does not seem to be a reliable mapping of particular emotions onto particular brain regions. Instead, emotion simulation seems to involve a mosaic of affective, motor and somatosensory components. The relative contributions of these components to a particular emotion and their interrelationship are largely unknown, although recent experimental evidence suggests that motor simulation may be a trigger for the simulation of associated feeling states. This mosaic of simulations may be necessary for generating the compelling insights we have into the feelings of others. Through their integration with, and modulation by, higher cognitive functions, they could be at the core of important social functions, including empathy, mind reading and social learning.

Do we really need vision? How blind people "see" the actions of others

Observing and learning actions and behaviors from others, a mechanism crucial for survival and social interaction, engages the mirror neuron system. To determine whether vision is a necessary prerequisite for the human mirror system to develop and function, we used functional magnetic resonance imaging to compare brain activity in congenitally blind individuals during the auditory presentation of hand-executed actions or environmental sounds, and the motor pantomime of manipulation tasks, with that in sighted volunteers, who additionally performed a visual action recognition task. Congenitally blind individuals activated a premotor-temporoparietal cortical network in response to aurally presented actions that overlapped both with mirror system areas found in sighted subjects in response to visually and aurally presented stimuli, and with the brain response elicited by motor pantomime of the same actions. Furthermore, the mirror system cortex showed a significantly greater response to motor familiar than to unfamiliar action sounds in both sighted and blind individuals. Thus, the mirror system in humans can develop in the absence of sight. The results in blind individuals demonstrate that the sound of an action engages the mirror system for action schemas that have not been learned through the visual modality and that this activity is not mediated by visual imagery. These findings indicate that the mirror system is based on supramodal sensory representations of actions and, furthermore, that these abstract representations allow individuals with no visual experience to interact effectively with others.

Goals, intentions and mental states: challenges for theories of autism

The ability to understand the goals and intentions behind other people's actions is central to many social interactions. Given the profound social difficulties seen in autism, we might expect goal understanding to be impaired in these individuals. Two influential theories, the 'broken mirror' theory and the mentalising theory, can both predict this result. However, a review of the current data provides little empirical support for goal understanding difficulties; several studies demonstrate normal performance by autistic children on tasks requiring the understanding of goals or intentions. I suggest that this conclusion forces us to reject the basic broken mirror theory and to re-evaluate the breadth of the mentalising theory. More subtle theories which distinguish between different types of mirroring and different types of mentalising may be able to account for the present data, and further research is required to test and refine these theories.

Interindividual differences in neonatal imitation and the development of action chains in rhesus macaques

The capacity to imitate facial gestures is highly variable in rhesus macaques and this variability may be related to differences in specific neurobehavioral patterns of development. This study evaluated the differential neonatal imitative response of 41 macaques in relation to the development of sensory, motor, and cognitive skills throughout the 1st month of life. The results show that infants who imitate facial gestures display more developed skills in goal-directed movements (reaching-grasping and fine hand motor control) than nonimitators. These differences might reflect, at least in part, the differential maturation of motor chains in the parietal and motor cortices, which partly overlap with those of the mirror neuron system. Thus, neonatal imitation appears to be a predictor of future neurobehavioral development.

Evolving the language-ready brain and the social mechanisms that support language

We first review the mirror-system hypothesis on the evolution of the language-ready brain, stressing the important role of imitation and protosign in providing the scaffolding for protospeech. We then assess the role of social interaction and non-specific knowledge of language in the emergence of new sign languages in deaf communities (focusing on Nicaraguan Sign Language).

LEARNING OUTCOMES

(1) Readers will understand the difference between mirror systems in humans and monkeys, and see how the evolution of imitation and protosign required the biological evolution of mirror systems with linkages to diverse regions beyond the mirror system. (2) Readers will see how social structure complements brain mechanisms in yielding language through cultural evolution supported by having language-ready brains, rather than through possession of an innate Universal Grammar. (3) Readers will understand that ontogeny does not recapitulate phylogeny, but will appreciate what mechanisms currently operative in modern children acquiring language may also have served early humans during the cumulative invention of the idea of language.

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.

Activation of the left inferior frontal gyrus in the first 200 ms of reading: evidence from magnetoencephalography (MEG)

BACKGROUND

It is well established that the left inferior frontal gyrus plays a key role in the cerebral cortical network that supports reading and visual word recognition. Less clear is when in time this contribution begins. We used magnetoencephalography (MEG), which has both good spatial and excellent temporal resolution, to address this question.

