Neural Substrates of Lasting Motor Skill Learning by Spacing Effect

This study will explore the optimum training schedule for stroke patients to learn motor skills. It will see if motor training is more effective when training sessions are distributed over time (spaced training) or when the sessions are scheduled close together (massed training). The results of this study may help researchers devise the best training schedule for patients to derive the maximum benefit from rehabilitation therapy.

Healthy normal volunteers and people who have had a stroke may be eligible for this study. Patients must be 3 months post-stroke. All participants must be right-handed and between 18 and 80 years of age.

Participants practice a pinch motor task and receive transcranial magnetic stimulation (TMS). Hand muscle activity is measured using surface electromyography (EMG). Pinch training involves training the participant to pinch as strongly as possible, using a device that records the force. For TMS, a wire coil is held on the subject s scalp. A brief electrical current is passed through the coil, creating a magnetic pulse that stimulates the brain. The subject hears a click and may feel a pulling sensation on the skin under the coil. There may be a twitch in the muscles of the face, arm or leg. For surface EMG, electrodes (small metal disks) are filled with a conductive gel and taped to the skin over the muscle.

Following one practice session of pinch task training and TMS, participants have four training sessions, which are scheduled 24 hours, 2 weeks, 1 month and 3 months after the practice session.

For the 4- to 5-hour practice session, subjects do the following:

• Perform a single session of pinch motor task for familiarization
• Undergo TMS to measure brain activity
• Practice five 6-minute blocks of pinch motor task with rest periods between sessions and perform a calculation task (addition and subtraction tasks) during each rest period
• Receive TMS over 15 minutes. (Some sessions may have sham TMS.)
• Read books and magazines during a 45-minute rest period
• Perform a single block of the pinch motor task
• Undergo TMS to measure brain activity
• Complete a questionnaire that measures attention, fatigue and mood

For the remaining four sessions, participants perform one practice block and TMS. Each session lasts about 2 hours.