Emotions Flashcards
Components of Emotional Response
- behavioral
- autonomic
- hormonal
key brain structure for mediating negative emotions (anxiety, fear, anger)
amygdala
coordinates and integrates the behavioral, autonomic and hormonal components of emotional responses
amygdala
central nucleus, functions
- aversive stimuli – expression of emotion provoked by (single most important part of the brain for this)
- aversive learning (i.e. learning a situation is dangerous from past experience)
- part of amygdala
amygdala, input
receives input from sensory and executive parts of brain, all areas of cortex including / in addition to:
- vmPFC – emotional regulation
- thalamus – sensory input
- hippocampus – memory
amygdala, output
projects to
- thalamus → prefrontal cortex
- vmPFC
- various structures: hypothalamus, midbrain, pons, medulla which control various aspects of emotional responses
central nucleus, damage
Damage reduces or abolishes wide range of emotional behavior and physiological responses
- animals no longer show fear to threatening stimuli, are more tame, less timid in new places
- blood levels of stress hormones (cortisol) are lower
- less stress-related health problems, like ulcers
Also, if CN/amygdala is destroyed (in animals), conditioned emotional response does not take place
central nucleus, stimulation
Electrical or amino acid stimulation of central nucleus in animals
- behavioral and physiological signs of fear and agitation
- long-term stimulation produces stress-related illnesses i.e. ulcers
- indicates amygdala controls autonomic and endocrine response that are involved in the harmful effects of long-term stress
conditioned emotional response
- mixer example from book
- specific & non-specific responses
- non-specific response – generalized physiological response controlled by autonomic ns
- specific response – way to cope/escape; if learned, non-specific emotional responses will eventually disappear
- if CN/amygdala is destroyed (in animals), conditioned emotional response does not take place
extinction
- fading/dissolution of paired response
- vmPFC mediates
- lesions of vmPFC impair extinction in animals
- stimulation of vmPFC interferes with acquisition of conditioned emotional responses
stimulation of hypothalamus produced autonomic responses of fear and anxiety but…
only stimulation of amygdala produced feeling of fear
human patients with amygdala damage
- showed impaired acquisition of conditioned emotional response
- do not show increased startle response when feeling unpleasant emotion as normals do
- do not show increased memory for emotionally connated story elements or pictures as normals do
- could not identify scary music but could id happy and sad music
Humans can acquire CER by…
- observation
- instruction
human brain structures activated during CER and extinction
CER: amygdala
Extinction: vmPFC
attaching negative emotional valence to memories
Amygdala is responsible
- R amygdala was activated when s’s recalled arousing/violent film vs. non-arousing
- s’s most likely to recall emotional scenes that highly activated amygdala upon first viewing
- increased amygdala activation when viewing “threatening” vs. not words, even though only asked to identify color of ink
in animals, 3 areas involved in mediation of aggression
periaqueductal gray – movement response component
hypothalamus – autonomic NS/sympathetic
amygdala – fear
neurotransmitter that inhibits aggression
serotonin (5-HT)
low serotonin = higher aggression
monkeys with low serotonin
- engaged in more risk taking behavior including high levels of aggression towards older and larger monkeys
- more likely to take dangerous leaps between tree branches over 25 ft. high
- 46% died in 4 years, while all with high 5-HT lived
- most of those that died were killed by other monkeys
low serotonin in humans
- associated with aggression and antisocial behavior including: assault, arson, murder, child abuse
- men with lowest levels of 5-HT activity more likely to have relatives with antisocial behavior (but it was not possible to determine to what extent this was due to genetic or environmental factors)
- Prozac (SSRI) decreased irritability and aggressiveness “as measured by psychological test scores”
executive functioning headquarters for emotional responses
vmPFC
hemisphere more involved in social judgments
R
perceiving and understanding the meaning of social situations…
- involves the integration of sensory info with memories and cognitive abilities to render judgments
- among the most complex processing we do
- vmPFC is centrally involved in this function
vmPFC emotional processing inputs
what’s going on, activation, emotional valence of what’s going on
- amygdala – relevant info about negative emotions
- dorsomedial thalamus (sensory info)
- temporal lobe (sensory info)
- ventral tegmental area – arousal
- olfactory system
vmPFC emotional processing outputs
- cingulate cortex – allows control of behavior
- amygdala
- hippocampus – memory
- hypothalamus – autonomic
- temporal lobe
- other prefrontal areas involved in cognitive processes including dlPFC
vmPFC damage
- Phineas Gage, prefrontal lobotomy (personality changes, childishness, irresponsibility)
- impairment of extinction of paired responses
case study of damage to bilateral orbitofrontal cortex
(problems in this area are also seen in personality disorders)
- was able to verbalize reasonable, appropriate, logical plans and responses to hypothetical situations
- was unable to apply the knowledge so that it regulated his behavior
vmPFC, moral judgments
- increased activation in vmPFC when decisions involve emotions/personal morality (not non-moral)
- normals make utilitarian decisions for non-moral and impersonal moral scenarios; emotional basis for making personal moral decisions
- pts with vmPFC damage make utilitarian decisions in non-moral, impersonal moral, AND personal moral scenarios
anterior cingulate cortex (ACC)
- serves as interface between frontal lobe (i.e. decision making), amygdala, and the brain areas controlling movement
- ACC has strong connections to dlPFC
- ACC provides excitatory influence for emotions and motivation in general
- electrical stimulation of ACC produces feelings of either positive or negative emotions
- damage can result in akinetic mutism – person loses motivation, does not speak or move, life-threatening
functional imaging studies show activation of anterior cingulate when people are…
initiating behavior, especially emotional behavior
