Experimental Brain Research

, Volume 142, Issue 4, pp 562–569

Modulation of rodent cortical motor excitability by somatosensory input

  • Andreas R. Luft
  • Alain Kaelin-Lang
  • Till-Karsten Hauser
  • Manuel M. Buitrago
  • Nitish V. Thakor
  • Daniel F. Hanley
  • Leonardo G. Cohen
Research Article

DOI: 10.1007/s00221-001-0952-1

Cite this article as:
Luft, A.R., Kaelin-Lang, A., Hauser, T. et al. Exp Brain Res (2002) 142: 562. doi:10.1007/s00221-001-0952-1
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Abstract.

It is assumed that somatosensory input is required for motor learning and recovery from focal brain injury. In rodents and other mammals, corticocortical projections between somatosensory and motor cortices are modified by patterned input. Whether and how motor cortex function is modulated by somatosensory input to support motor learning is largely unknown. Recent human evidence suggests that input changes motor excitability. Using transcranial magnetic stimulation (TMS), this study tested whether motor cortex excitability is affected by patterned somatosensory stimulation in rodents. Motor potentials evoked in gastrocnemius muscles in response to TMS (MEPTMS) and to cervical electrical stimulation (MEPCES) were recorded bilaterally. Initially, the first negative peak of the MEPTMS was identified as a cortical component because it disappeared after decortication in three animals. Subsequently, we studied the effects of 2 h of electrical stimulation of one sciatic nerve on the cortical component of the MEPTMS, i.e., on motor cortex excitability. After stimulation, its amplitude increased by 117±45% (P<0.01) in the stimulated limb. A significantly smaller effect was found in the unstimulated limb (P<0.02) and no effect was observed in unstimulated control animals. The subcortically evoked MEPCES were not affected by stimulation. It is concluded that somatosensory input increases motor excitability in rat. This increase outlasts the stimulation period and is mediated by supraspinal structures, likely motor cortex. Modulation of motor cortex excitability by somatosensory input may play a role in motor learning and recovery from lesion.

Neuroplasticity Rat Motor system physiology Transcranial magnetic stimulation Stimulation

Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • Andreas R. Luft
    • 1
  • Alain Kaelin-Lang
    • 3
  • Till-Karsten Hauser
    • 2
  • Manuel M. Buitrago
    • 1
  • Nitish V. Thakor
    • 4
  • Daniel F. Hanley
    • 1
  • Leonardo G. Cohen
    • 3
  1. 1.Department of Neurology, Johns Hopkins University, 600 N. Wolfe St., Meyer 8–140, Baltimore, MD 21287, USA
  2. 2.Department of Neurology, University of Tübingen, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany
  3. 3.Human Cortical Physiology Section, NINDS, National Institutes of Health, Bldg. 10, Room 5N234, 10 Center Drive, MSC 1430, Bethesda, MD 20892, USA
  4. 4.Department of Biomedical Engineering, Johns Hopkins University, 720 Rutland Ave., Traylor 701, Baltimore, MD 21254, USA