Brain Connectivity and Sensorimotor Integration During Dual/Single Motor Tasks

This study will examine how the areas in the brain are connected when they are controlling two finger movements at the same time. It will look at how people use what they see to help guide two different movements. This ability, which is important in everyday life, can be a problem for patients with neurological problems.

Healthy right-handed volunteers 18 years of age and older may be eligible for this study. Candidates are screened with a medical history, physical examination and magnetic resonance imaging (MRI) of the brain. MRI uses a strong magnetic field and radio waves to obtain images of body organs and tissues. The MRI scanner is a metal cylinder surrounded by a strong magnetic field. The subject lies on a table that can slide in and out of the scanner, wearing earplugs to muffle loud noises that occur during the scanning.

Participants undergo functional MRI (fMRI). This is a standard MRI that is done while the subject performs skilled finger tasks in response to instructions they see on a screen. Researchers localize brain areas which show activity changes while the tasks are performed. Before the test session begins, subjects complete a questionnaire and have an opportunity to practice the task.

Subjects control the position of one or two cursors on a screen using one or two fingers. They perform tracking or pointing tasks according to what they see on the screen. During the single-task experiment only one task is presented on the screen. During the dual-task experiment, two tasks are presented on the screen. Subjects perform either the single-task or dual-task experiment, but not both. The fMRI lasts about 90 minutes, with subjects asked to lie still during the scan for up to 9 minutes at a time.

After completing the fMRI, subjects are scheduled for a research electroencephalogram (EEG) and magnetoencephalogram (MEG). The test is done while the subject performs tasks so that researchers can learn about the timing of changes in activity in certain brain regions during performance of the same tasks done for the fMRI.