Final answer:
The central nervous system, particularly the motor cortex, basal ganglia, and cerebellum, in conjunction with the intrinsic muscles of the hand, plays a critical role in mediating fine, voluntary movements of the hands and fingers.
Step-by-step explanation:
The key role in mediating performance of fine, discrete, voluntary movement of the hands and fingers is played by the central nervous system, which includes interconnected brain areas such as the motor cortex, basal ganglia, and the cerebellum. The intrinsic muscles of the hand allow for precise movements necessary for actions like typing or playing an instrument. These muscles receive signals from the central nervous system to execute movements with high precision. Furthermore, the peripheral nervous system contributes to the coordination of these movements, ensuring that both intrinsic and extrinsic muscles of the hands and fingers work harmoniously.
These sophisticated systems enable not only the solo performance of tasks requiring fine motor skills but also complex cooperative tasks like playing a duet on a piano or a violin, where coordination and synchronization with another person or with a changing external stimulus are critical. This is facilitated through a combination of muscle control, visual processing, and motor planning, which is demonstrated in exercises like the finger-to-nose test, indicating the cerebellum's role in fine-tuning motor actions.