Deck 3: Neuronal Plasticity

Question 1

Which of the following is NOT a reason that Aplysia makes a good model organism for studying synaptic plasticity?

A) it is an invasive species
B) it has very few neurons
C) it has a number of behaviors that are modified by experience
D) all of the above

Answer 1

A

Question 2

The gill withdrawal reflex of aplysia

A) is only seen in live animals.
B) involves the quick escape of aplysia due to a jet of water from its gills.
C) describes the withdraw of its gills after the siphon is touched.
D) is less pronounced after sensitization.

Answer 2

C

Question 3

What is the relationship of serotonin to the gill withdrawal reflex?

A) serotonin must be present for sensitization to occur
B) serotonin must be present for the muscles that govern the reflex to contract
C) serotonin production is inhibited following tail shocks
D) all of the above are true

Answer 3

A

Question 4

Make a diagram of aplysia sensory neurons and show how they are affected by serotonin in the gill-withdrawal reflex. Include pre-synaptic sensitization, serotonin receptors, second messenger molecules, and ion channels. Show how serotonin binding leads to depolarization and therefore an increased response.

Question 5

What is the primary difference between short-term sensitization and long-term sensitization?

Question 6

Place the following events in order that occur when long-term sensitization occurs, with 1 being first.
____ Protein kinase A concentrations increase
____ phosphorylated CREB binds to DNA
____ cAMP levels increase
____ serotonin binds to a GPCR serotonin receptor
____ adenylate cyclase activity increases
____ genes are transcribed that are involved in long-term synaptic changes

Question 7

Figure 3.3 In the text shows the results of an experiment. Predict what would most likely happen if the concentration of oligonucleotides was increased and relate it to the graph shown under "CRE Oligonucleotides".

A) The red line would likely be higher than the blue line
B) The blue line would remain higher than the red line
C) Both lines would flatten out and become straight
D) The lines would overlap

Question 8

Read the text that accompanies figure b3.1. In the text Many invertebrates are listed that have characteristics or behaviors that are used as a model system for understanding more complex species. Propose another invertebrate organism that might serve as a good model for understanding a process or behavior that is not discussed in the text. Give reasons for your response.

Question 9

If a neuron that innervates a muscle is repeatedly stimulated (using tetanic stimulation), after a brief period of time the muscle response will be (increased/decreased) relative to before the tetanic stimulation.

Question 10

Which of the following functions is NOT associated with the hippocampus?

A) forming new spatial memories of locations
B) forming new episodic memories of people and places
C) place cells that fire when an animal is near a specific location
D) sensitization in the dentate gyrus following tetanic stimulation
E) all of the above are associated with the hippocampus

Question 11

Examine box b3.2. Identify the most important message from the text.

A) the hippocampus has very different functions in humans and rodents, with rodents being spatial memory and humans being episodic memory.
B) the anterior hippocampus in humans is similar to the ventral hippocampus in rodents, and the human hippocampus is shifted caudoventrally compared to the rodent's.
C) the result of apparent discrepancies between hippocampal function in humans and rodents is due to the fact that hippocampus organization is different between the two species
D) none of the above are important messages from the text

Question 12

You are experimenting on 3 neurons in a brain slice that obey Hebbian principles of synaptic plasticity. Neurons 1 and 2 form separate synapses onto Neuron 3. Which neuron(s) must fire to increase synaptic strength at the Neuron 1-Neuron 3 synapse?

A) 1 and 2
B) 1 and 3
C) 1 only
D) 3 only
E) all of the above

Question 13

You are experimenting on 3 neurons in a brain slice that obey Hebbian principles of synaptic plasticity. Neurons 1 and 2 form separate synapses onto Neuron 3. If neurons 1 and 2 fire simultaneously and an action potential results in neuron 3, you might expect that

A) neuron 3 would be more easily depolarized to stimuli from neuron 1
B) neuron 1 would be more easily depolarized to stimuli from neuron 3
C) neuron 1 would be more easily depolarized to stimuli from neuron 2
D) all of the above

Question 14

Hebbian learning can be described by the phrase: "neurons that fire together, wire together". What does this mean?

