Behavioural brain research
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The pyramidal tract and red nucleus send prominent projections to the spinal cord and are thought to co-operate in producing skilled movements. In the present study, skilled reaching for food located on a shelf and spontaneous grasping, handling and eating pieces of pasta were video-recorded and analyzed in control rats, rats with unilateral ibotenic acid lesions of the red nucleus (RN), unilateral pyramidal tract lesions (PT) and combined lesions. The behavioral results suggest that skilled movements are organized as action patterns, easily recognizable and distinctive for each task. ⋯ Nevertheless, even after combined lesions, the rats were able to advance the limb, grasp food and withdraw the limb. The sparing following combined lesions suggests that other neural systems as well as compensatory adjustments assist the impaired limb. The results are discussed in relation to the possible distinctive contributions of the rubrospinal and corticospinal tract to the action patterns that comprise skilled movements in rats.