Time course analyses confirm independence of automatic imitation and spatial compatibility effects

Automatic imitation has been used as a behavioural index of the functioning of the human mirror system (e.g. Brass, Bekkering, Wohlschlager, & Prinz, 2000; Heyes, Bird, Johnson, & Haggard, 2005; Kilner, Paulignan, & Blakemore, 2003). However, several papers have criticised the assumption that automatic imitation is mediated by the mirror system on the grounds that automatic imitation has been confounded with simple spatial compatibility (Aicken, Wilson, Williams, & Mon-Williams, 2007; Bertenthal, Longo, and Kosobud, 2006; Jansson, Wilson, Williams, & Mon-Williams, 2007). Two experiments are reported in which, in contrast with previous studies, automatic imitation was measured on both spatially compatible and spatially incompatible trials, and automatic imitation was shown to be present regardless of spatial compatibility. Additional features of the two experiments allowed measurement of the time courses of the automatic imitation and spatial compatibility effects both within and across trials. It was found that automatic imitation effects follow a different time course from spatial compatibility effects, providing further evidence for their independence and supporting the use of automatic imitation as a behavioural marker of mirror system functioning

Mirror Adaptation in Sensory-Motor Simultaneity

Background: When one watches a sports game, one may feel her/his own muscles moving in synchrony with the player's. Such parallels between observed actions of others and one's own has been well supported in the latest progress in neuroscience, and coined “mirror system.” It is likely that due to such phenomena, we are able to learn motor skills just by observing an expert's performance. Yet it is unknown whether such indirect learning occurs only at higher cognitive levels, or also at basic sensorimotor levels where sensorimotor delay is compensated and the timing of sensory feedback is constantly calibrated. Methodology/Principal Findings: Here, we show that the subject's passive observation of an actor manipulating a computer mouse with delayed auditory feedback led to shifts in subjective simultaneity of self mouse manipulation and auditory stimulus in the observing subjects. Likewise, self adaptation to the delayed feedback modulated the simultaneity judgment of the other subjects manipulating a mouse and an auditory stimulus. Meanwhile, subjective simultaneity of a simple visual disc and the auditory stimulus (flash test) was not affected by observation of an actor nor self-adaptation. Conclusions/Significance: The lack of shift in the flash test for both conditions indicates that the recalibration transfer is specific to the action domain, and is not due to a general sensory adaptation. This points to the involvement of a system for the temporal monitoring of actions, one that processes both one's own actions and those of others

Translating novel findings of perceptual-motor codes into the neuro-rehabilitation of movement disorders

The bidirectional flow of perceptual and motor information has recently proven useful as rehabilitative tool for re-building motor memories. We analyzed how the visual-motor approach has been successfully applied in neurorehabilitation, leading to surprisingly rapid and effective improvements in action execution. We proposed that the contribution of multiple sensory channels during treatment enables individuals to predict and optimize motor behavior, having a greater effect than visual input alone. We explored how the state-of-the-art neuroscience techniques show direct evidence that employment of visual-motor approach leads to increased motor cortex excitability and synaptic and cortical map plasticity. This super-additive response to multimodal stimulation may maximize neural plasticity, potentiating the effect of conventional treatment, and will be a valuable approach when it comes to advances in innovative methodologies

Multiple roles of motor imagery during action observation

Over the last 20 years, the topics of action observation (AO) and motor imagery (MI) have been largely studied in isolation from each other, despite the early integrative account by Jeannerod (1994, 2001). Recent neuroimaging studies demonstrate enhanced cortical activity when AO and MI are performed concurrently (“AO+MI”), compared to either AO or MI performed in isolation. These results indicate the potentially beneficial effects of AO+MI, and they also demonstrate that the underlying neurocognitive processes are partly shared. We separately review the evidence for MI and AO as forms of motor simulation, and present two quantitative literature analyses that indeed indicate rather little overlap between the two bodies of research. We then propose a spectrum of concurrent AO+MI states, from congruent AO+MI where the contents of AO and MI widely overlap, over coordinative AO+MI, where observed and imagined action are different but can be coordinated with each other, to cases of conflicting AO+MI. We believe that an integrative account of AO and MI is theoretically attractive, that it should generate novel experimental approaches, and that it can also stimulate a wide range of applications in sport, occupational therapy, and neurorehabilitation

A Review of Verbal and Non-Verbal Human-Robot Interactive Communication

In this paper, an overview of human-robot interactive communication is presented, covering verbal as well as non-verbal aspects of human-robot interaction. Following a historical introduction, and motivation towards fluid human-robot communication, ten desiderata are proposed, which provide an organizational axis both of recent as well as of future research on human-robot communication. Then, the ten desiderata are examined in detail, culminating to a unifying discussion, and a forward-looking conclusion

Brief Report: Visuo-spatial Guidance of Movement during Gesture Imitation and Mirror Drawing in Children with Autism Spectrum Disorders

Thirteen autistic and 14 typically developing children (controls) imitated hand/arm gestures and performed mirror drawing; both tasks assessed ability to reorganize the relationship between spatial goals and the motor commands needed to acquire them. During imitation, children with autism were less accurate than controls in replicating hand shape, hand orientation, and number of constituent limb movements. During shape tracing, children with autism performed accurately with direct visual feedback, but when viewing their hand in a mirror, some children with autism generated fewer errors than controls whereas others performed much worse. Large mirror drawing errors correlated with hand orientation and hand shape errors in imitation, suggesting that visuospatial information processing deficits may contribute importantly to functional motor coordination deficits in autism

