12. The Central Nervous System

Identify and shade in the locations of all the ascending sensory tracts in the following diagram of the spinal cord.

Which three pairs of descending tracts make up the corticospinal pathway?

Which three motor tracts make up the medial pathway?

The corticospinal tract

(a) Carries motor commands from the cerebral cortex to the spinal cord

(b) Carries sensory information from the spinal cord to the brain

(c) Starts in the spinal cord and ends in the brain

(d) Does all of these

Describe the relationship among first-order, second-order, and third-order neurons in a sensory pathway.