The early work into the phenomenon called instinctive drift was performed by

Alternation between wakefulness and sleep depends completely on stimuli in the environment

a. True b. False Indicate whether the statement is true or false

George has gone into a deep depression after the death of his wife, for whom he had provided daily care for over 2 years after her first stroke. What role might cortisol play?

a. ?Over-response of the hippocampus may have led to reduced cortisol in the bloodstream, which is associated with depression. b. ?Under-response of the hippocampus may have led to reduced cortisol in the bloodstream, which is associated with depression. c. ?Consistently elevated levels of cortisol due to stress can overwhelm the hippocampus’s feedback loop and lead to excess levels of cortisol in the bloodstream, which is associated with depression. d. ?Erratic levels of cortisol due to stress can disrupt the hippocampus’s feedback loop and lead to erratic levels of cortisol in the bloodstream, which is associated with manic depression.