Stress

Question 1

Is stress always unhealthy?

Answer 1

Chronic stress is important to the etiology of many diseases. However acute stress is a functional, evolutionary highly successful model.

Question 2

What Models of Stress did:

A) Bernarnd
B) Cannon
C) Selye

propose?

Answer 2

Bernand: Stress is a response of the body in reaction to an external stimulus, in order to bring the body back into a state of homeostasis

Cannon: Stress is relevant to fight and flight

Selye: Stress is an non-specific response to any demand

Question 3

What model of stress did Selye propose? How would a stress response look like according to this model?

Answer 3

The general adaption syndrome (GAS) refers to the idea, that a stress response is non-specific and can apply to any demand.

typically there are 3 phases:

Alarm phase (stress sets on, bodily reactions such as cortisol release and ANS activation

Resistance phase (trying to power through the stressor, alarm processes are reaching their peak

Exhaustion (alarm and resistance stages demand a lot of resources -> cannot last forever -> exhaustion, recovery, getting back to homeostasis)

Question 4

What is the core idea of Lazarus Transactional Model of stress?

Answer 4

A Stressor is perceived, and evaluated in terms of its valence (positive/dangerous or irrelevant; primary appraisal) and in terms of one’s own recourses (secondary appraisal). Dangerous stressor + insufficient resources = afterward a stress response is elicited.

Coping is determined by focusing on the stressor or the emotion the stressor elicits.

Reappraisal can be used to change appraisal

Question 5

What is a simplified pathway of a stress response?

Answer 5

Threat -> perception -> amygdala processing -> hypothalamic processing -> Adrenocorticotropin hormone release -> cortisol/adrenalin release -> physiological response

Question 6

Name 5 Symptoms of stress

Answer 6

Increased Heart rate, Tunnel vision, bladder relaxation, dilated pupils, face flushing, shaking, inhibition of digestion, hearing loss, dry mouth

Question 7

Wich route does the Autonomous nervous system take in short term stress responses?

Answer 7

Hypothalamus -> spinal chord -> adrenal medulla -> release of catecholamines (e.g. epinephrine/norepinephrine) into the blood stream

Question 8

What is the pathway of a long-term stress response in the brain?

Answer 8

Hypothalamus releases Corticotropin-releasing hormones (CRH) -> corticotroph cells of the anterior pituitary gland receive CRH and release adrenocorticotropin hormone (ACTH) -> Adrenal cortex receives ACTH and releases mineral- and glucocorticoids

Question 9

Describe the HPA axis in excruciating detail (:

Answer 9

The paraventricular Nuclei of the Hypothalamus release CRH wich reaches the hypophyses portal system. Here ACTH is released through the circulation to the adrenal gland, producing cortisol. Cortisol then again crosses the brain blood barrier and influences the Hypothalamus resulting in an endless feedback loop.

Question 10

How “fast” is the HPA axis and what is its proposed mechanism concerning glucocorticoids ?

Answer 10

Rather slow actually (30 minutes to hours). The main idea concerning glucocorticoids (GC) is, that increases in GC do not reflect the protection against the reflector, but the protection against the own bodies defense mechanisms, sustaining homeostasis!

Question 11

Are GR or MR faster?

Answer 11

MR is faster! Take minutes not hours like GR!

Question 12

What hormones are GR and MR dependent on, and how much of it must still be there for GR/MR reactions?

Answer 12

Dependent on corticosterone, MR is reactive when corticosterone is high (shortly after stress) , GR when corticosterone is low again (longer after stress)

Question 13

What functional relevance do MR and GR have respectively?

Answer 13

MR: increased reactivity in limbic brain areas

GR: normalization of brain activity, storage of information

Question 13

How can GRs and MRs be classified in their functions? Wich “theme” do they respectively ascribe to?

Answer 13

MRs: Activation, Appraisal & Decision making
-> appraisal of the situation & selection of response
-> encoding of situation in memory for future use

GRs: Restoration, Adaptation & Homeostasis
-> ascribing resources back to cortex
-> consolidation of memory
-> prevents initial overshoot and dyshomeostasis

Question 14

What psychological impacts can stress have in memory and executive function?

Answer 14

Memory: Enhanced consolidation in memory processing; Impaired Retrieval of information, especially for emotionally arousing stimuli

Executive function: Impairment of working memory and cognitive flexibility

Question 15

Name 3 findings, concerning the psychological effects of stress

Answer 15

1. Riskier decision-making with a preference for near-future rewards
2. less goal-directed behavior and more habitual behavior
3. Increased Pro-Social behavior, especially for ingroup

Question 16

Name three possible ways to induce stress in a laboratory setting!

Answer 16

1.) Psychosocial stress induction (Trier stress test)
2.) Physiological stress induction (hand in cold water)
3.) pharmacological stress induction (medications)

Question 17

Name three ways of measuring physiological stress reactions.

Answer 17

1.) Blood pressure
2.) Heart rate
3.) electrodermal activity

Question 18

Name three ways of measuring hormonal stress reactions.

Answer 18

In:
1.) blood
2.) saliva
3.) hair

Question 19

What is the deal with people, who have chronic stress?

Answer 19

They show no adaptation to stress and have prolonged stress responses without recovery, adding to their allostatic load.

This can result in Amygdala mPFC & HC alterations, as well as in alterations of GC homeostatic functioning.

Question 20

What are the effects of too little/too much glucocorticoids?

Answer 20

too much GC (antiinflammatory):
more infections, aging and cancer progression
less vaccine efficacy, wound healing

too little GC (inflammatory)
more inflammation, autoimmune disease and pain

Question 21

How is chronic stress (CS) related to the Hippocampus, Amygdala, and medial PFC?

Answer 21

Amygdala: CS results in persistent dendritic growth and spine formation resulting in hyperresponsiveness correlated with symptom severity

Hippocampus: CS leads to reversible dendritic atrophy and reduced neurogenesis resulting in reduced volume and negative correlation with symptoms

mPFC: CS is connected to reversible dendritic and spine loss leading to hyperresponsivity and negative r

Question 21

Wich (stress)-system is typically connected to major depressive disorder MDD?

Answer 21

The HPA-axis: Enhanced basal & stimulated cortisol release, high CRF in CSF, exaggerated ACTH response to CRF, impaired negative feedback of the HPA axis

Interpreted as reflecting an exaggerated CRF drive and/or as a reduction of functioning of GRs