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Memory:
the processes or mechanisms by which we permanently store that which we have been exposed to or learn
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Psychologically, how can memory/learning be explained?
- conditioned responses (unpleasant odors)
- repetitive learning
- aversion learning
- conceptual learning
- integration learning
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Repetitive learning:
going over and over the info again and again
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aversion learning:
- used w/ smoking or dieting
- avoiding an activity
- i.e., rubber band snaps if you cuss
- negative way usually but may be seen in therapy
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Conceptual learning:
the big picture
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integration learning:
- association
- putting things together
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How does physiology explain how memory is stored in the CNS?
- only a very small portion of info is stored and retained; only if important to us
- we constantly process our environment, but we don't usually remember all of it
- there are many parts of the brain that process info
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What are the 2 most important parts of the brain that process info?
- amygdaloid nuclear process
- hippocampus
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Describe the amygdala and hippocampus:
- bilateral structures
- all experiences go through here and are processed for retention
- form neural circuits to other parts of the brain (to and from)
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Where are the amygdala and hippocampus?
deep in temporal brain
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Memory trace:
- neural circuit, that connects a sensory event w/ a learned behavioral response, is altered in some way to support learning
- part of conscious memory
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What is an example of memory trace?
Dr. Garrison getting pulled over by a cop; he may not remember what other cars are around him, but he remembers the cop
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Memory consolidations:
- occurs if the experience is somewhat permanently retained
- part of conscious memory
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What is an example of memory consolidations?
Dr. Garrison retelling his story numerous times to faculty and students
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How long does memory consolidation take?
can occur quickly or take long periods of time
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What variables influence consolidation? (how quickly, or long, or degree to which consolidations takes place)
- Catecholamine (adrenaline) levels in the body
- motivation
- physiological states
- sleep deprivation
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When do you have high adrenaline levels?
important events that you're very excited about (or dangerous events --car accident)
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Are you more likely to remember something when you have high or low adrenaline levels?
high
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High levels help you:
remember, low levels don't
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What type of learning is motivation?
context learning
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Do you learn better when motivated or not motivated?
- motivated
- when you are interested in what you're learning
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Motivation can be linked to:
importance or interest
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How does motivation apply to pts?
if you aren't doing something for pts that applies to them, then they won't learn as well
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What is our main way of learning?
through motivation (context learning)
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How do physiological states influence learning?
enhances poor memory consolidation
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What physiological states lead to poor memory consolidation?
- shock (decreased BP means blood isn't doing job as well and isn't feeding the brain)
- trauma
- emotional trauma
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If you see something very traumatic and you aren't use to trauma, you may:
be in shock so it is not good for you to be an eye-witness because your memory is not accurate
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How does sleep deprivation effect learning?
- adverse affects b/c you don't go through the consolidation process
- pulling all-nighters for tests isn't good
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All physiological states preclude efficient:
long-term potentiation and thus consolidation
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Trace memory -> consolidation memory -> anatomical parts ->
molecular level
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What does LTP stand for?
long-term potentiation
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Long-term potentiation:
- learn something over and over
- occurs at the cellular level involving cell membrane
- classical explanation of molecular basis of memory
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What type of process is long-term potentiation?
physiological/biological
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Original studies and most current studies of LTP use what?
- neurons (synapses) in the hippocampus
- dissect neurons of hippocampus and put them in petri dishes or do fMRI
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Where is memory retained?
synapses of brain
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Extensive research in animals shows that following a heavy train of stimulation (real fast stimulation), the postsynaptic excitatory potentials have:
an increase in amplitude which can last for varying periods of time (days or weeks)
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Hebbian Processing:
- occurs at molecular level
- following heavy train of stimulation, the postsynaptic excitatory potentials have an increase in amplitude which can last for varying periods of time
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If the postsynaptic amplitude is increased for weeks, then the neuron is:
different
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If the postsynaptic amplitude is increased for weeks, how is the neuron different?
