Limits on recovery in the corticospinal tract of the rat: Partial lesions impair skilled reaching and the topographic representation of the forelimb in motor cortex

Dionne M. Piecharka, Jeffrey A. Kleim, Ian Q. Whishaw

Research output: Contribution to journalArticle

39 Scopus citations


Although evidence suggests that there are impairments in skilled movements following very large lesions of the pyramidal component of the corticospinal tract, the behavioral and electrophysiological effects of partial lesion has not received equal attention. Here, rats with complete lesions or partial lesions (medial, central, or lateral third) of the pyramidal tract at the medullary pyramids were evaluated for their quantitative and qualitative postsurgical performance on a skilled reaching task, following which the topographic representation of their forelimb was mapped with intracortical microstimulation (ICMS). Complete lesions impaired reaching success, impaired the qualitative features of reaching movements, and abolished ICMS evoked movement from the forelimb region of motor cortex. Although partial lesions did not impair reaching success, they did impair qualitative aspects of limb movement including forepaw aiming, supination, and food pellet release. ICMS indicated a reduction in the size of the forelimb area, especially the distal area of the caudal forelimb area (CFA), of the motor map. The behavioral and electrophysiological impairments did not vary with lesion location within the pyramidal tract. The incomplete recovery, as measured both behaviorally and electrophysiologically, demonstrates that plasticity within the corticospinal system is limited even with lesions that permit substantial sparing of pyramidal tract fibers.

Original languageEnglish (US)
Pages (from-to)203-211
Number of pages9
JournalBrain Research Bulletin
Issue number3
StatePublished - Aug 15 2005
Externally publishedYes



  • Cortical stimulation and movement
  • Motor maps
  • Pyramidal tract
  • Rat pyramidal tract
  • Recovery from pyramidal tract lesion
  • Skilled reaching
  • Skilled reaching and pyramidal tract

ASJC Scopus subject areas

  • Neuroscience(all)

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