Imaging Laterality in Chronic Stroke Patients

In healthy individuals, unimanual movement (with either the left or right hand) is associated with activity in a network of predominantly contralateral brain regions, including the primary motor cortex (PMC). This laterality is often compromised following a middle cerebral artery (MCA) stroke. Neuroimaging studies of these patients have shown that unimanual movements with the effected hand are associated with elevated Blood Oxygen-Level Dependent (BOLD) signal in both the lesioned and the nonlesioned primary motor cortices. Elevated activity in the contralesional PMC is well-established in chronic stroke patients and is associated with poor motor rehabilitation outcomes. Yet the neurobiologic basis for this aberrant neural activity is equivocal. The overarching goal of this project is to determine the neurobiologic basis for elevated activity in the contralesional primary motor cortex.