Primary thumb sensory cortex located at the lateral shoulder of the inverted omega-shape on the axial images of the central sulcus

T. Kumabe, N. Nakasato, T. Inoue, T. Yoshimoto, D. W. Roberts, T. Sakaki, Hiroaki Shimizu

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Useful landmarks on magnetic resonance (MR) images were identified for preoperative prediction of the relationship of a tumor to the primary sensory cortex of the thumb. Functional MR (fMR) imaging and magnetoencephalography were used to retrospectively localize the hand-digit sensorimotor area in four patients who underwent tumor resection around the central sulcus with intraoperative neurophysiological mapping. fMR imaging revealed the hand-digit motor cortex in the so-called 'precentral knob' inside the characteristic inverted-omega on axial MR images. Equivalent current dipoles of the N20m response in somatosensory evoked fields (SEFs) of the thumb, median nerve, and ulnar nerve stimuli were localized at the lateral portion of the inverted omega-shape from the lateral to medial directions. The SEF-based thumb sensory cortex was verified by intraoperative functional mapping with a neuronavigation system. The hand-digit somatosensory cortices were localized at the lateral shoulder of the inverted-omega, in the lateral anterior inferior position to the hand-digit motor cortices in the precentral knob. Axial MR imaging can provide useful preoperative planning information for the surgical treatment of tumors within or adjacent to the motor-somatosensory cortex.

Original languageEnglish
Pages (from-to)393-403
Number of pages11
JournalNeurologia medico-chirurgica
Volume40
Issue number8
DOIs
Publication statusPublished - 2000 Jan 1

Keywords

  • Brain mapping
  • Central sulcus
  • Functional magnetic resonance imaging
  • Magnetoencephalography
  • Motor cortex
  • Sensory cortex

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology

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