Lecture 10 - Learning and memory Flashcards
Define learning?
And adaptive process in which the tendency to perform a particular behaviour is changed by experience
- system tries to adapt to changes in environment
Experiences causes change physiological changes to nervous sytem
- circuits involved in perceiving, performing, thinking and planning are modified
Define long term potentiation
Involved in synpatic plasticity
- makes synapses more potent/ strengthens connections
- requires a combination of :
• membrane depolarisation
• activation of NMDA receptors (Ca2+ calcium(
What do learning theories focus on?
focus on acquisition processes
- how infor gets into the system
- influenced by distraction
- once info is in, we retrieve it
What do memory theories focus on>
focus on retention and retrieval processes, consolidation of info - how we get info back
What are the 4 types of learning?
- S-R learning
- motor learning
- perceptual learning
- Relational learning
- all linked to different areas of the brain
Outline SR learning
Connects perception/ stimulus to movement/ response, to anticipate stimulus
- can be automatic (reflex) or a complicated movement
- CC must regularly offuc prior to presentation of UCS and CS shouldnt regularly occur without UCS
- operant: Thorndike/ skinner, fruit loops maze thing - we learn via operating on our environment
What did Donald Hebb say/do?
he added a physiological basis to SR learning, argued learning involves:
• synaptic plasticity - changes in structure/ biochemicstry that changes how they effect post-synaptic neurons
WHAT FIRES TOGETHER, WIRES TOGETHER
What is Hebbs Rule?
If neuron A is active and trying to fire on neuron B, the connection could be strengthened via a plastic change. If Neuron B is receiving strong input from elsewhere (AP’s), it forms a better connection with neuron A as Neuron A is constantly there
- This explains condition/associative learning as neuron A becomes associated with the AP’s of Neuron B
What does Hebb therefore define memory as?
Change in synaptic strength/weight
What were Pavlov’s view of the physiology of learning?
CC reflected a strengthened connection between a brain area that represented cs and a brain area that represented UCS
What did Lashely (1929,1950) do?
Wanted to investigate CC in the brain, removed portions of rat brains. He found:
• More brain removed = more problems with learning
• Doesnt matter where ,always worse at learning
• cut through connecting fibers = gneralised locatlisation about which areas do what
Falsely concluded that:
- memories were widely/ evenly distributed across the brain
What did damage in animal studies prove?
Damage to Amygdala = no reinforcement/ conditioning
Damate to PFC = differences in goal directed behaviour which leads to reinforcement - struggle with behaviour that brins us towards a goal
What did animal studies with dopamine show?
it Induces synpatic plasticity by facilitating LTP
- does this in the nuclues accumbens, amygdala and PFC
- important for memory consolidation - expecting a reward
Amygdala is important for LTP - it is the physiological version of wiring then firing together
Define perceptual Learning
Result of changes in synaptic connections within SENSORY ASSOCIATION CORTEX
- connections are reinforced, so we know which 2 stimuli go together
- fMRI shows that memories of pictures, sounds, movements or spatial locations activate the appropriate areas of SAC
- sounds are in occiptal love - which then goes to inferior temporal and parietal lobe
What does dame to inferior temporal cortex do?
Problems in visual discrimination
which areas are important for CC?
Info between CS and UCS converges in LATERAL AMYGDALA
- high frequency stimulation to lateral amygdala leads to LTP
- blocking NMDA receptors here prevents CC
What areas apart from amygdala are important for CC
- Supplementary motor area (learning sequences of movements)
- Pre motor area - selecting movements to make in response to stimli
- Basal Ganglia - involved in automated responses - why there is no automated responses in parkinsons
- ventral Tegmental area - lots of dopamine here
Where does VTA project to?
• Amygdala/ lateral hypothalamus
- Neurons fire in response to stimuli capable of reinforcing behaviour or pleasurable things
- PFC - plans for movement, select movement/sequence/bodypart
- Nucleus accumbens - reinforces behaviour - addiction
In terms of perceptual learning, what did DAVIS & SQUIRE (1984) argue?
Argues that perceptual learning involves changes in brain chemistry. Found that when animals were trained:
• INcreased productino of chemicals (RNA)
• increased production of proteins
Outline SQUIRES MODEL (1987)
Info -> visual cortex -> prestriate cortex -> inferior temporal cortex
Outline Wernicke-Korsakoff syndrome
Extreme ANTEROGRADE amnesia (alcohol amnestic syndrome)
- Fixed n time, cant learn anything new, think youre still young
- OFten caused by alcohol (vitamin B1, Thiamine deficiency)
Caused by damage to:
• thalamus and mamillary bodies (hypothalamus - gets input from hippocampus via fornix)
- areas crucial for learning and memory
What are the symptoms of wernickes - korsakoff syndrome?
- Apathy, lack of insight, confusion, confabulation
* Disruption to front lobe functioning (reality checks)
Outline patient HM
had Severa anterograde amnesia - due to a bilateral removal of temporal lobes to treat epilepsy (including hippocampus)
• couldnt form new, but could remember old, like korsakoff
Outline DONALD WEBB (1949)
argued that no one mechanism could be rapid enough for immediate memory, but stable enough for permanent memory, argued there must be two things
