Anatomy of Emotion
u Limbic System Structures –
experience & expression of emotion
• Hypothalamus critical for
• Amygdala critical for
experiencing fear, rage
u Cortex, especially frontal
lobe – moderates & controls expression
• “Decorticate” animals highly
u ANS & endocrine system– routes for
triggering body signs of emotion
The Limbic System
u Frontal lobe & limbic
The Case of
Reconstructions of Prefrontal Damage
u Lack of tact, restraint,
empathy; decreased “conscience”, immature, irresponsible, coarse, lack of
u More common after
orbitofrontal damage(bottom part of prefrontal cortex)
u Patients don’t experience
Responses to Stress
u Stress activates the
sympathetic portion of the autonomic nervous system (the “fight-or-flight”
system), including release of
adrenaline from the middle of our adrenal glands (“adrenal medulla”).
u Release of adrenaline
u Increase HR & BP
u Increase respiration
u Increase blood flow to heart
u Dilate pupils
u Release stored energy
u Sweat to cool body
u GI tract slows down; mouth
Decrease blood to skin
u Decreases HR & BP
u Slows breathing
u Lubricates mouth
u Stimulates digestion and
storing of energy
u Constricts pupil
u Responsible for elimination
blood flow to skin
u These are real physical
symptoms (increased blood pressure, ulcers, asthma, headaches, etc) that have a
psychological cause or contributing factor.
u Depend in part on your
genetic predisposition, lifestyle, stresses, and coping strategies.
u Painful lesions in the
stomach/duodenal lining are more common in humans or rats experiencing stress
u More recently ulcers have
been linked to bacterial infection in almost all cases except those taking
NSAIDS like aspirin or ibuprofen.
u BUT: 75% of us without
ulcers still have this bacterial infection
u Stress and infection seem to
interact to induce ulcers, perhaps through lowered resistance
u During sympathetic arousal
gastric secretions are decreased, but in the aftermath of stress they rebound.
u Likewise cases of “voodoo
death” or death due to expectancy or giving up appears to be due to excess
parasympathetic slowing of heart!
Physiological Responses to Stress – Part 2
u Sympathetic activation is
usually rapid and temporary.
u More prolonged stress
activates the 2nd component of our stress response: the
“Hypothalamus-pituitary-adrenal cortex axis” (HPA).
u Hypothalamus controls
anterior pituitary via hormones secreted into portal blood supply
Chain of command –
u Hypothalamus tells pituitary
to release ACTH.
u ACTH tells adrenal cortex to
release cortisol, an adrenal steroid.
Adrenal cortex vs
u System which produces a
variety of cells and a variety of responses to protect the body against
u 2 categories of immune
• Quick (1-2 hrs) Nonspecific
Reactions to destroy invaders or decrease their reproduction
• Slower (4-5 days or more)
Specific Reactions to specific strains & lasting immunity
Trigger 2 Types of
u Cell-mediated defenses:
T-cells with surface antibodies attack invaders & stimulate the production
of more immune system cells
u Chemically-mediated or
“humoral” defenses: B-cells
which produce circulating antibodies. When the antibodies attach to the
intruder, they mark those sells for destruction
u Interdisciplinary field
studying the connections between psychological processes, the nervous system
and the immune system function
Stress Effects on
u Cortisol initially helps
supply energy & reduce inflammation to sustain your ability to function
under stress, but, in the long-run, suppresses immune function.
u Stress hormones decrease
production of both T and B cells lowering resistance to infection.
u Immune cells also have
receptors for neurotransmitters
u Stress hormones also affect
lower resistance of areas of CNS
u Research shows that not only
do major stresses decrease immune function (re-entry of space shuttle; caring
for family member with serious cancer or Alzheimer’s), so do:
u the end of a relationship
u exam periods
u frustrating tasks, stressful
Immune System to
u Cytokines activate vagus
nerve which in turn signals hypothalamus & hippocampus to produce brain
u Cytokines produce changes in
feeling (pain, fatigue, lack of energy) and behavior (decreased activity,
eating, sexual behavior, increase shivering, desire to curl up under the
covers) to combat infection and promote healing
fMRI to seeing a
Reactivity Partly Determined by Genes
u Those who inherit gene
causing less effective 5HT transport show stronger responses
u Rare, hereditary metabolic
disorder causing calcification of amygdala, disrupting its normal functions.
u Do not seem to experience or
recognize negative emotions (fear, anger, upset, dislike) in faces or body
language. Do not develop classically conditioned fear responses.
u Excitatory transmitter in
amygdala: CCK (cholecystokinin)
u Inhibitory transmitter: GABA
Increased CCK or
decreased GABA à increased fear/anxiety
action à decreased anxiety
barbiturates, alcohol do this)
Research on The
Biological Basis of Aggression & Violence
u Brain research
u Identical twins: ~.60
concordance for aggressive/antisocial/criminal behaviors
u Fraternal twins: ~ .30
u In adoption studies,
criminality/aggression of biological dad is better predictor of child’s adult
behavior than that of adopted parent.
u BUT: Highest probability of
aggression in those with both “bad” biological & adoptive parent.
u Electrical stimulation of
amygdala or ventromedial hypothalamus can trigger aggressive behaviors
u Seizures in the temporal
lobe are one of the few types of epilepsy associated with violent behavior.
u Removal of the amygdala
results in tameness and placid behavior.
u Aggression associated with
reduced 5HT turnover in mice, rats, monkeys.
u Reduced 5HT turnover also
observed in humans, from aggressive adolescents to those convicted of violent
u Also seen in those who
attempt suicide by violent means.
u Low turnover was also a good
predictor of future aggressive acts & future violent suicide attempts.