Motor System
In humans, two clinical syndromes have provided insight into the basic function of the basal ganglia: Parkinson’s disease and Huntington’s disease
Huntington’s disease:
- degeneration of neurons within the striatum including neurons that synthesize the neurotransmitters GABA and acetylcholine
- effect of this cell loss is disinhibition of motor activity (increased activity)
individuals with this disorder show several symptoms including:
- progressive dementia--cognitive deficits
- choreiform movements--rapid, irrregular flow of motion associated with fingers, arms and facial muscles; effects can include: “piano-playing” fexion-extension movements of the fingers, elevation and depression of the shoulders and hips, crossing and uncrossing of the legs, and grimacing movements of the face
Huntington’s disease is a hereditary disease; onset of symptoms occurs during the third or fourth decade of life (30s and 40s)