Somatotopic organization of cortical fields in the lateral sulcus of Homo sapiens: Evidence for SII and PV

Elizabeth Disbrow, Tim Roberts, Leah Krubitzer

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Abstract

The human somatosensory cortex in the Sylvian fissure was examined using functional magnetic resonance imaging to describe the number and internal organization of cortical fields present. Somatic stimuli were applied to the lips, face, hand, trunk, and foot of 18 human subjects. Activity patterns were transposed onto three-dimensional magnetic resonance images of the brain so that the location of activity associated with the different stimuli could be related to specific regions of the cortex. There were several consistent findings. First, there were three regions of activity in the lateral sulcus associated with stimulation of the contralateral body. The most consistent locus of activation was on the upper bank of the lateral sulcus, continuing onto the operculum. The other two areas, one rostral and one caudal to this large central area, were smaller and were activated less consistently. Second, when activity patterns in the large central area resulting from stimulation of all body parts were considered, this region appeared to contain two fields that corresponded in location and somatotopic organization to the second somatosensory area (SII) and the parietal ventral area (PV). Finally, patterns of activation within SII and PV were somewhat variable across subjects. Repeated within-subject stimulus presentation indicated that differences across subjects were not due to inconsistent stimulus presentation. Comparisons with other mammals suggest that some features of organization are found only in primates. It is hypothesized that these features may be associated with manual dexterity and coordination of the hands, a characteristic generally restricted to the primate lineage. (C) 2000 Wiley-Liss, Inc.

Original languageEnglish (US)
Pages (from-to)1-21
Number of pages21
JournalJournal of Comparative Neurology
Volume418
Issue number1
DOIs
StatePublished - Feb 28 2000

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Keywords

  • Functional magnetic resonance imaging
  • Parietal ventral area
  • Second somatosensory area
  • Somatosensory cortex

ASJC Scopus subject areas

  • Neuroscience(all)

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