learning and memory 1

learning

acquisition of new knowledge or skills

adaptive

memory

retention of learned information

linked to storage and retrieval

types of memory and definition

• declarative (explicit)

  • facts and events

• non-declarative (implicit)

  • procedural skills/habits

  • associative → conditioned response

what did karl lashey do

roduced lesions of specific regions of brains to examine how they affected performance in learning and memory tasks

hippocampus stores what type of memory

stores explicit, declarative memory

cerebellum and basal ganglia and memory

implicit, non-declarative → procedural memory

amygdala and memory

emotional responses

prefrontal cortex and neocortex and memory

involved in short term and long term explicit memory

what is the hippocampus part of

limbic system

place field and memory

• place cells in hippocampus

• fire high rate when animal is in a specific location in the environment

• important for cognitive maps

cognitive maps

• internal neural representation of the landscape of which an animal travels

• formed by birds and mammals

taxi drivers and hippocampus

• more year in job, greater the grey matter in the hippocampus

• grey matter associated with spatial knowledge

short term memory characteristics

• last for seconds to hours

• repetition improves retention

• limited capacity

• labile

• does not require new rna or protein synthesis

labile

sensitive to disruption

working memory

• hold information in mind by repetition

  • limited capacity

  • doesnt last long

  • refers to maintenance and manipulation of information

    • retains information to use it

    • eg remembering number until you need to write it down

long term memory

• lasts for days to years

• unlimited capacity

• consolidated - insensitive to disruption

• does require new RNA or protein synthesis

stages of memory

1. brain receives sensory stimulus

2. encoding - brain stores information, acoustic coding for short term, visually and acoustically for long term

3. storage - brain retains information

4. retrieval - long term is association whereas short term is sequential

5. brain utilises information

hebb idea of activity dependent synaptic plasticity

• neurons that fire together wire together

long term potentiation

persistent increase in strength of synapses following high frequency stimulation of chemical synapse

induction of LTP

• artificial

• high frequency stimulation shows increase in excitatory postsynaptic potential

• there has to be titanic stimulation → brief bursts of high frequency stimulation

receptors involved in LTP mechanisms

• AMPA receptors - requiring glutamate for Na + influx

• NMDA receptors requiring glutamta and glycine and depolarisation to open for Na+ and Ca+ influx

effects from long term potentiation

• inc neurotransmitter vesicles

• inc dendritic area and spines

• long lastic increase in synaptic transmission

long term depression

long lasting decrease in efficiency of synaptic transmission, specifically transmission that is mediated by AMPA receptors

when does LTP occur

synaptic transmission occurring at the same time as strong depolarisation of the postsynaptic neuron causes LTP of the active synapses

when does LTD occur

synaptic transmission occurring at the same time as weak depolarisation of the postsynaptic neuron causes LTD of the active synapses

amnesia

• loss of memories

• due to trauma, concussion, alcoholism, tumours

• tranisent or permanent

anterograde amnesia

• difficulty in learning new period

retrograde amnesia

difficulty in remembering past information

dementia

• group of symptoms affecting memory , thinking and social abilities

• alzheimers disease is most common cause of dementia

  • most recent memories go first

• progressive - symptoms get worse over time

alzheimers disease

presence of intracellular neurofibrillary tangles and accumulation of extracellular beta-amyloid plaques

vascular dementia

• develop after stroke or anything that decreases blood circulation such as diabetes high blood pressure

• second most common cause of dementia

• includes problems with memory reasoning planning or judgement

treatment of dementia

• focuses on managing health conditions and risk factors that contribute eg meds that reduce blood pressure

  • this could slow down the rate of decline