The subject stays still when the substantia nigra is stimulated with electricity .
The co-dependence between the striatum and substantia nigra can be seen in this way : when the substantia nigra is stimulated , and dopamine is released , movement can be initiated ( via suppression of movement buffering effects of caudate nucleus ) ; however , the stiff motor symptoms of nigral degeneration due to Parkinson 's is a poignant example of the substantia nigra 's influence on initiation of movement .
Substantia nigra