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The Stress-Response. Mobilization of energy Increased cardiovascular tone Suppression of digestion Suppression of growth Suppression of reproduction Enhancement of immune system Sharpening of cognition . The consequences of chronic stress.
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The Stress-Response • Mobilization of energy • Increased cardiovascular tone • Suppression of digestion • Suppression of growth • Suppression of reproduction • Enhancement of immune system • Sharpening of cognition
The consequences of chronic stress • Mobilization of energy………………………Fatigue, diabetes, muscle loss • Increased cardiovascular tone…………….Hypertension, heart disease • Suppression of digestion…………………..Stress ulcers • Suppression of growth……………………..Stress dwarfism • Suppression of reproduction………………Anovulation, erectile dysfunction • Enhancement of immune system…………Immune suppression, accelerated • chromosomal aging of immune • cells • Sharpening of cognition……………………Impaired memory and judgment
The consequences of chronic stress • Mobilization of energy………………………Fatigue, diabetes, muscle loss • Increased cardiovascular tone…………….Hypertension, heart disease • Suppression of digestion…………………..Stress ulcers • Suppression of growth……………………..Stress dwarfism • Suppression of reproduction………………Anovulation, erectile dysfunction • Enhancement of immune system…………Immune suppression • Sharpening of cognition……………………Impaired memory and judgment
Stress effects on the hippocampus: the realm of memory Impaired synaptic plasticity Atrophy of dendritic networks of communication Fewer new neurons Dead neurons! Decreased overall hippocampal volume
Result: Impaired formation and retrieval of long-term memories
Effects of stress and GCs on fear and anxiety Increased: -post-shock freezing -consolidation of fear conditioning -cued & contextual fear memory -resistance to fear extinction -anxiety Conrad, Fanselow, Korte, LeDoux, McGaugh, Quirk, Roozendaal, Sandi Effects of stress and GCs on the amygdala Increased: -synaptic excitability -dendritic aborization LeDoux, Vyas, Mitra, Chatterjee
Result: More anxiety, faster fear-conditioning, slower habituation
Combining hippocampal and amygdaloid effects of chronic stress: Weakened conscious memories;Exaggerated autonomic memories.
The effects of chronic stress in the mesolimbic dopamine system Depletion of dopamine Piazza, Maccari, Le Moal
Result: Loss of the capacity for pleasure:DEPRESSION
The effects of stress in the frontal cortex Decreased connectivity in neural networks by way of fewer dendritic branches and spines Recovery that produces a “different” frontal cortex, cytoarchitecturally Wellman, Radley, Morrison
Result: Dumb-Ass decisions that seem really insightful at the time you make them
When does predictive information help?Latency until stressor Long in future Immediate Helpful No time to plan coping strategy The anticipatory anxiety outweighs the advantages
When does predictive information help?Likelihood of stressor ExtremelyLikely Extremely Unlikely Helpful You already assume it will happen You’re not worrying about it
When does a sense of control help?Severity of stressor Mild stressor Disastrous stressor Helpful Look how much worse It could have been Look how much better It could have been
DOPAMINE Signal Work Reward
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Ishi, last of the Southern Yahi Tribe in California, forced to live in Anthropology Museum at Berkeley