PSCL 352 Exam 3 Part 4

Damage to the amygdala in humans

damage to the amygdala in humans alters emotional memories- no longer show preference for remembering emotion-laden events (normal, evolutionarily beneficial)

Davidson model and depression

depression is associated with L-frontal hypoactivation (Robinson, Starr, and Price's stroke patients); "approach" behavior is reduced in depression (including anger), so is "positive" behavior

Phineas Gage

dynamite tamping rod penetrated his orbitofrontal cortex (but not exclusively- large lesion, so diffuse damage to frontal lobes); exhibited reduced inhibitions and self-concern; before accident was nervobilious (stable), healthy, and a good worker- after, he had a major personality change and became became impulsive

Electrical stimulation of the central nucleus

electrical stimulation of central nucleus induces fear and agitation

Cannon-Bard Theory

emotion is felt first and then action follows cognitive appraisal; the thalamus and amygdala (evidence from neuro, e.g., MRIs) play roles in "perceiving emotion", and this happens quickly for evolutionary reasons; almost simultaneously, the perceiver will act

James-Lange Theory of Emotion

emotional stimuli evoke physiological reactions including muscle contraction; sensory feedback from reactions is perceived to generate feelings; physiological responses are the 1st thing that happen, and only then does person understand emotions being experienced; efferent before afferent

What positive stimuli have been found to cause amygdaloid activation?

erotic nudes (LaBar, et al.); intensely pleasurable music (as determined by the individual; Blood & Zatorre); perception of hysterical laughing (hearing people laugh; Sander & Scheich)

Evidence for the Tucker model- Mandel et al. study

tachistoscopically showed emotional faces to 10 R- and L-hemisphere damaged subjects, and 10 control subjects; RHD was associated with difficulties in negative affect perception- in order of accuracy and speed: controls > LHD (somewhat impaired) >> RHD (significantly impaired); conversely, LHD resulted in deficits in processing positive affect- order of accuracy and speed: controls > RHD (somewhat impaired) >> LHD (significantly impaired)

Emotions- response patterns

subserve function; behavioral- muscle response (run away, approach, facial expressions), approach/withdraw; autonomic- sympathetic and parasympathetic activation (fight or flight due to fear/anger); hormonal- secretion of stress hormones (adrenaline)

Borod Model- Ley and Bryden

tachistoscopically (quick stimulus display) presented negative and neutral faces to subjects' LVF (R cerebrum) or RVF (L cerebrum); found significant LVF (LVF -> L nasal, R temporal retina -> R cerebrum) bias for identifying when the face was affective in nature- subjects were quicker and more accurate in identifying valence faces in the LVF

What are the three models/theories surrounding the role of the right hemisphere in emotion?

the Borod Right-Hemisphere Model (all emotion is associated with the right hemisphere); the Tucker Lateralization Model (positive emotion in L hemisphere, negative emotion in R hemisphere); the Davidson Lateralization model (approach emotions in L hemisphere, withdrawal emotions in R hemisphere)

The Davidson Model

the L cerebrum is involved in "approach" behavior- joy, happiness, positive interest; the R cerebrum is involved in "withdrawal" behavior- sadness, fear, disgust

The Borod Right-Hemisphere Model

the R cerebrum seems to be dominant in the expression and perception of emotion; evidence based on studies of human perception and expression

Schachter-Singer theory

the experience of emotions involves both physiological and cognitive processes; arousal could come from emotional stimulus or something completely different

Central nucleus of the amygdala

the main area of the amygdala; many important outputs

The Tucker Model

the right hemisphere (RH) is dominant in negative affect processing

Why do we have emotions?

they elicit autonomic responses to prepare for body movement; they are motivating (approach or withdraw- important for body to get this right); they persist, helping to ensure goal-directed behavior; they enhance social bonding; they get us out of bed in the morning- without emotion, we wouldn't do anything, you go to class because you care (enjoy class or fear consequences of not going to class or combo of both)

Fear and the amygdala

threat stimuli increase neural firing within central nucleus of the amygdala; tested by exposing mice to bright lights and the silhouette of a hawk

Ventromedial lesions and morals decision-making

ventromedial region is also activated by moral decision-making (inferring pros and cons of situations); persons with lesions are very utilitarian (numbers based, little/no emotion)- often have difficulty weighing which decisions are more important (involves emotional reactions), e.g., saving 4 older lives at expense of 3 younger lives is roughly analogous to going to a more expensive 4-star restaurants vs a less expensive 3-star restaurant

Recognition of emotion

we infer emotional states using visual cues (facial expression, body language; body lean away from/toward others is used in ending conversations); auditory cues (intonation)

Is there a difference between aggression and predation?

yes, they are distinct constructs

Borod model- studies of brain-damaged individuals

5 empirical studies incorporated a total of 31 individuals with right hemisphere damage (RHD), 30 with left hemisphere damage (LHD), and 34 controls; each study independently found that RHDs were significantly less emotionally expressive relative to LHDs and controls; but almost solely assessed negative emotional expression (being in the hospital = stressful time)

