Deck 14: Hunting for Engrams

Question 1

Memories are stored in the brain like items in a warehouse.

Answer 1

False

Question 2

The neural (physical) basis of memories are widely distributed.

Answer 2

True

Question 3

Karl Lashley invented the term engram?

Answer 3

False

Question 4

Richard Simon invented the term engram?

Question 5

Simon's term ecphory is another word for engram.

Question 6

The term ecphory is roughly equivalent to the term retrieval.

Question 7

An engram is a memory.

Question 8

An engram is the physical basis of a memory.

Question 9

Hebb's concept of a cell assembly is still generally accepted as correct.

Question 10

A neuronal ensemble is quite different from a cell assembly.

Question 11

Brain lesion techniques can be considered a starting point in the search for engrams.

Question 12

If a brain lesion of a particular regions disrupts memory storage or retrieval it can be concluded that this region contains engram cells.

Question 13

In order to conclude that a set of neurons are engrams, these neurons must be activated only by the retrieval test.

Question 14

In order to conclude that a set of neurons are engrams, these neurons must be active both by the learning event and by the retrieval test.

Question 15

If engram cells are deleted, it should have no effect on retrieval.

Question 16

Immediate early genes can serve as markers or tags for neuron activated by a behavioral experience.

Question 17

Immediate early gene markers for of neural activity do not persist long enough to serve as markers for long-term memory engram cells.

Question 18

A major advantage of the TetTag mouse is that it permits engram cells to be tagged with a fluorescent marker that can endure for many days.

Question 19

Regarding the TetTag mouse, if a neuron expresses the marker a time of the behavioral retrieval test then it can be concluded that it is an engram cell.

Question 20

An advantage of the TetTag mouse is that it permits the temporal control over when a behavioral experience can tag a cell.

Question 21

If following a retrieval test, a neuron expresses a marker for an immediate early gene and the fluorescent marker, it can be concluded that this neuron is an engram cell.

Question 22

Optogenetics provides a methodology for testing the requirement that the activation of engrams must activate the behavioral measure of the memory.

Question 23

All neurons activated by the learning experience will become engram cells that support the memory.

Question 24

Neurons that overexpress CREB win in the competition for becoming engram cells.

Question 25

Neurons that overexpress CREB win in the competition for becoming engram cells because when activated by the behavioral experience, CREB targets more memory genes that other cells.

Question 26

Neurons that overexpress CREB win in the competition for becoming engram cells because their intrinsic excitability is increased.

Question 27

If engram cells are inhibited at the time of retrieval, the test performance will be impaired.

Question 28

Neuronal subensembles activated by the learning experience but not replayed during sleep will become engram assembles.

Question 29

What is an engram?

Question 30

What does it mean to say "An engram has the potential for ecphory"?

Question 31

Briefly describe Hebb's concept of a cell assembly.

Question 32

Why must a neuron be active both the learning experience and the retrieval test to be considered an engram cell?

Question 33

What should happen during the retrieval test if engram cells are inhibited?

Question 34

What is the value of immediate early gene markers to the pursuit of engram cells?

Question 35

How was the TetTag mouse an improvement over Guzowski's immediate gene methodology?

Question 36

What would be your conclusion if there was no overlap in the cells tagged by the training experience and those labeled by the retrieval test?

Question 37

How was Mayford able to temporally control when neurons in the TetTag mouse could be labeled with the fluorescent tag?

Question 38

Why does the optogenetics method require the use of a viral vector system?

Question 39

In the optogenetics experiment, what was the role of DOX?

Question 40

In the optogenetics experiment, what was the role of the blue light?

Question 41

The study of neural dynamics by Inokuci's group (Gandour et al.) revealed several important discoveries. Describe two.

Question 42

What is the role of CREB in determining what neurons are selected to become engram cells?

Question 43

How did Josselyn demonstrate that neurons that overexpress CREB became engram cells?

Question 44

The term _______ is roughly equivalent to the term retrieval.

Question 45

The term engram was invented by _______.

Question 46

The _______ is the physical basis of a memory.

Question 47

Modified connections among neurons that Hebb called _______ are the basis of memory.

Question 48

Immediate early gene markers can tell if a cell has been _______ by the retrieval test.

Question 49

In order to conclude that a neuron is an engram cell, it must be activated by the learning experience and by _______.

Question 50

_______ is used to temporally control when a neuron can be tagged.

Question 51

Neurons that _______ CREB win in the competition for becoming engram cells.

Question 52

The increased excitability of CREB expressing neurons enables them to _______
other neurons and prevent them from becoming engram cells.

Question 53

In order to conclude that cells are part of an engram, which condition(s) must be satisfied? (Select all that apply.)

A) The cells must be active both at the time of the learning experience and at the time of the memory test.
B) Their presence must be correlated with the generation of the appropriate memory.
C) When directly activated they can produce the behavioral expression of the memory.
D) When inhibited or deleted, the behavioral expression of the memory will be prevented or reduced.
E) None of the above

Question 54

The TetTag mouse was an improvement over the sole use of the immediate early gene Arc to tag cells because _______. (Select all that apply.)

A) immediate early genes do not respond to cell activity
B) cells in the TetTag mouse always respond to activation
C) immediate early gene markers do not persist
D) the tag established during learning can persist for many days in the TetTag mouse
E) the TetTag mouse permits temporal control over when the tag can occur.

Question 55

Optogenetic stimulation is critical in the search for engrams because _______. (Select all that apply.)

A) it is critical to tagging neuron2
B) light stimulation is critical to expression of ChR2.
C) when dox is removed from the diet ChR2 channels can be expressed.
D) this method permits the activation of tagged engram neurons that responded to behavioral training
E) None of the above

Question 56

The study of the dynamics of engram formation by Kaoru Inokuci's group revealed that _______. (Select all that apply.)

A) Hebb's reverberatory trace idea was false
B) engram cells fired more repetitively than the non-engram cells
C) all cells active at the time of the learning experience remained active for several hours after training
D) some cell clusters activated by the learning experience did not persist over the sleep period
E) only subensembles active during sleep were activated during retrieval

Question 57

Which statement(s) is/are true? (Select all that apply.)

A) All cells that are activate by the learning experience become engram cells.
B) Cells expressing CREB are most likely to become engram cells.
C) Cell expressing CREB are intrinsically more excitable than cells that do not.
D) Cells expressing CREB inhibit those cells not expressing CREB.
E) None the above