STRESS

What does it mean to you?

StressHow do you deal with it?

Understress

Overstress

Eustress Distress

Stress

• Claude Bernard – le milieu internel

Homeostasis

Allostasis : body’s way of dealing with stress

• Allostasis – body’s ability to remain stable by being themselves able to change

Allostatic load

Is the load too heavy?

Allostasis : fight or flight

any changes – major / minor events

getting up in the morning, chasing the bus,

getting fired

Allostasis overload

• child who try but could not write• boss• spouse with chronic illness• physical problems – feet, hand, eyes etc.• poor eating habits• poor sleeping habits• poor interpersonal relationships• over/under exercise• our imagination

Hormonal Reaction

Sleep deprivation

GLUCOSE CORTISOL

Sleep deprivation is

the most common

brain impairment.

William C. Dement (from The Promise of Sleep, 1999, p. 231)

• Claude Bernard – internal balance

• Walter Cannon – emotional stress and health (1914)

• Hans Seyle – (1930s) – signs of generalized response

Seyle’s experiment

• list of stimuli – “nocuous”

heat

cold

pain

fatique

fasting

nervous stress -- immobilization

Hans Seyle experiments

general adaptation syndrome –

alarm reaction

stage of resistance

state of exhaustion

• Whether a stressor is a slight change in posture or a life-threatening assault, the brain determines when the body’s inner equilibrium is disturbed; the brain initiates the actions that restores the balance.

Bruce McEwen

Stress and the Brain

• Allostasis begins in the hypothalamus adrenal glands adrenaline/epinephrine

• adrenalineheart—pump more blood to muscles & organs (less to

extremities)Oxygen – rushes up to the brainHair – stands on end because adrenaline constricts the

blood vessels to the skin thus preventing bleedingFibrinogen – speeds up blood clottingGlugose release – from energy storage as glycogen and

release fatty acids – provide energyRelease endorphins – natural pain killer

How: HPA axis• Hypothalamic – pituitary – adrenal axis (CRH – adreno- cortisol corticotropin corticotropic goes into blood releasing hormone factor) from blood moves thru to kidney the blood to pituitary

• Nervous – hormonal glands – immune system

Cortisol

• -- made from cholesterol

• function: replenish energy depleted from adrenaline rush by converting food to storage forms as glycogen or fat

• makes us hungry

Too much cortisol

• blocks actions of insulin to stimulate muscle to take up glucose

• storage of fat – in abdominal fat

• loss of protein from muscles and converts to fat

• mineral loss from bones

Too much cortisol

• suppress immune system, get sick easier

• short term help deal with infection/injury

Too little cortisol

* rashes, allergies

• autoimmune diseases when immune system attack body’s own health tissue.

Cortisol and the Brain

• Circadian rhythm

• provides us with energy

Cortisol cycle

• Morning -- evening

Cortisol level upset

• abdominal fat

• muscle loss

• bone demineralization

• memory loss

• cognitive problems

Abnormal secretion causes hippocampus and amygdala to overwork

atrophy of brain cells and even brain damage

• Animals can show stress-related wear and tear even in the wild. But in general they tend not to experience allostatic load because once a stressful situation is over, the stress response subsides.

• For the most part, only humans can keep the HPA axis going indefinitely – because of how our faculties of perception, thought, and emotions are produced and how they are connected to stress response.

• Stress begins in the brain.• Bruce McEwan

• Memory –– declarative– episodic– cellular

Hippocampus

• Memory formation vs Memory storage

• Hippocampus – memory formation

• Hippocampus + amygdala => unconscious memory

Amygdala

• our input – visual stimulus amygdala before the visual cortex

Joseph LeDoux

• diff ./. memory from amygdala / hippocampus

• (amygdala - -out of fear;

• hippocampus – memory formation)

• Woman with amnesia – damage to her hippocampus; unable to form new memory

Extinction***

• a repatterning process

• e.g. a rat – sound + shock• sound no shock• sound no fear

• this is so important because it shows that we can re-wire, although depending on the negative experience we have, the rewiring may at times take longer. But the rewiring takes place in the prefrontal lobe.