Flashcards in Emotion & Stress Deck (35):
3 components of emotional response
Relevance of amygdala to emotion?
located in medial temporal lobe, round "almond", set of nuclei
integration of behavioral, autonomic, hormonal components- esp. in cases of biological significance
When is amygdala activated?
when emotionally relevant stimuli is present ; research traces input & output pathways to determine how fear response is produced
Central nucleus (of amygdala)
most important part of brain for expression of emotional responses evoked by aversive stimuli
Becomes activated when threat is PERCEIVED
If Central nucleus (of amygdala) is damaged?
animals no longer show fear to conditioned stimuli
tame when handled
less stress hormones
If Central nucleus (of amygdala) is stimulated?
animals show fear & agitation
long term stimulation produces stress-induced illness (ie gastric ulcers)
Describe Kluver-Bucy syndrome
amygdala damage (first studied in monkeys)
-monkeys are calm & placid
-display less than normal fear of snakes
-altered social behaviors; decreased ability to interpret threat gestures
Describe toxoplasma gondii parasite
causes damage to amygdalae of rats which leads them to approach & get eaten by cats
If you were conditioned to be fearful of something mundane, what physiological responses might you have to the conditioned stimulus?
-increased heart rate
-increased blood pressure
-muscles become tense
-adrenal glands secrete corticosteroid hormones & adrenaline
Describe fear conditioning
learned fear in response to a previously neutral stimulus
lateral nucleus via central nucleus
inhibition of Conditioned response expression
supplied by vmPFC
Describe how the amygdala affects emotional response in humans
startle reflex is more vigorous if already tense
(modulation by amygdala; if damage then normal startle reflex present but no modulation of reflex)
-event is more memorable if strong emotions exist (except for those with amygdala lesion-also Alzheimer's patients have some damage there)
rare genetic condition that causes calcium to build up into the amygdala until it wastes away (case study of SM)
-experiences fearlessness that is dangerous; robberies at gunpoint; no inhibition w/strangers; reports feeling angry but not afraid
amygdala responds to stimuli not consciously perceived- eg amygdala reactivity to emotional faces in a patient with cortical blindness
Describe aggressive behavior
species typical; many related to reproduction and self-defense
-defensive behaviors: controlled by Periaqueductal Gray Matter (PAG)
-submissive behaviors (giving up in face of unfair fight)
Why is predation not considered to be anger related?
predation is when one species attacks another- it's controlled by a different region of PAG more related to defensive behaviors
What neurotransmitter is related to aggression?
Serotonin; inhibits aggression
-destroys serotonin axons
-monkeys with low serotonin die young
-humans: linked with aggression, anti-social, violent crime, attempted suicide (not predictive)
Explain the relevance of the Ventromedial prefrontal cortex (vmPFC) to emotion and aggression
important for social skills;inhibiting emotional response
-activated when a joke is funny
-interface btw brain mechanisms involved in automatic emotional responses & those involved in executive control.
Lesions? cause impairments in behavioral control & decision-making (Phineas Gage)
- damage leads to utilitarian moral judgment in moral dilemmas (psychopaths)
-impairs understanding of jokes
Explain how hormones influence anger/aggression
Testosterone has organizational & activational effects on offensive attack. Men with highest rates of violent behavior have slightly higher testosterone levels
-Increases arousal: may increase amygdala response to angry expressions
-Decreases emotion regulation ability
What about testosterone's affect on women?
-also facilitates aggression by organizational effect
may be thru enhancement of motivation for social dominance
-decreased ability to recognize angry faces
-Increase in aggressive behaviors in monkeys more substantial w/alcohol & mating season timing
Summarize Darwin's Theory of the Evolution of Emotion
Emotions are products of evolution; same emotional responses for same emotional states w/in species; evolved from other animals.
-emotional expressions of blind & sighted children are similar
- universality of emotion expression true for vocal exp as well
- less facial expression when alone
Talk about how amygdala damage affects ability to recognize facial emotions
- effect is particularly strong for fear & disgust
-affects memory for emotional faces
-attention to certain aspects of the face (SM looked at eyes vs mouth) may acct for the emotion recog. difference.
What is the superior temporal sulcus (STS) important for?
recognition of gaze direction
amygdala reactivity only if gaze is averted vs direct
Insula & Basal Ganglia are important for...
Recognition of disgust
- insular cortex is strongly activated during exposure to stimuli perceived as 'disgusting'
-also primary taste cortex
-insula also related to changes w/in ur own body
Describe Duchenne's expression of smiles
genuine vs fake smiles
genuine: involves contraction of muscles around the eyes
fake: cheek contracts but no eye crinkles
method acting enables a real smile
Volitional Facial Paresis vs Emotional Facial Paresis
Volitional- damage to face region of primary motor cortex; can't do a fake smile; can produce a real one
Emotional- damage to insular region of PFC, white matter of frontal lobe or parts of thalamus; can move face muscles voluntarily; cannot move muscles on affected side during a real smile
Seizures associated with laughter when the pt is not happy are...
gelastic; begin in left anterior cingulate gyrus- when you remove tumor from that area seizures & laughing stop.
suggests this area controls muscles of laughing
Which hemisphere plays a more significant role in recognizing and expression emotion
James-Lange 1st physio theory of emotion
suggests that autonomic arousal occurs first in an emotion; feeling is the label we give the arousal of organs and muscles
Do people with pure autonomic failure perceive emotions?
Yes, but they feel them less intensely; suggests other factors are involved in perception of emotion
Describe the general adaptation syndrome
threats to the body activate a general response to stress- regardless of type of threat or stressor
Alarm stage: increased sympathetic nervous system activity
Resistance: sympathetic response declines; releases cortisol; prolonged alertness;fight infections
Exhaustion: occurs after prolonged stress; inactivity, vulnerable, decreased energy
Describe the 2 systems in the body that stress activates
1)Sympathetic nervous system: 'fight or flight' response
2) HPA axis: hypothalamus, pituitary gland & adrenal cortex
How does stress activate the HPA axis?
activates hypothalamus causing pituitary gland to secrete ACTH-->stimulates adrenal cortex to secrete cortisol
After prolonged stress, HPA axis becomes dominant response
What can prolonged stress result in?
impaired memory;damage to hippocampus
cortisol enhances metabolic activity in body/hippocampus- neurons more sensitive to damage by toxins or over-stimulation
also impairs hippocampal neurogenesis