Brain & Plasticity Learning Exam 2 Chapter Questions

Describe two sources of evidence that BDNF is important for memory consolidation?

(1) BDNF protein levels are increased in the hippocampus by contextual fear conditioning and place learning and in the BLA by fear conditioning; (2) Interfering with BDNF function by either the BDNF scavenger TrkB-lgG or the TrkB receptor antagonist K252a impaired the development of long-term memory

What are the three immediate early genes targeted by CREB?

(1) BDNF; (2) Arc; (3) C/EBPb

What are the four research strategies used to study CREB's contribution to memory?

(1) Genetic deletion of CREB; (2) CREB antisense; (3) Genetic overexpression of CREB; (4) CREB selection of neurons that participate in the memory trace

What gives memories functional significance?

(1) Repetition; (2) Recall; (3) Arousal

Roberto Malinow used two strategies to prove that fear conditioning drives AMPA receptors into amygdala neuron synapses. What were they?

1. He created identifiable glua1 receptors and infected neurons in the amygdala with these receptors to show that fear conditioning would drive them into synapses 2. He created dummy receptors to compete with endogenous receptors and showed that their presence impaired fear conditioning

What is time limited retrograde amnesia?

A failure to remember an experience that happened just prior to the occurrence of the disrupting event, yet maintaining memories of older experiences.

The mTORC2 complex regulates processes that contribute to the regulation of __________.

Actin

To influence NMDA function, Morris: Used a pharmacological approach Infused APV into the brain Implanted a cannula into a cerebral ventricle Tested rats in the space-learning swim task All of the above

All the above

Which of the following statements about memory is false? CREB deletion impairs LTM Blocking CREB translation impairs STM CREB overexpression can improve LTM under certain conditions Neurons that overexpress CREB do not compete successfully for selection in the neuronal ensemble that supports a fear memory Both B and D

Blocking CREB translation impairs STM Neurons that overexpress CREB do not compete successfully for selection in the neuronal ensemble that supports a fear memory

Which of the following statements about the CA1KO mouse is true? GluN1 subunits are absent in the dentate gyrus GluN1 subunits are absent in the CA1 region LTP cannot be induced in the CA1 in slices GluN1 subunits are absent in the dentate gyrus Both B and C

Both B and C

Neurons containing more ________ will likely win the competition for participating in the memory-supporting ensemble.

CREB

When investigating a drug or some other manipulation that is hypothesized to strengthen a memory trace, researchers should use lower intensity shock to avoid the ______________.

Ceiling effect

When the response measure if at its maximum, researchers should be wary of the __________.

Ceiling effect

Which of the following statements about opsins is true? Channelrhodopsin can excite neurons by depolarizing them Channelrhodopsin can inhibit neurons by hyperpolarizing them Halorhodopsin can inhibit neurons by hyperpolarizing them Halorhodopsin can inhibit neurons by depolarizing them Both A and C

Channelrhodopsin can excite neurons by depolarizing them Halorhodopsin can inhibit neurons by hyperpolarizing them

What is the dependent variable in inhibitory avoidance conditioning?

Crossover Latency

The electroconvulsive shock (ECS) methodology did not advance our understanding of memory because it was already known that brain trauma can _________.

Disrupt new memories

List three differences between a short-term memory trace and a long-term memory trace.

Duration State Vulnerability to disruption/decay state

What are the unconditioned stimulus, the conditioned stimulus, and the conditioned response in fear conditioning?

Electrical shock, auditory stimulus, freezing

The hippocampus is targeted because it is critical for ___________ and the __________ is targeted because it is critically involved in the storage of emotional memories.

Episodic memory; Amygdala

List two dependent variables in the water-escape task.

Escape Latency Path length Percent time spent in the target quadrant on a probe trial

List three methods for influencing brain function.

Experimentally damaging a particular region of the brain Injecting drugs Genetic engineering

T/F: AMPA receptors are needed only for memory acquisition, but NMDA receptors are required for both acquisition and retrieval.

