Objective: 

Lesions of the frontal cortex produce motor deficits which are evident at three months post-injury. The aim of this study was to investigate whether short-term rehabilitation in a critical period post-injury improves the deficit in motor ability produced by motor cortex lesions in adult rats. Additionally, we studied the expression of the brain-derived neurotrophic factor (BDNF) in the brains of animals injured and rehabilitated.

Methods: 

Rats were conditioned in a paw-reaching-for-food task and the preferred paw was determined. Animals were lesioned in the forelimb motor cortex contralateral to the preferred paw and retested to evaluate the effectiveness of the lesion. Fourteen days post-injury rats were re-tested with the forced use of the paw affected by the lesion by placing a bracelet on the non-preferred paw.

Results: 

Our findings showed that: a) rehabilitation therapy produced an improvement of motor deficits induced by the frontal cortex lesion when animals were forced to use the paw affected by the injury; b) the effectiveness of the rehabilitation therapy was determined by its application within a critical period post-injury; c) the immunohistochemical results suggested an overexpression of BDNF in the peri-lesional area.

Conclusions: 

Our findings provide evidence that rehabilitation therapy within a critical period post-injury induce an amelioration of motor deficits, suggesting that there is a timeframe when the brain provides optimal conditions for the beneficial effect of rehabilitation. Supported by MAPFRE Foundation. The authors thank to N.González and J.Blanco for their excellent technical assistance.