E. Learning, Memory, and Amnesia - Part 2

Question 1

What type of memory is associated w/ the medial temporal lobe?

Answer 1

declarative mem

Question 2

Describe how the delayed non-matching to sample is a model of declarative memory

Answer 2

Unlike humans animals are unable to verbally state whether they remember something or not. So this experiment teaches a primate about their being a treat under the obj. Then to keep getting the treat they need to lift the new obj every time. The act of knowing to go to the new obj immediately shows memory of the old obj

Question 3

When doing the delayed non-matching to sample (DNMS) performance to test declarative memory there was a lot of controversy wrt whether it was associated specifically w/ the amygdala, hippocampus or both.
a) Why were different results found?
b) In which brain part was the problem?
c) Who figured out a way to bypass this problem?

Answer 3

a) This was due to the way they were causing damage to the amygdala/hippocampus. They were damaging the cortical tissue around it. The extent of that damage dictated more wrt declarative memory
b) the perirhinal cortex
c) Murray + Mishkin used a neurotoxic lesion which involves causing an excitotoxic cascade (flood w/ glucose) causing that brain region to shut down.

Question 4

Match the following terms to the brain areas. Indicate which ones are on the outside of the brain vs inside. Which one is involved w/ declarative memory?
a) Hippocampus
b) Parahippocampal cortex
c) Entorhinal cortex
d) amygdala
e) Perirhinal cortex

Answer 4

• outside = b, c, + e
• inside = a + d
• declarative memory = e + a

Question 5

There is a functional double dissociation b/w the perirhinal cortex and hippocampus. What does this mean? - 3

Answer 5

• they are both associated with declarative memory. However their fxn wrt declarative memory are indep from each other.
• perirhinal cortex is associated w/ declarative memory that is related to obj recognition.
• hippocampus is associate w/ declarative memory that is related to spatial memory

Question 6

If you use the neurotoxic lesion technique to lesion the hippocampus and the amygdala will declarative memory in the following situations be impaired? Why?
a) object recognition test
b) spatial memory test

Answer 6

a) no, because neither the amygdala nor the hippocampus are associated w/ this type of memory. The perirhinal cortex is though which is still intact
b) yes, because the hippocampus is associated w/ this type of declarative memory

Question 7

Describe homogeneity wrt the MTL

Answer 7

the idea that all regions within the medial temporal lobe are equally important for declarative memory fxn

Question 8

In this image what does the dotted line around the ‘short-term memory’ box mean?

Answer 8

It is indicating the instability of memories when they are in short-term memory

Question 9

Categorize the following terms in either short-term memory or long-term memory
a) inactive
b) active
c) less vulnerable to disruption
d) Vulnerable to disruption

Answer 9

Question 10

Who coined the term “cells that fire together wire together” and what does it mean

Answer 10

a) Hebb’s
b) cell assembly concept = when one cell activates another cell persistently it strengthens their efficiency to communicate to the pt where if one of the cells is partially stimulated the entire assembly of cells will activate

Question 11

What are the 3 paths associated w/ LTP in the hippocampus?

Answer 11

1. performant path
2. mossy fibers
3. schaffer collaterals

Question 12

What are the 3 cells assocated w/ LTP in the hippocampus?

Answer 12

1. Granule cell
2. CA3 pyramidal cell
3. CA1 pyramidal cell

Question 13

Put the following LTP pathway terms in the hippocampus in order
a) mossy fibers
b) CA1 pyramidal cell
c) Schaffer collaterals
d) Perforant path
e) CA3 pyramidal cell
f) granule cell

Answer 13

Question 14

If you were to provide a weak stimulus followed by a strong stimulus, then go back to the weak stimulus in the hippocampus, what would be the result of that stimulus? Explain your ANS.
a) stronger than original WS
b) weaker than original WS
c) stronger than original SS
d) Weaker than original SS
e) no change in WS

Answer 14

a - the act of providing a SS strengthened the neurons communication efficiently making them more sensitive so when WS was given again that more efficient communication showed itself

Question 15

What are the 3 receptors that are involved in LTP? What type of receptors are they (NTX)

Answer 15

• glutamate receptors - cause excitation
  1. AMPA receptors
  2. kainite receptors
  3. NMDA

Question 16

the NMDA receptors are known as ‘coincidence detectors’. What does this mean?

