Squire - January 21-28

Question 1

1. what can be said about the assumptions of
   the brain being “highly interconnected” vs “modular”?
2. would brain lesion approaches be limited if the brain is truly highly interconnected?
3. what other approaches would be useful in unraveling brain contributions to the study of memory if this were true?

Answer 1

1. memory is a distinct cerebral function separate from perceptual & cognitive abilities, and identified in the temporal medial lobes - but the cerebral functions require an interconnected framework to function…
2. yes, because lesioning one area of the brain would affect multiple brain functions
3. maybe using tracers, ibotenic acid

Question 2

identify the 3 points of view regarding the location of memory or site of
memory storage in the brain that evolved from brain researchers in the early 20th century

Answer 2

1. brain is modular and specialized (focused on sensory, motor, and language; not memory)
2. memory is distributed throughout the cortex equally
3. memory is distributed, but different areas store different parts of a whole, but no brain region is specifically dedicated to memory

Question 3

identify 5 consequences of HM’s surgery on his learning and memory capacity that ruled out some of the early 20th century views of memory

what new perspectives/principles on the site of long-term memory evolved from these observations?

Answer 3

(these are all guesses until further noted)

1. hippocampal damage is enough to produce clinically significant memory impairment AND additional damage to adjacent cortical regions in parahippocampal gyrus exacerbate memory impairment
   - HM & RM
2. medial temporal and diencephalic structures are necessary for establishment of new representations in long term memory
   - HM had access to previous facts and events
   - HM could pay attention and retain information
3. medial temporal lobe is important for declarative memory and perceptual functions
   - HM performed well on perceptual functions & lexical knowledge
4. space is required in the limited capacity short-term memory in order for ppl without a medial temporal lobe to remember anything
   - HM relied on immediate memory capacity and on how successfully material was maintained in working memory with rehearsal
5. medial temporal lobes are not the site for long-term memories
   - HM had temporally graded retroamnesia

Question 4

how does the specificity of brain damage observed in patient R.B. extend support for the view on memory that emerged from studies of H.M?

why did these findings not exclude the significance of other temporal lobe structures in memory storage since the brain damage was limited exclusively within a subdivision of the hippocampus?

Why did Rbs study include the significance of other structures if the damage was only to he CA1?

Answer 4

RB also developed a memory impairment after ischemic episode in 1970

the bilateral lesion affected other areas of the brain because it was at the base of 3 other structures

• uncircumscribed bilateral lesion involving entire CA1 field of hippocampus
• which is the base/bottleneck of dentate gyrus, subiculum, and entorhinal cortex

Doesn’t have to be all of the hippocampus. Mainly cA1

Question 5

identify the 4 over-arching observations of the skills and mnemonic abilities that were spared or disrupted in HM and provided some clarification of the specific roles of the hippocampus and MT lobe structures in memory vs other cognitive processes

how were these and other findings integrated to develop the view that the brain has Multiple Memory Systems

Answer 5

1. acquired motor skills - memory isn’t a single thing
2. structures damaged in memory-impaired patients were thought not to be involved in intellectual and perceptual function
3. able to pay attention/retain information - medial temporal lobe structures are not needed for immediate memory
4. medial temporal lob cannot be ultimate place for long-term memory storage

if medial temporal lobe or diencephalic structures are not functional at the time of learning, memory is not established in a usable way and not available at a later time

basically memory isn’t in one place and requires other areas in order to completely function.

Question 6

Are you aware of the single name of the mechanism that is attributed to the neural and molecular processes occurring in the hippocampus during learning, that are required to encode new experiences into more stable long term memories?

Can you describe the processes that enable this mechanism to store new events into memory?

Answer 6

Atkinson and Shiffin Model of Memory

Question 7

identify 3-4 types of skills that were preserved in subjects with hippocampal damage and what separate brain system was attributed a role in acquiring and storing memory for this form of learning

Answer 7

1. motor skills - procedural (i)
2. perceptual skills - episodic (e)
3. cognitive skills - semantic (e)
4. priming - priming (i)