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Action Observation (action + observation)

Distribution by Scientific Domains

Life Sciences	71%

Selected Abstracts

Concurrent action observation modulates practice-induced motor memory formation

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2008
K. Stefan
Abstract Motor practice is associated with the formation of elementary motor memories. Here we tested in human subjects the hypothesis that observation of a motor training associated with physical practice will modulate the encoding process of a motor memory relative to physical practice alone. Voluntary thumb motions were practiced (i) alone in a direction opposite to the baseline direction of transcranial magnetic stimulation (TMS)-evoked movements (physical practice, PP) and in combination with observation of synchronous movements that were either (ii) directionally congruent (same direction, PP + AOc) or (iii) non-congruent (opposite direction, PP + AOnc) to the practiced ones. We evaluated the following measures of motor memory formation: percentage of TMS-evoked thumb movements falling in the direction of practiced motions, acceleration of TMS-evoked movements along the principal movement axis and corticomuscular excitability of training muscles as indexed by motor-evoked potential amplitudes. Both PP and PP + AOc, but not PP + AOnc, significantly increased the percentage of TMS-evoked movements falling in the practiced direction, changed the compound acceleration vector into the trained direction and enhanced the motor-evoked potential amplitudes in the training agonist muscle. The percentage of TMS-evoked movements falling in the practiced direction increased significantly more after PP + AOc than after PP. Across all measures of motor memory formation, PP + AOc was most efficacious, followed by PP and PP + AOnc. Action observation modulates practice effects on formation of a motor memory. Strengthening of the process of motor memory encoding depends on the directional congruency of the observed model. [source]

Neurons in primary motor cortex engaged during action observation

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2010
Juliana Dushanova
Abstract Neurons in higher cortical areas appear to become active during action observation, either by mirroring observed actions (termed mirror neurons) or by eliciting mental rehearsal of observed motor acts. We report the existence of neurons in the primary motor cortex (M1), an area that is generally considered to initiate and guide movement performance, responding to viewed actions. Multielectrode recordings in monkeys performing or observing a well-learned step-tracking task showed that approximately half of the M1 neurons that were active when monkeys performed the task were also active when they observed the action being performed by a human. These ,view' neurons were spatially intermingled with ,do' neurons, which are active only during movement performance. Simultaneously recorded ,view' neurons comprised two groups: approximately 38% retained the same preferred direction (PD) and timing during performance and viewing, and the remainder (62%) changed their PDs and time lag during viewing as compared with performance. Nevertheless, population activity during viewing was sufficient to predict the direction and trajectory of viewed movements as action unfolded, although less accurately than during performance. ,View' neurons became less active and contained poorer representations of action when only subcomponents of the task were being viewed. M1 ,view' neurons thus appear to reflect aspects of a learned movement when observed in others, and form part of a broadly engaged set of cortical areas routinely responding to learned behaviors. These findings suggest that viewing a learned action elicits replay of aspects of M1 activity needed to perform the observed action, and could additionally reflect processing related to understanding, learning or mentally rehearsing action. [source]

Concurrent action observation modulates practice-induced motor memory formation

Effects of different viewing perspectives on somatosensory activations during observation of touch

HUMAN BRAIN MAPPING, Issue 9 2009
Michael Schaefer
Abstract Previous studies showed that neurons in the monkey premotor cortex became active when performing a particular action and also when observing the same action performed by others. These findings suggest a mirror system for action observation. Recently, bimodal neurons, sensitive both to visual and tactile stimulation, were reported in the parietal cortex, suggesting a potential mirror neuron system for observing and experiencing tactile stimulation. Subsequently, a mirror neuron system for observed touch has been suggested. The current study was designed to determine whether the activation of a sensory mirror system during touch observation is affected by possible attributions of the observed touch to oneself (subjective view) or to somebody else (objective view). In the study, healthy volunteers observed video clips of a touched or nontouched hand either in an egocentric or in an allocentric perspective during functional magnetic resonance imaging. Results showed activation of somatosensory cortices when observing the hand being touched in egocentric as well as in the allocentric perspectives. Moreover, somatosensory responses differed depending on the perspective of the observed touch. We discuss the results in terms of a possible mirror neuron system for observed and experienced touch. Hum Brain Mapp 2009. © 2009 Wiley-Liss, Inc. [source]

Common Coding of Observation and Execution of Action in 9-Month-Old Infants

INFANCY, Issue 1 2006
Matthew R. Longo
Do 9-month-old infants motorically simulate actions they perceive others perform? Two experiments tested whether action observation, like overt reaching, is sufficient to elicit the Piagetian A-not-B error. Infants recovered a toy hidden at location A or observed an experimenter recover the toy. After the toy was hidden at location B, infants in both conditions perseverated in reaching to A, demonstrating that active search by the infant is not necessary for the A-not-B error. Consistent with prior research, infants displayed an ipsilateral bias when reaching, the so-called mysterious midline barrier. A similar ipsilateral bias was also observed depending on the manner in which the experimenter reached; infants perseverated following observation of ipsi- but not contralateral reaches by the experimenter. Thus, infants perseverated only following observation of actions they themselves were able to perform, suggesting that they coded others' actions in terms of motor simulation. [source]

Unbroken mirror neurons in autism spectrum disorders

THE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 9 2010
Yang-Teng Fan
Background:, The ,broken mirror' theory of autism, which proposes that a dysfunction of the human mirror neuron system (MNS) is responsible for the core social and cognitive deficits in individuals with autism spectrum disorders (ASD), has received considerable attention despite weak empirical evidence. Methods:, In this electroencephalographic study, we examined mu suppression, as an indicator of sensorimotor resonance, concurrent with oculomotor performance while individuals (n = 20) with ASD and control participants (n = 20) either executed hand actions or observed hand actions or a moving dot. No difference in visual attention between groups was found as indicated by fixation duration and normalized fixation number on the presented stimuli. Results:, The mu suppression over the sensorimotor cortex was significantly affected by experimental conditions, but not by group membership, nor by the interaction between groups and conditions. Individuals with ASD, similar to the controls, exhibited stronger mu suppression when watching hand actions relative to a moving dot. Notably, participants with ASD failed to imitate the observed actions while their mu suppression indicating the MNS activity was intact. In addition, the mu suppression during the observation of hand actions was positively associated with the communication competence of individuals with ASD. Conclusion:, Our study clearly challenges the broken mirror theory of autism. The functioning of the mirror neuron system might be preserved in individuals with ASD to a certain degree. Less mu suppression to action observation coupled with more communicational severity can reflect the symptom heterogeneity of ASD. Additional research needs to be done, and more caution should be used when reaching out to the media. [source]