Final answer:
The corticospinal tract originates in the motor cortex and is involved in sending motor commands to lower motor neurons, affecting voluntary muscle movements.
Step-by-step explanation:
The corticospinal tract originates from the motor cortex of the brain. Specifically, it is a part of the descending motor pathway that begins at the primary motor cortex, where motor commands are relayed from the Betz cells. These commands are then transmitted to the lower motor neurons located in the spinal cord's ventral horn or the cranial motor nuclei. The corticospinal tract is predominantly contralateral, which means that it crosses the midline of the brain stem or the spinal cord to affect the muscles on the opposite side of the body.