Viewing the body modulates tactile receptive fields

Tactile discrimination performance depends on the receptive field (RF) size of somatosensory cortical (SI) neurons. Psychophysical masking effects can reveal the RF of an idealized “virtual” somatosensory neuron. Previous studies show that top–down factors strongly affect tactile discrimination performance. Here, we show that non-informative vision of the touched body part influences tactile discrimination by modulating tactile RFs. Ten subjects performed spatial discrimination between touch locations on the forearm. Performance was improved when subjects saw their forearm compared to viewing a neutral object in the same location. The extent of visual information was relevant, since restricted view of the forearm did not have this enhancing effect. Vibrotactile maskers were placed symmetrically on either side of the tactile target locations, at two different distances. Overall, masking significantly impaired discrimination performance, but the spatial gradient of masking depended on what subjects viewed. Viewing the body reduced the effect of distant maskers, but enhanced the effect of close maskers, as compared to viewing a neutral object. We propose that viewing the body improves functional touch by sharpening tactile RFs in an early somatosensory map. Top–down modulation of lateral inhibition could underlie these effects.

[1]  W. Penfield.  The Cerebral Cortex of Man , 1950 .

[2]  I. Kaufman.  The Cerebral Cortex of Man: A Clinical Study of Localization of Function , 1951 .

[3]  S Weinstein,et al.  Intensive and extensive aspects of tactile sensitivity as a function of body part, sex, and laterality , 1968 .

[4]  J. Marshall.  THE SKIN SENSES , 1969 .

[5]  W. Spencer,et al.  Cutaneous masking. I. Psychophysical observations on interactions of multipoint stimuli in man. , 1979, Journal of neurophysiology.

[6]  W. Spencer,et al.  Cutaneous masking. II. Geometry of excitatory andinhibitory receptive fields of single units in somatosensory cortex of the cat. , 1979, Journal of neurophysiology.

[7]  J. Kaas,et al.  The reorganization of somatosensory cortex following peripheral nerve damage in adult and developing mammals. , 1983, Annual review of neuroscience.

[8]  R. Dykes,et al.  Functional role of GABA in cat primary somatosensory cortex: shaping receptive fields of cortical neurons. , 1984, Journal of neurophysiology.

[9]  J. Craig,et al.  Vibrotactile masking and the persistence of tactual features , 1987, Perception & psychophysics.

[10]  J C Craig,et al.  Interference in localizing tactile stimuli , 1989, Perception & psychophysics.

[11]  K O Johnson,et al.  The limit of tactile spatial resolution in humans , 1994, Neurology.

[12]  G. Gerstein,et al.  Networks with lateral connectivity. I. dynamic properties mediated by the balance of intrinsic excitation and inhibition. , 1996, Journal of neurophysiology.

[13]  J. DiCarlo,et al.  Structure of Receptive Fields in Area 3b of Primary Somatosensory Cortex in the Alert Monkey , 1998, The Journal of Neuroscience.

[14]  M S Graziano,et al.  Coding the location of the arm by sight. , 2000, Science.

[15]  P. Haggard,et al.  Noninformative vision improves the spatial resolution of touch in humans , 2001, Current Biology.

[16]  N. Kanwisher,et al.  A Cortical Area Selective for Visual Processing of the Human Body , 2001, Science.

[17]  J. Driver,et al.  Crossmodal links in endogenous and exogenous spatial attention: evidence from event-related brain potential studies , 2001, Neuroscience & Biobehavioral Reviews.

[18]  Patrick Haggard,et al.  Vision Modulates Somatosensory Cortical Processing , 2002, Current Biology.

[19]  P. Haggard,et al.  Visual enhancement of touch in spatial body representation , 2003, Experimental Brain Research.

[20]  H. Freund,et al.  Somatosensory and motor disturbances in patients with parietal lobe lesions. , 2003, Advances in neurology.

[21]  M. Corbetta,et al.  Extrastriate body area in human occipital cortex responds to the performance of motor actions , 2004, Nature Neuroscience.

[22]  H. Burton,et al.  Quantitative measurements of receptive field changes during antagonism of GABAergic transmission in primary somatosensory cortex of cats , 2004, Experimental Brain Research.

[23]  Patrick Haggard,et al.  Persistence of visual–tactile enhancement in humans , 2004, Neuroscience Letters.

[24]  P. Brown,et al.  From innervation density to tactile acuity 1. Spatial representation , 2004, Brain Research.

[25]  P. Haggard,et al.  Viewing the body prepares the brain for touch: effects of TMS over somatosensory cortex , 2005, The European journal of neuroscience.

[26]  Harvey A Swadlow,et al.  Thalamocortical specificity and the synthesis of sensory cortical receptive fields. , 2005, Journal of neurophysiology.

[27]  M. Eimer,et al.  Vision and gaze direction modulate tactile processing in somatosensory cortex: evidence from event-related brain potentials , 2005, Experimental Brain Research.

[28]  J Driver,et al.  Influence of gaze direction on crossmodal modulation of visual ERPS by endogenous tactile spatial attention. , 2005, Brain research. Cognitive brain research.

[29]  O. Blanke,et al.  Neural Basis of Embodiment: Distinct Contributions of Temporoparietal Junction and Extrastriate Body Area , 2006, The Journal of Neuroscience.

[30]  Lindsey J. Powell,et al.  My body or yours? The effect of visual perspective on cortical body representations. , 2006, Cerebral cortex.

[31]  P. Haggard.  Sensory Neuroscience: From Skin to Object in the Somatosensory Cortex , 2006, Current Biology.