Stress 2

Question 1

What is the Dutch Hunger winter findings with prenatal stress and what is the Dutch hunger winter?

Answer 1

• Nazis pushed back
• Dutch tried to aid allies for liberation
• As punishment, Nazis cut off all food transport
• Typical food consumption: 400-800 calories/ day
• After liberation sudden increase in food
• Effects: cohort of people with increased risk of heart disease, type 2 diabetes aged 50 years
• Pregnancy during famine:
   Fetus ‘learns’ that food is scarce
   Metabolism of fetus has permanent shift: ‘metabolic imprinting’
• Afterwards, foetus becomes good at storing consumed food, retaining salt from diet
• Developed ‘thrifty’ metabolism

Question 2

What was Kajantie et al’s Finish study on birthweight?

Answer 2

• Large cohort of study of 421 men born 1924-33
• Birthweight and size was recorded, evaluated cortisol levels aged around 70
• The lower the birthweight (adjusted for height), the higher the basal cortisol levels in adults: particularly for premature birth
• Early exposure to stress programs your stress-reactiveness

Question 3

What happened when offspring of stressed pregnant rats were placed in stressful situations?

Answer 3

• Test anxiety in new environment:
   Food placed in middle of bright cage
   Placed in with new rats
• Prenatally stressed rats show:
   Freezing in bright lights, difficulties learning and take longer to socially interact
   All evidence of greater anxiety
   Amygdala shows greater glucocorticoid receptor density

Question 4

What did Plotsky and Meaney find the effects of postnatal stress were?

Answer 4

• Maternal separation of rats
• As adults, rats showed increased glucocorticoid response to stress: greater fearfulness
• Stress in infancy can reduce growth hormones – lower adult height

Question 5

What was Gunnar’s finding with stress and Romanian orphanages?

Answer 5

• Compared daytime cortisol measured in children from:
   Romanian orphanages for >8 months
   Romanian orphanages for <= 4 months and were then adopted into Canadian families
   Canadian children
• Studied at 7-8 years old
• Found that
   Early adopted children showed similar cortisol levels to Canadian children
   Children in Romanian orphanages for a long amount of time have increased cortisol at all time

Question 6

What does noradrenaline do, when is it at it’s lowest and highest levels and where does it act?

Answer 6

• Noradrenaline prepares body and brain for action
• Lowest release in sleep, highest during stress
• Acts on amygdala

Question 7

Where is noradrenaline primarily release in the brain?

Answer 7

From Locus Coeruleus

Question 8

What does noradrenaline do as a neurotransmitter?

Answer 8

It can enhance formation and retrieval of memory

Question 9

Which brain structure has a high density of corticosteroid (rats)/cortisol (humans) receptors

Answer 9

Neurons of the hippocampus

Question 10

What do we see with rats with high levels of stress in early life?

Answer 10

A loss of structure in the hippocampal neurons

Question 11

What can be done to test the effects of stress on humans?

Answer 11

Expose people to vicious animals, make people endure pain, infect with diseases

Question 12

What was Nili’s stress experiment exposing people to vicious animals?

Answer 12

• people with snake phobias recruited – put in MRI scanner with snakes on conveyer
• Used toy bear as control
• At each point, participants chose whether to bring the live snake closer – or further away – from them
• Found a fear response with snake
• When choosing to let snake closer you would see increased activity in subgenual activity cortex (when they are being brave)
• Also, when fearful people chose to advance the snake, amygdala activities was reduced (when people gave into their fear amygdala activity was increased)

Question 13

What was Vuilleumier’s experiment for seeing how the brain recognises threats in the environment and what does this show?

Answer 13

• fMRI study, subjects decided
   Are the vertical or horizontal boxes the same
   They were shown either faces or houses (faces weren’t relevant to task)
• Some faces were neutral, others were fearful
• Participants slower at judging houses if faces happened to be fearful
• Regions active to faces:
   Fusiform gyrus
• Regions active to houses
   Parahippocampal gyrus
• When participants were incidentally seeing fearful faces (not involved in task) the amygdala was more active: the limbic structures that detect threat respond and interact with other parts of the brain that regulate stress response

Question 14

What clinical cases of poor emotion regulation can you examine to find out which brain areas are involved in regulating the stress response?

