Lecture 2: Stress in the Brain

Question 1

Why does the effect of stress differ between individuals?

Answer 1

Stress is the response to a PERCEIVED aversive or threatening situation.

Question 2

What is the critical component of stress?

Answer 2

Lack of control over the stressor.

A complete lack of control is experienced negatively.

Question 3

Define ‘acute stress’.

Answer 3

A single event leads to increased flight or fight response, raising levels of arousal.

Question 4

Define ‘episodic acute stress’.

Answer 4

Repeated independent instances of acute stress. (e.g. excessive worry about normal events)

Question 5

Define ‘chronic stress’.

Answer 5

endless and uncontrollable stress.

Question 6

List 2 examples of chronic stress.

Answer 6

1. violent/dysfunctional family
2. war zone
3. repeated exposure to trauma
4. financial hardship

Question 7

Why use animal studies of stress.

Answer 7

1. Ethical reasons

2. direct measure of effects of stressors on biology

Question 8

Give examples of a physical stressor.

Answer 8

immobilisation bag, restraint

Question 9

Give examples of a psychosocial/naturalistic stressor

Answer 9

predator odour, maternal separation, social defeat

Question 10

Name the two stress systems.

Answer 10

1. HPA system (cortisol)

2. Sympathetic Nervous System (epinephrine, noepinephrine)

Question 11

What are the effects of moderate stress on the brain?

Answer 11

aroused and optimal functioning of PFC (inhibits amygdala).

Allows for a top-down regulation of thought, emotions and action

Question 12

What are the effects of high stress on the brain?

Answer 12

i) impairing function of PFC; ii) increasing influence of emotional responses (amygdala dominates); iii) habitual action (primitive brain regions); iv) bodies arousal repsonse

Question 13

List 3 long-term effects of chronic stress on the brain.

Answer 13

Reflective to a reactive brain.

1. amygdala - number and strength of neuronal connections increased
2. hippocampus - number/strength of neural connections reduces
3. PFC - number/strength of neural connections reduces

Question 14

More stress = more _______ to stress

Answer 14

Sensitivity.

Question 15

List the effects of chronic stress on emotion and memory function.

Answer 15

1. reduce flexible emotional processing
2. reduce separation between memories - OVERGENERALISATION (cedes anxiety)
3. less capacity to cope with new real/potential stressors

Question 16

What are the effects of acute stress on the body?

Answer 16

Increased energy available in muscles for breaking down fats and proteins into glucose.

Question 17

List 3 effects of chronic stress on the body?

Answer 17

1. suppression of immune system
2. high blood pressure
3. reduced fertility

(carry-over effects on job security, financial hardship, etc.)

Question 18

Evolution of acute stress?

Answer 18

Adaptive - help animals respond to threats to chance for survival

Question 19

Evolution of chronic stress?

Answer 19

Unknown. Early stress is negative and leads to increased antisocial behaviour, aggression and social isolation

Question 20

Define PTSD.

Answer 20

Experiencing or witnessing death or serious harm (actual or threatened). Or learning of this to loved one.

Question 21

List some effects of PTSD.

Answer 21

1. recurrent dreams, panic attacks, flashbacks
2. environmental and genetic factors
3. impacts brain structures - smaller hippocampus
4. increased amygdala
5. reduced ventromedial prefrontal inhibitory activity to threat

Question 22

Stress hormones = _______ memory consolidation

Answer 22

Greater.

Question 23

How could memories potentially be reconsolidated.

Answer 23

Propranolol.

Blocks activation of beta-adrenergic receptor by noradrenalin and adrenal stress hormones. Memories relearned without fear component.

Mindfulness-based stress reduction (MBSR).

non reactive purposeful monitoring. Moderate effects in healthy population.