Comparative Cognition: Memory Mechanisms Flashcards
Does information retained in memory deal with events that occurred in the past?
yes
for example, football players (North American Football) must remember plays learned
in practice associated with numbers
* This is retrospective encoding
cognitive ethology
- nonhuman animals are capable of consciousness and intentionality
- based on complexity, flexibility, cleverness
comparative cognition
- used by contemporary experimental psychologists
- ties cognitive mechanisms to theoretical constructs and models used to explain aspects of B
- used for things that connot be explained by SR
- uses simple + possible explanations
anthropomorphism
- inferences about rich mental life of animals
- projecting our human thoughts, emotions, intentions onto animal
memory
- ability to respond on basis of earlier acquired information
- similar to learning: both require acquisition, retention and retrieval
- learning studies focus on exposure to stimuli (acquisition), manipulation of acquisition and retention + retrieval intervals are kept constant
- memory studies focus on retention and retrieval
- existence of memory in animals: current B is based on some aspects of earlier experiences
stages of info processing
REFER TO DIAGRAM IN NOTEBOOK PAGE 46
procedural memory
- part of implicit memory
- memory of how to perform relatively complex tasks that allow us to perform them
- done without conscious control
working memory
- retention of recently acquired info (just long enough to complete tasks)
- discarded after completion of task to prevent it from interfering with the next task
- most useful when more enduring, longterm knowledge already exists
- e.g. chef keeps track of spices when creating a new recipe; when he does it again, the spice list is in his LTM
reference memory
- LTM retention of info = necessary for successful use of incoming and recently acquired info
- knowledge that remains relatively constant over time for particular situations
delayed matching to sample
- participant presented with sample stimulus that designates which response will be correct at end of trial
- stimulus = removed for retention period
- participant given memory test: “which is the original sample?”
- choice of sample stimulus is correct response = reinforced
delayed matching to sample: phases
- test stimuli appeared immediately after - remained available until choice was made
- once subject has learned to select correct option 80% of time delay is introduced
delayed matching to sample: schizophrenia patients vs neurotypical patients
phase 1.
controls + schizophrenics performed equally
phase 2.
schizophrenics showed performance deficit
determinants of delayed matching
- nature of stimulus
- duration of exposure
- delay interval
note:
- if sample is presented longer, more likely to perform better
- more likely to make mistakes with longer delay
- training with longer retention interval improves memory performance
- sample and choice test performance depends on similarity between training and test conditions
general vs specific rule of learning
specific:
- participants learn series of speifci rules or SR relations
- difficult to adapt when tested with novel stimuli
general:
- can be used to solve any matching to sample problem
- learning not restricted to a series
- more latitude to transfer learning to novel stimuli
spatial memory in water mazes
- refer to slides 16-17
- goal of study: wanted to see if next time, how fast the rats would find the platform
- will they look for contextual cues?
