Bimanual coordination in young adults, older adults and MS patients

Normally, motor tasks performed with the right hand are controlled by motor
areas in the left, contralateral hemisphere. However, if the task requires more
effort also the right, ipsilateral hemisphere becomes active. This phenomenon
is seen in older adults and patients with multiple sclerosis (MS) in less
effortful tasks. Whether this ipsilateral activation functions as a
compensation mechanism or this is a mere effect of decreased inhibition in
control subjects and patients is unknown. If this activation is functional,
this could implicate that when MS patients become older that they have less
resources left to compensate for age-related deficits. Therefore we would like
to study the difference in uni- and bimanual performance in young adults, older
adults and patients with MS. We use a hand-leg task to control for
effort-related differences in the tasks.

We aim to determine the difference in uni- and bimanual coordination between
young adults, older adults and MS patients. Additionally we want to determine
the relation between the different measures of cortical inhibition and task
performance.

This is an intervention study during which subjects perform multiple motor
tasks with one or both hands and one foot. During the tasks TMS responses will
be evoked.

Subjects will perform different coordination tasks with one hand, two hands and
one hand and one foot during which the motor cortex is stimulated with magnetic
stimulation.

Subjects visit the department of Neuroscience twice for 2 hours. During the
experiments, subjects receive electrical stimulation of the ulnar nerve and
magnetic stimulation of the motor cortex. There are no known risks to either
stimulation method. Subjects also need to fill in a questionnaire (Oldfield
questionnaire) to determine their handedness.