METHODOLOGY/PRINCIPAL FINDINGS

MEG data were recorded during a passive viewing paradigm, chosen to emphasize the stimulus-driven component of the cortical response, in which right-handed participants were presented words, consonant strings, and unfamiliar faces to central vision. Time-frequency analyses showed a left-lateralized inferior frontal gyrus (pars opercularis) response to words between 100-250 ms in the beta frequency band that was significantly stronger than the response to consonant strings or faces. The left inferior frontal gyrus response to words peaked at approximately 130 ms. This response was significantly later in time than the left middle occipital gyrus, which peaked at approximately 115 ms, but not significantly different from the peak response in the left mid fusiform gyrus, which peaked at approximately 140 ms, at a location coincident with the fMRI-defined visual word form area (VWFA). Significant responses were also detected to words in other parts of the reading network, including the anterior middle temporal gyrus, the left posterior middle temporal gyrus, the angular and supramarginal gyri, and the left superior temporal gyrus.

CONCLUSIONS/SIGNIFICANCE

These findings suggest very early interactions between the vision and language domains during visual word recognition, with speech motor areas being activated at the same time as the orthographic word-form is being resolved within the fusiform gyrus. This challenges the conventional view of a temporally serial processing sequence for visual word recognition in which letter forms are initially decoded, interact with their phonological and semantic representations, and only then gain access to a speech code.

Motor abstraction: a neuroscientific account of how action goals and intentions are mapped and understood

Recent findings in cognitive neuroscience shed light on the existence of a common neural mechanism that could account for action and intention to understand abilities in humans and non-human primates. Empirical evidence on the neural underpinnings of action goals and on their ontogeny and phylogeny is introduced and discussed. It is proposed that the properties of the mirror neuron system and the functional mechanism describing them, embodied simulation, enabled pre-linguistic forms of action and intention understanding. Basic aspects of social cognition appear to be primarily based on the motor cognition that underpins one's own capacity to act, here defined as motor abstraction. On the basis of this new account of the motor system, it is proposed that intersubjectivity is the best conceived of as intercorporeity.

Neurofunctional modulation of brain regions by distinct forms of motor cognition and movement features

Extrastriate, parietal, and frontal brain regions are differentially involved in distinct kinds of body movements and motor cognition. Using functional magnetic resonance imaging, we investigated the neural mechanisms underlying the observation and mental imagery of meaningful face and limb movements with or without objects. The supplementary motor area was differentially recruited by the mental imagery of movements while there were differential responses of the extrastriate body area (EBA) during the observation conditions. Contrary to most previous reports, the EBA responded to face movements, albeit to a lesser degree than to limb movements. The medial wall of the intraparietal sulcus and adjacent intraparietal cortex was selectively recruited by the processing of meaningful upper limb movements, irrespective of whether these were object-related or not. Besides reach and grasp movements, the intraparietal sulcus may thus be involved in limb gesture processing, that is, in an important aspect of human social communication. We conclude that subregions of a frontal-parietal network differentially interact during the cognitive processing of body movements according to the specific motor-related task at hand and the particular movement features involved.

Mirror neurons and the social nature of language: the neural exploitation hypothesis

This paper discusses the relevance of the discovery of mirror neurons in monkeys and of the mirror neuron system in humans to a neuroscientific account of primates' social cognition and its evolution. It is proposed that mirror neurons and the functional mechanism they underpin, embodied simulation, can ground within a unitary neurophysiological explanatory framework important aspects of human social cognition. In particular, the main focus is on language, here conceived according to a neurophenomenological perspective, grounding meaning on the social experience of action. A neurophysiological hypothesis--the "neural exploitation hypothesis"--is introduced to explain how key aspects of human social cognition are underpinned by brain mechanisms originally evolved for sensorimotor integration. It is proposed that these mechanisms were later on adapted as new neurofunctional architecture for thought and language, while retaining their original functions as well. By neural exploitation, social cognition and language can be linked to the experiential domain of action.

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.