Initial evidence that the R cerebrum is dominant in emotional expression

Borod and Caron found that frowns were larger on the left hemiface- they showed subjects a sad stimulus, took a picture of their expression, cut the picture in half, and showed it to participants blind to the study who rated the L hemiface as sadder; true regardless of gender or handedness

Failure of the Borod model

Borod model failed at a certain level due to the almost sole use of negative emotion in studies; due to the fact that negative emotions were where interests/funding was because people wanted to solve problems associated with negative emotions

Tucker model- evidence for RH dominance in negative affect expression

Borod, Koff, and Buck discovered that negative-, relative to positive-, affect expressions were rated as more intense on the L hemiface (and positive more expressed on R hemiface); Davidson, Ekman, et al. found that spontaneous expressions of disgust and happiness correlated with R- and L-prefrontal activity (using QEEG)

Facial expressions signal emotion- Darwin

Darwin: emotions involve innate patterns of muscle contraction, often of the facial muscles -> same way in different species

Facial feedback hypothesis testing

Ekman asked subjects to move facial muscles so as to create facial expressions that accompany emotions; found that different emotional expressions produced different changes in autonomic NS activity- anger -> increased HR and skin temp, fear -> increased HR but decreased skin temp, happiness -> decreased HR, no change in skin temp; consistent with James-Lange and Schachter-Singer; participants also reported feeling most in-line with the expression they were asked to imitate

When might James-Lange vs Cannon-Bard be useful?

James-Lange- useful in evolutionary responses, e.g., seeing snake; Cannon-Bard- when you have to think about how to respond, e.g., receive a negative comment

Reactions with L- and R-frontal strokes

L- and R- frontal strokes have predictable consequences (first noted in clinical observations in 1920s)- L-frontal: "catastrophic" reactions- panicked about deficits (losing positive L, left with negative R); R-frontal: indifference- aware of deficits, but no catastrophic emotional response

L- and R-frontal arousal and neutral stimuli perception

L- and R-frontal arousal predicts the perception of neutral stimuli- relative L-frontal arousal is associated with a more positive perception of neutral stimuli, relative R-frontal arousal is associated with a more negative perception of neutral stimuli

Dutton and Aron (1974)

Schachter-Singer findings replicated in cross bridge study -> when people crossed higher bridge (more arousal), they found a person at the other end of the bridge to be more attractive than participants who crossed a shorter bridge (less arousal)

Support for James-Lange Theory

Sweet's study of reduced emotional sensation to music in a man whose sympathetic nerves were transected on one side of the body as part of a treatment for hypertension (case study); Hohman's study of emotions in persons sustaining accidental spinal cord transcetions- high spinal cord transections produced greater reduction in emotional intensity

Functionality of aggressive behavior

aggressive behavior can be functional- gain access to mates, defend offspring against intruders

Aggressive behavior

aggressive behaviors include threatening gestures (hissing, posturing) and physical attack (biting, striking)

General pattern to approach and withdrawal behavior + the exception

approach behavior is generally associated with positive emotions, while withdrawal behavior is generally associated with negative emotions; except for anger, which is a negative emotion that elicits approach behavior (activates L frontal)

Prosody

auditory cues- involves pitch and cadence flow -> low register staccato (short and quick) is more threatening, high register flowy is more friendly

Benzodiazepines and the amygdala

benzodiazepines (GABA agonists) have profound effect on the central nucleus to reduce anxiety

Tucker model- infants

brain electrical activity served as a predictor of emotional response; measures of L- and R-frontal activity predicted infant response to maternal separation (stressor)- relative L-frontal arousal at baseline -> babies were more content/handled it better, relative R-frontal arousal at baseline -> babies were crying/more emotional

Emotions- persistence and goal-directed behavior

cognitive things don't last long, e.g., "what is 7 x 7?" -> 49 doesn't last long in your brain; but anger doesn't just go away -> lasts until station is resolved; negative emotions last longer than positive because they often surround an issue that needs to be resolved

Emotions- social bonding

critical for social bonding; emotions are reciprocal in nature between people- if a person is angry at someone, the emotions may be reflexive (other person feels remorse) or the same (other person is also angry); seen in empathy/sympathy for another's loss; humans are extremely adept at sensing emotions -> microexpressions = person shows emotion for as little as 30 ms

Culture influence of facial expression of emotions

culture can influence facial expression of emotion- frequency and strength of emotional expression, not how emotion is expressed; in some cultures, the social norm is to repress emotional expression, and in others, more extreme emotional expression is the norm

Dorsolateral lesions

damage to the L dorsolateral results in depression; due to heavy lateralization, not true for homologous tissue in R cerebrum, which damage to causes mania (positive affect but prone to anger outbursts); positive and negative emotion elicit activation of L and R dorsolateral cortices, respectively

How are feelings measured?

