PSY 220 EXAM 4

learning

→ change in thinking or behavior due to experience

→ learning is closely tied to memory

classical conditioning

→ specific form of implicit memory in which pairing the presentation of two stimuli, (closely in time), creates a learned association and produces a learned response

→ AKA pavlovian conditioning

Ian Pavlov

accidentally discovered classical conditioning

pavlov experiment

* bell (NS) + food (UCS) = salivation (UCR)
* bell (CS) = salivation (CR)

unconditioned

automatic

conditioned

learned

before conditioning

bell (NS) = NO RESPONSE

AND

food (UCS) = salivation (UCR)

during conditioning

bell (NS) \[repeatedly paired with\] food (UCS) = salivation (UCR)

after conditioning

bell (CS) = salivation (CR)

cerebellum and classical conditioning

lateral interpositus nucleus within the cerebellum important for classical conditioning

* if temporarily lesion in the lip nucleus, subjects no longer showed classical conditioning learning

fear conditioning

conditioning subject to fear an unconditioned stimulus into a conditioned feared response

normal rats

UCS → startle (UCR)

NS + UCS → startle (UCR)

CS + startle (CR)

rats with damage to lateral nucleus of the amygdala don’t exhibit a conditioned fear response

UCS → startle (UCR)

NS + UCS → startle (UCR)

CS → no startle

humans with amygdala damage

show absence of fear conditioning

fear conditioning: Little Albert

→ Little Albert conditioned to fear fuzzy things

* paired white fuzzy rat w/loud sound → cry
* eventually sight of rat alone → cry
* fear was generalized to other similar stimuli

taste aversion

→ learned aversion to food after getting sick

* an example of classical conditioning
* unique: often learned in only one pairing

application of classical conditioning

advertising

extinction

when the conditioned response goes away after repeatedly experiencing the conditioned stimulus without the unconditioned stimulus

spontaneous recovery

reappearance of a conditioned response after extinction (or a prolonged period without the response)

operant conditioning

learn based on the consequences of behavior

→ the likelihood of future behaviors is based on

* reinforcement
* punishment

→ AKA instrumental conditioning

reinforcement

an event that increases thee frequency of a specific behavior

punishment

an event that decreases the frequency of a specific behavior

positive reinforcement

an outcome that is presented immediately following a behavior that increases the frequency of that behavior

negative reinforcement

removal of an aversive stimulus resulting in an increased frequency of that behavior

PR

\+ (+) = + increase

NR

\- (-) = +

positive punishment

the presentation of an aversive stimulus following a behavior resulting in a decreased frequency of that behavior

negative punishment

the removal of something favorable following a behavior that results in a decreased frequency of that behavior

PP

\+(-) = -

NP

\-(+) = -

behavior increases + stimulus added

positive reinforcment

behavior increases + stimulus removed

negative reinforcement

behavior decreases + stimulus added

positive punishment

behavior decreases + stimulus removed

negative punishment

primary reinforcers

something that is inherently rewarding

→ (food, entertainment)

secondary reinforcer

something that has been learned to be rewarding

→ (money, applause)

B.F. Skinner

→ “father” of operant conditioning

→ famous behaviorist who demonstrated that animals could be trained (i.e., could learn) with operant conditioning

skinner box

controlled environment for an animal, where reinforcement or punishment could be administered to have animals learn a behavior

→ ex: press lever for food

schedules of reinforcment

→ fixed ratio

→ fixed interval

→ variable ratio

→ variable interval

fixed ratio

deliver reinforcement after (n) number of responses

fixed ratio example

rat is reinforced with water/food after pressing the lever 5 times

fixed interval

deliver reinforcement after a specified amount of time

(weak)

fixed interval example

worker in a toy factory will receive a pay check every friday

variable ratio

deliver reinforcement after a random number of responses

(strongest)

variable ratio example

gambling

variable interval

deliver reinforcement after random amount of time (weak)

variable interval example

buy a child a toy after a varying amount of time

shaping

a process of conditioning a target behavior by progressively reinforcing behaviors that come closer and closer to the target behavior

operant conditioning and the brain

→ nucleus accumbens involved in processing reward

→ basal ganglia involved in directly self-initiated behavior toward reward

* other brain areas also involved

what is memory

* the retention of facts, events, or other experiences over time, whether or not it’s conscious
* amount of time information is retained varies
* type of information retained varies
* awareness of memory varies

memory processes

→ encoding

→ retrieval

→ storage

* can have memory failure at any point

encoding

initial processing of incoming information

storage

maintenance of information over an extended period of time

retrieval

bringing the information back to mind (recovering stored memory)

types of memory

* sensory memory
* short term memory (STM)
* long term memory (LTM)
* explicit memory
* semantic memory
* episodic memory
* implicit memory
* classical conditioning
* procedural memory (skill learning)

sensort memory

→ immediate and fleeting memory of sensory information

→ large capacity (we are able to process a lot of sensory information)

→ duration: milliseconds

→ modality-specific sensory memory:

* iconic memory
* echoic memory

iconic memory

visual sensory memory

echoic memory

auditory sensory memory

short-term memory

→ memory that is maintained for a short period of time (seconds)

→ can be “refreshed” in STM with rehearsal

working memory

memory that is maintained and manipulated within one’s mind over a short period of time (seconds)

short-term memory and working memory

→ information within working memory can be incoming sensory information or information retrieved from long-term memory

