Topographic mapping of human motor cortex with transcranial magnetic stimulation: Homunculus revisited

Leo Verhagen Metman, Jacqueline S. Bellevich, Seth M. Jones, Matt D. Barber, Leopold J. Streletz

Research output: Contribution to journalArticle

37 Citations (Scopus)


The purpose of this study was to non-invasively evaluate the homuncular organization of the motor cortex in man. We used transcranial magnetic stimulation to induce motor evoked potentials (MEP's) in Abductor Pollicis Brevis (APB) and Biceps Brachii (BB) muscles of 10 healthy volunteers. The practicality and accuracy of magnetic stimulation to scalp sites one cm apart was increased by the application to the scalp of a flexible nylon grid with grid size of 1×1 cm. Responsive scalp sites collectively contributed to distinct but overlapping muscle representational areas for the two muscles. The topography of these motor maps along and slightly anterior to the central fissure corresponds to the homuncular configuration as described by Penfield and Boldrey in 1937.

Original languageEnglish
Pages (from-to)13-19
Number of pages7
JournalBrain Topography
Issue number1
Publication statusPublished - 1 Sep 1993



  • Homunculus
  • Human motor cortex
  • Motor Evoked Potential
  • Topographical map
  • Transcranial Magnetic Stimulation

ASJC Scopus subject areas

  • Anatomy
  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging
  • Neurology
  • Clinical Neurology

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