learning and memory

topic 5

limbic system

a system involving connections that relate to learning, motivtaion and emotions

what is learning - psychology

a relatively permanent change in behaviour that occurs as a result of experience

what is learning - neuroscience

the response of the brain to environmental events/experiences and involves adaptive changes in synaptic connectivity, which in turn alters behaviour (plasticity)

innate responses

reflexes (single set of muscles, e.g. patellar), taxes (entire body movement e.g. phototaxis), instincts (FAPs e.g. food begging)

limitations of innate responses

• stimulus must be present

• behaviour is fixed, little trial and error learning

• any change is slow, over generations

types of learning

non-associative → learning that stimuli exist in the world

associative → classical and operant

classical conditioning

acquisition (pairing of CS and US to create CR), extinction (from a loss of contiguity), spontaneous recovery, reacquisition, generalisation, discrimination

summary of CC

• adapt to environment

• ontogenetic adaptation

• ubiquitous, and preserved by evolution

CC example

little albert

operant conditioning

associations between actions and their consequences

Thorndike’s laws of learning (OC)

• law of effect - positive consequence, higher freq

• law of exercise - connections strengthened by repetition

• law of readiness - learning motivated by internal state

OC example

Skinner - reinforcers

schedules of reinforcement

continuous - each behaviour response is reinforced each time

partial - only reinforced part of the time

fixed and variable ratio schedules

fixed and variable interval schedules

taxonomies of memory

declarative - explicit, semantic or episodic

non-declarative - implicit, procedural

principle of equipotentiality

all cortical regions can mediate learning equally

principle of mass action

ability to learn is proportional to the amount of cortex available

memory storage areas of brain

hippocampus → declarative and spatial memories

cerebellum → procedural memories

amygdala → emotional memories

frontal cortex → short term/working memory

structural basis of memory

Cajal proposed that new structural/morphological changes store memories - e.g. formation of new synapses, growth of dendritic processes

cellular/synaptic basis of memory

synapses generated and modified to store memories

synapse generation

happens continuously. not a part of a memory network, but can be strengthened to be incorporated into it.

Hebbian synapse

cells that fire together wire together (LTP)

hippocampus

where most research on synaptic connections occurs