Elsevier

NeuroImage

Volume 14, Issue 3, September 2001, Pages 617-631
NeuroImage

Regular Article
Human Somatosensory Area 2: Observer-Independent Cytoarchitectonic Mapping, Interindividual Variability, and Population Map

https://doi.org/10.1006/nimg.2001.0858Get rights and content

Abstract

We analyzed the topographical variability of human somatosensory area 2 in 10 postmortem brains. The brains were serially sectioned at 20 μm, and sections were stained for cell bodies. Area 2 was delineated with an observer-independent technique based on significant differences in the laminar densities of cell bodies. The sections were corrected with an MR scan of the same brain obtained before histological processing. Each brain's histological volume and representation of area 2 was subsequently reconstructed in 3-D. We found that the borders of area 2 are topographically variable. The rostral border lies between the convexity of the postcentral gyrus and some millimeters deep in the rostral wall of the postcentral sulcus. The caudal border lies between the fundus of the postcentral sulcus and some millimeters above it in the rostral wall. In contrast to Brodmann's map, area 2 does not extend onto the mesial cortical surface or into the intraparietal sulcus. When the postcentral sulcus is interrupted by a gyral bridge, area 2 crosses this bridge and is not separated into two segments. After cytoarchitectonic analysis, the histological volumes were warped to the reference brain of a computerized atlas and superimposed. A population map was generated in 3-D space, which describes how many brains have a representation of area 2 in a particular voxel. This microstructurally defined population map can be used to demonstrate activations of area 2 in functional imaging studies and therefore help to further understand the role of area 2 in somatosensory processing.

References (60)

  • P.E. Roland et al.

    Functions and structures of the motor cortices in humans

    Curr. Opin. Neurobiol.

    (1996)
  • A. Schleicher et al.

    Observer-independent method for microstructural parcellation of cerebral cortex: A quantitative approach to cytoarchitectonics

    Neuroimage

    (1999)
  • A. Schleicher et al.

    A stereological approach to human cortical architecture: Identification and delineation of cortical areas

    J. Chem. Neuroanat.

    (2000)
  • M.F. Shanks et al.

    The ipsilateral cortico-cortical connexions between the cytoarchiteconic subdivisions of the primary somatic sensory cortex in the monkey

    Brain Res. Rev.

    (1985)
  • K. Amunts et al.

    Broca's region revisited: Cytoarchitecture and intersubject variability

    J. Comp. Neurol.

    (1999)
  • P. Bailey et al.

    The Isocortex of Man

    (1951)
  • A. Bodegard et al.

    Somatosensory areas in man activated by moving stimuli: Cytoarchitectonic mapping and PET

    Neuroreport

    (2000)
  • A. Bodegard et al.

    Hierarchical processing of tactile shape in the human brain

    Neuron

    (2001)
  • K. Brodmann

    Beiträge zur histologischen Lokalisation der Groβhirnrinde. Erste Mitteilung: Die Regio Rolandica

    J. Psychol. Neurol.

    (1903)
  • K. Brodmann

    Beiträge zur histologischen Lokalisation der Groβhirnrinde. Sechste Mitteilung: Die Cortexgliederung des Menschen

    J. Psychol. Neurol.

    (1908)
  • Brodmann, K. 1909, Vergleichende Lokalisationslehre der Groβhirnrinde, Barth,...
  • H. Burton et al.

    Ipsilateral intracortical connections of physiologically defined cutaneous representations in areas 3b and 1 of macaque monkeys: Projections in the vicinity of the central sulcus

    J. Comp. Neurol.

    (1995)
  • H. Burton et al.

    The posterior thalamic region and its cortical projection in new and old world monkeys

    J. Comp. Neurol.

    (1976)
  • A.W. Campbell

    Histological Studies on the Localization of Cerebral Function

    (1905)
  • R.M. Costanzo et al.

    A quantitative analysis of responses of direction-sensitive neurons in somatosensory cortex of awake monkeys

    J. Neurophysiol.

    (1980)
  • E.P. Gardner et al.

    Neuronal mechanisms underlying direction sensitivity of somatosensory cortical neurons in awake monkeys

    J. Neurophysiol.

    (1980)
  • S. Geyer et al.

    Two different areas within the primary motor cortex of man

    Nature

    (1996)
  • J. Hyvärinen et al.

    Receptive field integration and submodality convergence in the hand area of the post-central gyrus of the alert monkey

    J. Physiol. London

    (1978)
  • Y. Iwamura et al.

    Converging patterns of finger representation and complex response properties of neurons in area 1 of the first somatosensory cortex of the conscious monkey

    Exp. Brain Res.

    (1983)
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