Lecture 2 stress

Question 1

What is stress?

What are the feelings of stress?

Answer 1

Stress is a response to a perceived aversive or threatening situation

Associated with feelings of being overloaded, wound-up tight, tense and worried

Question 2

What are the positive effects of stress?

What are the negative effects of stress?

Answer 2

Positive - exciting, motivating, improving alertness & performance

Negative - harmful for health, gives you PTSD, impairing optimal performance

Question 3

What is a critical condition for stress?

How do people react to this condition?

Answer 3

Lack of control over stressor

Thrill seekers attracted to calculate risks, but with some control

Complete lack of control or the threat of it is generally experienced very negatively

Question 4

What is acute stress episodic acute stress and chronic stress?

Answer 4

Acute stress - a single event that leads to increased fight or flight response, raising levels of arousal

Episodic acute stress - repeated but independent acute stress

Chronic stress - seemingly endless nad uncontrollable

Question 5

Why do we use animals to study stress?

Answer 5

For ethical reasons human studies are often correlational or observational.

However, if we want to manipulate hte conditions, we have to use animals in order to have direct measures of effects of different types of stress on biology

Question 6

What horribles conditions could we subject the rats to?

Answer 6

Conditions - type of stress (constraint, predator odor, separation, elevated platform, social threat), length of exposure, single or repeated

Question 7

Describe the mechanism of the fight or flight response

Answer 7

Two system mediated by the hypothalamus - HPA system (cortisol) and sympathetic NS (epinephrine)

see slides for graphical detail lol

Question 8

What are the physical effects of fight or flight response

Answer 8

Heart rate increase, bladder relaxation, tunnel vision, shaking, dilated pupils, flushed face, dry mouth, slowed digestion, hearing loss

Question 9

What are the acute effect of stress on hte brain?

Answer 9

Fight or flight

The balance between the brain and body is tipped. over. Optimal performance imparired

Question 10

Difference between moderate stress and high stress

Answer 10

Moderate levels of stress = aroused & optimal functioning of the PFC allowing top-down regulation of thought, actions & emotions
PFC inhibits amygdala

High stress = arousal increases further overwhelming/impairing function of prefrontal cortex & releasing/increasing the influence of emotional responses, habitual action and bodies arousal response.
PFC offline, amygdala dominates

Question 11

What can weaken PFC mediated inhibitory control to increase substance abuse

Answer 11

Acute uncontrollable stress

Acute stress can also increase amygdala response to increase memory consolidation of stressful events

Acute stress can enhance fear conditioning function of amygdala

Question 12

What long-term changes are associated with chronic stress?

Answer 12

Amygdala (important in mood) the number & strength of neural connections increases
Behavioural function and activity up

Hippocampus (important for memory storage) number & strength of neural connections reduces (more cell death & less neurogenesis).
Behavioural functino, volume and activity down

Prefrontal cortex (important in “executive function) number & strength of neural connections reduces.
Behavioural function, volumne and acitivity down

Question 13

How to turn a rational man into a beast

Answer 13

Exposure to stressors causes chemical changes in the brain that impair higher cognitive functions why strengthening “primitive” brain reactions. People become more emotionally reactive with impaired rational thinking.

Question 14

What does impaired emotional and memory function lead to?

Answer 14

Reduced flexible emotinoal processing and reduce separation between memories causing overgeneralization and less capacity to cope iwth new or potential stressful events. Provide an example using myself

Question 15

Effects of stress on the body

Answer 15

Acute stress - increased energy availability in muscles breaking down fats and protein to glucose

Chronic effects - suppression of immune system, high blood pressure, reduced fertility

Question 16

Evolutionary reason for stress

Answer 16

fight or flight helps us survive, reactive/reflexive brain may be more advantageous in immediate danger.

Chronic stress - early stress lead to negative outcome, including antisocial behaviour, aggression and social isolation. Might prepare an organism for similar adversities later in life. Tough life bro, your aggression or social mistrust prevents you from being hurt and robbed when hsits are scarce

Question 17

Describe the chicken and egg relationship between hippocampus size and PTSD

Answer 17

Some people found smaller hippocampus in twin brothers of veteran who has not been exposed to stress - so disposition to develop PTSD

but also other people said the reverse….

Question 18

What phisiologicla change is associated with PTSD?

Answer 18

FMRI says - increased amygdala and insula activity to threat and reduced ventromedial prefrontal inhibitory activity to threat

Question 19

What is the link between stress and psychiatric disorders?

Answer 19

Depression - similar brain areas implicated in chronic stress and depression, depression considered a stress related disorder

Schizophrenia and bipolar disorder - triggers increased severity of symptoms

Alzheimer’s - women with serious stressors in middle age more likely to develop memory impairments

Question 20

Effect of stress on emotional memory

Answer 20

Glucocorticoid - noradrenergic response in basolateral nucleus of the amygdala - enhancing retentino of emotional stimuli

stress hormones - greater memory consolidation in animal and human studies

Question 21

Link between stress, emotional memory and PTSD

Answer 21

Trauma - release of stress hormones - overconsolidation of trauma memories - PTSD symptoms (intrusive memories)

Question 22

Evidence for reprograming bad memories

Answer 22

Condition a fear response for spider, give some people propanolol - reduced startle response

Question 23

The implication of reprograming bad memories?

Answer 23

Memories can be relearned without fear response

Other considerations - tool for evil - reduced ompensation, less compassion?

How does this impact someone’s identity

Question 24

What are the benefits of meditation?

Answer 24

Non-reactive purposeful monitoring of the moment-to-moment content of experience.

Improve anxiety, distress, stress and quality of life

Mya work by increasing cognitive flexibiliyt, tolerance for uncomfortable physicla stress/anxiety sensation. Could reduce escalation of physical symptoms and hyperarousal and reduce perception of threat

Question 25

How does early life stress affect hte brain?

Answer 25

Early life stress - epigenetic hcanges - lasting biological changes that impair decision making and health

More negative behaviour and life circumstances