Representation of tactile curvature in macaque somatosensory area 2

Jeffrey M. Yau, Charles E. Connor, Steven S. Hsiao

Research output: Contribution to journalArticlepeer-review

Abstract

Tactile shape information is elaborated in a cortical hierarchy spanning primary (SI) and secondary somatosensory cortex (SII). Indeed, SI neurons in areas 3b and 1 encode simple contour features such as small oriented bars and edges, whereas higher order SII neurons represent large curved contour features such as angles and arcs. However, neural coding of these contour features has not been systematically characterized in area 2, the most caudal SI subdivision in the postcentral gyrus. In the present study, we analyzed area 2 neural responses to embossed oriented bars and curved contour fragments to establish whether curvature representations are generated in the postcentral gyrus. We found that many area 2 neurons (26 of 112) exhibit clear curvature tuning, preferring contours pointing in a particular direction. Fewer area 2 neurons (15 of 112) show preferences for oriented bars. Because area 2 response patterns closely resembled SII patterns, we also compared area 2 and SII response time courses to characterize the temporal dynamics of curvature synthesis in the somatosensory system. We found that curvature representations develop and peak concurrently in area 2 and SII. These results reveal that transitions from orientation tuning to curvature selectivity in the somatosensory cortical hierarchy occur within SI rather than between SI and SII.

Original languageEnglish (US)
Pages (from-to)2999-3012
Number of pages14
JournalJournal of neurophysiology
Volume109
Issue number12
DOIs
StatePublished - Jun 15 2013

Keywords

  • Neural coding
  • Neurophysiology
  • Orientation
  • Single unit
  • Touch

ASJC Scopus subject areas

  • Neuroscience(all)
  • Physiology

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