A) adjacent neurons tend to fire at the same time
B) synaptic connections are strengthened by neuronal activity
C) synaptic connections only form when neurons fire simultaneously
D) repeated neuronal activity leads to desensitization of the post-synaptic response
E) all of the above

Question 15

NMDA receptors

A) open in response to extracellular ATP
B) open with depolarized voltages because of positively charged amino acids in a voltage-sensing region
C) open with depolarized voltages when Mg2+ ions dissociate from the protein and permit ion influx
D) are GPCRs
E) all of the above

Question 16

For LTP to occur, which of the following is most critical?

A) calcium entry through AMPA receptors
B) calcium entry through NMDA receptors
C) calcium entry through metabotropic glutamate receptors
D) all of the above

Question 17

You are studying electrical currents in cortical neurons. In a particular experiment, you notice that current doesn't flow into the cell until the cell has been depolarized. Current flows normally when the solution that bathes the cell is free of magnesium. The current is likely passing through

A) AMPA receptors
B) NMDA receptors
C) metabotropic glutamate receptors
D) all of the above

Question 18

Consider the diagram at right, which shows glutamatergic neurons. If Neurons A and B fire nearly simultaneously (causing LTP to occur), which of the following is most likely true?

a) LTP occurs at synapses 1 and 2 only
b) LTP occurs at synapses 1, 2, and 3
c) after LTP there will be many more NMDA receptors present in Neuron D
d) Neurons A and B are likely to release more glutamate after LTP induction
e) all of the above

Question 19

Consider the diagram at right, which shows glutamatergic neurons. What does it mean that Synapses 1 and 3 become paired via LTP?

a) The combined activity at synapses 1 and 3 sufficiently depolarized Neuron D to cause LTP to occur
b) After pairing, a weak stimulus at synapse 1 will lead to a stronger response than before pairing
c) Synapses 1 and 3 have been physically changed by events that require gene transcription
d) all of the above

Question 20

Consider the diagram at right, which shows glutamatergic neurons. In a Hebbian synapse, if Neuron A fires and Neuron D is depolarized by an electrode (so that the combined depolarization is above threshold) then which of the following would occur?

a) Synapses 1, 2, and 3 would all be strengthened
b) Only synapse 1 would be strengthened
c) Synapses 1, 2, and 3 would all be weakened
d) all of the above

Question 21

Imagine you want to design a drug to increase memory, and you'd like to do this by targeting the molecular pathways that underlie long term potentiation (LTP). How would you do it? Assume you have the ability to make chemical compounds that inhibit or activate any protein you choose. In your answer, describe how manipulating this pathway will increase LTP.

Question 22

Consider the experiment depicted in figure 3.11. In the text Which of the following best characterizes these results?

A) EPSPs are increased in the control condition, therefore LTP has occurred.
B) Proteins required for LTP stabilization are made very near the synapse (rather than in the cell body)
C) Proteins must be transported from the dendrites to the synapse to stabilize ATP
D) all of the above

Question 23

Which of the following is thought to play a role in LTP?

A) glutamate receptors
B) CaMKII
C) calcium
D) changes to gene expression through chemical modification of DNA
E) all of the above

Question 24

In an experiment to understand LTP you apply a drug that limits phosphorylation while activating NMDA receptors. How would this affect your results?

A) synapses would likely be strengthened even more than expected
B) synapses would likely be strengthened less than expected
C) calcium levels would decrease substantially in the cells
D) no calcium entry would occur through NMDA receptors
E) all of the above might be a result of this drug's application

Question 25

Which of the following is NOT true of Purkinje cells?

A) They are thought be involved in movement and balance.
B) They are found in the cerebellum.
C) They use NMDA receptors for glutamate detection
D) They receive inputs from granule cells

Question 26

You examine a cerebellar slice under the microscope and observe a cell that is present in great numbers than a larger cell type around it. You are most likely seeing what type of cell?

A) Purkinje cell
B) granule cell
C) cortical neuron
D) all of the above

Question 27

Construct a table that lists features of long-term potentiation (LTP) on one side and long-term depression (LTD) on the other.

Question 28

Which of the following is NOT true of long-term depression (LTD)?

A) It is mediated by increases in intracellular calcium
B) It involves the weakening of synaptic connections
C) It relies on the insertion of additional AMPA receptors in the neuronal membrane
D) It has been studied extensively in the cerebellum

Question 29

You are performing experiments using brain slices of the cerebellum and find that synaptic changes lead to weakened associations between stimuli. This is an example of ___________________________.

