FINISH Neurobiology of learning, memory and cognition: memory

Question 1

Retrograde amnesia

Answer 1

Forgetting of events occurring prior to trauma e.g closed head injury/ electroconvulsive shock therapy

Question 2

Anterograde amnesia

Answer 2

Inability to retain in a permanent form new material: i.e an inability to learn

Question 3

Causes of amnesia (KAINE)

Answer 3

Anoxia, ischaemia, encephalitis, alcoholism & associated dietary insufficiency (Korsakoff’s syndrome), neurosurgery e.g to relieve epilepsy

Question 4

Alzheimers disease- regions affected

Answer 4

Amnesia is a prominent component

Neuropathology strikes especially hippocampus & entorhinal cortex (within parahippocampal gyrus) of temporal lobe

Question 5

Medial temporal lobe amnesia- patient HM

Unilateral lesions to R or L?

Answer 5

Received bilateral resection of his temporal lobes to relieve epilepsy.
Profound, polymodal anterograde amnesia for verbal & non-verbal material. However can hold a conversation, perform mental arithmetic, remember events from more distant past (a few years prior to op)

• severe recognition memory deficit as shown on performance matching to sample
• milder retrograde amnesia
• intact digit & spatial span and short term memory
• preserved IQ.
• sparing of procedural memory: can learn to draw in a mirror even though no recollection of daily sessions of testing.

Unilateral lesion limited to right: generally produce nonverbal memory deficits

Unilateral lesion limited to left: generally produce verbal memory deficits.

Question 6

Diencephalic amnesia: patient NA, Korsakoff’s

Answer 6

NA: lesion of mediodorsal nucleus of the thalamus. Developed anterograde amnesia

Korsakoff patients have damage to diencephalic structures, including Papez’s circuit. Show anterograde amnesia (NB but also greater degree of retrograde amnesia than HM)

Sparing of procedural memory: learn perceptual skill of mirror reading as rapidly as controls, but are impaired at remembering what words they read. NB contrast Huntington’s Disease: impaired at developing mirror reading skill but perform better on word recognition.

Question 7

Papez’s circuit

Answer 7

Cortex -> Hippocampus -> via fornix -> Mammillary body -> Thalamus -> Cortex

Question 8

Damage to the posterior cortex, generally temporal-parietal junction.

Answer 8

Selective deficit in intermediate memory, shown by deficient memory span. However are able to consolidate info into LTM- not anterograde amnesiacs
Often conduction aphasiacs.
May involve a specific type of STM that evolved to allow us to follow conversations?

Question 9

Agnosias

Answer 9

Higher level sensory deficits

Question 10

Movement agnosia

Answer 10

Subject cannot ‘see’ movement

Question 11

Prosopagnosia

Answer 11

Subject cannot recognise faces

Question 12

Associative agnosia

Answer 12

Type of visual agnosia
Patient cannot recognise, name, or use objects appropriately. But can identify objects by selecting correct drawing, and can draw object accurately

Question 13

Apperceptive agnosia

Answer 13

Type of visual agnosia
Patient can name an object is appropriate perceptual cues are present but cannot draw object. Also impaired at ‘naming’ object if presented if presented in unusual view.

Question 14

Declarative vs procedural memory systems

Definitions?
Brain regions implicated?

Answer 14

Squire suggests that pattern of memory loss for anterograde amnesiacs gives evidence for distinction.

Declarative: facts, events. Suggested to have evolved more recently, depend on e.g temporal lone & diencephalon.

Procedural: knowledge gained through performance, Skill, habits, priming, conditioning etc. Brain systems less well defined, may include basal ganglia, cerebellum.