Neurobiology of Anxiety Flashcards
4 changes that happen the alarm phase of “General Adaptation Syndrome”?
Mobilization of glucose
Changes in circulation
Increase in HR and RR
Increased energy use by all cells
What’s the Yerkes-Dodson Law?
Mice and people perform best at an intermediate level of arousal (via shocks or caffeine, respectively).
4 long-term metabolic adjustments in the resistance phase of General Adaptation Syndrome?
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+.
What’s the 3rd phase of General Adaptation Syndrome?
Exhaustion -> depletion of E stores, messed up electrolytes, organ damage, bad stuff.
3 monoamines involved in anxiety?
Mainly 5-HT and NE, but there’s some evidence for DA involvement.
Review again: Where is NE made? Where is serotonin made? (in the brain)
Locus coeruleus -> NE
Raphe nuclei -> serotonin
Which GABA receptor is linked with anxiety?
GABA-A
Do SRIs work for anxiety?
Yes.
Which NE receptor is most studied in relation to anxiety?
alpha-2 adrenergic receptor. (too much signaling -> anxiety)
What 3 specific anxiety-related conditions is dopamine thought to affect?
Social anxiety disorder (SAD)
PTSD
OCD
How does behavioral inhibition relate to anxiety? Does this seem to have a genetic basis?
Inhibition -> timidity in novel situations, social withdrawal, slow habituation -> predisposition to panic disorder and social phobia.
Yes, it’s highly heritable.
How does neuroticism relate to genetics relate to brain structures…. relate to anxiety?
Neuroticism associated with short 5-HTT allele, which is associated with smaller (but hyperactive) amygdala and cingulate, and abnormal hippocampus and fronto-limbic circuits.
What’s a “negative reinforcer” in the context of pavlovian learning? Relation to avoidance in phobias / anxiety disorders?
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.
What’s a positive punishment?
Decreases behavior by providing negative stimulus in response to action.
What’s a negative punishment?
Decreasing behavior by removing positive stimulus in response to behavior. (“No TV!”)
What’s Mowrer’s Two Factor theory for why anxiety is maintained?
Anxiety begins with classical conditioning.
Anxiety is maintained with operant conditioning (negative reinforcement).
Can fears/phobias be reversed? What is this process called? Can it be context-dependent?
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.
In the modern understanding of learned fears, what really happens when fears are extinguished?
Fears aren’t erased, but rather the US-CS conditioned response is just inhibited. It can be reactivated.
What brain area drives the “stress response”?
Locus coeruleus -> NE and sympathetic nervous system
Review: What’s the Papez circuit?
Hypothalamus -> anterior thalamus -> cingulate cortex -> hippocampus -> hypothalamus.
Area of brain involved in regulating emotion?
ventromedial / medial Prefrontal Cortex?
What did fMRI studies that flashed fearful or happy whites of eyes for 17ms show us?
Fearful whites of eyes can activate the amygdala despite 17th being below the threshold for conscious perception.
Is the amygdala, the hippocampus, or both responsible for “fear in response to a cue”?
Just the amygdala.
Is the amygdala, the hippocampus, or both responsible for “contextual fear”?
Both the hippocampus and amygdala seem to be involved.
What was the stated role of the insula?
Internal awareness of the individuals subjective state….
