5- Declarative Long-Term Memory Flashcards
What does declarative memory need?
Conscious effort
How did Lashley investigate brain areas storing D-LTM?
Lesion study of rats in a maze
What was done to the rats in Lashley’s study?
Trained to run through a maze
What did lesions to rats create (Lashley)?
Mistakes
What was the volume of the lesion correlated with (Lashley)?
Performance loss
What were mistakes dependent on, and what were they not? (Lashley)
How large the lesion was, not where the lesion was
What did Lashley’s study show?
Brain areas are equipotential (having the same potential) in storing memory
How were humans studied for investigating areas involved in D-LTM?
Follow up in patients after surgery (different amounts of brain areas removed)
What was a poor surgery outcome determined by instead of what?
Majorly predicted by seizure recurrence and contralateral abnormalities rather than size or side of surgery
How did human studies contradict Lashley’s principle?
Shows it is to do with connectivity and functionality, not amount of brain we have
What does maze running involve?
Sensory memory of many senses that all contribute to performance
What were Lashley’s 3 conclusions?
Memory is-
1. Widely distributed
2. Not unitary and different types rely on different brain structures
3. Likely stored in brain areas involved in original sensory processing
What brain area does visual memory contain?
Higher visual cortex
What 2 pathways are involved in visual memory?
‘Where’ and ‘what’ pathways
What brain area involves the ‘where’ pathway?
Intraparietal sulcus
What brain area involves the ‘what’ pathway?
Inferior temporal cortex
What was found in inferior temporal cortexes of visual memory in monkeys?
Different neurons in this area associated with different faces
When do certain neurons spike more frequently in monkey visual memories?
For repeated presentations of certain faces- neurons can be tuned to a certain face
What are inferior temporal cortex neuron spiking a correlate of?
Visual memory trace
What brain area stores visual memory?
Inferior temporal cortex
What do fMRIs of expertise in recognition show in humans?
Experts in specific recognition show stronger activity in IT in response to expertise
What part of the hippocampus is particularly associated with spatial memory?
Parahippocampal gyrus
When was spatial memory investigated in mice?
In the radial arm maze and Morris’ water maze
Why is the water maze task showing spatial + episodic memory?
The mouse must remember location and event
What prevents performance in Morris’ water maze?
Hippocampal lesion
What is shown by Morris’ water maze?
Experience-based spatial memory relies on the hippocampus
What are place cells?
Hippocampal neurons that spike when in a location that has been previously explored
What are grid cells?
Spatial correspondence between place cells
How do London taxi drivers demonstrate the role of the hippocampus in human spatial memory?
Larger posterior part of hippocampus- volumetric hippocampus changes correlate with time spent driving taxi
What did studying brains of London taxi drivers show?
Hippocampus is involved in spatial memory- place cells are encoded and retrieved in the Parahippocampal gyrus
What is episodic memory?
Memory for events and their context
How was the hippocampus shown to be involved in episodic memory?
Stronger hippocampus and parahippocampal gyrus activity was shown when context of studied material is recollected correctly
What type of amnesia did HM have and what did this mean?
Anterograde amnesia- he was unable to store any new episodic memories and hardly any new semantic long-term memories
What parts of HM’s memory were intact?
His procedural memory and STM
What did research on HM show?
The hippocampus is involved in acquiring rather than storing memory
Lesions to which part of the brain cause Korsakoff’s syndrome?
The thalamus
3 potential causes of Korsakoff’s syndrome
- Thiamin deficiency from alcohol abuse
- Anorexia/overly-stringent dieting
- Physical health- AIDS, kidney dialysis, chronic infection
How does Korsakoff’s syndrome show us that the thalamus is involved in memory?
There is anterograde and retrograde amnesia seen in the disorder
What is intact in Korsakoff’s syndrome?
Procedural memory
What are concept cells?
Clusters of neurons working together to encode a concept
How are memory entries stored in concept cells?
By a single neuron
How do certain neurons fire in the hippocampus that means concept cells are useful?
Exclusively + invariantly in response to a stimulus
What are super-concepts?
Association between one type of stimulus and another/more conceptually similar means associations between response
What is an example of a super concept?
‘Jennifer Aniston neuron’ also responds to Lisa Kudrow- recognises Friends concept
What is vulnerability like in concept cells?
Loss of this cell does not cause loss of concept
How is complexity of concept cells shown?
Diverse aspects of memory cannot be coded for by a single cell alone
How are memory entries stored in distributed representation?
By distributed networks of many neurons
What is sparse distributed coding?
Modelling our brain using biologically inspired artificial neural networks
What is created by sparse distributed coding?
Invariant response of concept neurons and multimodal recognition
What is shown by sparse distributed coding?
Memories are coded by relatively sparsely distributed neuronal networks/assemblies
How are memories stored in distributed networks set up?
By simultaneous activation during learning
What can be the effect of assembly partial activation?
Reactivating the whole assembly
Where are semantic memories stored?
The inferior temporal and parietal cortex
Where are episodic memories stored?
The hippocampus and the thalamus
How is declarative LTM stored and how is this strengthened?
In sparsely distributed representations and strengthened through Hebbian modification
