Stress Flashcards
What is stress
The subjective experience of actual or anticipated threat to the body’s homeostasis
‘Stress’ refers to both stressor and stress response
Often negative attention (media), but only unhealthy when excessive
A dynamic process with a distinct acute and recovery phase
Stress timeline (Challenge or no challenge)
Stimulus > stressor > homeostasis
(no challenge > no stress)
challenged > stress > stress response > effect
Hormesis theory of stress
a hyperbolic graph as pressure increases and performance increases
low pressure - low performance
mid pressure - best performance
high pressure - low performance (high stress, anxiety, unhappiness)
stress systems
Immune system:
slowest (hours > days)
HPA axis:
(minutes > hours)
ANS:
very fast (seconds > minutes)
Regulates initial response
Sympathetic and parasympathetic
CRH acts on adrenal medulla
HPA axis
Functions
* Hypothalamus produces CRF
* Pituitary gland produces ACTH
* Adrenal glands produce cortisol
Regulation
* Negative feedback loop regulates cortisol secretion
* Hypothalamus contains internal clock
cortisol negative feedback loop (inhibits pituitary, hypothalamus
daily cortisol rhythms
Ultradian rhythm: pulsatility, short peaks every 1-2 hrs, alertness, adaptivity
Circadian rhythm: diurnal variation, 24-hr rhythm, morning peak, metabolism, immune system, sleep
Cortisol stress reactivity
Mineralocorticoid receptor MR:
- high affinity (little cortisol binds easily), adaptation, Mostly active during acute phase
Glucocorticoid receptor GC:
- low affinity, only activated at high concentrations of cortisol, Important in recovery phase
Stress system dynamics: physiology and cellular
Acute phase
Catecholamines rise in conc
Delayed phase
Corticosteroids rise in conc
Stress system dynamics: immune system
In delayed phase
1) pro-inflammatory phase
2) anti-inflammatory phase
Stress system dynamics: cognition
Acute phase:
emotion processing
Delayed phase:
reward sensitivity, memory contextualization + consolidation, cog flexibility, rational decision-making
Stress system dynamics: behavior
Acute phase:
fight-flight
delayed phase:
tend-and-befriend
risk avoidance
goal-directed behavior
Stress system dynamics: brain networks
Acute phase:
salience network activation to enhance threat detection, attentional vigilance, and rapid, habitual responses.
Delayed phase:
Central executive network and default mode network activated but suppressed during acute stress
As you recover these networks recover as well
Laboratory stressors
Social evaluation: sitting infront of committee of people judging you
Emotional stimuli: emotional videos or pictures
Physical stimuli: sticking hand into ice cold water
Cognitive tasks
Virtual stressors e.g with VR walking high up on a building
Trier social test
Presentation task
* Job interview speech task
* 3-minute preparation time
* No social engagement
* Video + audio recordings
Arithmetic task
* E.g.: “count back from 2021 in
steps of 17”
* No social engagement / feedback
What is childhood trauma
‘Emotional, physical or sexual abuse or emotional or physical neglect before the age of 18
Characteristics and effects of childhood trauma
Characterized by prolonged increase of stress and cortisol levels during important developmental period
This may cause overactivation of the glucocorticoid receptor (GR) during development
Overactivation of the GR may lead to altered development of the stress system
Increased risk of mental disorders
> Earlier onset, more severe symptoms, increased suicidality and comorbidity, poorer treatment outcomes.
Increased risk of somatic disorders
> Including obesity, cardiovascular diseases and respiratory diseases
Vulnerability following childhood trauma
altered gene expression of GR receptors > persistent vulnerability
long-term impact on stress recovery (happens slower)
childhood trauma to psychopathy
childhood trauma > poorer stress recovery > increased stress sensitivity > increased risk of psychopathology
Stress research
Network dynamics might be relevant for stress vulnerability and resilience
Targeting biological consequences of excessive stress during childhood may
alleviate depressive symptoms
Stressors definition
physical and psychological
events that threaten homeostasis in organisms
Neuroendocrine and Neuromodulatory Responses:
Catecholamines (e.g., norepinephrine, dopamine): Released rapidly during stress, they enhance salience network activity (e.g., amygdala) while impairing executive control network function (e.g., prefrontal cortex).
Corticosteroids (e.g., cortisol): Released more slowly, they initially amplify catecholamine effects but later reverse them, promoting recovery by suppressing the salience network and restoring executive control.
