Flashcards in Week 11 - Memory and learning - finished Deck (31):
The acquisition of new knowledge.
The perception of an association between ourselves and our environment or between various elements of our environment.
Retention of learned information.
Adaptation of our brain circuitry to interact with our environment.
Allows us to respond appropriately, as quickly as possible, by anticipating outcomes.
What are the 2 systems of learning? What types of information as applied to each of these systems?
Implicit and Explicit
What is declarative learning?
Recall is deliberate and usually has to do about people, places and things.
It can be easily stored and is easily forgotten.
Classified as either semantic or episodic
What kind of information is classified in episodic declarative learning?
The recall of events and personal experience
What kind of information is classified in semantic declarative learning?
The recall of facts and objective knowledge
What is declarative working memory? When is it used? How is that space used? (is it always full?)
The working memory is perpetually used.
It stores many memories at once in multiple areas of the brain so that we aren't consciously aware of everything.
Long term memories can be brought into the working memory as required, but are then returned to the long term memory.
The space allocated to working memory is recycled as soon as we turn our attention to something else.
Are all working memories stored in the long term memory?
Working memories aren't automatically consolidated into the long term memory, but can be stored in the short term memory with repetition, and the consolidated to the long term memory
How many items can the average person hold in the short term memory at once?
How can the volume of the short term memory be increased temporarily?
By chunking or categorising the information.
How does information get consolidated from the short term memory to the long term memory? Does this vary between people?
It undergoes sufficient repetition, although, 'sufficient' repetition varies highly between people.
Is the long term memory limited in its capacity?
How are some better at their long term memory than others? (those special few)
They consolidate information directly to the long term memory without the need for repetition in the short term memory.
How are memories stored?
What does this mean when parts of the cortex are damaged?
'Cells that fire together wire together"
Memory is fragmented:
Stimulation of high order visual association cortex: patient sees things, faces or experiences
Stimulation of high order auditory association cortex: patient hears things, re-experiences conversations
The same cells that allow us to experience or perceive sensations record our experiences of them via interconnections to the cells that were simultaneously active perceiving other elements of our experience
Damage to the cortex typically only effects fragments of memories
What are the 2 types of non-declarative/ procedural learning?
What is associative learning?
Is timing important?
What are the 2 types?
The subject learns about the relationship between two stimuli or a behaviour and its consequence
The temporal/timing relationship between the two stimuli is critical
- Classical conditioning
What is non-associative learning?
Is timing important?
What are the 2 types?
The subject learns about the properties of a single stimulus. Subjects learn about the properties of a single stimulus so that repeated administration of the same stimulus results in a different response
The timing of the stimulus is inconsequential
What is operant associative learning? E.g.?
Trial and error: spontaneous behaviour which occurs in the first instance without identifiable stimulus
Rat in a cage. Accidentally pulls lever. Food drops. Will repeat.
What is classical conditioning? What type of learning is it? E.g.?
It is procedural/non-delcarative associative learning
Learning to associate two stimuli
Unconditioned stimulus (US)
typically evokes a strong response in subject without training, this will become the learned response to the conditioned stimulus.
Pavlov’s dog: US = meat
Conditioned stimulus (CS)
typically evokes a weak response in subject which is not related to the response which will be learned
Pavlov’s dog: CS = bell
repeatedly ring bell & present the dog with meat ie. Train the dog to associate the two stimuli
dog has learned to associate the two stimuli…ring bell, withhold meat….dog still salivates
What is extinction in terms of classical conditioning?
Extinction is the undoing of classical conditioning
- Withhold US
- Results in no response to CS
What is Habituation?
A decrease in a response to a benign stimulus when repeatedly applied.
E.g. when you first hear fireworks they might be scary but if you hear them a few times they don't provoke the same scary response because you have been conditioned to recognise that they are not threatening.
What is the physiological process involved in habituation?
This is the depression of the synaptic transmission through the reduction of neurotransmitter released from the input neuron. This requires presynaptic modification.
The presynaptic membrane ion channels are inactivated by:
- a decreased ability to mobilise synaptic vesicles into active zones.
- a decreased ability to release neurotransmitters.
Is habituation short or long term typically?
Short term and usually only lasts for a few minutes after the stimulus is withdrawn
How does long term habituation occur? What is the physiological process that happens?
It happens after long term exposure to a stimulus and results in long term changes to the synapse.
This happens by:
- a decrease in the number of synapses due to a withdrawal of axons
- a decrease in active zones in the remaining synapses
What is sensitisation?
What is the physiological process that happens here?
An increase in the response to various stimuli following the application of an intense or noxious stimulus.
e.g. a person is habituated to fireworks and then sounds really loud and hurts them, the next time the sound of fireworks will cause an increased response to them.
The process is:
- Serotonin release
- Acts on G protein coupled receptors
- Activates 2nd messenger cascade
- Prolongs the presynaptic action potential
- Increases the ability to mobilise synaptic vesicles into active zones
- Increases ability to release neurotransmitter
- Generates larger postsynaptic potential
What are the physiological changes that occur with long term sensitisation?
Increased number of synapses
Increased number of dendrites on the post synaptic neuron
Increased number of active zones on the presynaptic neuron to allow greater mobilisation of vesicles.
What is retrograde amnesia?
The memory loss and resultant incapacity with retrograde amnesia tends to be relatively minor
Memory appears to be stored in multiple areas of the brain
Believed to be stored in higher order association cortices
Semantic memories of a particular stimulus appear to be fragmented and stored in relevant cortices eg. Kluver – Bucy syndrome
Episodic memories appear to be stored in prefrontal cortex
What is anterograde amnesia? Where does the damage usually occur?
What is it associated with lesions of? Name 3
Tends to be due to damage to much smaller area of cerebrum
Deficit tends to be much more incapacitating
Associated with lesions of:
Hippocampus - needs to be bilateral - mild deficit
Perirhinal cortex - most profound deficit
Enterorhinal cortex - first area affected by Alzheimer’s
Mamillary bodies - mild deficit
Medial thalamus - major deficit
- anterior nucleus
- dorsomedial nuclei
- any one of these nuclei gives milder but still significant deficit
What is the role of the hippocampus in memories? How does it differ between the sides? (dominant or non dominant)
Appears critical in the consolidation of declarative memories
We may be able to consciously increase its function (basal nuclei of the amygdala)
Function appears to be slightly different from dominant to non-dominant sides or left to right, it is not clear which at this stage
Appears to vary but one appears to have a greater function in verbal memory and one appears to play a large role in spatial orientation
What types of memory the hippocampus NOT important in?
Memory not stored here