18/ memory Flashcards
1
Q
definitions of learning, memory, recall, the engram
A
- acquisition of info
- storage of learned info
- reacquisition of stored info
- the physical embodiment of a mem
2
Q
procedural vs declarative memory
A
- procedural: skills and association largely unavailable to conscious mind - riding a bike, piano
- available to conscious mind. can be encoded in symbols and language, can be passed between organisms
2
Q
memory durations
A
- immediate mem - few secs
- short term mem - secs or mins - working mem
- long term - days, months, yrs
2
Q
explicit vs implicit mem
A
- explicit: mem that can be consciously recalled
- implicit: can’t be consciously recalled, eg HOW you learnt how to ride a bike. includes procedural mem, classical conditioning, priming (when 1 stimuli influences response to a later stimuli)
3
Q
how is the temporal lobe linked to mem
A
- electrical stimulation - hallucinations and recollection of past experiences
- epileptic seizures - complex sensations and mems had by patient HM
- temporal lobotomy: patient HM. Removed 8cm of medial temporal lobe. intelligence, personality etc intact. but extreme anterograde amnesia
- unable to form new mems - medial temporal lobe needed to form new mems
4
Q
important brain structures for mem
A
- pre-frontal cortex: working mem
- hippocampus: converting short to long term mem. declarative, esp spatial
- amygdala: multiple processed sensory inputs (eg smell), implicit, emotional, learnt fear
- cerebellum: procedural, sensorimotor
5
Q
what do hippocampal lesions cause
A
mem loss
6
Q
hippocampus: number of layers, where are inputs from, where are outputs to, who is it enlarged in
A
- 3 layered cortex
- inputs from entorhinal cortex and beyond
- enlarged in ppl whose work needs good spatial mem
7
Q
what is long term potentiation
A
- continued strengthening of synaptic connections between neurons, resulting in long lasting increase in signal transmission
- tetanic ltp causes a high frequency burst that strengthens ltp of a particular pathway
- paired LTP: coincident stimulus and depolarisation, associativity
- long term depression: ltd in hippocampus. if you stimulate neurons w low frequency for long time epsp amplitude would need to decrease
7
Q
aplysia californica gill withdrawal reflex
A
- if you touch siphon gill withdraws
- stronger stimulation increases sensitivity of reflex - will withdraw more despite same stimulation
- repeated gentle stimulation to siphon causes reduced gill withdrawal - habituation
- pair single tail pinch with siphon tough re establishes siphon reflex short term
- long term: repeated pairing of siphon touch and tail pinch - non-habituating siphon reflex
7
Q
mechanisms of memory: reverberating circuits vs hebbian synapse concept
A
- reverberating circuits: neurons kept active until we forget - not possible, would take too much energy. potentially for short term
- hebbian: activity modifyable, plastic synapse. mem stored in structural changes. when neurons fire at same time synapse strength increases/decreases (calcium availability/ vesicle depletion). synapses that fire together wire together
8
Q
what does ltp and ltd require
A
- receptor activation - glutamate, serotonin
- altered synaptic responsivity
- mediated by 2nd messengers
- protein phosphorylation changes in early stages
- protein synthesis for late stages
- involves biochemical and structural pre and post synaptic changes
8
Q
short term habituation and sensitisation
A
- repeated gentle stimulu to siphon causes
9
Q
how does ltp occur
A
- often a post synaptic event
- calcium important
- involves trafficking of ampa receptors to post synaptic memb
