The main goal of this research is to advance understanding of how stroke changes both the structure and function of the brain. The investigators will determine which is the key driver of recovery of arm function after stroke: changes in the structure of the brain or changes in how brain regions interact with one another.

The main goal of this research is to advance understanding of how stroke changes both the structure and function of the brain. Further, the investigators will determine which is the key driver of recovery of arm function after stroke: changes in the structure of the brain or changes in how brain regions interact with one another. Together, these data will advance the investigators understanding of how neural systems support recovery from stroke. The investigators will use a MRI technique that allows us to assess the health of a brain structure called myelin. This structure is important as it allows information to travel down nerves faster; the more myelin the quicker the signal can be conducted. The investigators aim is to test whether or not movement training can restore myelin in the brain. If movement training does restore myelin in the brain, the investigators will have identified an important new target for rehabilitation interventions.

Inclusion Criteria:

• individuals aged 40-75
• movement-related deficits associated with a middle cerebral artery stroke
• first time stroke affecting the corona radiata and/or internal capsule
• Fugl-Meyer upper extremity motor score of at least 15 but not greater than 55.

Exclusion Criteria:

• outside the age range of 40-75
• show signs of dementia (score < 24 on the Montreal Cognitive Assessment)
• have aphasia (score < 13 on the Frenchay Aphasia Screen)
• history of head trauma, a major psychiatric diagnosis, neurodegenerative disorder or substance abuse;
• taking any drugs (GABAergic, N-methyl-D-aspartate A-receptor (NMDA) antagonist) known to influence neuroplasticity;
• report contraindications to MRI (see supporting documents)