Broca's area: nomenclature, anatomy, typology and asymmetry

In this review, we (i) describe the nomenclature of Broca's area and show how the circumscribed definition of Broca's area is disassociated from Broca's aphasia, (ii) describe in detail how the gross anatomy of Broca's area varies between people, and how the definitions vary between studies, (iii) attempt to reconcile the findings of structural asymmetry of Broca's area with the differences in methodological approaches, (iv) consider the functional significance of cytoarchitectonic definitions of Broca's area, and (v) critically elucidate the significance of circumscribed regions of cortex for language lateralisation and language development. Contrary to what has previously been reported in the literature, asymmetry of Broca's area has not been reproducibly demonstrated, particularly on a gross morphological level. This may be due to major inconsistencies in methodology (including different anatomical boundaries, measurement techniques and samples studied) or that the sulcal contours defining Broca's area are so naturally variable between people making a standard definition difficult. Cytoarchitectonic analyses more often than not report leftward asymmetry of some component of area 44 and/or area 45. If a structural asymmetry of Broca's area does exist, it is variable, which differs from that of the functional asymmetry of language, which is more consistent. One reason for this might be that the link between cellular architecture, connectivity and language function still remains to be elucidated. There is currently no convincing explanation to associate asymmetry of Broca's area with the lateralisation of language.

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.

Bilateral motor resonance evoked by observation of a one-hand movement: role of the primary motor cortex

In humans, observation of movement performed by others evokes a subliminal motor resonant response, probably mediated by the mirror neurone system, which reproduces the motor commands needed to execute the observed movement with good spatial and temporal fidelity. Motor properties of the resonant response were here investigated with the ultimate goal of understanding the principles operating in the transformation from observation to internal reproduction of movement. Motor resonance was measured as the modulation of excitability of spinal motoneurones, evoked by the observation of a cyclic flexion-extension of one hand. The first two experiments showed that the observation of a one-hand movement always evoked a bimanual resonant response independent of which hand was observed and that these bilateral responses were consistently phase-linked. H-reflexes simultaneously recorded in right and left flexor carpi radialis muscles were always modulated 'in-phase' with each other. The goal of the third experiment was to define the role of primary motor cortex in the bilateral resonant response. Bilateral H-reflexes were recorded during a temporary inactivation induced by transcranial magnetic stimulation over the left cortical hand motor area of observers. The finding that such cortical depression abolished the H-reflex modulation of only the right flexor carpi radialis motoneurones, leaving it unchanged on the left side, suggested that both primary motor areas were activated by the premotor cortex and transmit the resonant activation through crossed corticospinal pathways. The data provide further evidence that the subliminal activation of motor pathways induced by movement observation is organized according to general rules shared with the control of voluntary movement.

Culture in the mind's mirror: how anthropology and neuroscience can inform a model of the neural substrate for cultural imitative learning

Cultural neuroscience, the study of how cultural experience shapes the brain, is an emerging subdiscipline in the neurosciences. Yet, a foundational question to the study of culture and the brain remains neglected by neuroscientific inquiry: "How does cultural information get into the brain in the first place?" Fortunately, the tools needed to explore the neural architecture of cultural learning - anthropological theories and cognitive neuroscience methodologies - already exist; they are merely separated by disciplinary boundaries. Here we review anthropological theories of cultural learning derived from fieldwork and modeling; since cultural learning theory suggests that sophisticated imitation abilities are at the core of human cultural learning, we focus our review on cultural imitative learning. Accordingly we proceed to discuss the neural underpinnings of imitation and other mechanisms important for cultural learning: learning biases, mental state attribution, and reinforcement learning. Using cultural neuroscience theory and cognitive neuroscience research as our guides, we then propose a preliminary model of the neural architecture of cultural learning. Finally, we discuss future studies needed to test this model and fully explore and explain the neural underpinnings of cultural imitative learning.

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.

Ideomotor action in cooperative and competitive settings

Ideomotor movements may arise in observers while they watch other people's actions. Previous studies have shown that ideomotor movements are guided by both perceptual and intentional characteristics of the actions being observed (perceptual induction and intentional induction, respectively; cf. Knuf, Aschersleben, & Prinz, 2001; de Maeght & Prinz, 2004). In the present study we explore the functional basis of intentional induction. More specifically we raise the issue of whose intentions count for intentional induction: observers' own intentions or observees' (implied) intentions? We studied ideomotor movements in a cooperative and a competitive task setting. In the cooperative setting observers' and observees' intentions were identical, but in the competitive setting they were different. Results indicate that ideomotor movements are guided by the observers' own intentions, not the observees' implied intentions. Our findings suggest that, though observers understand the intentions of others, their ideomotor movements are guided by their own intentions, expressing what they themselves wish to see the other is doing.

