Striatal grafts alleviate deficits in response execution in a lateralised reaction time task.

It has been reported that homotopic neural transplants can ameliorate behavioural impairments induced by striatal lesions in a reaction time (RT) task. In the present study we seek to replicate and extend this observation in a new lateralised choice RT task based on the conventional Skinner box apparatus. Rats were trained to make rapid lateralised lever press responses to a visual stimulus presented on either the left or the right side of the animal. The RTs required to initiate and execute correct responses were recorded, along with other accuracy and performance indices. Following unilateral lesions of the dorsal striatum, the rats exhibited an increased number of error trials, a bias to respond towards the ipsilateral side, a decreased accuracy on the contralateral side, and an increase of the execution time to respond correctly to contralateral stimuli. Striatal grafts alleviated the lateralised response deficits, prevented the development of lateral disparity, and restored the speed of responding back to pre-lesion levels. Control grafts of cortical tissues also increased task accuracy and reduced the ipsilateral bias in responding, but were without effect on the RT deficit.