Semantic memory Flashcards
What do list learning tasks measure
Encoding abilities [episodic memory]
What do recall tasks measure
consolidation and retention of novel information and retrieval abilities
WHere does memory retention happen?
MTL
Where does memory retrieval happen?
FL
What do recognition tasks measure
retrieval abilities
Describe dissociation between recall and recognition
low recall + low recognition - retention is impaired, doesn’t tell you if retrieval is impaired
low recall + high recognition - retention good, retrieval is impaired - if you put in support system will be able to find information
Describe associate agnosia
can draw a teapot but won’t know what it is - can’t recognise it [held in different parts of brain - like Wernicke’s and Broca’s Aphasia]
What is neuroanatomy of semantic dementia
bilateral degeneration / atrophy of brain regions housing semantic memory - inferolateral and anterior temporal lobes
What part of brain is first affected in semantic dementia?
lateral temporal lobes
What is spread of semantic dementia
inferolateral / anterior temporal lobes –> ventromedial frontal lobes
What is effect of SD on normal working memory [Verbal and NV]?
None
What is effect of SD on anterograde episodic memory [Verbal and non-V]
None
What is effect of SD on retrogrrade episodic memory?
may be poor
- reverse temporal gradient
- long established life events may be similar to semantic info
Describe phonology and syntax in semantic dementia
preserved
Describe topographical, visuo-spatial deficits and organisation skills in SD
None
What is most common initial deficit in SD?
anomia [can’t find correct word for object]
What follows anomia in SD?
impaired word comprehension [language becomes impoverished]
- paraphasias [‘chair’ for table]
- circumlocutions
- omissions
Describe category dissociation in SD
- can have loss of knowledge in discrete category of semantic memory [eg numbers, body parts, natural objecs]
- not due to continuum of difficulty
Describe modality dissociation in SD
can have impaired semantics in verbal modality but intact semantics in visual [and vice versa]
How do you assess semantic memory?
word definitions
picture drawing
picture naming
word-picture matching
What did Tulving say about episodic - semantic dissociation
double dissociation between episodic and semantic isn’t possible; only single dissociations [impaired episodic and preserved semantic] can occur
How does semantic dementia question Tulving’s hypothesis?
Episodic memory still functioning when semantic isn’t
What did Graham’s test say about SD patients cf AD patients on perceptually identical / different objects?
SD: poorer naming than AD
SD no different to controls on PI items but worse on PD [PI - episodic memory encoding and retention; PD - semantic]
AD poorer than SD on PI and PD, no difference btwn PI and PD
What did Graham’s test say about Tulving’s hypothesis?
Disproves it [though still best we have]. Episodic memory only became impaired if relying on semantic memory.
What supports double dissociation btwn episodic and semantic encoding?
Varga-Khadem’s children; semantic demntia
What are the three autobiographical / remote amnesic states?
temporal gradient
reverse temporal gradient
no temporal gradient
Where are remote [non autobiographical] memories stored?
frontal and temporal neocortex, diencephalon
