Question

Which cortical layer is reduced in the primary motor cortex (M1)?

a) Layer I
b) Layer II
c) Layer V
d) Layer VI

Answer 1

Layer V is reduced in the primary motor cortex (M1), where the motor homunculus maps the body's musculature with space allocated based on the finesse of muscle movements.

Step-by-step explanation:

The cortical layer that is reduced in the primary motor cortex (M1) is Layer V. In the cerebral cortex, the primary motor cortex is responsible for generating motor commands and it has a topographical representation of the body known as the motor homunculus. The motor homunculus reflects the fact that the amount of cortical space is proportional to the finesse required by the muscles, with areas responsible for fine, agile movements being more expansive than those for coarser movements.