(1) emotional valence- rating from negative to positive, e.g., scale from 1 (negative) to 10 (positive) with 5 being neutral, but limited because someone could be at a 2 because they're angry, sad, fearful, etc.; (2) discrete emotions- the main discrete emotions are generally considered to be (although there is disagreement) happy, sad, angry, fear, disgust -> there are more negative than positive discrete emotions

Schachter-Singer and exercise

exercise increases strength of emotion, especially after a period of time (physiological and cognitive); late 50s Princeton- S&S had male students ride a stationary bike and measured HR; as expected, after biking stopped, HR went back to baseline slightly before 20 min; experimental group- at either time 0, 5, 10, 15, or 20 mins after biking stopped, a female RA gave a questionnaire; S&S asked participants how attractive they found her at the end of the study; they expected highest attraction would be reported at 0 min due to misattribution of arousal when arousal is highest; but it was actually at 15 mins- participant has to ask self: (1) am I more aroused than normal? (at 20 min, no), and (2) to what do I attribute arousal? (at 0 min, attributed to biking, at 15 attribution switches to attraction)

Facial expressions signal emotion

facial expressions signal our emotional states to others

Conditioning of emotional responses

fear stimuli elicit emotional responses (e.g., loud noises, painful stimuli); fear stimuli can be associated with neutral stimuli (e.g., tone that occurs prior to a foot shock- classical conditioning); eventually, the neutral stimulus will elicit an emotional response (tone paired with shock elicits fear)

What emotion does the amygdala become most activated in response to?

fear; but also activated by other negative and even some positive emotions

Orbitofrontal cortex

humans are able to interact socially and understand social situations- the analysis of social situations requires an intact orbiotfrontal cortex

Central nucleus outputs

hypothalamus (sympathetic), parabrachial nucleus (increased respiration), nucleus accumbent (reward pathway, motivation- approach positive or avoid negative), locus coeruleus (vigilance), trigeminal pathway (facial fear)

Predation

involves an attack of a member of one species on another (for food); distinct from aggression- predation does not involve sympathetic arousal; researchers studying lions didn't find extreme sympathetic activation when they hunted gazelles, but did find robust activation when lions were protecting their DNA (themselves or nuclear family)

Ventromedial lesions

lesions impair ability to foresee positive and negative emotional consequences of behavior; trouble planning/following through with future-oriented plans

Lesions of central nucleus

lesions of central nucleus diminish emotional responses: reduced fear responses to threat stimuli; reduced levels of stress hormones; reduced chance of developing ulcers due to stress (first research to empirically show that emotional well-being impacts physical well-being)

Central amygdala nucleus and fear

lesions of the central nucleus abolish CER to tone previously paired with foot shock (LeDoux experiments)

Orbitofrontal lesions

lesions reduce inhibition of behavior and impair the ability to have "appropriate" emotional responses; impacts emotional dialogue with others

Davidson model and mania

mania is associated with size and proximity of damage to the R frontal pole (Jorge, Robinson, Starkstein, et al.); positive affect and anger outbursts

Emotions- feelings

negative (fear, anger, sadness, disgust); positive (happiness, amusement- rarely studied)

Conditioned emotional response (CER)

neutral stimulus that is associated with neutral stimulus that eventually will elicit an emotional response, e.g., tone previously paired with shock elicits fear

Is there a right model?

no right model, all have value in some emotions

Regions of prefrontal cortex

orbitofrontal, ventromedial, dorsolateral

Major outputs of the amygdala

periaqueductal gray matter (species-specific responses, e.g., freezing), medial basal forebrain and hypothalamus (sympathetic arousal), ventral striatum, dorsalmedial nucleus of thalamus, output of the central nucleus

Facial expressions- commonalities across cultures

positive emotions involve zygomatic (corners of mouth) muscle activity; negative emotions involve corrugated muscle activity (forehead); facial expressions are similar in blind and sighted children

Which hemisphere is involved in recognition of others' emotions?

recognition of emotion in other persons involves the right hemisphere; left-ear and left-visual field advantage for recognition of emotion; right hemisphere lesions impair recognition of emotions from facial expressions or hand gestures; however, we know more now than since the book was written -> the idea of left hemisphere being involved in language and right hemisphere being involved in emotion is not completely true- not separate/isolated

Issues with facial feedback testing and how they were addressed

results could have been due to demand characteristics (participants gave Ekman the answer they thought he wanted about what emotions they were feeling) or due to the fact that being asked to imitate an expression caused participants to recall memories of times when they actually felt that emotion; Ekman had participants put a pen in their mouths in different ways to activate different muscles involved in emotional expressions -> autonomic NS data supported hypothesis and participants reported having no idea what the study was testing

Major inputs to the amygdala

sensory cortex and sensory thalamus, hippocampal formation (memory), main accessory and olfactory bulb

Serotonin and aggression

serotonin appears to inhibit aggression; damage to prefrontal 5-HT neurons increases aggression; low 5-HIAA levels predict increased risk-taking behavior in monkeys

Paul Ekman

studied muscles around people's faces in cadavers -> 45 muscle groups around the face, and contractions in different patterns allows communication of emotions; provided evidence for commonalities across cultures