Positron Emission Tomography (PET) is a technique used to investigate activity in areas of
the brain. The PET technique allows researchers to study the normal processes in the brain
(central nervous system) of normal individuals and patients with neurologic illnesses
without physical / structural damage to the brain.
When a region of the brain is active, it uses more fuel in the form of oxygen and sugar
(glucose). As the brain uses more fuel it produces more waste products, carbon dioxide and
water. Blood carries fuel to the brain and waste products away from the brain. As brain
activity increases, blood flow to and from the area of activity also increases. This is
known as regional cerebral blood flow (rCBF). Knowing these facts, researchers can use
radioactive water (H215O) and PET scans to observe what areas of the brain are receiving
more blood flow.
In this study researchers plan to investigate the changes in regional cerebral blood flow
(rCBF) as patients participate in different activities. The activities are designed to
stimulate the areas of the brain responsible for voluntary motor activity and sensation. By
comparing the results of PET scans performed in different conditions, researchers can locate
regions of the brain responsible for specific tasks.
This study should provide new information about voluntary movements in humans and the
preparation involved in controlling them.
The main purpose of the studies presented in this protocol is to investigate the physiology
of motor control in health as well as the pathophysiological modifications taking place
during disease. To this end, we will investigate changes in regional cerebral blood flow
(rCBF) as an index of regional neuronal activity, associated with various motor and sensory
tasks using Positron Emission Tomography (PET). The rCBF will be obtained by measuring the
distribution of the cerebral radioactivity during emission scans following the intravenous
bolus injection of 15O-labeled water. The very short half-life of 15O (2 minutes) allows us
to measure rCBF repeatedly under different task conditions (see methodology and
experimental procedures). With the comparison between PET scans performed in different
conditions, we can detect the specific task-related activated regions. PET images will be
coregistered to high resolution Magnetic Resonance Images (MRI) to get more accurate
anatomical information regarding the activated areas. The results will be correlated with
that from other physiological approaches including Electroencephalography (EEG),
Transcranial Magnetic Stimulation (TMS), functional Magnetic Resonance Imaging (fMRI), and
Magnetic Resonance Spectroscopy (MRS). These studies should provide new information not
only about the executive component of the voluntary movements in humans but also the
different organizational aspects of the preparatory processes that control them.
Patients with movement disorder and normal volunteers.