Episodic & semantic memory

Question 1

Amnesia is characterised by intact ___

Answer 1

IQ

Question 2

Clive wearing & patient KC show impaired episodic & semantic memory encoding & impaired ___ retrieval but intact ___ retrieval. One explanation for intact SM retrieval is that SMs are encoded ___ & so become ___ than EMs which are encoded only once. Does this explanation stand up to testing?

Answer 2

Episodic. Semantic. Repeatedly. Stronger. No, because whilst KC recalls the difference between stalagmites and stalactites (a weak SM), he cannot recall a huge, toxic train crash which occurred during his lifetime (an EM which would have been strong)

Question 3

Given Vargha-Khadem’s (1997) findings, is there any evidence that amnesic patient KC can encode new semantic memories but not new episodic memories? (Tulving, 2002)

Answer 3

Yes, patient KC shows very slow but sure semantic learning & not episodic learning e.g. he could gradually learn absurd definitions but not encode his visits to the lab into memory (note retrieval is a confounding V), despite the same frequency of exposure

Question 4

Semantic dementia is characterised (unlike amnesia caused by hippocampus lesions) by…

Answer 4

1) SM retrieval impairments e.g. picture naming, description naming, picture/ word matching & describing picture/ word properties, 2) intact EM or specifically autobiographical memory retrieval & 3) intact WM & problem-solving

Question 5

What does SM vs. EM require at cognitive and neural levels?

Answer 5

To extract generalities vs. remember specifics. Neocortex vs. hippocampus

Question 6

What is the evidence for content-specific EM stores? (Milner, 1971)

Answer 6

LH lesions impair verbal EM more than visual EM
RH lesions impair visual EM more than verbal EM
E.g. Did I show or say this to you recently?

Question 7

Give 4 e.g.s of spared vs. impaired content-specific SMs which suggest that SMs may be stored in a content-specific manner

Answer 7

In semantic dementia: remembering 1) living vs. non-living items, 2) fruit/ veg vs. animals & 3) tools/ actions vs. objects not used to act upon other objects
4) Agnosia (losing object but not vocab knowledge), alexias (losing regular rules but not stores of irregular past tense forms)

Question 8

What evidence suggests that episodic memories are not only/ always dependent on the MTL? What is the semantic dementia parallel of this finding?

Answer 8

1) The amnesic temporal gradient (older EMs are more likely to be recalled after a MTL lesion). Recall could be verified against his patient PZ’s written biography :)
2) The reverse temporal gradient in semantic dementia (SMs are more likely to be recalled with age)

Question 9

Maguire (2000) found that the ___ hippocampus was more active in taxi drivers relative to NCs in a ___ ___ task. Ranganath (2005) found that the hippocampus is also active in ___ ___ tasks involving novel info

Answer 9

Posterior. Spatial memory. Working memory

Question 10

What is the stability-plasticity dilemma?

Answer 10

The need to remember both specifics & generalities. It is part of the overall need to learn new info without overriding old info

Question 11

How is the stability-plasticity dilemma resolved at the neural level?

Answer 11

By keeping info separate in the hippocampus to learn specifics & by integrating info in neocortex to learn generalities

Question 12

How does slow vs. fast learning relate to the encoding of specifics vs. generalities in the complementary learning systems theory?

Answer 12

1) The hippocampus is responsible for fast learning, keeping memories separate, forming arbitrary links & remembering specifics
2) Neocortex is responsible for slow learning, overlapping memories, forming consistent links & extracting generalities

Question 13

So the different sites of encoding semantic vs. episodic memories may instead reflect…. I.e. the brain sites may not encode memories in a ___-specific manner per se

Answer 13

The processes required to encode semantic vs. episodic memories e.g. slow extraction of generalities to which we are exposed repetitively (semantic) vs. fast learning of distinct events to which we are exposed once (episodic) I.e. neocortex vs. hippocampus. Content

Question 14

Does complementary learning systems theory fit with the SMC & MTT?

Answer 14

With MTT which argues for an episodic vs. semantic difference in reliance on the MTL
Not with the SMC which argues that both EM & SM become independent of the MTL, rather than just semantic memory (CLST)

Question 15

Make sure you discriminate between the extraction of generalities by neocortex to form SMs and the…

Answer 15

Binding of contextual cues by the hippocampus to form EMs. Here we care only about the former