Brain and Behavior Test 4 Study GuideStress and Health1. What is a stressor?A stressor is anything that throws the body out of allostatic balance.2. What is allostasis?Allostasis is the range of measures appropriate for situation (sleep vs. bungee-jumping)3. What are the 3 stages of a stress response?1. Alarm: SNS activation2. Resistance: decreased SNS activity; increased HPA activitycortisol and other hormones for maintaining prolonged alertness and increased immune function (to fight infections and to heal wounds)3. Exhaustion: NS and immune system are spent…person is tired, inactive, and vulnerable to illness4. What is the role of the sympathetic NS in the stress response? 5. What is the HPA and what is it’s role in the stress response?-The HPA is the hypothalamus, pituitary gland, and the adrenal cortex.-The hypothalamus makes CRH(corticoptropic releasing hormone)pituitary makes ACTH(adrenocorticotropic)adrenal secretes cortisolincrease in blood sugar and metabolism-The role of the HPA is activated with prolonged stress, it is beneficial in the short term and detrimental in the long term-acute activation of HPA boosts immune system and even improves memory6. Why do you feel terrible during finals week?Powerful, inescapable, temporary stress can lead to your body reacting with illness with increased immune activity -body increases production of natural killer cells (cell helps with fighting infection)-immune system gets tiredmore susceptible to illness7. What are some effects of long-term stress?-hippocampal damage-reproductive effects:-decreased libido in women-can inhibit mestrual cycle, ovulation in women-decreased sexual performance in men-decreased immune function, prolonged sickness syndrome-increased blood sugar causes pancreas to release glucagonkidney damageLearning and Memory1. What is an engram, and what were Lashley’s critical mistakes in looking for the engram?Engram: is a physical representation of a memoryLashley’s mistake was he thought certain areas of cortex effected performance but itwas really the size of the lesion-TWO FALSE ASSUMPTIONS-memory is in cortex-all memories are physiologically the same2. What are implicit memory and explicit memory? What brain regions are important for each?-Explicit Memory: remembering events (episodic memory) and knowing facts (semantic memory). Deliberate recall of info that one remembers as a memory-brain regions: hippocampus, nearby cortical areas, and medial diencephalon-Implicit Memory: skills and habits, emotional associations, and conditional reflexes,the influences of recent experiences on behavior, w/o necessarily realizing that one is using memory-brain regions: striatum, motor areas of cortex, and cerebellum, amygdala, and cerebellum**Both are types of long-term memory3. What are some differences b/t short-term memory (working memory) and long-term memory? What brain region is important for working memory?Short-term memory: working memory-small capacity, fades quickly unless rehearsed, once forgotten its gone-where you parked your carLong-term memory: ex. (phone number and recalling school teacher)-infinite capacity-lasts indefinitely-could be forgetting and then recalled with appropriate cues**Brain areas important in working memory is dorsolateral prefrontal cortex4. What were some of HM’s impairments; what could he still do?-HM lost declarative (explicit) memory and spatial memory-He still had intact procedural memory (type of implicit) and intact working memory5. With regard to memory, what are some functions of the hippocampus?-declarative/explicit memory-spatial memory-consolidation (short term can lead to long term) 6. What other brain regions are important in learning and memory, and what type oflearning do they subserve?-cerebellum: for learning a conditioned response, and also for motor learning (skills and cognitive stuff too-parietal lobe: if damaged don’t spontaneously elaborate on memories-temporal lobe: damage causes semantic dementia-prefrontal cortex: learning reward and punishment and working memory7. What is a Hebbian synapse?Hebbian synapse is a synapse that increases in effectiveness because of simultaneous activity in pre- and postsynaptic neurons8. What is LTP? What receptors are necessary? LTP is long-term potentiation. LTP is a burst of stimulation from axons. For example100 excitations per second for 1-4 seconds onto dendrites, can result in potentiated (strengthened) synapses for minutes, days or weeks.**Glutamate receptors needed are AMPA and NMDA9. What are some presynaptic changes that occur in LTP? What are some postsynaptic changes that happen in LTP?-presynaptic changes: retrograde transmitter from dendrite to axon terminal, usually nitric oxide. Decreased threshold for producing APs, increased release of neurotransmitter, expansion of axon, and release of NT from more sites along axon-postsynaptic changes: more NMDA receptors in postsynaptic membrane10. What is evidence that there is a functional connection between LTP and actual learning?-drugs that block LTP block retention of learned material-drugs that facilitate LTP facilitate learning-LTP increases certain proteins and blocking those proteins weakens memories**IN PEOPLE: partial NMDA agonist (so ramp-up excitability of synapses) given withbehavioral treatment for PTSDlearn fasterAlzheimer’s Disease and other Dementias1. What are some cognitive and non-cognitive symptoms of dementia? What are the4 A’s of demenita?-Impairment in memory and cognition, accompanied by decreased ability to relate/function at home work or social settings.-noncognititve symptoms: delusions, suspicions, hallucinations, agitation, and depression-4A’s of dementia-amnesia: loss of memory-agnosia: loss of ability to recognize objects-apraxia: loss of knowledge about how to do things-aphasia: loss of speech2. What are some symptoms of Alzheimer’s Disease (AD)?-deficits in explicit and implicit memory-gradual progression to more serious memory loss -language problems, depression, sleeplessness, loss of appetite, etc-sundowning: state of increased agitation activity and negative behaviors which happen in the day through the evening hours3. What is the difference b/t early-onset and late-onset AD? Which one has a stronger genetic contribution?Early onset AD: people less than 40 years old, gene on chromosome 21, gene for ApoE4 which breaks down beta-amyloid, other genes on other chromosomes linked to more of these
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