Physiology of Emotions II

Class 10

Quiz 1

13-15 A12 A-/B+13 B9-10 B-8 C9 D5-6 F

15 10 pts16 9.3 pts13 8.7 pts12 8.0 pts13 7.3 pts14 6.7 pts 9 6.0 pts

8 5.3 pts7 4.7 pts6 4.0 pts 5 3.3 pts

MIDTERM ON MARCH 10

Limbic System

Evidence That Limbic System Regulates Behavior

Electrode Studies (Hess, 1940s)

1. Superfine electrode stimulation of rats' LS

2. Rats respond to jolts as if hugely rewarding:

a. Go to where jolts occurred

b. Work long to get jolts

c. Learn tasks paired with jolts

3. Refers to this as "self-stimulation behavior"

4. 85% of limbic system --> self stim behavior, rare outside of limbic system

Rats' response to jolts is like what kind of problematic human behavior?

Addiction

More Evidence That Limbic System Regulates Behavior

Psychomotor Epilepsy

1. Occurs when brain cells in certain area fires in waves

2. Psychomotor epilepsy restricted to limbic system

3. Has similar effect in humans as electrode shocks in rats.

4. Results of limbic epilepsy (emotional auras):

a. Happiness: Dostoevsky reports "indescribably happiness."

b. Other emotions: Desire, sadness, affection, fear, anger.

Behaviors associated with P.E. 1. Shadow boxing

2. Kissing fits

Amygdala

1. Emotion central: pleasure and pain

2. Sensitive to unfamiliar stimuli

3. Makes first assessment of event’s emotional significance

4. Neural pathway to amygdala bypasses the cortex

Klϋver-Bucy Syndrome

Removal of monkey amygdala leads to:

1. Lose fear to/aggressiveness towards humans

2. No facial expression

3. Examine things regardless of danger: fire, broken glass

4. Eat everything: meat, feces

5. Mate everything: other sex, same sex, inanimate objects

Klϋver-Bucy Syndrome occurs when amygdala is damaged. Shows same effects in humans as amygdala removal in monkeys.

What does K-B Syndrome say about emotions and judgment?

LeDoux’s Neural Pathways

STANDARD ROUTE:

SENSORY THALAMUS CORTEX AMYGDALA

EMERGENCY ROUTE: SENSORY THALAMUS AMYGDALA

This route indicates what comes first, thinking or feeling?

This route indicates what comes first, thinking or feeling?

Thinking: cortex precedes amygdala

Feeling: Direct line to amygdala

Amygdala and Emotions: Key Points

 1. Input connections—Visual centers, auditory centers

2. Output connections—hypothalamus (directs emot. behavior)

3. Activation leads to self stimulation behavior, a range of emotions

4. Assigns emotional significance to events

* Conditioning occurs without cortex, just amygdala

* Directs attention to important events

* Sets up species specific action systems

5. Does amygdala support appraisal or separate systems?

The Role of the Cortex in Emotions:

Hemispheric Lateralization

Right Hemi.

Left Hemi.

Hemis. Lateralization and Emotions

Lateralization: L hemisphere guides right side of body

R hemisphere guides left side of body

Lateral functions: L hemisphere – speech, reasoning

R hemisphere – emotional recognition and

interpretation.

All reversed if Left-handed (i.e., L hemi. guides emotion, etc.)

Research on hemisphere lateralization

1. Split-brain studies of epileptics

2. Emotional ID of faces and hemi. dominance

3. Lie detection and hemisphere dominance

Split Brain Studies of Epileptics

Epilepsy treatment—removal of corpus collosum

Corpus Collosum is: Membrane connects L hemi to R hemi

Removal permits exclusive presentation to L or R hemi

Patients shown emotional displays to L or R side of brain

Can recognize emotions when shown to:

Can verbalize emotions when shown to:

Right side

Left side

Aphasia and Lie Detection

a•pha•sia (uh-fay'-zhuh) n. An impairment of the ability to use or comprehend words, usually acquired as a result of a stroke or other brain injury (National Aphasia Association).

Oliver Sacks and laughter from the Aphasia Ward during Ronald Reagan’s speech.

Aphasiacs depend on emotional cues

So good at “reading” emotions, hard to see that they don’t understand language.

Respond to HOW things said, not WHAT said.

Valence Lateralization

Emotional Perception: R hemi is superior to L hemi

Does one side FEEL more emotion than the other? NO

Hemis differ in type, or “valence” of emotions they favor.

