Study Guide Test 4 PSB2000 1 Stress and Health 1 What is a stressor Anything that throws the body out of allostatic balance 2 What is allostasis Range of measures appropriate for situation sleep vs bungee jumping 3 What are the 3 stages of a stress response 1 Alarm SNS activation 2 Resistance decreased SNS activity increased HPA activity cortisol other hormones for maintaining prolonged alertness increased immune function Hypothalamus pituitary gland adrenal Individual s perception of their own ability to 3 Exhaustion NS and immune system are spent person is tired inactive vulnerable to illness 4 What is the role of the sympathetic NS in the stress response The SNS is activated during the alarm stage SNS activity is decreased during the Resistance stage 5 What is the HPA what s its role in the stress response cortex Hypothalamus makes CRH Pituitary makes ACTH adrenal secretes cortisol increase in blood sugar metabolism activated with prolonged stressors 6 Why do you feel terrible during finals week Powerful inescapable temporary stress causes the body to react like an illness with increased immune activity the body increases production of cytokines the body s way of telling the brain you are sick so you have sickness syndrome 7 What are some factors that affect the stress response cope with stress intensity of the stressor individual s control over the stressor duration of stressor personality traits individuals with high anxiety are more likely to show impaired memory after stressor gender males more affected than young females age older more vulnerable to deleterious effects of stress than younger early stress might not show cognitive effect until later in life 8 What are some effects of long term stress Hippocampal damage increased cortisol makes hippo Neurons more vulnerable chronic infant stress leads to deceased hippo Plasticity impaired spacial memory in adults explicit memories are vulnerable to stress while implicit memories are not reproductive effects decreased libido in women can inhibit menstrual cycle ovulation decreased sexual performance in men decreased immune function prolonged sickness syndrome increased blood sugar 9 How does stress affect the hippocampus amygdala These are 2 brain regions with lots of receptors for cortisol so they serve as substrates for negative feedback to turn off cortisol production 10 PTSD Post Traumatic Stress Disorder What are the symptoms flashbacks and nightmares about event avoidance of reminders of events exaggerated arousal in response to noise and other stimuli What types of events can precipitate it Severe injury or threat witness others harmed or killed soldiers victims of rape kidnapping or torture car crash survivors sudden loss of loved one Why doesn t everyone in such situations develop PTSD PTSD victims have smaller hippocampus PTSD victims have lower than average cortisol levels at time of event two weeks later maybe people with low cortisol are equipped to deal with extreme stress Vietnam vets with brain damage PTSD those with damage to amygdala never had PTSD lasting longer than a month Learning and Memory 1 What is an engram A physical representation of a memory What are Lashley s critical mistakes in looking for the engram Lashley trained rats then cut certain areas of the cortex no significant effect on performance 2 false assumptions memory is in cortex all memories are physiologically the same Study Guide Test 4 PSB2000 2 2 What are implicit memory and explicit memory What brain regions are important for each Explicit Memory remembering events knowing facts hippocampus nearby cortical areas medical diencephalon Implicit memory skills habits striatum motor areas of cortex cerebellum emotional associations amygdala and conditioned reflexes cerebellum 3 What are some differences between short term working long term memory Short term small capacity fades quickly unless rehearsed once forgotten it s gone Working memory alternate way of thinking of STM lasts hours to days without rehearsal where car is parked when lunch date is etc time needed for consolidation varies especially depending on familiarity of topic and emotional content Long term infinite capacity lasts indefinitely could be forgotten then later remembered with cues phone number names of grade school teachers What brain region is important for working memory Prefrontal cortex 4 What were some of HM s impairments HM anterograde amnesia lost declarative explicit memory spatial memory intact procedural memory a type of implicit and working memory 5 With regard to memory what are some functions of the hippocampus Active during formation of memories Consolidation STM LTM Declarative explicit memory spatial memory increased activity in hippocampus when doing a special task 6 What other brain regions are important in learning and memory and what type of learning do they sub serve Cerebellum for learning a conditioned response also for motor learning cognitive stuff Parietal Lobe if damaged don t spontaneously elaborate on memories Temporal lobe damage causes semantic dementia Prefrontal cortex learning reward punishment also working memory 7 What is a Hebbian synapse A synapse that increases the effectiveness because of simultaneous activity in pre and postsynaptic neurons cells that fire together wire together In other words when an axon successfully stimulates a cell it will be even more successful in the future the synapse is strengthened 8 What is LTP Long term potentiation a burst of stimulation from axons results in potentiated strengthened synapses for minutes days or weeks What receptors are necessary Glutamate receptors AMPA and NMDA receptors What are some presynaptic changes that occur in LTP Retrograde transmitter from dendrite to axon terminal usually nitric oxide NO decreased threshold for producing Aps increased release of neurotransmitter expansion of axon release of NT from more sides along axon What are some postsynaptic changes More NMDA receptors in postsynaptic membrane more AMPA receptors made or redistributed or existing ones become more responsive 9 What is evidence that there is a functional connection between LTP and actual learning In rats abnormal NMDA receptors impair learning drugs that block LTP block retention of learned material drugs that facilitate LTP facilitate learning LTP increases certain proteins blocking those proteins weakens memories LTP increases GAP 43 overproduction of GAP 43 enhances learning and problem solving
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