Lecture 16 Flashcards
James-Lange theory of emotion
physiological activity precedes emotional experience
Darwin proposed that
autonomic responses are an intricate part of emotional experience
Walter Cannon theory of emotion
Disagreed with James-Lange, thought we feel emotion simultaneously with autonomic response
sympathetic NS
fight or flight
parasympathetic NS
rest and digest
Walter Cannon - Sham rage
w/ cats, cut off/damage cortex + slight stimulation
- not directed towards provoking stimulus
Cannon-Bard lesion experiments
Disconnect cerebral cortex from outflow pathways in cats
- when just forebrain, sham rage behaviours observed
- hissing, arching of back, extension of claws, etc.
- when posterior hypothalamus was disconnect, no sham rage seen
Papez + emotion theory
Added the limbic system into the mix
- cingulate gyrus, hippocampal gyrus, hippocampal formatiom, mammillary glands and hypothalamus
- argued that medial surface of brain is evolutionarily conserved
Kluver-Bucy Syndrome
links amygdala and temporal lobes to emotion
- removed temporal lobes (w/ amygdala and hippocampus) from monkeys
- hyper sexual, hyper oral, change in diets, “psychic blindness” (tame, fearless, blunted emotions)
- amygdala is key structure w/ emotional effects
John Downer Study
cut optic chiasm, lesioned one amygdala
- open eye -> intact amygdala = normal fear response
- shut eye -> intact amygdala = blunted response
- main finding is that the amygdala is required for fear responses (anterior temporal lobe)
Amygdala
looks like almond
- sits infront of anterior part of hippocampus
- key coordinator of emotional behaviour
- essential for fear response
Most commonly studied emotion in neuroscience
Fear
Low road fear pathway
sensory thalamus -> amygdala
- quick + dirty
High road fear pathway
sensory thalamus -> sensory cortex -> amygdala
- slow but accurate (more consolidation, more appropriate response)
lateral nucleus of amygdala
major sensory input structure
central nucleus of anygdala
output structure to hypothalamus
Neural circuit of fear conditioning
CS and US converge on lateral amygdala, LA communicates to central amygdala, CE connects w/ brainstem and hypothalamic regions
Associative learning fear conditioning happens on what neurons
Lateral amygdala pyramidal neurons
LTP in amygdala w/ fear conditioning
insertion of more AMPA receptors
spine growth, more synapses btwn neurons
Patient SM
the woman who was never afraid
- rare, autosomal recessive condition - Urbache-Wiethe disease
- bilateral atrophy of anterior medial temporal lobes
- extensive amygdala damage, little hippocampus damage
- cannot recognize fear, didn’t look at eye region on faces, could be trained tho
Stress is
physical or psychological reaction to a threatening or demanding stimulus
- when our perceived abilities are less than the perceived demands
HPA is an _______ response to stress
adaptive
Effects of HPA axis
increased heart rate, increased energy substrates in blood, alertness, increased blood pressure, increased breathing, decreased growth and reproduction
chronic stress causes
increased glucocorticoids, cellular changes in hippocampus, decreased regulation of cortisol
