Final answer:
The basal ganglia require a sufficient supply of dopamine to function properly. In Parkinson's disease, the degeneration of dopaminergic neurons leads to a decrease in dopamine levels, resulting in motor impairments.
Step-by-step explanation:
The basal ganglia, a group of interconnected brain areas, require a sufficient supply of dopamine to function properly. Dopamine is a neurotransmitter that plays a crucial role in movement control and regulation of motivation. In Parkinson's disease, the degeneration of dopaminergic neurons leads to a decrease in dopamine levels, resulting in motor impairments.