extroverts/introverts
Extroverts showed higher level of activation in anterior cingulate
Introverts showed decreased level of activation in anterior cingulate, but increased activation in prefrontal area which mediates inhibition of behavior
s’s who listened to narratives of their own life experiences that “would be expected to make them angry” showed…
increased activation of R anterior cingulate
Personal moral dilemmas activate…
vmPFC, ACC, and dlPFC
dlPFC
involved in cognitive functions including working memory, response selection, verification of info retrieved from long-term memory, evaluation and implementation of strategies
Theory is that conflict between utilitarian and emotional influences in decision making activates…
ACC which activates dlPFC
- dlPFC initiates process of weighing emotional and rational factors and “comes to a decision” about what action to take
- While specifics are still not clear, prefrontal lobes (reasoning) inhibit amygdala (emotional responding) to achieve balance between the two
S’s with antisocial personality disorder had reduction in…
volume of prefrontal gray matter, 11%
Unsuccessful psychopaths had 22% reduction in volume of prefrontal gray matter
psychopathy and PFC thickness
“Data in the literature report a reduction in prefrontal gray matter volume, gray matter loss in the right superior temporal gyrus, amygdala volume loss, a decrease in posterior hippocampal volume, an exaggerated structural hippocampal asymmetry, and an increase in callosal white matter volume in psychopathic individuals. These findings suggest that psychopathy is associated with brain abnormalities in a prefrontal-temporo-limbic circuit - i.e. regions that are involved, among others, in emotional and learning processes. Additionally, data indicate that psychopathic individuals cannot be seen as a homogeneous group.” (Weber, 2008)
serotonin and prefrontal lobes
- PFC activated by large serotonin pathway, brainstem raphe nuclei to PFC
- Studies appear to indicate deficient serotonin input to PFC involved in aggression:
Serotonin releasing drug caused increased PFC activation (inhibition) in normals but not s’s with impulsive aggression, problem with pathways; fMRI study showed lower levels of 5-HT transporters in medial prefrontal area of s’s with impulsive aggression, suggests this area has decreased 5-HT input
HOWEVER…
Pt’s with hx of impulsive aggression, fMRI pre-post Fluoxetine (prozac) treatment, increased activity of prefrontal cortex and decrease in aggression - These condradict
testostorone
- theory that the effect of testosterone is to increase motivation for dominance
- but it may be establishing a position of dominance leads to increased testosterone rather than vice versa
- incr testostorone = incr aggression
- environment influences testosterone level
- may interact with alcohol
facial expression of emotions…
are innate, hard-wired, consistent across cultures, same in blind children as sighted children
Hemisphere that mediates perception of emotional content and expression
R
R hemis damage and emotional perception
summary: ppl w/R hemis strokes are impaired in identifying emotions from voice prosidy or from facial expressions, but they can identify emotions in word content or verbally given scenario
verbal comprehension of emotion
- comprehension of emotion from word meaning activated bilateral frontal lobes L > R
- comprehension of emotion from voice tone increased R prefrontal only
perception of emotion and amygdala
- large increases in amygdala activation when people view facial expressions of fear but not when viewing happy faces
- damage impairs ability to recognize facial expressions of emotions, especially fear (does not impair perception of prosidy in voice)
- Case: bilateral amygdala damage
a. Could not judge facial expressions of fear
b. Disinclined to look at eyes of person and spent a lot of time looking at their mouth
affective blindsight
Patients can recognize facial expressions of emotion even though they have no conscious awareness of seeing the face
i. PET of pt showed activation of superior colliculus, posterior thalamus (pulvinar) and amygdala when he viewed faces expressing fear
ii. Pt had no conscious awareness of seeing face
iii. Shows pathway that conveys info about emotion expressed in face is different than pathways that convey other visual info
disgust
- activates basal ganglia and insula
- damage to basal ganglia and insular cortex impair recognition of facial expression of disgust
voluntary facial movement is dissociable from…
emotional facial expression
facial paresis
- facial paresis
- difficulty making volitional facial movements due to damage in cortex or pathway
- full facial movements during spontaneous emotional expression - emotional facial paresis
- volitional facial movement intact
- weak or no facial movement during spontaneous emotional facial expression due to damage in insular, frontal white matter or thalamus
humor
Different types of jokes activate different areas of brain, but all activate R vmPFC
hemisphere with dominant role in facial emotional expression, also voice expression of emotion
R
- chimerical faces: L half composite was judged more emotionally expressive than R
- emotional facial expressions usually emerge on the L side of the face first, suggesting > R hemis involvement
- L hemis lesions usually do not impair expression of emotions in voice tone or facial expression, whereas R lesions often do
3 models of emotion
James-Lange
Cannon-Bard
Modern view
James-Lange model of emotion
environmental event elicits physiological reactions ⇒ brain is aware of these physiological reactions thru sensory feedback ⇒ perception of these physiological responses constitutes our experience of feelings or “feelings of emotion”
- Book author cites spinal-cord injury data that supports James-Lange; however, descriptive data could just reflect decreased intensity of emotion feelings because the physical component is not experienced, same results would be expected for other two models, does not prove that emotions are merely the product of our observations of physiological states
Cannon-Bard model of emotion
environmental event elicits both feelings and physiological reactions; the two proceed in parallel and, while both constitute emotional experience, they have no causal relationship with each other
Modern model of emotion
the environmental events, physiological reactions, and brain-based feelings of emotion are all interactive and affect each other
