Topic 6: Long-Term Memory Flashcards
priming
change in stimulus processing due to prio exposure to the same (direct) or related (indirect) stimulus without conscious awareness
direct vs. in direct priming
direct - que word is same as the target work
indirect - que word is different, but semantically related to the target
what are Gollin pictures?
broken up parts of picture where participant guess the figure; used for perceptual priming experiments
what was the outcome of the study by Warrington and Weiskrantz that used Gollin picutres?
- Korsakoff syndrome patients had amnesia, and were tested asking to guess the images in the Gollin pictures
- participants improved day to day, even though they did not remember he previous day’s training
Implicit memory task
- perceptual identification
- half new and half old words
- told flashed briefly on the screen, told to identify the word
explicit memory task
- word recognition
- half new and half old
- waiting until participant says it was from the study phase or not before moving onto the next question
what was the result of the patient with damage to the right occipital lobe in the single dissociation of the implicit and explicit memory study
patient was about the same (a tad better) than the control in the explicit word recognition; but significantly worse in the perceptual identification
What were the results of the semantic-priming task using lexical decisions?
significantly faster responses when primed the a related word than with an unrelated or pseudo (non-word) word
what was the brain area associated with the semantic priming task
left anterior temporal cortex and the left inferior parietal cortex
what part of the brain is associated with a) perceptual priming? and b) conceptual/semantic priming?
a) sensory cortices
b) unimodal and multimodal association cortices (anterior temporal, inferior parietal, prefrontal cortices)
semantic memory
declarative memory refers to general knowledge about the world, including knowledge of languages, facts, and the properties of objects
episodic memory
declarative memory the refers to memory for personally experienced past experiences
brain region activations for linguistic stimuli associated with:
a) actions
b) sounds
c) colour/movement
a) motor cortex and somatosensory cortex
b) auditory cortex
c) vental visual steam (occipital/temporal cortex)
sensory/functional theory
organization of semantic representations is based on relevant sensory and motor features (e.g. action words activate region of primary motor cortex associated with that certain body part - pick -> arm)
domain- specific theory
organization of semantic representations based on semantic categories
sensory/functional theory vs. domain-specific theory debate?
both possible correct: categories often correlate with sensory/functional distinctions (e.g. tools are strongly associated with actions - premotor cortex activation)
how is abstract semantic knowledge stored according to a distribution only view and a distribution plus hub view?
- for distribution-only, representations in multiple modalities with no specialized regions for abstract concepts (same as concrete objects)
- for distribution-plus-hub, possible integrating hub in anterior temporal lobe in addition to having distributed representations
how are semantic memories formed?
start out as episodic (e.g. I learned ___ today! And years later you don’t remember how you know it, you just know it)
how are episodic memories formed?
recent events are stored in the same place they are perceived, the cortex (prefrontal cortex/PFC and postures parietal cortex PPC). They are disconnected memories, reactivated together through connections (indices) in the hippocampus. As time goes on, the connections between the hippocampus become less important as new connections between those in the cortex form
simultaneous access to many memory traces throughout the cortex is monitored by the ____, as it acts as an _____ with summary representations for a whole event. It contains ______ to where aspects are stored.
a) hippocampus
b) index
c) indices/pointers
what are the two types of representation storages for episodic encoding?
distributed cortical traces and hippocampal indices
retrievals are triggered by _____
retrieval cues (piece of information associated with a particular aspect of the original event
how are episodic memories retrieved?
retrieval cues activate an aspect in either the cortex or the hippocampal index, which simultaneously activates the other cortical representations connected (assisted by the PFC and PPC)
role of the prefrontal cortex in episodic encoding and retrieval?
important for executive control of memory processes, including goal maintenance and top-down attention
role of posterior parietal cortex in episodic encoding and retrieval?
important for attentional control during memory processes, including top-down and bottom-up attention
primary brain activations during encoding? retrieval?
encoding: inferior frontal gyrus (IFG)
retrieval: left middle frontal gyrus (MFG), posterior midline region (PMR), and the posterior parietal cortex (PPC)
difference between ventral and dorsal parietal cortices for attentional processes
dorsal parietal cortex: mediates top-down; demanding memory search and monitoring operations
ventral parietal cortex: bottom up; salient memories or retrieval cues
subsequent memory effects (SMEs)
in functional neuroimaging studies, greater study-phase activity for items that are remembered rather than forgotten in a later memory test
results of an odour association task in rats with fornix lesions
rats could remember trained pairs (e.g. A is better then B, B is better than C), but could not infer relationships, or transitive inference (e.g. A is better then C)
cognitive map theory
hippocampus mediates memory for spatial relations among objects in the environment
relational memory theory
hippocampus is involved primarily in encoding and retrieving associations between items (including spatial associations, but other types of association as well)
place cells
fire when an animal is in a particular location
role of:
a) perirhinal cortex
b) parahippocampal cortex
c) hippocampus
a) binding features of objects rapidly (item-based)
b) encoding spatial layout
c) encoding relationships more generally
Hebbian learning
- by David Hebb
- when presynaptic and postsynaptic neurons fire action potentials together, they strength go the synaptic connections between them is enhanced
- cells that fire together, wire together
long-term potentiation
- a long-lasting enhancement of synaptic strength as a result of repetitive activity
- necessary for Hebbian learning
- found in hippocampus and other brain regions
habituation vs. sensitization
H: reduced response when the same stimulus is repeated over and over
S: increased response to the habituated stimulus when it is paired with an aversive stimulus
early vs. late LTPs
Early: increase presynaptic release of neurotransmitters and the number of postsynaptic receptors
Late: increase number of dendritic spines and synapses
long-term depression (LTD)
- neurons that fire apart, wire apart
- when presynaptic action potentials does NOT lease to a postsynaptic potential, connection is weakened
- reduction in neurotransmitter release, number of recepters, and number of synapses
retrieval of episodic memories = _________ based on…….
reconstruction based on memory trace, genes, past experience, internal state, environmental context
false memory test
- presented list of semantically related words, then doing a recall/recognition memory test
- assuming a related word was on the list, when it really wasn’t
results of false memory test
- related lures reported almost as often as words actually on the list
- high confidence in accuracy
- often reported specifically remembering the lure
- happens even if you know about the effect
5 reasons why episodic memory is often inaccurate
1) semantic relatedness
2) cultural experience
3) source misattributions
4) pragmatic inferences
5) misleading post-event information
what happened when patent H.M had a removal of their bilateral medial temporal lobes?
- severe anterograde amnesia
- temporarally-graded retrograde
difference between retrograde amnesia and anterograde amnesia
retrograde: unable to recall existing LMT from before
anterograde: unable to form new long-term memories
standard consolidation theory
hippocampus rapidly encodes an integrated representation of an event or concept, which is then slowly transferred to the cortex, and eventually becomes independent of the hippocampus
new memories depend on……..; old memories depend on………
new: representations in cortex and links from the hippocampus
old: representations and links in cortex
how is sleep involved in consolidation?
reactivation due to retrieval and replay or memories during sleep reduces dependence on the hippocampus
difference between cortical ad hippocampal memory systems
cortical: learns slowly; extracts generalities across events/instances; important for semantic memories
hippocampal: learns rapidly; creates distinct memories for each event/instance; important for episodic memories
