Acute Stress Effects on L&M Flashcards
What is the adrenal cortex?
the outer layer around the adrenal gland
What is the adrenal medulla?
the central core of the adrenal cortex
What does the adrenal cortex secrete?
cortisol
glucocorticoids
Corticosteroids(humans)
Corticosterone(mice)
What does the adrenal medulla secrete?
Epinephrine and norepinephrine
What is the SAM response to stressors?
Sensory input into the periventricular nucleus(hypothalamus) -> midbrain/spinal cord -> adrenal medulla -> sympathetic activation
What is the HPA response to stressors?
sensory input into the PVN(hypothalamus) release CRH -> pituitary gland release adrenocorticotropic hormone -> Adrenal cortex -> cortisol
What is the negative feedback loop that keeps the HPA response under control?
High levels of cortisol shuts down the release of CRH and ACTH
What does cortisol do in the body?
increase BGL
breakdown proteins
increase glucose uptake in the brain
activates brain regions
What is the setup of fear conditioning a mouse?
A light side and a dark side, the mouse, wants to go to the dark side but will get shocked if it does. associates dark with the shock even tho it naturally wants to go there
What happens if Epi is injected right after training happens?
it facilitates learning
What is the inverted-U dose-response relationship?
Too much or too little epi does not facilitate learning
moderate amounts facilitate learning
What happens if the epi is given an hour after learning and not immediately after?
no effect on learning
Does Epi cross the blood-brain barrier?
No
How does epi affect the brain?
it activates the vagus nerve -> activates the nucleus of the solitary tract(medulla) -> norepi axons -> BLA
What is microdialysis?
insertion with a semi-permeable membrane probe, CSF flows through the probe, molecules are collect in the probe
What does NE infusion into the amygdala post-training do?
it enhances the consolidation of the memory
What happens when propranolol is infused into the amygdala?
it blocks the memory enhancement by the peripheral Epi injection
What is shown by the propranolol injection into the amygdala?
shows that NE is necessary in BLA fear memory consolidation
What does the injection of corticosterone do right after training?
it improves memory for the fear
What happens when glucocorticoid agonist is injected into the BLA post-training?
It enhances memory
more activation facilitates the passive avoidance memory
What type of learning is facilitated by the vmPFC?
extinction learning
What happens when a mouse is fear conditioned and then placed in a stressful cage?
they have impairment of extinction recall and slower extinction learning
What happens to dendrites when these rats are put into the stressful cage?
the dendrites shorten which leads to less synapses than before
What happens to dendrites when the mouse is in a stressful cage?
the dendrites shorten which leads to fewer synapses
what is the correlation between short dendrites and extinction memory?
the shorter the dendrites the poorer the extinction memory
