Stress & Cognition: Mechanisms and Impact on Psychology

Brain, Mind and Behaviour Outline

• Defining (and measuring) stress
• The neuroendocrine system & HPA axis
• Stress and cognition

Caultparksunrise.com 2011

Understanding Stress

What do we mean when we are talking about stress?

Stress is a physiological & psychological response which can be encountered bu a trorat. Han happen anywhere to anyone at any time. It can be transactional, hard to cope with.

• Physiological & psychological response when encountering a threat that we feel we do not have the resources to deal with
• Perceived threat
• Perception we cannot cope
• Very subjective
• Transactional: involves person & environment Involves both factors on the individual
• Overwhelming
• Demands not able to deal with
• Overloaded, pressures
• Positive & negative? (in the literature stress generally seen as negative) - Depends on situation e.g. positive stress when you need to act immediately

Days or weeks comes and goes depending on time Adaptive response helps us build phase but can be maladaptive Acute (fight or flight) vs chronic

What is stress?

Stress arises when individuals perceive that they cannot adequately cope with the demands being made on them or with threats to their well-being (Lazarus, 1966)

Stress is a negative response

Stressors

Stress is induced by stressors Stressor: Perceived threat Vs Response to threat Stressors: Can be minor or major Can be acute or chronic Fight or flight Stress is when individuals perceive that they can't adequently cope with the demands being made or threat to their wellbeing. Stress is a negative response. Stressor are perceived treat or response to threat. Stressors can be acute or chronic miner er major

The Stress Response System

STRESS RESPONSE SYSTEM Hypothalamus Nerve Impulses Increased heart rate Dilation of bronchioles Liver converts glycogen to glucose CATECHOLAMINES Adrenal Glands Decreased digestive system activity High blood pressure

The stress response has 2 primary response systems, controlled by the hypothalamus. The (SAM ) Sympathetic adrenal medhillary which secrets adrenaline. The (HPA) hypamalmic pituarity adrenal which secrets cortisol . Cortisol magers the immune response - stress immitation. When overworked can lead to stress ( chronic ) . When malfunctioned can lead to i'll health .

Hypothalamus controls the two main stress response systems: The sympathetic adrenal medullary (SAM) axis - adrenaline The hypothalamic-pituitary-adrenal (HPA) axis - cortisol Cortisol triggers the immune response to stress - inflammation Together, these systems regulate the stress response. When they become overworked (i.e. chronic stress) these systems can malfunction and this can bring about ill health.

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The Neuroendocrine System

high level of strew breaks the response system down. fails to recognise. More vulnerable to spess. It should be balanced.

STRESS RESPONSE SYSTEM seitregulations monitors its own function Hypothalamus CRH causes tosecrete another ACTH Pituitary gland Medulla goesinto dood Stream ACTH & around body. CORTISOL Brain stem Adrenal gland secretes cortisol goes into general blood To immune supply system

The HPA axis secretes cortisol

Brain monoamines e.g. 5HT Stress CRH Cortisol Pituitary gland Adrenal gland ACTH Hypothalamus secrets CRH (portal blood vessels of the pituitary) I Pituitary response secreted ACTH ( main blood system) Adrenal Cortisol (everywhere including saliva)

Cortisol

Cortisol is ESSENTIAL for life - but either too much or too little associated with a very wide variety of pathologies Chronic stress associated with prolonged periods of excessive cortisol secretion and enlarged adrenal glands

I THINK IT'S STRESS !!

High cortisol levels associated with:

• Stroke
• Depression
• High blood pressure
• Angina
• Heart attack
• allergy
• Diabetes
• Slower wound healing
• Osteoporosis
• Increased infections
• Accelerated cancer progression
• Accelerated HIV progression
• Increase in fat , physical

The cortisol stress response

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Cortisol can be measured in saliva

goes into blood supply The Salivette >blood + direct measure - blood taking itself is stressful recorded forurine ELISA assay system

1 BE DE F: G H B

Exposure to a standardised stressor induces increased cortisol secretion

12 10 Cortisol (nmol/l) 8 T T 6 Stress 1 0 0 5 10 15 20 25 30 35 40 45 Time (minutes)

Pruessner et al, 1999

Acute/ chronic

Potency of different stressors

1.2 1.0 0.8 *** Effect size (d ) 0.6 ** 0.4 0.2 0.0 -0.2 -0.4 Passive Tasks Motivated Performance Motivated Performance with Uncontrollability Motivated Performance with Social-Evaluative Threat Performance with Social-Evaluative Threat and Uncontrollability

Figure 3. Mean (± SEM) cortisol effect size (d) for studies using passive tasks (k = 21), motivated performance tasks (k = 24), uncontrollable motivated performance tasks (k = 69), motivated performance tasks with social-evaluative threat (k = 43), and uncontrollable motivated performance tasks with social-evaluative threat (k = 51). ** p < . 01. *** p < . 001.

Example ! - o public Speaking 0 can't succeed despite their efforts Start judging them I stress . force to fail . when you combine all the factors they increase stress.

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Dickerson and Kemeny, 2004

The Trier Social Stress Test

> Individual differences factor. o sex ( gender) -> Don't give you enough detail. -> Self report = males say they are less stressed. Thormones show males are more stressed. > setterreem - come into room, ) microphone & camera facing you ) Panel is not friendly

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Effects of Cortisol on Cognition and Health

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Prefrontal regulation during alert, non-stress conditions

a Prefrontal regulation during alert, non-stress conditions DMPFC · Reality testing Error monitoring DLPFC · Top-down guidance of attention and thought rIPFC Striatum · Inhibition of inappropriate actions Hypothalamus VMPFC · Regulating emotion Amygdala NA DA -) losses it's regulatory control ) no control over thinking -> amygdala hijack ALA

Amygdala control during stress conditions

Loss of prefrontal regulation 1 Emotional habits Striatum Bottom-up attention Hypothalamus Amygdala NA Emotional associations DA Emotional reflexes Also involves activation of the neuroendocrine system Major changes in brain function during a response to stress b Amygdala control during stress conditions

Stress and cognitive function

Stress has marked and varied effects on cognitive function (both acute and chronic)

• Adaptive, in the short term
• Largely attributed to the actions of cortisol
• Most evidence: hippocampal and frontal functions (Law and Clow, 2020)

High cortisol levels associated with poor physical & mental health and memory

fat deposits inner wall of artery artery blood channel- (a) (b) 8 Stroke, depression, high blood pressure, angina, heart attack, allergy, diabetes, slow wound healing, osteoporosis, increased infections, accelerated cancer progression, accelerated HIV progression

Declarative memory and the cortisol stress response

a b 12 10 Placebo 9 * Cortisol 10 # of recalled words 8 6 4 r = -. 70 n = 13 p = . 007 -10 -5 0 5 10 15 20 25 cortisol increase (nmol/l) # of recalled words DONONTON 8 7 6 5 4 3 2 1 0 declarativ non-declarativ

Kirschbaum et al. (1996)

Summary and Conclusion

• Marked changes in brain function during stress
• Stress response is adaptive, but can become maladaptive
• Chronic stress linked to impaired cognition, risk for psychiatric disorders

Further Reading

• Law, R., & Clow, A. (2020). Stress, the cortisol awakening response and cognitive function. International review of neurobiology, 150, 187-217. (Available on Blackboard in this week's lecture folder)
• Sapolsky, R. M. (2004). Why zebras don't get ulcers (3rd Ed.). New York: WH Freeman. (Available from the library)