Rethinking Phylogeny and Ontogeny in Hominin Brain Evolution

Theories of hominin and human cognitive evolution have traditionally focused on the phylogeny of the human brain, and on comparisons of human and primate brains in relation to social or ecological variables. Far less attention has been paid to ontogenetic processes, despite the recognition that experience has a profound influence on adult cognition. In this paper we discuss the interplay between phylogeny and ontogeny by examining relationships between human brain size, developmental scheduling and cognition. The correlates of large brains include not only altered subsistence and life-history strategies to meet associated energetic costs, but also on macro- and micro-scale structural adaptations required to meet increased processing costs. This means that larger brains are of necessity more highly interconnected brains, with higher degrees of folding of the neocortex (gyrification) and higher ratios of myelinated connections between neurons (white matter) to neurons themselves (grey matter). Here we argue that the combination of these evolutionary trends underpins the complexity of human behaviour, as the neural circuits involved in cognitive mechanisms such as the mirror neuron system (the system governing motor emulation and imitation) and theory of mind (fundamental in social cognition) mature only slowly, and require considerable socially-scaffolded experience to develop to their full potential. These abilities are likely to be fundamental in characteristically human behaviours such as the cultural transmission of complex forms of tool manufacture and use, attested to in the archaeological record. Their elaborated modern human forms, we argue, are possible only in the context of the evolution of relatively slower trajectories of brain growth and hence longer periods during which the growing brain can be influenced by experience among modern humans relative to other primates. Here we review some of the differences in ontogenetic brain development between humans and other primates, and compare the rates and trajectories of neural development between ourselves and our closest living relatives the chimpanzees to suggest that the human pattern of expanded periods of growth coupled with slower trajectories of neural development is likely to have been of huge significance during hominin evolution. In addition, we discuss fossil and archaeological proxies which might allow the reconstruction of evolutionary patterns of development, suggesting that it is only post-Homo erectus and specifically among Homo heidelbergensis and Homo neanderthalensis populations that developmental patterns approximate those of modern humans, arguing for a similar – but not identical – role for socially-scaffolded learning of complex technical skills as among modern groups in these species

Time-Contrastive Networks: Self-Supervised Learning from Video

We propose a self-supervised approach for learning representations and robotic behaviors entirely from unlabeled videos recorded from multiple viewpoints, and study how this representation can be used in two robotic imitation settings: imitating object interactions from videos of humans, and imitating human poses. Imitation of human behavior requires a viewpoint-invariant representation that captures the relationships between end-effectors (hands or robot grippers) and the environment, object attributes, and body pose. We train our representations using a metric learning loss, where multiple simultaneous viewpoints of the same observation are attracted in the embedding space, while being repelled from temporal neighbors which are often visually similar but functionally different. In other words, the model simultaneously learns to recognize what is common between different-looking images, and what is different between similar-looking images. This signal causes our model to discover attributes that do not change across viewpoint, but do change across time, while ignoring nuisance variables such as occlusions, motion blur, lighting and background. We demonstrate that this representation can be used by a robot to directly mimic human poses without an explicit correspondence, and that it can be used as a reward function within a reinforcement learning algorithm. While representations are learned from an unlabeled collection of task-related videos, robot behaviors such as pouring are learned by watching a single 3rd-person demonstration by a human. Reward functions obtained by following the human demonstrations under the learned representation enable efficient reinforcement learning that is practical for real-world robotic systems. Video results, open-source code and dataset are available at https://sermanet.github.io/imitat

Description of interhemispheric disconnection syndrome in a patient with Marchiafava-Bignami disease

Interhemispheric disconnection syndrome (IDS), described by Sperry, Gazzaniga and Bogen, is characterized by the presence of visual and tactile anomia, absence of interhemispheric transference of unilateral somatosensory stimulation of both hands, hemialexia and unilateral left-side apraxia. Subsequently, changes were also observed in the sensory interhemispheric transfer and in tests of crossed motor control. In Marchiafava-Bignami disease (MBD) there have been descriptions of partial IDS. The aim is to describe the dissociations in IDS that are presented in a patient with MBD, using a specialized assessment methodology. Patient and Method: A 54-year-old patient, righthanded, with 11 years of schooling, presented with antecedent chronic alcoholism. Neuropsychological tests were administered for general assessment along with specific tests of interhemispheric transference. Results: Borderline changes were found in visual memory, visual-constructive abilities and attention and executive functioning. In tasks of interhemispheric transference the patient showed changes in: the imitation of hand poses; inter-manual pressure point localization (tactile stimulation); reading aloud of words by visual hemifield; and movement control. Conclusion: Our patient showed a wide lesion of the Corpus Callosum (CC) with relative preservation of the splenium, accompanied by partial disconnection syndrome in the context of a global cognitive deterioration from his chronic alcoholism.Fil: Politis, Daniel Gustavo. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tirigay, Romina Mara. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Gómez, Pablo Guillermo. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tabernero, María Eugenia. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin