Effect of task-specific training on functional recovery and corticospinal tract plasticity after stroke.
OBJECTIVE
To determine the optimal timing of rehabilitation and its role in corticospinal tract (CST) plasticity after stroke.


METHODS
Rats were subjected to photothrombotic infarct. The large stroke (LS) and small stroke (SS) groups were subdivided and task-specific training (TST) was initiated at 1, 5, or 14 days poststroke. Behavioral tests were performed at 2, 7, 14, 21, 28, and 35 days poststroke. The differences of axonal sprouting in the cortex, red nucleus, cerebral peduncle, and pyramid level were compared by immunohistochemistry.


RESULTS
SS groups with TST starting at 1 day and 5 days showed significantly better recovery in the behavioral tests. LS group with TST starting at 5 days showed better recovery, while those with TST starting at 1 day showed worse recovery. Contralesional axonal sprouting was increased in both groups with TST starting at 5 days. However, it was decreased in the LS group with TST starting at 1 day. Transcallosal axonal sprouting from the contralesional motor cortex was increased in the LS group with TST starting at 5 days.


CONCLUSIONS
Functional recovery after stroke may vary, depending on the lesion size and the timing of rehabilitation. The underlying mechanism may involve contralesional CST plasticity and transcallosal axonal sprouting.
Center for Neuroscience Research, SMART Institute of Advanced Biomedical Science, Konkuk University, Seoul, Korea.
Kyoung-Hee
KH
Lee
Ji-Hye
JH
Kim
Dong-Hee
DH
Choi
Jongmin
J
Lee
D000818:Animals; D001710:Biotin / Q000031:analogs & derivatives; D002545:Brain Ischemia / Q000503:physiopathology / Q000534:rehabilitation; D002544:Cerebral Infarction / Q000534:rehabilitation; D003337:Corpus Callosum / Q000473:pathology; D003911:Dextrans; D005456:Fluorescent Dyes; D007150:Immunohistochemistry; D020767:Intracranial Thrombosis / Q000150:complications / Q000473:pathology; D008297:Male; D009044:Motor Cortex / Q000473:pathology; D009416:Nerve Regeneration; D009473:Neuronal Plasticity / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D011712:Pyramidal Tracts / Q000503:physiopathology*; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function / Q000502:physiology*; D013003:Somatosensory Cortex / Q000473:pathology; D000071939:Stroke Rehabilitation; D014741:Video Recording
D003911:Dextrans; D005456:Fluorescent Dyes; C076397:biotinylated dextran amine; D001710:Biotin
Corticospinal tract plasticity; functional recovery; rehabilitation timing; stroke; task-specific training; transcallosal axonal sprouting