Week 5

Question 1

What is a retention interval, and what is usually the retention interval for STM

Answer 1

• The time between the experience that established a memory and the test used to retrieve the memory
• 4 hours

Question 2

What is the typical research design for testing memory formation/consolidation?

Answer 2

A subject is trained on a task and is tested after the retention interval to see if the memory remains - some pharmacological or genetic manipulation is given before or after the training

Question 3

When is a memory said to be consolidated?

Answer 3

When it is no longer vulnerable to manipulations that interfere with the transcription and translation processes initiated by its memory event

Question 4

What is typically used to interfere with translation?

Answer 4

Broadscale inhibitors such as anisomycin - inhibit protein synthesis

Question 5

What does anisomycin infusion prior to training do to memories?

Answer 5

The memory is only present for ~1 hour, but not longer intervals

Question 6

What does anisomycin infusion immediately after training do to memories?

Answer 6

The memory is available for 2 days after training

Question 7

What conclusions can be drawn from Alberini’s experiments?

Answer 7

• STM can be established without new proteins
• Memories lasting more than 3 days require a second wave of protein synthesis that occurs the day after training
• The memory is consolidated into the hippocampus after ~2 days

Question 8

mRNA and translation machinery are present in _____

Answer 8

The dendritic spine region

Question 9

What is the local protein synthesis hypothesis?

Answer 9

The initial wave of protein synthesis is the result of engaging the molecules that generate local protein synthesis, creating a memory that lasts for about 2 days

Question 10

mTOR is responsible for _____

Answer 10

Upregulating the translation machinery in the dendritic spine region

Question 11

What happens when delaying mTOR activation after training?

Answer 11

No effect on LTM, since mTOR is produced very rapidly after the memory-inducing event

Question 12

The second wave of protein synthesis can only occur if _____

Answer 12

The initial wave also occurred

Question 13

mTORC1 is _____ to rapamycin, while mTORC2 is _____ to rapamycin

Answer 13

• sensitive

- insensitive

Question 14

What do mTORC1 and mTORC2 do?

Answer 14

• mTORC1 regulates signaling cascades that increase local protein synthesis
• mTORC2 regulates processes that contribute to the regulation of actin

Question 15

What component of mTORC2 was knocked out to study mTORC2’s contribution to memory?

Answer 15

Rictor

Question 16

mTORC2 only contributes to ____

Answer 16

LTM

Question 17

What happens to BDNF levels after training?

Answer 17

Levels peak 1 hour and 12 hours after, but don’t return to baseline until 30 hours

Question 18

Interfering with BDNF function 30 minutes before training _____

Answer 18

Reduced fear conditioning for both 1 day 7 days

Question 19

Interfering with BDNF function 9 hours after training _____

Answer 19

Reduced fear conditioning only for 7 days

Question 20

A behavioural experience that initiates local protein synthesis also initiates _____

Answer 20

Genomic signaling

Question 21

CREB may be critical for

Answer 21

LTM formation

Question 22

What happens when antisense ODNs are administered to brain memory storage sites prior to training?

Answer 22

There will be less CREB protein available to target transcription of the new mRNA needed to produce the enduring memory

Question 23

What does C-EBPB do?

Answer 23

Targets BDNF for transcription, and is critical for the second wave of protein synthesis

Question 24

A behaviour that can produce a LTM rapidly activates ______

Answer 24

Post-translation processes that establish a STM which can endure for a few hours

Question 25

The activation of the ______ cascade initiates local protein synthesis

Answer 25

BDNF-TrkB-mTOR-TOP

Question 26

What is the positive feedback loop in the second wave?

Answer 26

BDNF-CREB-C/EBPB-BDNF

Question 27

What is the interference theory of forgetting?

Answer 27

Forgetting results from learning new information that interferes with/overwrites the old memory traces

Question 28

What happens to memory during sleep?

Answer 28

Neural activity that results in the reactivation or replay of neuronal ensembles recently established during learning

Question 29

Drugs that block proteasome ______

Answer 29

Prevent LTM formation

Question 30

Protein degradation mediated by _____ is critical for establishing enduring memories

Answer 30

the ubiquitin proteasome system

Question 31

What is UPS’s role in memory formation?

Answer 31

Degrades proteins that repress protein translation and transcription

Question 32

BDNF leads to the ______ of CREB

Answer 32

phosphorylation

Question 33

What are the two principles of memory consolidation?

Answer 33

• Enduring memories require that the behavioural experience initiate processes that generate new proteins
• The consolidation processes occur in waves that last 24-48 hours

Question 34

Shortly after an experience, memory retrieval is supported by _____

Answer 34

An active short-term trace

Question 35

What did Zola-Morgan & Squire do?

Answer 35

Lesioned the hippocampus of monkeys after learning multiple-object discrimination tasks at different intervals before the surgery

Question 36

Contextual fear conditioning is dependent on the ____, while cue fear conditioning is dependent on the _____

Answer 36

• Hippocampus

- Amygdala

Question 37

What did Kim & Fanselow do?

Answer 37

Lesioned the hippocampus of rats after learning multiple-object discrimination tasks at different intervals before the surgery

Question 38

There is more activation in the _____ with recent memories compared to more distant memories

Answer 38

Medial temporal lobe

Question 39

What are some challenges with studying consolidation in humans?

Answer 39

• Ethical concerns
• Lack of experimental control
• Can not separate encoding, consolidation, retrieval,
• Encoding may vary between participants

Question 40

How many new hippocampal neurons die before becoming adult neurons?

Answer 40

-80-90%

Question 41

What is Lewis’s active trace theory?

Answer 41

Memories exist in either a short-term active state or long-term inactive state