11 Stress

What are the three types of stress?

Neurologic. Endocrine, Immune

True or false: The brain and body respond to physical and emotional abuse in different ways.

False: They only respond to attack.

What nervous system does the stress response activate, and via what control?

sympathetic nervous system, via hypothalamic control

What are the influences of stress?

Duration

Type

Context

Age

Sex

Genes

What are the mediators for stress?

Noradrenaline

Dopamine

Serotonin

CRH

Urocortins

Vasopressin

Orexin

Dynorphin

Corticosteroids

Neurosteroids

What does the sympathetic nervous system do?

Activates fight-or-flight response

increases HR, blood flow, and RR to help us deal with the situation

What does the adrenal cortex do?

secretes cortisol

What is cortisol, and what is its function?

stress hormone secreted by adrenal cortex

increases blood glucose, breaks down protein

What does the adrenal medulla do?

releases epinephrine and norepinephrine

How do cortisol, testosterone, and epinephrine levels change from the first time a person skydives to when a person skydives again and again?

cortisol and epi go down, testosterone goes up

“each time we face our fear, we gain strength, courage, and confidence.”

Does stress have to be caused from physical danger?

No - a crowded train trip can cause stress

What do the hypothalamus, pituitary, and adrenal glands do during acute stress?

Hypothalamus/pituitary stimulate adrenal glands

adrenal glands release:

• epi/norepi - increase heart output, liberate glucose

• cortisol - provides sustained release of energy to cope

immune system is boosted

Can you die from too much acute stress?

Yes - acute stress can cause cardiac problems such as heart attacks.

What does chronic stress do to the body?

• interferes with memory, appetite, sexual desire, and performance

• deplates energy and disrupts mood

• increases body inflammation

• compromises immune system

• stress response exhaustion

What are DAMPs?

Danger/damage associated molecular patterns

What happens to DAMPs at rest, during accute stress, after stress, and during chronic stress?

At rest: miRNAs balance out DAMPs

Acute stress: epi and norepi cause immune cells to release DAMPs

After stress: balance is restored by cortisol/glucocorticoids

Chronic stress: low-grade excess production of DAMPs or block of miRNAs

DAMPs during stress diagram

what does stress do to our defensive walls?

pokes holes

What does stress do to the blood brain barrier (BBB)?

stress triggers inflammatory TNF/NF-kB - increased barrier permeability

stress downregulates claudin 5 (CLDN5) - opens BBB

What does stress do to the gut?

increase IL-17 + T cells

LPS enters blood to activate inflammation

What regions of the brain dominate when we are unstressed vs stressed?

unstressed: prefrontal cortex

• tighter control of thoughts, emotions, actions

stressed: PFC, amygdala

• weaker control

norepi is [lower/higher] in introverts

higher - blocks immune system

cortisol is [lower, higher] in married adults

lower

When does PTSD develop?

after an exceptionally threatening or catastrophic event (ex: assault, car wreck, rape, war)

What are PTSD symptoms

re-experiencing (flashbacks, nightmares)

avoiding triggers

hyperarousal symptoms (panic)

what are PTSD treatments

behavioral desensitization (“let me take you back to that time”)

ecstasy, psilocybin

treamtent means that about ___% more people with PTSD recover

20

true or false: all ptsd patients will recover naturally after 2 years

false - 50% natural recovery after 2 years, some may have significant social and occupationsal impairments

what percentage of PTSD patients remain symptomatic for how long?

33% for 3 yrs

natural course of ptsd diagram

Which brain regions are reduced in PTSD patients

frontal cortex and hippocampus

frontal cortex and hippocampus volume is _______ in people with ptsd

reduced

which tissue is reduced in torture victims

cortical tissue

what causes damage due to stress, and why?

cortisol - perhaps increased receptor sensitivity

where did the monkey that died of stress have damage

hippocampus - less cells, underwent structural remodeling

what do astrocytes do during early-life stress?

excessively prune excitatory synapses on inhibitory neurons

ex: rat has early social deprivation, goes on to have abnormal neuronal firing, reduced sociability, and depressive behavior

introverts with HIV have [higher/lower] virus titers than extroverts with HIV. why is this

higher

norepi levels are higher in introverts, norepi blocks immune system

what kind of subjects do flu antibodies increase more in

high left hemisphere activity (associated with pos emotions)

What are the buddhist coping strategies?

• Meditation

• Mindfulness

• Loving/kindness (i’m okay, you’re okay)

• morality (golden rule)

• impermanence (nothing lasts forever)

what does the eCB system do

resiliance during and/or after stress

what synthesis does chronic stress impair

stress → cortisol → impairs 2-AG synthesis

what causes habituation to stress

increased eCB system activity

diagram of the eCB synapse

What is aggression

behavior intended to harm

What are the two types of aggression

reactive - impulsive, provoked, emotionsal

proactive - premediated, unprovoked, emotionless

aggressive men and women have [large/small] amygdalae

seizure activity in amygdala [increases/decreases] aggression

murderers have higher activity of the ________ and the ____________

removing the amygdala [reduces/increases] aggression in ___________% of patients

small

increases

amygdala, hypothalamus

reduces, 33-100

Why are bullies aggressive? What brain regions become active when they watch pain inflicted on others

bullies find sadism rewarding

amygdala and striatum - feel-good areas

reactive aggressors have [higher/lower] activity in prefrontal cortex. what does this do?

lower

behave recklessly, overreact to provocation, sexually promiscuous

• ex: road rage

what condition is proactive aggression seen in

psychopathy

psychopaths have:

less autonomic response to stress

impaired amygdala function

what happened in the clicker case

kept changing personas - sociopathy

what is a sociopath

incapable of remorse - may commit very violent acts

what are some examples of sociopaths

charles manson, ted bundy, CHARLES WHITMAN

what is wrong with charles whitman?

brain tumor compressing the amygdala

A man killed a whole bunch of people, including his loved ones. In his diary, he has written that he has been experiencing irrational, overwhelming, and violent impulses. What is wrong with him?

brain tumor compressing the amygdala

small amygdala = more aggression

Which hormones are released due to acute stress?

Epinephrine and Norepinephrine (Increase heart rate and makes glucose available)

Cortisol (Increases metabolism)

Which part of the brain is known as “The Integrator” for emotion?

The limbic system

Which area of the brain does disgust activate?

Insula

- Activated by guilt as well

Which hemisphere of the brain interprets the topical meaning of a message?

Left hemisphere

- Right hemisphere identifies emotional tone

What type of aggression is impulsive, provoked and emotional?

Reactive aggression

What brain structure is small in aggressive people compared to others?

Amygdala