Neural dynamics of learning sound-action associations

A motor component is pre-requisite to any communicative act as one must inherently move to communicate. To learn to make a communicative act, the brain must be able to dynamically associate arbitrary percepts to the neural substrate underlying the pre-requisite motor activity. We aimed to investigate whether brain regions involved in complex gestures (ventral pre-motor cortex, Brodmann Area 44) were involved in mediating association between novel abstract auditory stimuli and novel gestural movements. In a functional resonance imaging (fMRI) study we asked participants to learn associations between previously unrelated novel sounds and meaningless gestures inside the scanner. We use functional connectivity analysis to eliminate the often present confound of ‘strategic covert naming’ when dealing with BA44 and to rule out effects of non-specific reductions in signal. Brodmann Area 44, a region incorporating Broca's region showed strong, bilateral, negative correlation of BOLD (blood oxygen level dependent) response with learning of sound-action associations during data acquisition. Left-inferior-parietal-lobule (l-IPL) and bilateral loci in and around visual area V5, right-orbital-frontal-gyrus, right-hippocampus, left-para-hippocampus, right-head-of-caudate, right-insula and left-lingual-gyrus also showed decreases in BOLD response with learning. Concurrent with these decreases in BOLD response, an increasing connectivity between areas of the imaged network as well as the right-middle-frontal-gyrus with rising learning performance was revealed by a psychophysiological interaction (PPI) analysis. The increasing connectivity therefore occurs within an increasingly energy efficient network as learning proceeds. Strongest learning related connectivity between regions was found when analysing BA44 and l-IPL seeds. The results clearly show that BA44 and l-IPL is dynamically involved in linking gesture and sound and therefore provides evidence that one of the mechanisms required for the evolution of human communication is found within these motor regions.

The observation and execution of actions share motor and somatosensory voxels in all tested subjects: single-subject analyses of unsmoothed fMRI data

Many neuroimaging studies of the mirror neuron system (MNS) examine if certain voxels in the brain are shared between action observation and execution (shared voxels, sVx). Unfortunately, finding sVx in standard group analyses is not a guarantee that sVx exist in individual subjects. Using unsmoothed, single-subject analyses we show sVx can be reliably found in all 16 investigated participants. Beside the ventral premotor (BA6/44) and inferior parietal cortex (area PF) where mirror neurons (MNs) have been found in monkeys, sVx were reliably observed in dorsal premotor, supplementary motor, middle cingulate, somatosensory (BA3, BA2, and OP1), superior parietal, middle temporal cortex and cerebellum. For the premotor, somatosensory and parietal areas, sVx were more numerous in the left hemisphere. The hand representation of the primary motor cortex showed a reduced BOLD during hand action observation, possibly preventing undesired overt imitation. This study provides a more detailed description of the location and reliability of sVx and proposes a model that extends the original idea of the MNS to include forward and inverse internal models and motor and sensory simulation, distinguishing the MNS from a more general concept of sVx.

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.

Unidirectional interference in use of nondominant hand during concurrent Grooved Pegboard and random number generation tasks

The interference effect between Grooved Pegboard task with either hand and the executive task of cued verbal random number generation was investigated. 24 normal right-handed subjects performed each task under separate (single-task) and concurrent (dual-task) conditions. Articulatory suppression was required as an additional secondary task during pegboard performance. Analysis indicated an unambiguous distinction between the two hands. Comparisons of single-task and dual-task conditions showed an asymmetrical pattern of unidirectional interference with no practice effects during pegboard performance. Concurrent performance with nondominant hand but not the dominant hand of random number generation performance became continuously slower. There was no effect of divided attention on pegboard performance. Findings support the idea that the nondominant hand on the pegboard and random number tasks draw from the same processing resources but that for the executive aspect random number generation is more sensitive to changes in allocation of attentional resources.

