Answer to Question #99799 in Biology for a

Question

8. A patient cannot feel pain or touch and his motor reflexes are absent. Yet he can voluntarily move any part of his body. The best possible explanation is:
a) He has damage to ventral motor neurons in the spinal cord
b) He has damage to dorsal sensory neurons in the spinal cord
c) He has damage to his frontal lobe in the brain
d) All input and output from his spinal cord is malfunctioning, yet the brain region that controls voluntary movement is intact

Answer 1

b) He has damage to dorsal sensory neurons in the spinal cord.

Dorsal sensory neurons have processes that should perceive information about pain or touch. If they do not function, the patient cannot feel it. In addition, motor reflexes require perceiving of some stimulus. Problem with sensory neurons explains the inability to perceive stimuli.

Variant a) is incorrect because patient can move any part of the body.

Variant c) is incorrect because patient can make voluntary movements.

Variant d) is incorrect because patient can move any part of the body, which implies that motor neurons, which create output, function normally.