In addition to their effects on serotonin and other neurotransmitters, what other brain effect do antidepressant drugs produce?

(a) They increase the velocity of action potentials in the cerebral cortex.

(b) They decrease the velocity of action potentials in the cerebral cortex.

(c) They increase production of a chemical that increases birth of new neurons in the hippocampus.

(d) They shift blood flow from the left hemisphere of the brain to mainly the right hemisphere.