title: Effects of different viewing perspectives on somatosensory activations during observation of touch.
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.
authors.affiliation: Human Cortical Physiology Section and Stroke Neurorehabilitation Clinic, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA. mischa@neuro2.med.uni-magdeburg.de
authors.forename: Michael
authors.initials: M
authors.lastname: Schaefer
authors.forename: Benjamin
authors.initials: B
authors.lastname: Xu
authors.forename: Herta
authors.initials: H
authors.lastname: Flor
authors.forename: Leonardo G
authors.initials: LG
authors.lastname: Cohen
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods; D004532:Ego; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007092:Imagination / Q000502:physiology; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009039:Motion Perception / Q000502:physiology; D009434:Neural Pathways / Q000033:anatomy & histology / Q000502:physiology; D009474:Neurons / Q000502:physiology; D019370:Observation / Q000379:methods; D009949:Orientation / Q000502:physiology; D010296:Parietal Lobe / Q000033:anatomy & histology / Q000502:physiology; D010364:Pattern Recognition, Visual / Q000502:physiology; D010812:Physical Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D011601:Psychophysics / Q000379:methods; D013003:Somatosensory Cortex / Q000502:physiology*; D013028:Space Perception / Q000502:physiology; D014110:Touch / Q000502:physiology*; D055698:Touch Perception / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*