- increase firing of postsynaptic neuron due to variety of stimuli (glutamate is the NT)
- increased firing rate associated w/ increased activation of glutamate receptors
- ligand gated channels open resulting in an influx of Ca
- increased Ca enhances enzymatic cascades in postsynaptic cell (modulates nature of postsynaptic membrane receptrs and makes them more sensitive)
- nitic oxide is formed and diffuses back across synapse to increase effectiveness of presynaptic membrane (making glutamate release easier)
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So Ca changes receptors on:
postsynaptic cells
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Nitric Oxide diffuses back to presynaptic cell and helps:
release glutamate
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What is LTD?
long-term depression
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Is long-term depression similar to long-term potentiation?
similar, but w/ an opposite/reverse effect (you lose memory!)
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What do biochemical changes do to long-term depression?
decrease effectiveness of synapses (overtime we forget things)
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What anatomical changes occur in LTP?
- increase in # and types of synapses and increase in function; associated w/ increase in activity
- neurons like to talk to each other
- dendritic tree forms new spines
- axons form collaterals
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What principle can be applied to memory?
- use it or lose it
- CNS needs to be challenged
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What anatomical changes occur in LTD?
- membranes lose sensitivity and proper synapses are not in place
- dendritic spines wither away when not used reducing the number of synapses
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What are the classification of memory?
- declarative memory
- non-declarative memory
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Declarative memory:
- conscious, explicit, cognitive
- remembering facts, events, concepts, and locations
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Are declarative memories easily verbalized?
yes
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What do declarative memories require during recall?
attention --not reflexive, you have to think about it
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How many stages are involved with declarative memory?
3
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What is the 1st stage of declarative memory?
- immediate memory (1-2 sec) similar to trace memory
- used to plan a response to some stimulus
- no long term memory here (unless very important)
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What is the 2nd stage of declarative memory?
- short-term memory/working memory/primary memory
- may last only minutes or days unless reinforced (doesn't last forever)
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Which cortex is involved w/ the 2nd stage of declarative memory?
pre-frontal cortex -primary intellectual area (cognition, intellect, IQ)
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Which association areas are involved w/ the 2nd stage of declarative memory?
- areas of primary functional cortical areas (association areas of all cortices)
- Ex: visual association area stores visual memory
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What is the 3rd stage of declarative memory?
- long-term memory/remote memory
- involves short-term memory which has been permanently consolidated and stored in the area which 1st processed it
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Where are 3rd stage declarative memories stored?
hippocampus or amygdala
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Where are visual or auditory stimuli ultimately processed?
- through hippocampus and association area
- then if consolidated and stored permanently, then it is stored in primary cortical area
- superior temporal gyrus - if you heard a great song
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Where is the memory of smell stored?
olfactory cortex
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What are the special types of declarative memory?
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Episodic memory:
- people remember their own experiences as they happened in a specific place and time in their own history (ex: can't tell the story unless they go through the whole process)
- type of long-term memory
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Semantic memory:
- form which deals w/ general knowledge
- learning in school
- provides database required for thinking/knowledge base allows you to think and make decisions
- type of long term memory
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If it is super specific memory, then it is:
semantic memory (very explicit info)
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Where do you 1st process a stimuli?
in cerebral cortex
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After processed in cerebral cortex info goes to:
hippocampus or amygdala
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From hippocampus/amygdala to be stored in:
pre-frontal cortex
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After stored in pre-frontal cortex it goes through:
consolidation process (stored where 1st processed)
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After consolidation process it is put:
in long-term memory in either hippocampus or area of brain that 1st processed it
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Non-declarative memory:
implicity memory/procedural/unconcscious/skill and habit memory
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In non-declarative memory, the person has no previous awareness of:
memory, can't describe learned info except through behavior and can't necessarily remember how, when, or where the learning occured
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What is an example of non-declarative memory?
- may remember to tie shoes, but don't remember exactly how you learned
- typing on keyboard, but can't remember even what year you learned how to type
- learning to play piano over time
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Where are non-declarative memories stored?
- cerebellum, basal ganglia, and amygdala
- stored in central pattern generators b/c these are learned motor activities
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What is the biggest problem with memory?
amnesia
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Amnesia:
loss of long term memory
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Retrograde amnesia:
loss of memory prior to trauma or disease
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Anterograde amnesia:
loss of memory of events which follow trauma or disease
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When does anterograde amnesia present?
amygdala and hippocampus are damaged and not processing info
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Which type of memory is involved in amnesia?
- both declarative and nondeclarative memory
- may forget how to tie your shoe or a birthday
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When is the Marine corps birthday?
Nov. 10th 1775
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