Lecture 2: Stress in the Brain Flashcards
Why does the effect of stress differ between individuals?
Stress is the response to a PERCEIVED aversive or threatening situation.
What is the critical component of stress?
Lack of control over the stressor.
A complete lack of control is experienced negatively.
Define ‘acute stress’.
A single event leads to increased flight or fight response, raising levels of arousal.
Define ‘episodic acute stress’.
Repeated independent instances of acute stress. (e.g. excessive worry about normal events)
Define ‘chronic stress’.
endless and uncontrollable stress.
List 2 examples of chronic stress.
- violent/dysfunctional family
- war zone
- repeated exposure to trauma
- financial hardship
Why use animal studies of stress.
- Ethical reasons
2. direct measure of effects of stressors on biology
Give examples of a physical stressor.
immobilisation bag, restraint
Give examples of a psychosocial/naturalistic stressor
predator odour, maternal separation, social defeat
Name the two stress systems.
- HPA system (cortisol)
2. Sympathetic Nervous System (epinephrine, noepinephrine)
What are the effects of moderate stress on the brain?
aroused and optimal functioning of PFC (inhibits amygdala).
Allows for a top-down regulation of thought, emotions and action
What are the effects of high stress on the brain?
i) impairing function of PFC; ii) increasing influence of emotional responses (amygdala dominates); iii) habitual action (primitive brain regions); iv) bodies arousal repsonse
List 3 long-term effects of chronic stress on the brain.
Reflective to a reactive brain.
- amygdala - number and strength of neuronal connections increased
- hippocampus - number/strength of neural connections reduces
- PFC - number/strength of neural connections reduces
More stress = more _______ to stress
Sensitivity.
List the effects of chronic stress on emotion and memory function.
- reduce flexible emotional processing
- reduce separation between memories - OVERGENERALISATION (cedes anxiety)
- less capacity to cope with new real/potential stressors
What are the effects of acute stress on the body?
Increased energy available in muscles for breaking down fats and proteins into glucose.
List 3 effects of chronic stress on the body?
- suppression of immune system
- high blood pressure
- reduced fertility
(carry-over effects on job security, financial hardship, etc.)
Evolution of acute stress?
Adaptive - help animals respond to threats to chance for survival
Evolution of chronic stress?
Unknown. Early stress is negative and leads to increased antisocial behaviour, aggression and social isolation
Define PTSD.
Experiencing or witnessing death or serious harm (actual or threatened). Or learning of this to loved one.
List some effects of PTSD.
- recurrent dreams, panic attacks, flashbacks
- environmental and genetic factors
- impacts brain structures - smaller hippocampus
- increased amygdala
- reduced ventromedial prefrontal inhibitory activity to threat
Stress hormones = _______ memory consolidation
Greater.
How could memories potentially be reconsolidated.
Propranolol.
Blocks activation of beta-adrenergic receptor by noradrenalin and adrenal stress hormones. Memories relearned without fear component.
Mindfulness-based stress reduction (MBSR).
non reactive purposeful monitoring. Moderate effects in healthy population.
