Neural Mechanisms of Tactile Motion Integration in Somatosensory Cortex

Abstract

Summary How are local motion signals integrated to form a global motion percept? We investigate the neural mechanisms of tactile motion integration by presenting tactile gratings and plaids to the fingertips of monkeys, using the tactile analogue of a visual monitor, while recording the responses evoked in somatosensory cortical neurons. In parallel psychophysical experiments, we measure the perceived direction of the gratings and plaids. We identify a population of somatosensory neurons that exhibit integration properties comparable to those observed in area MT to analogous visual stimuli. We find that the responses of these neurons can account for the perceived direction of the stimuli across all stimulus conditions tested. We show that the preferred direction of the neurons and the perceived direction of the stimuli can be predicted from the weighted average of the directions of the individual stimulus features (edges and intersections).

Path integration in tactile perception of shapes

“…Are there equivalent cells in touch? In [36] the authors identified a population of somatosensory neurons accounting for the perceived direction of the stimulus on the skin and they might be analogous to the head direction cells in the hippocampus. However, to the best of our knowledge an analogy to place or grid cells that would perform path integration has not been found in the tactile system so far.…”

Effect of mechanical tactile noise on amplitude of visual evoked potentials: multisensory stochastic resonance

“…This idea was based on a previous report by Deibert et al 1999 (see also Amedi et al 2002), who employed functional magnetic resonance to demonstrate that visual cortical areas are also active during tactile object recognition. In fact, there is evidence of mechanisms of tactile integration that are analogous to those related to visual processing (Bensmaia et al 2006;Pei et al 2011), thus suggesting an integration between both modalities. We also assume that in the central nervous system there are multisensory neurons participating in the tactile-visual cross-modal integration of signal and noise inputs (Barth and Brett-Green 2004;Calvert and Lewis 2004;Collins et al 2005;Gentile et al 2011;Kadunce et al 1997;Stein et al 1988Stein et al , 1996Wallace et al 1992).…”

Spatial and temporal codes mediate the tactile perception of natural textures

“…The somatosensory system is typically considered to be a spatial sense, one that draws strong analogies with the visual system (28)(29)(30). The extraction of information from oscillations of the somatosensory epithelium implies a complementary mode of processing for the primate somatosensory system, one that draws analogies with the auditory system (31) and with the vibrissal system of rodents (32).…”