Neuroplastic Change in Myelin of the Brain (Myelin)

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.

Increased paretic arm will be manipulated through the performance of a semi-immersive virtual reality-based intercept and release task called TRAIT (TRack And Intercept Task), which is performed in an interactive environment. TRAIT employs an open source Kinect sensor, which tracks 3-D joint movement. Participants are asked to control an on-screen icon using movements of their paretic arm to intercept a moving object as it emerges from the side of a computer screen. Once intercepted, they must accurately throw the object to hit a target. Participants move up through 10 levels of the game as their skill improves. Participants will complete 10 TRAIT training sessions in 4 weeks for a total of 10,000 experimental movements.

Myelin water fraction (MWF) is the area of the short T2 component (15-35ms) divided by the total T2 distribution expressed as a percentage (MWF% = MWF*100)

Diffusion properties will be defined by calculating a 6-element tensor ellipsoid to provide both the magnitude and direction of diffusivity in a local orthogonal coordinate system within each voxel. Fractional anisotropy (FA) will be calculated to provide an index of microstructural white matter integrity.

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)