→ highly dependent on rehearsal to maintain information

limited capacity

* older accounts say 7 +/- meaningful “chunks”
* newer accounts say 4 +/- meaningful “chunks”

backward digit span

→ assessment of working memory

→ asked to mentally rearrange numbers and repeat back in the opposite order

delayed response task

→ an assessment of working memory

→ correct response requires keeping “baited well” in mind without seeing it

→ monkeys and humans with lesions of DLPFC fail these tasks

→ infants younger than 12 months also fail versions of these tasks

delayed saccade tasks: neural evidence for goal representation

→ method: single unit recordings from DLPFC neurons

→ task:

* time 1: cue 1 of 8 locations
* time 2: 3 second delay
* time 3: fixation removed signaling make eye movement

→ monkeys saccade to remembered location

working memory function of DLPFC

→ delay activity of time 2

* location specific
* less activity when monkeys make errors

→ DLPFC lesions impair performance for a specific location called a “memory scotoma”

→ interpretation

* neural activity in DLPFC corresponds to the maintenance of WM representations

verbal working memory

→ verbal information to remember

* letters/words (left hemisphere activiation)

spatial working memory

→ spatial location information to remember

* right hemisphere activation

long-term memory

→ memory that is maintained over a prolonged period of time

→ duration: several minutes, days, years, decades

→ infinite capacity

→ can have encoding, storage, and retrieval failures

the modal model of memory

predicts that LTM depends on STM

modal model of memory

sensory memory → short-term memory (STM) (rehearsal) → long-term memory (LTM)

implicit memory

non-declarative memory

explicit memory

declarative memory

implicit memory (non-declarative)

memory not available to your conscious awareness

explicit memory (declarative)

memory available to your conscious awareness

episodic memory

→ memory of events/ personal experiences

* tied to a specific time and place

episodic memory and the brain

→ hippocampus

→ medical temporal lobe (MTL)

→ important for processing context

Morris Water Maze

→ forms of spatial memory (episodic)

→ rats learn location of platform by encoding spatial cues in the environment

→ measure the amount of time it takes the rat to reach platform

* dependent on intact hippocampus

episodic memory recollection

recalling episodic memories relies on a distributed network of brain regions

→ includes hippocampus and MTL

semantic memory

general knowledge that is not tied to a specific time and place (facts)

semantic memory and the brain

→ rely on hippocampus and medial temporal lobe to form new semantic memories

→ anterior temporal cortex

* important for semantic memory

→ retrieval of semantic memories can be distributed throughout cerebral cortex

what is amnesia

→ refers to memory loss

→ most often associated with damage to the hippocampus and/or medial temporal lobe

anterograde amnesia

inability to form new explicit memories

retrograde amnesia

→ inability to remember previously learned explicit memories

* temporally graded
* tend to have better memory for events and knowledge learned early in life

amnesia: explicit vs implicit memory

→ amnesia is associated deficits in explicit memory

→ implicit memory is relatively spared

* can still learn through implicit memory

Henry Molaison

→ famous patient with anterograde amnesia

* also has some retrograde amnesia

→ spared:

* working memory/STM
* implicit memory

→ had seizures located in the hippocampus; had them surgically removed seizures were lessened, but he became amnesic

imaging the future

→ amnesia also have difficulty imagining the future

→ evolutionary, remembering our past can help us survive in the future

* learn from our past experiences
* predict what might occur in the future

dysexecutive amnesia

→ memory impairments that result from frontal lobe damage

* called “dysexecutive” amnesia because the frontal lobes perform higher-level “executive” functions

dysexecutive amnesia impairment

→ difficulty with strategic encoding and strategic retrieval

→ greater difficulty with recall than recognition

→ impaired memory for the temporal order of events

→ impaired working memory

source amnesia

forgetting the context

impaired metamemory

awareness of one’s own memory

confabulation

making things up to try to make sense of the situation

dysexecutive amnesia: impaired recall

→ recall is dependent on strategic, self guided retrieval process

→ frontal lobe damage makes strategic retrieval more difficult

→ but spared performance on recognition test when self-initiated retrieval is not needed

→ yet, lots of variability

korsakoff’s amnesia

type of dysexecutive amnesia

hebbian learning

→ “cells that fire together, wire together”

* when neuron A consistently and repeatedly excites neuron B, some metabolic changes or growth processes take place in either or both of the neurons that increase the efficiency of neuron A exciting neuron B

→ proposed by Daniel Hebb

habituation

a decreased response to a stimulus after repeated exposure

sensitization

an increased response to a stimulus after exposure to an intense stimulus

long-term potentiation

→ long term changes at the neuronal level that are involved in learning and memory

* increased responsiveness of a neuron
* due to synaptic changes

→ much still remains to be understood about LTP

→ learning is more complex than solely LTP

→ often studied in the hippocampus

→ high frequency stimulation of a neuron produces increased amplitude of EPSPs that lasts for hours or days

experimental induction of LTP

→ experimental set-up

* electrode to stimulate a presynaptic neuron
* electrode to record PSPs from a postsynaptic neuron

→ apply a high frequency burst of stimulation (tetanus) to the presynaptic neuron

→ after tetanus, apply normal stimulation and observe larger EPSPs in postsynaptic neuron

* these heightened EPSPs are evidence of LTP
* the synaptic connection has become stronger!

AMPA and NMDA receptors

ionotropic receptors