Behavioral Neuroscience, Lecture on November 7 th
What is stress?
1) Faster response
Fight or flight
2) Slower response
Fight or flight (continued)
Learning and memory
Homeostasis, coordinated physiological processes which maintain most of the
steady states in the organism.
Body temperature extreme temperature (stressor)
Blood glucose level starving (stressor)
Stress, any circumstance that upsets the homeostatic balance.
The noxious stimulus causes stress; in response to this lapse in
homeostasis/stress the body has an adaptive response.
Properties of psychological stressors,
Novelty – anything new you haven’t seen before.
Unpredictability – anything you were not expecting.
Threat to the ego
Sense of control decreased – feel like you do not have control over a
The relativity of stressors,
A real threat
o Being in an accident
o Confronting a dangerous animal
o Extreme weather
An implied threat
o Public speaking task
*Summary of stress:
Stress, a threat, real or implied, to the physical or psychological
integrity of an individual.
Two categories of stressors:
Psychological or physiological Relativity of stressors:
Absolute or relative
How do our bodies respond to stress?
1. Faster response (happens in seconds)
a. Starts in the hypothalamus, moves to adrenal glands where
epinephrine and norepinephrine are released. (sympathetic-
b. Norepinephrine is also released from sympathetic nerve terminals.
c. Medulla is the middle section of the adrenal gland.
d. On the day of a stressful event, epinephrine and norepinephrine
will drastically increase.
e. Function: increase fuel mobilization, raise blood pressure and
increase cardiac output.
2. Slower response (happens in minutes to hours)
a. Moves from hypothalamus, to anterior pituitary glands, to adrenal
cortex where cortisol is released. (hypothalamus-pituitary-adrenal
axis) or (HPA) axis
i. Hypothalamus releases corticotropin-releasing hormone
(CRH) into the anterior pituitary, which releases
adrenocorticotropic hormone (ACTH) into the adrenal
cortex, which r