What happens in the brain following the onset of HD?
What parts of the brain are most affected in HD patients?
The part of the brain most affected by HD is a group of nerve cells at the base of the brain known collectively as the basal ganglia. The basal ganglia organize muscle-driven movements of the body, or “motor movement.” The major components of the basal ganglia are the caudate and the putamen (together known as the striatum) and the globus pallidus (external and internal regions). The substantia nigra and the subthalamic nucleus are often included as part of the basal ganglia as well. Below is a figure showing where the different parts of the basal ganglia are located.
In persons with HD, the structures of the basal ganglia are a lot smaller than normal (see Figure D-4). This reduction happens because nerve cells of the striatum are the first to die as HD progresses. Although other parts of the brain are also affected during HD, the basal ganglia appear to be the most heavily damaged. Understanding the functions of the basal ganglia and the ways in which these functions are disturbed during HD can help us understand why HD affects people the way it does.
Last Modified: 9-13-02
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