Novel activity-dependent approaches to therapeutic hypnosis and psychotherapy: the general waking trance

This paper presents a highly edited version of a videotape made in 1980 by Marion Moore, M.D., showing Milton H. Erickson and Moore demonstrating novel, activity-dependent approaches to hand-levitation and therapeutic hypnosis on their subject, Ernest Rossi. Erickson's naturalistic and utilization approach is described in his very direct and surprising induction in a trance challenged patient. These novel, and surprising inductions are examples of how Erickson was prescient in developing activity-dependent approaches to therapeutic hypnosis and psychotherapy several generations before modern neuroscience documented the activity-dependent molecular-genomic mechanisms of memory, learning, and behavior change. Erickson describes a case where he utilized what he called, "The General Waking Trance" when he "dared" not use an obvious hypnotic induction. It is proposed that the states of intense mental absorption and response attentiveness that are facilitated by the general waking trance are functionally related to the three conditions neuroscientists have identified as novelty, enrichment, and exercise (both mental and physical), which can turn on activity-dependent gene expression and activity-dependent brain plasticity, that are the molecular-genomic and neural basis ofmemory, learning, consciousness, and behavior change. We recommend that the next step in investigating the efficacy of therapeutic hypnosis will be in partnering with neuroscientists to explore the possibilities and limitations of utilizing the activity-dependent approaches to hypnotic induction and the general waking trance in facilitating activity-dependent gene expression and brain plasticity.

Gesture subtype-dependent left lateralization of praxis planning: an event-related fMRI study

Ideomotor apraxia is a disorder mainly of praxis planning, and the deficit is typically more evident in pantomiming transitive (tool related) than intransitive (communicative) gestures. The goal of the present study was to assess differential hemispheric lateralization of praxis production using event-related functional magnetic resonance imaging. Voxel-based analysis demonstrated significant activations in posterior parietal cortex (PPC) and premotor cortex (PMC) association areas, which were predominantly left hemispheric, regardless of whether planning occurred for right or left hand transitive or intransitive pantomimes. Furthermore, region of interest-based calculation of mean laterality index (LI) revealed a significantly stronger left lateralization in PPC/PMC clusters for planning intransitive (LI = -0.49 + 0.10, mean + standard deviation [SD]) than transitive gestures (-0.37 + 0.08, P = 0.02, paired t-tests) irrespective of the hand involved. This differential left lateralization for planning remained significant in PMC (LI = -0.47 + 0.14 and -0.36 + 0.13, mean + SD, P = 0.04), but not in PPC (-0.56 + 0.11 and -0.45 + 0.12, P = 0.11), when both regions were analyzed separately. In conclusion, the findings point to a left-hemispheric specialization for praxis planning, being more pronounced for intransitive gestures in PMC, possibly due to their communicative nature.

Empathy and identification in Von Donnersmarck's The Lives of Others

Florian Henckel von Donnersmarck's The Lives of Others, set in the German Democratic Republic in 1984, five years before the fall of the Berlin Wall, has been called the first accurate depiction of the psychological terror wielded by the Stasi, the East German secret police, who safeguarded the dictatorship of the proletariat. The film is about the psychological and political transformation of a Stasi officer, Wiesler, who undertakes the surveillance of a prominent playwright and his actress lover. The mechanisms through which Wiesler comes to empathize and identify with the subjects of his investigation, as he observes and listens in on the rich blend of passion, poetry, and politics that characterizes their lives, are explored in depth. Wiesler's transformation is based in part on the capacity to form implicit models of the behavior and experiences of others, based on the mirror neuron system, that Gallese and his colleagues call "embodied simulation." Underpinning the processes of empathy and identification so central to this film, embodied simulation is an unconscious and prereflexive mechanism through which the actions, emotions, and sensations we observe activate internal representations of the bodily and mental states of the other. Embodied simulation also expands our understanding of the power of the primal scene, which has long been identified as a major organizer of unconscious fantasies and conflicts throughout life, and which forms the central metaphor of the film. Embodied simulation scaffolds our aesthetic response to art, music, and literature, underlies the dynamics of spectatorship, and potentially catalyzes resistance to totalitarian mass movements.

Mirror neurons and mirror systems in monkeys and humans

Mirror neurons are a distinct class of neurons that transform specific sensory information into a motor format. Mirror neurons have been originally discovered in the premotor and parietal cortex of the monkey. Subsequent neurophysiological (TMS, EEG, MEG) and brain imaging studies have shown that a mirror mechanism is also present in humans. According to its anatomical locations, mirror mechanism plays a role in action and intention understanding, imitation, speech, and emotion feeling.