Answer:
substantia nigra
Step-by-step explanation:
Substantia nigra -
It refers to the basal ganglia structure which is present in the midbrain , whose main function is movement and reward , is referred to as the substantia nigra .
The ability of not able to perform any voluntary movement , indicates the malfunctioning of the substantia nigra .
Hence , from the given scenario of the question ,
The correct answer is substantia nigra .