Answer 14

 Post-traumatic stress disorder
 Social anxiety disorder
 Specific phobia

Question 15

In Etkin and Wagner’s meta-analysis of fMRI studies across PTSD, social anxiety disorder and specific phobias what did he find?

Answer 15

 Increased activation in amygdala (phobia/ social anxiety)

 Decreased activity in medial prefrontal cortex (PTSD)

Question 16

What in the medial prefrontal cortex seems to respond to regulating threats?

Answer 16

the midline of the brain in front of the motor cortex

Question 17

In examining brain responses to fear which brain regions did Etkin et al find were active when we consciously control our emotional response?

Answer 17

• ‘Bottom-up’ signalling from the amygdala indicates threats in the environment
• ‘top-down’ regulation from the medial pre-frontal cortex prevents this from triggering constant stress-responses

Question 18

What is how stress affects memory examined by studying?

Answer 18

• examined by studying stress during:
   Encoding
   Consolidation
   Retrieval

Question 19

Is information encoded during stressful events generally well remembered and what in particular?

Answer 19

Yes, particularly information that is relevant to the stressor

Question 20

What could dysregulation in stress encoding lead to?

Answer 20

psychological trauma
 E.g. post-traumatic stress disorder, characterised by flashbacks
 Feeling that traumatic event is recurring

Question 21

What was Henckens et al’s experiment for stress at encoding and what did they find?

Answer 21

• fMRI study – shown film clips (very violent or neutral) and pictures
• Later asked to remember pictures
• Heart rate recording, pupil dilation tracking, cortisol tracking
• Found increase in cortisol present, greater change in pupil diameter with people that saw violent pictures
• Stressful films led to better memory for pictures
• During stress LOWER activity in hippocampus at encoding = better memory for those pictures
• Poor separation of event info from relevant stimuli may overwhelm hippocampul activity

Question 22

What did Cahil et al’s find out with with Stress and consolidation?

Answer 22

• Stress enhances consolidation of emotional pictures, but not neutral pictures
• Limbic structure involved with consolidation of emotional memories

Question 23

What did the Trier test show with stress at retrieval?

Answer 23

 Unexpected 5 min talk
 Followed by 5 min arithmetic
 Combines feeling of peer evaluation with forced failure
- Memory retrieval during stress is impaired – e.g. Guez et al., 2016
- Suggest that systems involved in coding during stress are enhanced by systems to do with retrieval are inhibited

Question 24

What are the two factors in Lazarus’ cognitive appraisal theory?

Answer 24

1. Primary appraisal – is the situation relevant to someone’s needs?
2. Secondary appraisal – whether a person has resources and options to cope with the event

Question 25

What are the 3 patterns of conflict within the individual Lewin (1935) identified?

Answer 25

• Approach-approach conflicts are the least stressful. These involve choosing between pleasant options
• Avoidance-avoidance conflicts. Here you are choosing between equally negative options
• Approach-avoidance conflicts are equally as challenging. Here you need to decide to do something that could have either positive or negative effects. E.g. if you decide to propose to someone, you open the risk of being accepted or rejected

Question 26

What is it called when we seek out stressful experiences?

Answer 26

‘eustress’ – e.g. riding rollercoasters

Question 27

Why do people seek out stressful experiences?

Answer 27

Risky events trigger the activation of the sympathetic nervous system with consequent release of adrenaline/noradrenaline. They are also associated with the release of dopamine which is involved in the motivation to seek out a reward

Question 28

When is the release of dopamine greatest and how is this shown in Schultz’s study?

Answer 28

In this study they trained a monkey to press a lever 10 times. 10 seconds later the monkey would receive a food reward. When tracking dopaminergic neurons they found that the biggest release of dopamine wasn’t when the animal received the reward, but just before hand. Dopamine sees the greatest release from anticipation of a reward