Neurobiology of Anxiety

Question 0

4 changes that happen the alarm phase of “General Adaptation Syndrome”?

Answer 0

Mobilization of glucose
Changes in circulation
Increase in HR and RR
Increased energy use by all cells

Question 1

What’s the Yerkes-Dodson Law?

Answer 1

Mice and people perform best at an intermediate level of arousal (via shocks or caffeine, respectively).

Question 2

4 long-term metabolic adjustments in the resistance phase of General Adaptation Syndrome?

Answer 2

Mobilization of E reserves: from fat and muscle.
Conservation of glucose for brain (peripheral cells use more fat).
Elevation of blood glucose concentrations.
Conservation of salts and water, loss of K+ and H+.

Question 3

What’s the 3rd phase of General Adaptation Syndrome?

Answer 3

Exhaustion -> depletion of E stores, messed up electrolytes, organ damage, bad stuff.

Question 4

3 monoamines involved in anxiety?

Answer 4

Mainly 5-HT and NE, but there’s some evidence for DA involvement.

Question 5

Review again: Where is NE made? Where is serotonin made? (in the brain)

Answer 5

Locus coeruleus -> NE

Raphe nuclei -> serotonin

Question 6

Which GABA receptor is linked with anxiety?

Answer 6

GABA-A

Question 7

Do SRIs work for anxiety?

Answer 7

Yes.

Question 8

Which NE receptor is most studied in relation to anxiety?

Answer 8

alpha-2 adrenergic receptor. (too much signaling -> anxiety)

Question 9

What 3 specific anxiety-related conditions is dopamine thought to affect?

Answer 9

Social anxiety disorder (SAD)
PTSD
OCD

Question 10

How does behavioral inhibition relate to anxiety? Does this seem to have a genetic basis?

Answer 10

Inhibition -> timidity in novel situations, social withdrawal, slow habituation -> predisposition to panic disorder and social phobia.
Yes, it’s highly heritable.

Question 11

How does neuroticism relate to genetics relate to brain structures…. relate to anxiety?

Answer 11

Neuroticism associated with short 5-HTT allele, which is associated with smaller (but hyperactive) amygdala and cingulate, and abnormal hippocampus and fronto-limbic circuits.

Question 12

What’s a “negative reinforcer” in the context of pavlovian learning? Relation to avoidance in phobias / anxiety disorders?

Answer 12

A behavior that results in removal of a noxious stimulus will be reinforced.
If patient believes they’ve avoided a negative stimulus, their avoidance will be reinforced.

Question 13

What’s a positive punishment?

Answer 13

Decreases behavior by providing negative stimulus in response to action.

Question 14

What’s a negative punishment?

Answer 14

Decreasing behavior by removing positive stimulus in response to behavior. (“No TV!”)

Question 15

What’s Mowrer’s Two Factor theory for why anxiety is maintained?

Answer 15

Anxiety begins with classical conditioning.

Anxiety is maintained with operant conditioning (negative reinforcement).

Question 16

Can fears/phobias be reversed? What is this process called? Can it be context-dependent?

Answer 16

Yes. Fear extinction happens when the CS (conditioned stimulus) is presented in the absence of the US (unconditioned stimulus, i.e. negative thing).
Yes, it can be context dependent.

Question 17

In the modern understanding of learned fears, what really happens when fears are extinguished?

Answer 17

Fears aren’t erased, but rather the US-CS conditioned response is just inhibited. It can be reactivated.

Question 18

What brain area drives the “stress response”?

Answer 18

Locus coeruleus -> NE and sympathetic nervous system

Question 19

Review: What’s the Papez circuit?

Answer 19

Hypothalamus -> anterior thalamus -> cingulate cortex -> hippocampus -> hypothalamus.

Question 20

Area of brain involved in regulating emotion?

Answer 20

ventromedial / medial Prefrontal Cortex?

Question 21

What did fMRI studies that flashed fearful or happy whites of eyes for 17ms show us?

Answer 21

Fearful whites of eyes can activate the amygdala despite 17th being below the threshold for conscious perception.

Question 22

Is the amygdala, the hippocampus, or both responsible for “fear in response to a cue”?

Answer 22

Just the amygdala.

Question 23

Is the amygdala, the hippocampus, or both responsible for “contextual fear”?

Answer 23

Both the hippocampus and amygdala seem to be involved.

Question 24

What was the stated role of the insula?

Answer 24

Internal awareness of the individuals subjective state….