TY - JOUR
T1 - Limits on recovery in the corticospinal tract of the rat
T2 - Partial lesions impair skilled reaching and the topographic representation of the forelimb in motor cortex
AU - Piecharka, Dionne M.
AU - Kleim, Jeffrey A.
AU - Whishaw, Ian Q.
N1 - Funding Information:
Research supported by Canadian Stroke Network, CIHR, NSERC.
PY - 2005/8/15
Y1 - 2005/8/15
N2 - 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.
AB - 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.
KW - Cortical stimulation and movement
KW - Motor maps
KW - Pyramidal tract
KW - Rat pyramidal tract
KW - Recovery from pyramidal tract lesion
KW - Skilled reaching
KW - Skilled reaching and pyramidal tract
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U2 - 10.1016/j.brainresbull.2005.04.013
DO - 10.1016/j.brainresbull.2005.04.013
M3 - Article
C2 - 16023917
AN - SCOPUS:22144493873
SN - 0361-9230
VL - 66
SP - 203
EP - 211
JO - Brain Research Bulletin
JF - Brain Research Bulletin
IS - 3
ER -