9d. Navigating in Space and Time Flashcards
Retrograde Amnesia
Forgetting events prior to the trauma
Anterograde Amnesia
Forgetting events after the trauma and an inability to retain new information
Immediate memory
Seconds
Reflects the electrical activity of the neurone and its neurotransmitter release
Short Term Memory
- Limited capacity
- Short duration
Short Term Memory
- 2 Types
- Working memory, allows manipulation and re-organisation of information, important for reasoning and the guidance of decision making and behaviour
- Short term memory, which is information storage and does not entail manipulation or re-organisation
Delayed Match to Sample Test
- Description
Assesses working and short term memory.
Evaluates capacity to act on the basis of stored information rather than that available to them at the time.
Food morsel is shown to the monkey being hidden under one of 2 plates. After a variable delay the monkey must choose where the food is location to get the food reward.
Task is very familiar due to repetition.
Delayed Match to Sample Test
- Lesion
Prefrontal cortex lesions impair performance.
Delayed Matching to Sample Test
- 2 Measures
0-delay performance
- no delay so minimal requirements on memory
Performance half-life
- Delay for which performance has fallen halfway between 0 delay performance and chance
Declarative Memories
- Neural Location
Medial temporal lobe of diencephalon
Declarative Memories
- Episodic LTM
Recall of events you can remember
- Getting married
Declarative Memories
- Semantic LTM
Memories that we know are facts but cannot remember happening
- Being born
Declarative Memories
- 2 Types
- Episodic memory
- Semantic memory
Non-Declarative Memory
- Procedural skills and habits
- Priming and perceptual learning
- Simple classical conditioning
- Non-associative learning
Simple Classical Conditioning
- 2 Response Types
- Emotional responses via amygdala
- Skeletal responses via cerebellum
HM
- Lesion
- Results
Medial temporal lobe resection for epilepsy
Damage:
- Severe anterograde amnesia for declarative memory
- Mild retrograde amnesia
- Impaired short term memory = poor DMST scores
- Reduces seizure frequency
Not Damaged:
- Learn new writing skills
- Eyeblink and emotional conditioning
- IQ
NA
- Lesion
Medial diencephalon including the mediodorsal nucleus of the thalamus, mamillary bodies and mamillothalamic tract
Damage:
- Severe anterograde amnesia for declarative memory
Anterograde Amnesia
- Locations of Damage
- Hippocampus
- Mammillary bodies
- Anterior thalamic nucleus
Medial Temporal Lobe Lesions
- Impaired recognition memory
- Intact skill learning
- Mild retrograde amnesia
Measuring Recognition Memory
Delayed Non-Match to Sample test (DNMS)
Animal presented with a non-familial object
Then presented with this object and a novel object, and was rewarded if they chose the novel object, indicating that it knew which object was familiar.
Measuring Skill learning
Lifesave motor-skill tast
Retrieve a sweet from a bent stick
Excitotoxin
IBO
Spare passing axons but kills cell bodies
Lesions Impairing Recognition Memory
Rhinal cortices
- Perirhinal
- Entorhinal
Amygdala Damage
- Emotion
- Emotionless
Place Cells
Hippocampal cells whose firing increases when in a particular location in its environment
Hippocampus
- Roles
- Spatial mapping
- Scene coding
- Contextual conditioning
Morris Water Maze
Submerged, hidden platform
Morris Water Maze
- Block Learning
- Hippocampal lesions
- Rats with hippocampal lesions cannot learn the location of a hidden, submerged platform, failing to take advantage of the spatial cues.
- If a single spatial cue is present in front of the platform the rat can swim towards it
- Glutamate NMDA receptor antagonist AP-5, which blocks LTP
Declarative Memory Inhibition
Hippocampal lesions
Hippocampus
- Trisynaptic Circuit
- Cortex
- Rhinal cortices, particularly the entorhinal cortex
- Dentate gyrus via perforant pathway
- Hippocamus CA3 via mossy fibre pathway
- Hippocampus CA1 via Schaffer collateral pathway
