Long Term Memory

problem LTM is trying to solve

how to acquire information from past experiences and use this info to guide future actions (learning)

short term memory

aka working memory. what we currently have in mind. (requires active neural connections to maintain) would be gone if we got distracted. similar to RAM/cache in computers

long term memory

passively stored in the long term.

common underlying representation of human memory

number and strength of associated synaptic connections

encoding

initial creation of memory from incoming information (first process of LTM)

consolidation

second process of LTM. active process where memories are stabilized

storage

3rd process of LTM. memories sit stable in brain waiting to be recalled

retrieval

4th process of LTM. when we access/used stored information

reconsolidation

5th process of LTM. when we retrieve memories they can change/reorganize

explicit memory

type of LTM that remembers declarative things with conscious awareness like events or facts

implicit memory

type of LTM that remembers nondeclarative things without conscious awareness like procedures, classical conditioning, perceptual priming and habituation/sensitization. we cannot explain them

episodic memory

type of explicit LTM that remembers events in our life

semantic memory

type of explicit LTM that remembers facts about words, objects, language and concepts

procedural skill learning (def/part of brain)

type of implicit LTM that remembers motor and cognitive skills via the basal ganglia, cerebellum and skeletal muscles

perceptual representation system (def/part of brain)

type of implicit LTM that remembers perceptual priming via the perceptual and association neocortex

classical conditioning (def/part of brain)

initially neural stimulus comes to elicit a conditioned response. type of implicit LTM that remembers conditioned responses to stimuli via the cerebellum

fear conditioning

initially neutral stimulus is associated with something negative and is conditioned to be associated

nonassociative learning (def/part of brain)

part of implicit LTM that remembers habituation and sensitization via the reflex pathways

habituation

decreased response to an unchanging stimulus

sensitization

increased response to an unchanging stimulus

double dissociation

research finding that shows two mental processes are separate when two patients w different brain damage show opposing patterns of results

perceptual priming

change in stimulus processing due to prior exposure to same or related stimuli WITHOUT conscious awareness. happens in sensory cortices

conceptual/semantic priming

exposure to a stimulus influences processing of a subsequent related stimulus. case study: word vs non word. finding: when word is related to prime they can tell if it is a real word much faster

how do semantic memories form

generally they start out as episodic and become semantic over time as we forget where/when we learned them

brain organization: where in the cortex are semantic memories stored

likely grouped based off both meaning and relevant sensory/motor areas

what parts of the brain are involved in the encoding of episodic memories

the hippocampus receives memories and binds them to specific parts of the cortex

binding

how episodic memories are linked together for storage in the cortex based off events that occurred around the same time

cognitive map theory

there are place cells that only fire when you are in a specific location

long-term potentiation

neurons that fire together wire together. when potential strength increases between two neurons their connection is increased. 2 phases, early and late that strengthen synapses (neurotransmitters) and grow more neurons, respectively

long-term depression

neurons that fire apart wire apart. when potential strength decreases between neurons and next neuron does not fire their connection is weakened. leads to less receptors and less synapses on this connection

episodic retrieval

a best guess that can be inaccurate,. depends on memory traces, past experiences, genetics etc.

the DRM paradigm

when given a list of semantically related words, some distractions and a lure that isn’t present people are great at saying semantically related words and the mistaken lure but not the distractions

anterograde amnesia

unable to form new LTMs

retrograde amnesia

unable to recall existing LTMs

temporally graded amnesia

when someone can remember early memories better than recent memories

consolidation depends on:

the link between the hippocampus and the cortex