Experimental Brain Research

, Volume 158, Issue 4, pp 397–404

Surround inhibition in human motor system

Research Article

DOI: 10.1007/s00221-004-1909-y

Cite this article as:
Sohn, Y.H. & Hallett, M. Exp Brain Res (2004) 158: 397. doi:10.1007/s00221-004-1909-y


In sensory systems, a neural mechanism called surround inhibition (SI) sharpens sensation by creating an inhibitory zone around the central core of activation. In the motor system, the functional operation of SI remains to be demonstrated, although it has been hypothesized to contribute to the selection of voluntary movements. Here we test this hypothesis by using transcranial magnetic stimulation of the human motor cortex. The motor evoked potential of the little finger muscle is suppressed or unchanged during self-paced, voluntary movements of the index finger, mouth or leg, despite an increase in spinal excitability. This result indicates that motor excitability related to little finger movement is suppressed at the supraspinal level during these movements, and supports the idea that SI is an organizational principle of the motor system.


Motor cortexSurround inhibitionTranscranial magnetic stimulationVoluntary movements

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  1. 1.Human Motor Control SectionNINDS / NIHBethesdaUSA
  2. 2.Department of Neurology and Brain Research Institute, Brain Korea 21 Project for Medical ScienceYonsei University College of MedicineSeoulKorea