neural basis of learning and memory Flashcards
neural plasticity
- enables learning
- neural connections are formed, removed, remade continuously
- capacity of brain and neurons to change and adapt
developmental plasticity
- changes to brain occur more frequently in foetal stage
adaptive plasticity
- is not diminished with age
- adults continue to develop synapses as a result of stimulating experiences and changes in environment
long term potentiation
- increased tendency of a group of neurons to fire after being electrically stimulated in a particular electrical frequency (long lasting strengthening of synaptic connections, more effective synaptic transmission between neurons)
- because synapses between them has been strengthened due to previous firing to that frequency
- each time the same electrical frequency is administered, the same neurons ‘fire’ and synapses between them become stronger
effects of LTP
- increased release of the relevant neurotransmitter and less stimulation needed to release them
- increased receptor sensitivity (more receptor sites)
- more dendrites
long term depression
- frequency of electrical stimulation is reduced and can weaken an existing synapse
- role in clearing brain of old memories to make room for new learning
what happens after LTP
- creation of new neural pathways
- strengthening of existing ones
neural pathway
- bundle of myelin-covered neurons that provide a connection between one part of nervous system and the other
what happens when learning - synaptogenesis
- existing synapses are moulded or new synapses are formed
learning process
- terminal buttons of pre-synaptic neuron release glutamate into the synapse.
- neurons form new connections with each other
- the more a particular neural pathway is activated during learning, more likely it is to be strengthened and less likely the learning will be forgotten
glutamate
- excitatory neuron for learning
- release of dopamine, prompts growth of dendritic spines on post synaptic neuron, increasing its sensitivity to firing; thus increasing efficiency of neural pathways for learnt behaviour
2 types of glutamate receptors
- AMPA - activates post synaptic neuron
- NMDA - produces long lasting modifications on synapse
adrenalin and learning
- low amounts secreted within 30 seconds of learning consolidates learning
- thus, memories formed with emotional arousal have strength and are vital for survival
- too much adrenalin can be counterproductive to consolidation
pros and cons of adrenalin
- if hormone is present in bloodstream during a highly emotional event, it might enhance encoding
- helpful, learn to avoid dangerous situations
- problem, PTSD (victims suffer symptoms such as sleep deprivation and flashbacks of a traumatic event)
flashbulb memories
- detailed, vivid long lasting memories of important events
- affected by adrenalin because they are long lasting but not necessarily accurate
learning
- relatively permanent change in behaviour as a result of experience
3 ways of neural plasticity
- synaptic growth or pruning
- improved efficiency of neural transmission
- increased excitability of neurons
neurotransmitters
chemical messengers produced by neurons and released into a synaptic gap
neurohormones
chemical messengers released by neurons but released into bloodstream then carried to other neurons or cells
consolidation
- process of making new memories stable after learning (new information to durable long term memory)
adrenaline and consolidation
- release of adrenaline due to heightened emotional arousal
- adrenaline stimulates release of noradrenaline in amygdala, has a vital role in processing emotions
- presence of noradrenaline during consolidation causes the signal to hippocampus (consolidation of LTM) that the memory is significant and long term storage should be strengthened.
consolidation theory
- if consolidation is disrupted, new information may not transfer from STM to LTM
- vulnerable to disruption in first 30 mins of learning,
reconsolidation
when memory is retrieved and must be ‘re-established’