False

T/F: C/EBPb is a transcription factor that targets the CREB gene.

False

T/F: CREB KO mice have impaired STM and LTM because plasticity products are depleted.

False

T/F: CREB antisense prevents the transcription of CREB protein.

False

T/F: CREB phosphorylation results in the immediate transcription of C/EBPb.

False

T/F: GluN1 subunits are not required to form functional NMDA receptors.

False

T/F: LTP is memory.

False

T/F: Morris used genetically engineered mice in the first study that investigated the role of NMDA receptors in memory formation.

False

T/F: PKMZ KO mice cannot acquire and maintain fear and place-learning memories.

False

T/F: Protein degradation by the UPS has no effects on STM, but it disrupts the consolidation of LTM.

False

T/F: Remembering the plot of a book you read a few months ago is an example of working memory.

False

T/F: The CA1KO mouse was able to display LTP in the CA1 regions but not in the dentate gyrus.

False

T/F: The concept of consolidation is supported by the fact that old events are more vulnerable to disruption than new memories.

False

T/F: The consolidation period ends when the memory trace is no longer vulnerable to the disruption of ZIP.

False

T/F: The mTORC2 complex regulates protein synthesis but the mTORC1 complex regulates actin polymerization.

False

T/F: Working memory cannot be studied in animals because they cannot communicate what problems they are trying to solve.

False

T/F: ZIP erases established memories, even at 25 days old, and prevents the acquisition of new ones.

False

T/F: ZIP will erase taste-aversion memories only if injected at a specific time after acquisition.

False

Every functional NMDA receptor has __________ subunits.

Four

In fear conditioning, shocked rats, display more ____________ than rats that were not shocked.

Freezing

In fear conditioning, the duration of the ___________ is an indicator of the __________ of the memory.

Freezing response; Strength

What genetic engineering methods were used to study the role of NMDA receptors in memory formation?

Genetic engineering methods have been used to selectively delete or overexpress one of the NMDA subunits in mice.

Tonegawa deleted the _______ in _______ in the CA1 field of the mouse hippocampus.

GluN1; Pyramidal Cells

The Doogie mouse is genetically engineered to overexpress ________ subunits.

GluN2B

As the nervous system develops, _______ subunits tend to be replaced by _____ subunits of nmdars

GluN2B; glun2a

When ______ subunits of NMDARs dominate, it is easier to induce LTP than when _______ subunits of nmdars dominate

Glun2b, glun2a

What was the Richard Morris' experiment? What was he trying to study?

He implanted a cannula to deliver the NMDA receptor against APV into the ventricular system of a rat's brain where it would enter the cerebral spinal fluid. He was testing the hypothesis that the initial formation of a memory trace depends on the activation of NMDA receptors.

In the brain, insulin growth factor-II (IGF-2) is mostly found in the ____________.

Hippocampus

The third wave of consolidation depends on the transcription factor C/EBPb and ____________.

IGF-2

Inhibiting a molecule important for memory consolidation but not for memory formation will

Impair performance at a 24-hour but not 1-hour retention interval

Which of the following explains why antisense methodology works for the study of LTM? It completely blocks all protein synthesis It can prevent the synthesis of a specific protein It can be used to study the role of a specific protein It is a transcription inhibitor Both B and C

It can prevent the synthesis of a specific protein It can be used to study the role of a specific protein

Which of the following statements about C/EBPb is FALSE? It is a transcription factor that targets other memory genes Its mRNA level increases as soon as CREB is phosphorylated Its translation is necessary for enduring memory Using antisense ODNs to block its translation 20 hours prior to training has no effect on LTM Its mRNA level is increased 20 hours after conditioning

Its mRNA level increases as soon as CREB is phosphorylated

The mTORC1 complex regulates ____________.

Local protein synthesis

The de novo protein synthesis hypothesis states that

Long-term memory depends on behavior initiating the synthesis of new protein

PKMZ likely plays an important role in the trace

Maintenance phase

Provide an example of working memory.

