Memory Organisation

Question 1

How are memories represented at a neuronal level?

Answer 1

Memory is represented by a change in the shape of the postsynaptic spine.

Question 2

How are learning and memory related?

Answer 2

Learning is the process of acquiring new information. Memory refers to the persistence of learning (i.e., retaining information).

Question 3

What is a memory impairment called?

Answer 3

Amnesia

Question 4

What are the subdivision into stages of memory?

Answer 4

Encoding, made up of acquisition and consolidation.
Storage
Retrieval

Question 5

How is visual agnosia related to memory impairment?

Answer 5

The patient exhibits difficulty reporting the names of objects based on visual input, but can provide the name based on tactile or olfactory input.
The latter behaviour indicates that the region of the brain that stores information about the objects is intact, but retrieval of that information is impaired when the object is presented visually. This is a selective retrieval problem.

Question 6

What are two tests of short-term memory?

Answer 6

Digit span test = verbal memory

Corsi block test = spatial memory

Question 7

What are two long-term memory tests?

Answer 7

Ask about historical events and personal history = declarative memory
Ability to learn procedures = procedural memory

Question 8

What are the two types of amnesia?

Answer 8

Retrograde Amnesia = loss of memories from a period of time before the brain injury
Anterograde Amnesia = deficit in forming new memories after the brain injury

Question 9

Patient NA - brain injury from fencing coil, mammillary bodies are missing (among other damage) and has anterograde amnesia.
What does this patient inform us about memory?

Answer 9

His short term memory is spared while his long term memory was affected. Specifically, his procedural memory is intact but his declarative memory has been disrupted.
This tells us that neural substrates underlying long-term memory are distinct from those underlying short-term memory. Furthermore, that the neural substrates underlying long-term declarative memory are distinct from long-term procedural memory.

Question 10

Patient HM - removal of medial temporal lobes in an attempt to control seizure activity, this involved the removal of the anterior portions of the hippocampi. What deficits did he show and what does this tell us?

Answer 10

Short-term memory = spared.
Long-term procedural memory = spared
Long-term declarative memory = disrupted (mainly anterograde).
Tells us:
1. Long-term memory distinct from short-term.
2. LT declarative is distinct from LT procedural
3. The damage is restricted to the medial temporal lobes, bilaterally, allowing a direct association between his deficits and the medial temporal lobes.

Question 11

Patient EE - The patient had two seizures. After the second seizure, neuroimaging revealed a tumour in the region of the left temporo-parieto occipital junction.
He underwent neurosurgery for removal of the tumour, after which EE had a distinct and persistent short-term memory impairment. Impaired performance on language tests could be attributed to his short-term memory deficit.
What short-term memory deficits did he show and what does this tell us?

Answer 11

Long-term memory = normal
Corsi block test = normal (short-term spatial memory)
Digit span test = impaired (short-term verbal memory)
Tells us:
1. EE’s selective impairment for short-term memory in the absence of long-term memory deficits suggests that the neural substrates underlying short-term memory are distinct from those underlying long-term memory.
2. EE’s selective impairment for verbal short-term memory in the absence of spatial short-term memory deficits suggests that the neural substrates underlying short-term memory for verbal material are distinct from those underlying short-term memory for spatial locations.