PNI

• Mind, brain, and immune system are connected
• Mind can somewhat heal virally induced infections (i.e. warts)

• Stressor - very individualized
• Most of time stress is a useful, good response
• There are negative feedback loops that turn the stress off
• HPA (hypothalamus-pituitary adrenal cortex) - more likely to be active during chronic stress; incr cortisol levels in stress and depression
• SNS - fight or flight response; epinephrine
• PNS - opposes SNS; involved w/ release of oxytocin

• Acute stress - activation of immune system EX: Near car accident
• Chronic stress - suppression of immune system EX: Chronic sadness
• Reactivity - react to environment EX: pop quiz

• Top-down stress activation - self talk about what is going on; threats vs. challenges; negative vs. positive
• Bottom-up stress activation - outside things that cause brain to react w/ stress response

Classes of stress responses - defense vs. defeat (often leads to learned helplessness)

Learned helplessness - learn that you can't change anything; hopeless

• Most positive social interactions seem to buffer stress and even improve immune function when stressed
• Negative life events produce their strongest effect on health when social support is low
• Marriage benefit - those who marry even if get divorced, live longer than single people
• It is the perception not the actual amount or type of social support that makes a difference

• Type A - time driven, can't wait, hostile, multi-tasker, talk fast
• Type B - relaxed, easy-going, lack sense of urgency, disengaged
• Type C - more likely to get autoimmune disease or cancer, won't allow themselves to feel emotion

Laughter decreases cortisol and improves immunity

• Can be a stress buffer
• For those who like to exercise it improves immune function
• Elite athletes immune system suffers and they appear to be chronically stressed
• Older people who rate themselves as physically active have better health (fewer infections) and improved immune function

• Known relationship with depression and poor health
• Pt's with CV disease who are depressed have two times the mortality
• Sleep disturbances in depression may contribute to mortality and may be through immune mechanisms
• CRH brain levels incr in depression
• Brain regulation of peripheral immunity through CRH mediated regulatory autonomic nervous system pathways
• HPA is dysregulated in depression (hypercortisol)
• Vegetative symptoms of depression are similar to the behaviors assoc with sickness (fatigue, social isolation, decr appetite, lack of interest)
• Antidepressant drugs decr pro-inflammatory cytokine expression
• Other influences: smoking, alcohol, lack of exercise, sleep disturbances

• CNS responds to peripheral blood levels of cytokines
• Cytokines do not appear to be able to cross blood brain barrier
• Cytokines in blood may produce a corresponding incr in neurological synthesis of cytokines and changes firing in certain parts of brain