Memorizing a list of groceries and discarding it from your memory once you are done shopping.

Richard Morris was the first researcher to directly investigate the role of ______ in memory formation.

NMDA Receptors

Which of the following statements about NMDA receptors is true? NMDA receptors are activated by calcium NMDA receptor channels allow calcium to enter the cell NMDA receptors composed of the NR1/NR2A subunits remain open longer than those composed of NR1.NR2A subunits. Early in development, the ratio of NR1/NR2B to NR1/NR2A containing NMDA receptors favors the NR1/NR2A complex None of the above are true

NMDA receptor channels allow calcium to enter the cell

Which of the following statements about memories is TRUE? Newly established memories are more resistant to disruption than older memories. Old memories have a shorter decay time than new memories. Old memories are more resistant to disruption than new memories. Both A and C. All of the above are true.

Old memories are more resistant to disruption than new memories.

What is the importance of the two distinct peak levels of BDNF expression?

One peak of BDNF occurs 1 hour after training and is critical for fear response memory on 1-day and 7-day retention intervals. The second occurs 12 hours later and supports the memory on the 7-day retention test.

________ allows scientists to control one type of cell without altering other types.

Optogenetics

In the radial methodology maze task, rats

Rarely make reference of working memory errors

In the radial arm maze, if a rat revisits an Arm that was never baited, it is making a _________ error.

Reference memory

What is the key independent variable manipulated to determine if a molecule is selectively involved in LTM but not STM?

Retention Interval

Amnesia for events experiences prior to the blow to the head that caused it is an example of _____________.

Retrograde amnesia

Systemic injections of anisomycin following training impairs LTM but has no effect on STM. Which of the following conclusions are NOT justified by this finding? LTM depends on new proteins synthesized in response to the behavioral experience STM depends on new proteins synthesized in response to the behavioral experience STM does not depend on new proteins synthesized in response to the behavioral experience STM depends only on post translational modifications Both a and b

STM depends on new proteins synthesized in response to the behavioral experience

Which of the following statements about memory is FALSE? Short-term memory traces are in the inactive state and are easy to disrupt. Long-term memory traces are in the inactive state and are hard to disrupt. Time limited retrograde amnesia is more likely to affect short-term memory. Time limited retrograde amnesia is more likely to affect long-term memory. Both A and D.

Short-term memory traces are in the inactive state and are easy to disrupt. Time limited retrograde amnesia is more likely to affect long-term memory.

CREB knockout mice displayed normal fear conditioning when the retention interval was __________ but were impaired when the retention interval was ____________.

Short; Long

T/F: PKMZ can enhance already established memories.

TRue

What is the Doogie mouse?

The Doogie mouse was a genetically engineered to overexpress GluN2B subunits in the cortex and the hippocampus. They displayed enhanced LTP, memory formation and superior performance in behavioral tests.

Explain why the following statement is false: "CREB antisense remains present at the injection site for days, causing LTM impairment."

The antisense is present for less than 20 hours, but rats still show LTM impairment even 3 days after training. The impairment is not due to the antisense directly but is a result of CREB being unavailable at the time of the training, so it was not present to facilitate the transcription of the new mRNAs needed to produce enduring memory.

Explain why it is possible to induce LTP in the dentate gyrus of the CA1KO mouse, but not in the CA1 region of the brain. How does this affect the mouse's performance in the place learning task?

The genetically engineered deletion targeted the NMDA receptors in CA1 pyramidal cells but not the dentate gyrus. The mouse's memory was impaired and it couldn't learn to swim the platform.

Which of the following is a feature of the place learning task? The platform remains in the same location in each trial. The platform is visible to the rodent. The rodent is always released from the same location inside the pool. Both A and B. All of the above.

The platform remains in the same location in each trial.

What is cerebral spinal fluid?

The substance that bathes the brain and spinal cord and cushions them against impact. It also provides them with oxygen and nutrients and removes waste products.

