Neuroscience of Memory Flashcards
What is learning?
It is the acquisition of knowledge or skills
as a result of experiences and consequently it can alter behaviour on the basis of this experiences
What is memory?
Mechanism for storing what is learned
What are the different types of learning?
Non-associative and associative
What are the two types of non-associative learning?
Habituation and sensitisation
What are the two types of associative learning?
Classic conditioning and operant conditioning
What is non-associative learning?
The subject learns whether to ignore or react to a certain stimulus.
It is a simple way of learning that does not need to associate two stimuli
What is habituation?
Gradual decrease in the response to stimulus when it is frequently repeated. It is simple and widespread
What is the biology of habituation
Seminal work in a sea slug (Aplysia). There is a siphon withdrawal reflex
What is siphon withdrawal reflex?
Repeated stimulation results in long-lasting habituation for several weeks
Who looked at the biology of habituation?
Eric Kandel
What is habituation caused by?
Changes in synapse between the sensory cell and the motor neuron
What is the response for long term habituation?
No response
What is the response for short term habituation?
Gill withdrawal
What is sensitisation?
It is a potentiation in the response to stimulus
(painful or pleasant).
It is simple and widespread.
Heightened awareness to a stimulus or class of stimuli for a period of time.
What is biology of sensitisation?
Shock to tail results in sensitisation of gill withdrawal. Modulatory neurone increases synaptic transmission of the sensory neurone onto the motor neurone
Is habituation specific or general?
Specific to a particular stimulus and response
Is sensitisation specific or general?
General to a variety of stimuli and response and to a particular brain circuit
What does habituation result in?
Decreased response magnitude
What does sensitisation result in?
Increased response magnitude
What does sensitisation do to circuits?
Heightens response
When does habituation occur?
Occurs after repetition
When does sensitisation occur?
Occur after a single instance
What is associative learning?
The subject learns about the relationship that can associate one stimulus to another
What does a conditioned process result in?
The formation of learned responses called conditioned reflexes
What is a conditioned reflex?
Automatic response to a stimulus (conditioned stimulus) which did not previously evoke response
acquired by repeatedly associating this stimulus with another stimulus (unconditioned stimulus)
What did Pavlov find in classic conditioning?
He noticed that his experimental dogs salivate just on seeing the animal house keeper who used to feed them
What is a unconditioned stimulus?
A stimulus that does not require learning to
yield a response
What is a conditioned stimulus?
A stimulus that requires associative learning
with a US to yield a response
What brain regions is involved in classical conditioning?
Amygdala and cerebellum
What is operant conditioning?
Subject is taught to perform some voluntary action in response to a particular stimulus that alert them to perform the learned action in order to obtain reward to avoid punishment
What is the alerting signal?
Conditioned stimulus
What is the pleasant/unpleasant event?
Unconditioned stimulus
What is the mechanism of conditioning?
Short-term learning involves changes in synaptic efficiency. Increase in transmitter release, increase in receptor density, or both/ Leads to changes in interneuron modulation, changes through synapse formation, change through synaptic plasticity
What is memory?
The process by which knowledge of the
world is encoded, stored, and later retrieved (Kandel,
2000). It is the ability of the brain to store information and recall it at later time
What are the memory processes?
Encoding, storage, retrieval
What is encoding?
The input of information into the memory system.
What is storage?
The retention of the encoded information.
What is retrieval?
Getting the information out of memory and back into awareness.
What is the simple model of memory?
Sensory information, short term memory and consolidation to get to the long term memory
What is the short term memory?
Immediate memory for events, which may or may
not be consolidated into long-term memory.
What are the brain regions involved in short term memory?
Sensorimotor and prefrontal cortex
What is consolidation?
Process by which short term memories are converted into long-term memories.
What is the long term memory?
Relatively stable memory of events that occurred in the more distant past.
What is the duration of the short term memory?
Seconds to minutes
What is the duration of the long term memory?
Hours to years
What is the digit span?
Capacity, 7+/-2
What is the working memory?
Overlap between the short term memory, attention, intelligence
What are the components of the Baddeley-Hitch multicomponent model?
Visuo spatial sketch pad, central executive, phonological loop
What is the visuo spatial sketch pad?
Storage of visual and spatial information
What is the central executive?
Maintenance, manipulation, forgetting
What is the phonological loop?
Storage of verbal information
What are the two types of long term memory?
Explicit (declarative) and implicit (non-declarative)
Is semantic and episodic explicit or implicit?
Explicit
What brain regions are involved in episodic memory?
Hippocampus, medial temporal lobe and neocortex
What brain regions are involved in semantic memory?
Lateral and anterior temporal cortex, prefrontal cortex
Is procedural and priming explicit or implicit?
Implicit
Where is the procedural memory?
Cerebellum and the striatum
Where is priming in the brain?
Neocortex
What is the delayed match to sample task?
A test of declarative memory where the response of a neurone in the prefrontal cortex during a delayed match to sample task
What is the stages for long term memory?
- There is an external stimulus
- Activation of the cell assembly by stimulus
- Reverberating activity continues activation after the stimulus is removed
- Hebbian modification strengthens reciprocal connection between neurones that are active at the same time
- Strengthened connections of the cell assembly contain the engram for the stimulus
What does memory involve?
The same regions that are involved in processing the stimulus, strengthening the association between neurones of the memory trace
What occurs when the strengthening association between neurones occurs?
Full activation
What happened with Clive Wearing?
Bilateral damage leads to profound anterograde amnesia
What happened with HM?
Had epilepsy and became intractable so had bilateral medial temporal lobe resections/ Developed anterograde amnesia.
What is amnesia?
Amnesia is a severe impairment of memory, usually as result of accident or disease
What are the two types of amnesia?
Retrograde and anterograde
What is retrograde amnesia?
Memory loss of events prior
to the amnesia, able to form new memories after
What is anterograde amnesia?
Inability to form new
memories after the onset of the amnesia
What happened to HM after his surgery?
- Good retrograde semantic memory
- Cannot recall events that have just happened
- Cannot recall any new facts
- Cannot remember new faces
- Showed a clear dissociation between fully intact perception and cognition
versus severely impaired memory
What is the hippocampus important for?
Formation of new
episodic memories, encoding perceptual
aspects of memories, novel events, places, and stimuli
What long term memory did HM’s surgery not effect?
Procedural and some implicit
What was NA missing (Squire, 1989)
Thalamus and mamillary body
What memory was effected in NA?
Semantic and episodic memory (particularly verbal episodic)
What amnesia did NA have?
Profound anterograde
What is Korsakoff’s syndrome?
A memory deficiency caused by lack of thiamine, seen in chronic alcoholism.
What is confabulating?
Done in Korsakoff’s syndrome where they fill in a gap in memory with a falsification that they accept as true
What happened to patient K.C?
Damage to the cortex and shrinkage of the hippocampus and parahippocampal cortex
What effects did the damage have on K.C?
Cannot retrieve episodic memory
What was found in London taxi drivers?
Larger hippocampus due to them having to memorise the routes of london (Maguire et al)
What was found in people in Alzheimer’s?
Hippocampus degenerates explaining the core dementia symptoms such as getting lost in familiar places
What does early work indicate in animals?
They form a cognitive map
What occurs in the place cells of the hippocampus?
They become active when an animal is in or moving towards a location
When do grid cells fire?
When an animal crosses intersection points of an abstract gri
What happens during the firing of entorhinal border cells?
Arrival at the perimeter of a spatial map is signalled
