#95 - Trauma, Fear, and Anxiety.

Question 1

Key diagnostic features of PTSD - 4

Answer 1

1. Life threatening trauma
2. Re-experience - nightmares, sweating, nausea, etc.
3. Avoiding reminders - avoiding anything associated with the event/ avoiding emotional attachment.

4 Being on guard - hyperarousal, difficulty concentrating.

Depression and Substance abuse are common but not diagnostic.

Question 2

How is Propanolol used for PTSD?

Answer 2

Propanolol is a b-adrenergic receptor antagonist.
It dampens hyperarousal, and if given directly after a trauma, it dampens hyperarousal, and “weakens” the memory - skin conductance responses are much lower when asked about the trauma 3 months later.

Question 3

How is d-cycloserine used for PTSD?

Answer 3

d-cycloserine is a NMDA agonist.
NMDA receptors are important in fear learning/ recall, but also extinction learning. d-cycloserine administered with exposure therapy quickens/strengthens extinction (eg, fear of heights).

Question 4

How is anisomycin used for PTSD?

Answer 4

it is a protein synthesis inhibitor.

once the “fear memory “circuit in the amygdala is reactivated, it undergoes a period of destabilization, in which protein synthesis
is needed to “rebuild” the synaptic connections to maintain the memory.

If anisomycin (protein synthesis inhibitor) is given to animals at this time, then it can help to “erase” the memory.

Question 5

What do the five anxiety disorders have in common?

Answer 5

Fear and anxiety at the core.

Fear/anxiety can be learned or unlearned..

Question 6

What are the 5 anxiety disorders?

Answer 6

1. panic disorder
2. Social phobia
3. Specific Phobia
4. Generalized anxiety disorder
5. PTSD

Question 7

PTSD affects _% of the population

Answer 7

3-10%

Question 8

PTSD typically presents how long after return from tour?

Answer 8

3-9 months

Question 9

T/F - uncommon to have PTSD symptoms more than 20 years after event.

Answer 9

False - sticks with you throughout life.

Question 10

T/F education confers resiliency to PTSD

Answer 10

True.

Question 11

What is the mainstay of treatment for PTSD?

Answer 11

cognitive behavior therapy, exposure therapy, desensitization.

No specific pharmacological treatments yet. Drugs target symptoms - eg antidepressants, calming drugs .

Question 12

Which brain area is central to theories of learned fear?

Answer 12

amygdala - it receives inputs from many regions, and outputs to many regions to produce manifestations of fear.

Question 13

How does the hippocampus play a role in the 2 types of fear conditioning?

Answer 13

It is required for “context” fear conditioning, but not “cue” fear conditioning.

Question 14

how does the amygdala play a role in the 2 types of fear conditioning?

Answer 14

It is required for both context and cue-based fear conditioning.

Question 15

Why does taking out the hippocampus only affect context conditioning, not cue conditioning?

Answer 15

Cue conditioning, like the tone before a shock, can reach the amygdala on its own, without being integrated through the hippocampus. Therefore, cue conditioning is unaffected when the hippocampus is taken out. On the contrary, contextual information must be filtered through the hippocampus before reaching the amygdala, therefore taking out the hippocampus eliminates contexxt conditioning.

Question 16

Stimulating fibers from which brain regions produce long term potentiation (formation of fear memory) in the amygdala?

Answer 16

thalamus

cortex

Question 17

Which type of receptors are critical for synaptic transmission and plasticity in the amygdala?

Answer 17

NMDA receptors!!!

Question 18

What are all the ways NMDA antagonists can modulate fear conditioning?

Answer 18

-It can inhibit acquisition/learning of fear conditioning if administered to the amygdala during conditioning.
- it can also inhibit recall of conditioned fear, after the conditioned fear is learned.
-HOWEVER
NMDA antagonists facilitate extinction of conditioned fear, so inhibiting them after a certain time period will hurt recovery/extinction.

Question 19

Explain extinction. What type of therapy is it the basis for?

Answer 19

Repeated presentation of the CS - conditioned stimulus (tone) generates a new inhibitory memory - essentially you relearn that the stimulus with the trauma
is not actually harmful.

Extinction is the basis for exposure therapy!!!

Question 20

How do drugs impact extinction in PTSD?

Answer 20

Stress, alcohol and other drugs impair extinction - this may contribute to PTSD!

Question 21

Describe “spontaneous recovery”

Answer 21

sounds good but not really. After a while, the extinction memory weakens, and the fear memory recovers and asserts itself again

Hence, Extinction memory is weaker than conditioned fear memory!!

Question 22

T/F - Extinction memory is context dependent, so if a rat is taken out of the context it extinguished its fear in, its fear response will kick in again.

Answer 22

True. This concept is called renewal!

Question 23

Describe reconsolidation.

What is a potential treatment that incorporates this concept?

Answer 23

once the “fear memory “circuit in the amygdala is reactivated, it undergoes a period of destabilization, in which protein synthesis
is needed to “rebuild” the synaptic connections to maintain the memory.

If anisomycin (protein synthesis inhibitor) is given to animals at this time, then it can help to “erase” the memory.

Question 24

Define/describe “renewal” as it relates to fear conditioning. .

Answer 24

Extinction memory is context dependent, so if a rat is taken out of the context it extinguished its fear in, its fear response will kick in again (fear response is “renewed”..

Question 25

Which brain pathway affects drug relapse?

Answer 25

The circuit between the pre-frontal cortex and the nucleus accumbens is altered.