Grant: Operating Grant

A stroke is a vascular lesion within the brain. Following a stroke located in the motor cortex, patients have several deficits including loss of upper extremity function. However, patients undergo substantial motor recovery in the weeks and months following the lesion. One hypothesis, for which there is now remarkable support, is that the recovery is dependent upon adaptive reorganization of intact, remaining brain structures. The changes in the hemisphere that had sustained the lesion (ipsilesional) are generally believed to be beneficial to the recovery. Conversely, the role of the reorganization that occurs in the hemisphere opposite to the lesion (contralesional) is controversial. Some studies conclude that plasticity in that hemisphere supports recovery, while others conclude that it actually interferes with it. The goal of the present project is to study the nature of the reorganization in the contralesional hemisphere in order to understand how it can either participate or interfere in recovery. We will record neurons in various contralesional cortical areas in monkeys using electrode arrays while they perform a motor task. We will identify changes of the neural activity that are related to the recovery of the impaired limb. This information will be of great value for the development of experimental protocols modulating brain activity to favor beneficial plasticity in humans after stroke. Because the greatest contralesional plasticity is often observed in individuals with the highest impairments after stroke, understanding this reorganization will be particularly useful for our care of these patients, for whom we currently have the fewest treatment options to offer.