Transcript Memory Dr J O`Donovan 22nd June 2012x

Disorders of memory made
simple
John O’Donovan
Functional anatomy of cognitive
functions
Distributed
• Consciousness
• Memory
• Higher order intellectual
functions, personality and
executive functioning
Focal
• Dominant versus non
dominant hemisphere
Attention
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•
•
•
ARAS
Thalamus
Hypothalamus
Multimodal association
cortex
• Right parietal cortex
Tests of attention
• Orientation
• Digit span
• Recitation of months of
year or days of weeks
• Words forwards and
backwards
• Serial 7s
• Remember, if attention
does not work then
neither does anything
else.
Memory
• Very messy-need to know it inside out.
• You will have questions on memory as it
covers psychology, neurology and psychiatry.
Episodic
Episodic
Semantic
Memory divisions
Explicit or declarative
• Available to conciousness
Implicit or procedural
• Not available to
consciousness
Explicit memory
Epidodic
• Personal events
• Autobiographical events
Semantic
• General knowledge
•
•
•
•
• Capital of France?
• Who wrote War and Peace?
• Distance from Exeter to
Plymouth?
Birthday last year?
First kiss?
First job?
What was on TV last night?
Memory divisions
Episodic
• Hippocampal formation
• Limbic system
• Diencephalic system: basal
forebrain and thalamus.
Semantic
• Temporal neocortex with
perhaps more verbal
semantic memory on left
and more visual semantic
memory on right.
Implicit
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•
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Motor skills
Basal ganglia
Cerebellum
Riding a bike, car, playing the piano, motor
skills.
Short versus long term memory
• Avoid the term short term memory, it’s a
mess.
• Think instead in terms of working memory
and long term memory.
• Simple concept of working memory,
remembering information for 5-30 minutes
• Working memory is better as a concept.
Working memory and loops
• Central executive probably based in frontal
lobes
• Phonological loop to verbal area in dominant
hemisphere and visuospatial loop to non
dominant loop
• Ongoing simultaneously and not completely
independent of long term memory
Retrograde and anterograde memory
• Retrograde: recall of previously learnt
material.
• Anterograde: acquisition of new memories.
Where is memory stored?
• Seems that verbal memory is dominant
hemisphere
• Seems that visual memory also known as
iconic memory is non dominant.
The amnesic syndrome
• Pure deficit in memory.
• All other areas more or less intact.
Amnesic syndrome
Acute and transient
• TGA
• Epilepsy
• Closed head injury
• Drugs
• Psychogenic
Chronic
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Hippocampal
Herpes simplex
Anoxia
Surgical resection of temporal lobes
Bilateral posterior cerebral artery
occlusion
Closed head injury
Alzheimer’s disease
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•
Diencephalic
Korsakoff’s
3rd ventricle tumours
SAH-ACAM anuerysm
Amnesic syndrome
• 1 generally preserved IQ.
• 2 preserved short term/working memory for
example digit span.
• 3 anterograde amnesia
• 4 retrograde amnesia which is generally more
severe in diencephalic amnesia
• 5 preserved procedural/implicit memory
Amnesic syndrome
Diencephalic
• Problems with encoding
• Problems with retrieval of
memory from long term
storage
Hippocampal
• The main problem is either
encoding or consolidation,
unlikely to be retrieval.
Memory MCQs
Semantic memory
• Is constantly acquired
• Is intact in Korsakoff’s
• Is intact in Alzheimer’s
Disease
• Is intact in semantic
dementia
• Non dominant temporal
lobe lesions can result in
prosopagnosia for famous
faces
Episodic memory
• Is impaired in Alzheimer’s.
• Is the same as
autobiographical memory.
• Is normal in poorly
controlled epilepsy
• Is intact in Korsakofff’s
• Is normal in psychogenic
fugue.
Memory MCQs
Implicit memory
• If brought into
consciousness, is then
explicit.
• Is affected by cerebellar
disease.
• Also has an
autobiographical element.
• Is intact in the amnesic
syndrome
• Cannot be tested
Short term memory
• Has a time limit of 30
minutes
• Is the same as working
memory
• Is intact in Korsakoff’s
• Is a term best avoided due
to imprecision.
• Is intact in Alzheimer’s
disease.