- effects of delays
cellular messagin
IMPORTANT REFER TO NOTEBOOK PAGES 13-14
- CREB - cAMP response element binding protein
- transcription factor (process of making mRNA)
- CREB binds to cAMP response element
- functions as transcriptional activator only after it is phosphorylated by PA or MAPK
- critical for making changes/adding new proteins (protein synthesis)
- for LTP, refer to slide 20 on powerpoint
memory process + LTP
IMPORTANT REFER TO SLIDE 21
genes and learning
- to be established, long term memories (longer lasting LTP adn LTD) require activation of genes to create new protein products
- lasting alteration in a synapse depends on gene expression
transgenic mouse
- mouse engineered to examine hippocampal LTP and learning
- extra gene added = e.g. flawed CaMKII mutated gene
- a tTA that governs this gene’s production = under control of tetO
- flawed CaMKII:
1. will not elicit added AMPA receptors to be added to the neuron membrane
2. would impair LTP and disrupt learning
3. if mouse food has DOX, tTa = inactivated
SLIDE 23 = IMPORTANT
LTM and mRNA
- explicit, declariitve memories for people, objects, events and facts = mediated by hippocampal memory system
- implicit memory (involving unconscious or skills + habits) = mediated by amygdala, cerebellum and striatum
- LTP, recall, strengthens synaptic connections of involved neurons (“cells that fire together, wire together”)
- LTP requires synthesis of new proteins, as new connections = grown
LTM and mRNA: short term memory
- involved in modification of preexisting proteins
- changes in strength of preexisting synaptic connections
acquisition and stimulus coding
- memory depends on us having experienced event and having made some kind of record of that experience
- stimulus coding:
1. critical phase of memory acquisition
2. experiences are coded in nervous system for purposes of retention + retrieval - for spatial memory, animals use:
1. cognitive map
2. landmarks (when they have fixed relation to the goal)
3. beacon = cue to locate the goal
4. geometrics cues (provided by shape of arena)
retrospective coding
retrieving what you learned to use currently; restrospection
prospective coding
imagining future so as to remember what to do in real time
mental time travel
mentally moving forward/backward in time
rehearsal
- keeping info in active state, readily available for use
- typically involves repeating and rehearsing info
directed forgetting (refer to slide 27)
- accuracy of recall can be modifed by cues that indicate if something should(n’t) be remembered
- memory = active process that can be brought under stimulus control
- memory performance improves if cue during retention interval signals that the correct response will be reinforced with large reward (rather than small one)
- Fcue (forgetting cue) signaled there would be no test - no rewatd
- anticipation of reward helps retain recent event in memory
- increase in PFC neuron activation during delay interval on Rcues but decrease activation on Fcues
retrieval
- recovered stored info used to guide B
- coding (acquisition) + rehearsed focus on working memory paadigms
- retrieval focuses on reference memory (long term retention of info for application to new info) + learned association
- ## retrieval failure us usually cause of loss of information
retrieval: importance of context
memory = most succesful if contextual cues at retrieval are same as contextual cues present during original learning
retrieval: retrieval cues
triggers/reminders for retrieval processes
retrieval: memory priming
retrieval cue presenyed at end of long retention interval; can help memory
priming can…
- faciliate retrieval
- serve as contextual cue
- improve memory
forgetting
- memory fails; we don’t respond in accordance with past experience/learning
- can have unpleasant consequences
- can be adaptive (PTSD coping mechanism)
- time is not the cause of forgetting
- poor memory performance reflects failure to retrieve info; failure to ACCESS
- memory failure: preferable term referring to instances of poor performance on memory tests
proactive interference
interfering info acts forward t disrupt memory of future target event
retroactive interference
interfering stimulus acts backward to disrupt memory of preceding target event
consolidation window and amnesia
- when stimulus first encountered, enters short term, temporary memory store
- while in short term memory, info = vulnerable - can be lost- because of interfering stimuli/neuropsych disturbances
- if proper conditions = met, info gradually becomes consolidated into relatively permanent long term memory
- REFER TO SLIDE 33
retrograde amnesia: consolidation failure
- if memory disrupted, never properly recovered in long term memory
- can never be retrieved during subsequent memory tests
- amnesia = attributed to disruption in acquisition of memory
retrograde amnesia: retrieval failure hypothesis
- amensic agent alters coding of new memories
- makes them more difficult to recover
- amnesia = problem with retrieval phase, not acquisition
consolidation
- amnesic agents and physiological manipulations = effective in disrupting memories only during limited period after that memory has been activated
- after consolidation window, memory becomes immune to disruption and modification
- traditional view: in STM to LTM process of consolidation, we can access LTM while in STM, but cannot modify them (like a PDF file)
reconsolidation: contemporary view
- distinguishes between active and inactive form of memory
- if memory previously learned (+ consolidated), is reactivated, it returns to state where it can be modified and reconsolidated
- refer to page 50 in notebook
types of consolidation
synaptic consolidation
- changes in synaptic efficacy that underlie learning
- may occur in minutes and involves molecular level changes
systems consolidation
- involves memory representation in hippocampal and cortical circuits
- neural systems level
- consolidation = much slower for neural systems
