The Corticolimbic Circuit: Order

Question 1

elements of fear learning

Answer 1

(all fear is learned)
1. fear conditioning
2. fear extinction
3. recall

Question 2

fear conditioning

Answer 2

learned to associate a previously neutral stimulus with an aversive experience
- usually freeze in response

Question 3

fear conditioning & rat example

Answer 3

the tone was the conditioned stimulus (because they learned to associate it with pain) and the electrified grid is the unconditioned stimulus (because they don’t have to learn that it is painful).

Question 4

amygdala and fear conditioning

Answer 4

The conditioned stimulus and conditioned stimulus, inputs converge on the same neuron in the BLA, a “fear neuron,” to include fear in the CeA
This leads to the potentiation of activation of the neuron and integrates the information (long-term potentiation – LTP)

Question 5

one-trial learning

Answer 5

able to associate something with fear after a scary encounter w it once (ex. getting bitten by a snake and being scared off by a stick that looks like a snake)

Question 6

neural response to salient visual stimuli

Answer 6

PET scan of participants exposed to CS visual paired with a loud noise
- this led to activation in amygdala and structures for arousal, encoding, integrating and pulvinar
*consider study about pulvinar density and response to visual stimuli

Question 7

what is the relationship between the amygdala and the conditioned response

Answer 7

more activation of the amygdala is associated with a greater strength of the conditioned response

Question 8

observational fear learning

Answer 8

watching someone else experience fear learning
(ex. watch someone see blue square and get shocked while you’re in the same room w shock equipment)
- leads to bilateral activation of the amygdala and greater activation in dACC when you see a blue square
SURROGATE US

Question 9

Indirect fear learning

Answer 9

fear “warning”
- you are just told to be scared of smth (ex. warning sign)
- greater activation of the dACC, HF, insula by seeing a blue square and told you ‘may’ receive a shock from it
- greater activation in the amygdala

Question 10

how does relationships affect fear learning

Answer 10

study of observer watching demonstrater get shocked and they learn the conditioned stimulus a day later
*more impactful when observing friend/ family be shocked

Question 11

fear extinction

Answer 11

removing the response of fear to the CS
- in different context with same CS but no shock (US)
- eventually learns not to express fear

Question 12

the medial prefrontal cortex and fear extinction

Answer 12

fear extinction creates a new memory and decreases the conditioned behavior with the rise of the extinction memory
dmPFC:
- Drives extinction neurons and inhibits fear neurons by directly inhibiting input in BLA
- Excitatory projects inhibit output (by influencing the ICMs which inhibit the CeA)

Question 13

does fear extinction erase fear?

Answer 13

no, it is selective inhibition, which shapes output
- it doesn’t erase fear, just adds an extinction response

Question 14

learning trace

Answer 14

through pathways between the amygdala and dmPFC, it mediates extinction of the original trace

Question 15

fear recall

Answer 15

(24 hours later)
- exhibit extinction and no extinction behavior in different environments

Question 16

the hippocampus formation and fear recall

Answer 16

It is a switch between safety and danger with just one of the conditions changing (ex. would fear a snake in the woods but not in a museum even if you see something that looked similar)

Question 17

fear-conditioning context

Answer 17

• stimulus and context associated with fear boosts the response
• the hippocampus formation amplifies the CS bc its in the context associated with the fear, which induces a fear response in the CeA

Question 18

fear extinction context

Answer 18

• the hippocampal formation and dmPFC inhibit the conditioned stimulus’ fear response and also activate the ICM’s which inhibit the CeA
• so there is no fear response without the proper context

Question 19

fear potentiation in the fear-conditioning context

Answer 19

exaggerated reactions because of greater arousal when the amygdala is activated in a fear response

Question 20

amygdala activity and strength of conditioned response

Answer 20

magnitude of activity in response to the conditioned stimulus predicts the strength of the fear response

Question 21

Hippocampal formation and vmPFC extinction retention magnitude

Answer 21

magnitude of activity in vmPFC and HF predict its ability to successfully inhibit fear following extinction

Question 22

what is the impact of a disconnect between the vmPFC and HF?

Answer 22

PTSD (inappropriate demonstration of fear)
- ability to integrate information in the vmPFC is impact by the ability to appropriately inhibit by dmPFC

Question 23

hippocampal and amygdala lesions

Answer 23

amygdala lesions– don’t generate a fear response, but remember facts about the experiment
hippocampal lesions– normal fear response but poor recall of details from the experiment

Question 24

how many universal facial expressions are there?

Answer 24

6 (but 5 agreed upon, surprise is a bit of an outlier)
happy, sad, fear, anger, disgust, … surprise

Question 25

disgust and amygdala response

Answer 25

(to protect us from contaminants)
- registers in the insula but not the amygdala

Question 26

anger and fear as an amygdala response

Answer 26

• strong activation of the amygdala
• CS is paired with bad things happening

Question 27

STUDY: Orienting to fear in sclera and pupil

Answer 27

(briefly shown a fearful face so you’re not conscious of it directly)but the response cognitively changes, most activation in the sclera

Question 28

STUDY: direct/ averted gaze and fear response

Answer 28

(anger, direct; anger, averted; fear, direct; fear, averted)
- more amygdala activity when its anger, averted and fear, direct
- because info of the threat is more unknown (what are they looking at, why are they looking at me with anger?)

Question 29

size of pupil and association with amygdala response

Answer 29

undilated pupil is associated with a greater amygdala interaction

Question 30

amygdala habituation

Answer 30

• overtime extinction of fear and lower amygdala activation leads to less of a response
• lower activity in the amygdala when repeated presentations of CS without the US (aversive simulation)

Question 31

trait anxiety

Answer 31

tendency to experience anxiety when presented with a threat
- increases amygdala activity and decreases habituation

Question 32

subjective evaluation

Answer 32

vmPFC activated by the amygdala which then goes back and forth with the dmPFC, which eventually inhibits the amygdala to reduce the fear response