Negative emotions felt mainly on?

Positive emotions felt mainly on?

Right Side

Left Side

Chimeric Faces

EEG Evidence of Lateralization

EEG = Electroencephalogram

Electrodes placed on scalp, record brain activity

Subjects see funny or gruesome movie, facial expression and EEG are recorded.

Funny Smiling, happy

EXPRESSION HEMI ACTIVATED

Left Side

Gruesome Nose wrinkle, disgust

Right Side

MOVIE

Muscle Contraction and Mood States

Ss contract L-side/R-side of face or squeeze ball in R or L hand.

These actions activate (R-hemi/L-hemi)—per handedness.

These actions, in turn, lead to mood changes:

L-side activity

R-Side activity

Right

Left

Hemi

Hemi

sadness

positive, assertive

Hemispheric Activation and Social Judgment: TAT Study

TAT = Thematic Apperception Test

People see pictures, and tell stories about them.

Commonly used as a clinical psychology device

L-side activity R-hemi

R-side activity L-hemi

More negative interpretations

More positive interpretations

Why Are Emotions Lateralized?

What kind of emotions leads to approach, positive or negative?

Positive

With which hand to we approach things, Left or Right?

Right (dominant)

Which hemi controls these kinds of emotions, right or left?

Left

Which hemi controls Right hand, Left or Right?

Left

Conclusion: Emotions help guide approach/avoidance

Emotional Lives of Stroke Patients

Stroke to Left Hemisphere ? Depression

Stroke to Right Hemisphere ? Mania

Chronically depressed people show less Left Frontal Activation

Clinical Condition

Neurological Development and the Limbic System

R-Hemi has closer connections to limbic system than L-Hemi.

R-Hemi develops earlier in infancy than L-Hemi

Emotions appear in babies before language

Emotionally expressive babies start talking later

When babies start to talk, don’t show emotion

13 mos—talk, no emotion

19 mos—talk + emotion

What does this say about separate systems?

Are Affective Styles Genetic? Davidsons, Kagan et al. 1993

Subs: 2.5 year olds (N = 386) tested with moms present.

Start (“T”): Hang out with mom

T + 10: Talking robot appears

T+ 13: Robot leaves to “take a nap”

T+ 20: Stranger with fun toys “Want to play?”

T + 23: Stranger leaves

Three types of children identified:

1. Inhibited: hover near mom, quiet, avoid robot, stranger

2. Un-inhibited: Less time w’ mom, engage in activities

3. In-betweeners: Between inhibs and un-inhibs

Hemisphere Activation and Temperament:Kagan, et al. Study of Inhibited/Uninhibited Kids

-0.06-0.04-0.02

00.020.040.060.08

0.10.12

Inhibited Middle Uninhibited

Lowe

r = R

ight,

High

er =

Lef

t

Implications for shyness: Learned or inherited?

Hemisphere activation measured using?

Neurochemicals and Emotions

OTTO LOEWI AND THE DISCOVERY OF NEURO-CHEMICALS

Heart #1 Heart #2

1. Stim vagus nerve, slows Heart 1 (H1)

2. Extract fluid from H1 bath

3. Apply H1 fluid to H2.

What happens to Heart 2? It slows. Why? Acetyl-choline

Neurochemicals and Emotions1. Neurotransmitters (e.g., acetyl-choline)

2. Hormones (e.g., adrenaline, from adrenals)

3. Neuromoderators (e.g., endorphins)

Relevance to emotions

* Different emotional systems employ different neuro-chemical messengers

* Different chemicals lead to different emotional states

* What clinical value in locating "emotional" chemicals?

Discovery of psychotropic drugs to treat: depression, anxiety, hyper-arousal.

L-Dopa

1. Pre-cursor to dopamine, a neurotransmitter

2. Acts on striatum—motor activity

3. “Re-awakens” sleeping sickness patients

Revived planning, spontaneous action

Revived emotions--probably b/c revived striatum communicates with ???

Awakenings, (1990)

Amygdala

Panic Attacks

Sudden rush of fear, lasts 15-30 minCome "out of the blue"Feels like heart attack, will lose controlCan lead to agoraphobia--fear of being in the open

CCK (cholecytokinin)

1. CCK is peptide, large molecule neurotransmitter

2. CCK --> increased blood to limbic system

3. Tied to panic attacks

4. Give CCK to humans, monkeys, rats --> panic attack