Answer 16

They are only activated if multiple processes take place. In this case glutamate must be released by the pre-synapse and the AMPA receptors must causes enough of an influx (depolarization) into the post-synapse in order to remove the lodged Mg so it can be activated.

Question 17

What is the main difference b/w the AMPA and NMDA receptors? Which one is the most important for LTP? Why?

Answer 17

a)
- AMPA = open and let influx of Na into the post-synapse when glutamate binds to it
- NMDA = same as AMPA except the post-synapse needs to be depolarized enough in order to removed the Mg ion that is blocking the pore before an influx of ions can occur. Also influx of both Na + Ca
b) NMDA due to Ca being needed for LTP

Question 18

What kind of receptors is this. Provide 2 reasons for how you know.
a) AMPA
b) NMDA
c) Kainite

Answer 18

b - Ca influx, Mg block,

Question 19

Describe the following terms wrt memory
a) acquisition
b) consolidation
c) retrieval

Answer 19

a) the act of encoding information
b) integrating encoded information into long-term memory
c) getting information out of long-term memory

Question 20

Match the following terms to the 3 groups. Explain each.
a) consolidation
b) retrieval
c) acquisition/encoding

Answer 20

a - the delay provides time for the rat to take the information about the obj and put it into long-term memory
b - the act of deciding which obj is new uses retrieved info about old obj
c - Providing the rat time to investigate and encode information about the obj

Question 21

Match the following terms; How do these terms relate to each other?
a) NMDA receptor
b) AMPA receptor
1. AP5
2. CNQX

Answer 21

a) 1 - antagonist
b) 2 - antagonist

Question 22

Which type of glutamate receptor is important for long-term potentiation of the post-cell? Why?

Answer 22

NMDA receptors because they allow for an influx of Ca which is used as a second messenger that causes a cascade of activation in different molecules resulting in long-term potential

Question 23

In the object recognition experiment which of the following would be impacted if AP5 is administered right before the sample phase? What if CNQX was used instead?
a) acquisition
b) consolidation
c) retrieval

Answer 23

a) a b/c AP5 is an NMDA receptor antagonist and for a memory to be acquired into the long-term memory NMDA receptors are needed to pass that signal from pre to post synapse
b) CNQX is an AMPA receptor antagonist, therefore, the acquisition phase would still be affected b/c in order to trigger the NMDA receptors to open the post-synapse needs to be depolarized enough. This depolarization is don’t by the influx of Na ions that occur at the AMPA receptors

Question 24

Which glutamate receptor is needed for long-term potentiation expression? induction? Which of the following do these terms match
a) acquisition
b) consolidation
c) retrieval

Answer 24

a) LTP induction = both AMPA + NMDA
c) LTP expression = just AMPA due to the recycling of AMPA receptors

Question 25

match the following wrt object recognition in rats and memory
a) sample phase
b) 24h delay
c) choice phase
1. retrieval of memory
2. acquisition/encoding of memory
3. consolidation

Answer 25

a) 2
b) 3
c) 1

Question 26

T or F - if you use AP5 on a rat right before it goes into the choice phase it impaired the acquisition of memory

Answer 26

F - CNQX (antagonist for AMPA) and impairment will be found in the acquisition, consolidation and retrieval phases

Question 27

Which glutamate receptors are required for the encoding, consolidation, and retrieval of memory?

Answer 27

AMPA

Question 28

Which glutamate receptor is required for just the encoding, and consolidation of memory?

Answer 28

NMDA