What is the retention interval?

The time between the training experience that establishes the memory and the test used to retrieve the memory.

Why might ZIP erase memories in PKMZ KO mice?

There are compensatory, redundant molecules for PKMZ that are also ZIP targets.

A drug inhibits molecule X, and it impaired performance at the long, 24-hour retention interval but had no effect on performance at the short, 1-hour retention interval. What can be said about the contribution of molecule X to memory?

These results indicate that molecule X contributes to the consolidation of the long-term memory trace but is not required for short-term memory.

T/F: A behavioral experience that produces a memory is likely to result in more phosphorylated cofilin and more autophosphorylated CaMKII.

True

T/F: Arc antisense infused into the lateral amygdala impaired memory for a fear-conditioning experience when the retention interval was 24 hours but not when the interval was 3 hours.

True

T/F: Behavior is the product of many subcomponent systems.

True

T/F: C/EBPb is a transcription factor.

True

T/F: CREB is activated by post-translation modifications.

True

T/F: Disrupting either the mTORC1 or the mTORC2 complex will impair the development of long-term memory but have no influence on the formation of short-term memory.

True

T/F: It is safe to conclude that C/EBPb-protein-dependent processes operate for at least 24 hours following training.

True

T/F: Limited retrograde amnesia produced by a concussion likely affects only memories in the active state.

True

T/F: Memories in the active state are more vulnerable to disruption than memories in the inactive state.

True

T/F: Memories in the active state decay more rapidly than memories in the inactive state.

True

T/F: The consolidation period ends when the memory trace is no longer vulnerable to the disruption of transcription and translation processes.

True

T/F: The mTORC1 complex regulates protein synthesis but the mTORC2 complex regulates actin polymerization.

True

T/F: To rule out the possibility that a drug interferes with the way the animal normally samples the environment, the drug should be administered immediately after training.

True

T/F: Transcription and translation processes that support enduring memory traces take place over at least 24 hours.

True

The ______ is often used as a control task to evaluate alternative interpretations of the effect of brain manipulation on performance in the place-learning task

Visible-platform task

Explain the floor effect.

When a treatment is hypothesized to impair the memory processes that produce avoidance behavior, but the performance measure was too low to be further reduced by the drug.

What is the function of channelrhodopsins and halorhodopsins?

When activated by blue light, channelrhodopsins (channel proteins) could be stimulated to open and close with millisecond precision and conduct positive ions with the result of depolarizing the neuron. Halorhodopsins, when stimulated with green light, conduct negative charges chloride ions and thereby hyperpolarize the neuron.

In the radial arm maze, if a rat revisits an arm starts with baits, it is making a ________ error.

Working memory

Describe how the radial arm maze can be used to study both working and reference memory.

Working memory requires that the animal remember which arm was already visited, while reference memory requires that the animal discriminate between the arms always baited and the arms never baited.

As the nervous system develops, would you expect to see any changes in LTP induction? Explain why or why not.

Yes, because GluN2B subunits are replaced by GluN2A subunits and these subunits have different channel-opening properties. NMDA receptor complexes that contain GluN2B subunits remain open longer than those that contain GluN2A subunits and presumably permit more CA2 to enter the spine. When the GluN2B subunits dominate, it is easier to induce LTP than when GluN2A subunits dominate.

Which of the following statements about ZIP is false? There is no time window constraining the effects of ZIP ZIP alters the acquisition of new taste aversion memories ZIP erases taste aversion memories when injected into the insular cortex and the hippocampus ZIP targets PKMZ and other memory maintenance kinases Both B and C

ZIP alters the acquisition of new taste aversion memories ZIP erases taste aversion memories when injected into the insular cortex and the hippocampus

Which of the following statements about inhibitory avoidance conditioning is TRUE? Longer latencies reflect a stronger memory trace. Crossover latency is the dependent variable. As shock intensity increases, so does response latency. Both A and C. All of the above are true.

all of the above