Question 30

Consider figure 3.14. In the text What statement below represents the best characterization of these results?

A) The modification of synaptic strength can be dependent on the order that neuronal impulses arrive at the post-synaptic cell.
B) Synaptic strength is highly unpredictable.
C) The more closely that neuronal impulses occur in time, the stronger the synapse grows with the post-synaptic cell.
D) Spike timing is important for establishing LTP but not LDP.

Question 31

There is a balance between neurons being overly sensitive to stimuli and not sensitive enough. Outline the reasons why a neuron needs to regulate how it responds to stimuli. Propose another reason why a neuron might want to adjust its sensitivity to some type of stimulus besides those given in the text.

Question 32

A cortical neuron is cultured in the presence of a sodium channel blocker (TTX) for two days. Assuming that synaptic scaling occurs at a relatively constant rate, what would be the most reasonable prediction for the average EPSC after 24 hours in response to stimulation?

A) Less than 100% of control conditions.
B) About 150% of control conditions.
C) Greater than 192% of control conditions.
D) No EPSCs would be observed after 24 hours.

Question 33

Synaptic scaling is a phenomenon where

A) neurons adjust their sensitivity to stimuli dependent on their activity
B) synapses are increased or decreased in size proportional to the size of the neuron
C) the number of neurons in a given region of the brain corresponds to the activity in that region
D) synapses release neurotransmitters in amounts that correspond to their previous level of activity

Question 34

In an experiment, you find that cortical neurons that have not been exposed to glutamate for several days give far stronger responses than those that have been continuously exposed. This is an example of which phenomenon?

A) synaptic scaling
B) long-term potentiation
C) long-term depression
D) none of the above

Question 35

Which of the following is true of dendritic spines in the brain?

A) their sizes do not change
B) they are likely not involved in learning and memory
C) once formed, they tend to remain in place throughout an organism's lifetime
D) none of the above are true

Question 36

Based on the studies of birds mentioned in the beginning of section 3.5, what would you predict would be true of humans?

A) Adults would possess the same spines that were present as infants
B) Infants would have a lower rate of spine turnover than adults
C) Spines in adults would be larger than spines in infants
D) none of the above are true

Question 37

Analyze the experiment described in figure 3.17. In the text Which of the following is true?

A) new axonal growth may accompany learning to associate stimuli.
B) pseudoconditioned mice experience increases in axonal growth.
C) connections between the pons and cerebellum decrease following exposure to noxious stimuli
D) none of the above are true

Question 38

The tonotopic map in the auditory cortex is similar to the somatotopic map in the somatosensory cortex in that

A) The locations of sound and touch are both represented by specific parts of these cortical areas
B) Specific stimuli map to specific cortical regions
C) The frequency of perceptions of vibration in the periphery and eardrum maps to specific cortical areas
D) they are the only known examples of spatial mapping in the nervous system
E) all of the above are true

Question 39

In this chapter there are many instances where the brain structure and function is altered in response to experience. Select one of these examples as having implications for how human behavior might be a product of upbringing or past experience. What parallels can be drawn between these animal studies and possibilities for human experiences and behaviors?

Question 40

Consider figure 3.18. In the text If the rats had been given water every time they heard a 25Hz tone what would you predict would be different in the figure A that represents the trained animals?

A) More yellow would be present
B) More blue would be present
C) More red would be present
D) More green would be present

Question 41

Consider figure 3.18. In the text Do you think trained rats can still hear the same frequencies as naïve rats? Justify your response.

Question 42

What is true of rats that are trained to expect water in response to a given tone frequency?

A) The number of cortical neurons devoted to the detection of that frequency increases
B) The number of neurons in the auditory cortex increases
C) The rats experience a loss of ability to detect other frequencies
D) all of the above

Question 43

A tonotopic map in the brain describes a region where neurons are grouped together based on __________________________________________.

Question 44

Which of the following is NOT true regarding cortical areas devoted to sensory processes (such as auditory cortex) and motor control (motor cortex)?

A) Functionally related neurons are grouped closely together in these cortices
B) Experience changes the function of neurons in these cortices
C) Plasticity has only been documented in animals and it is unknown whether experience modifies cortical function in humans
D) Cortical plasticity is likely limited to only a few specific areas of the brain

Question 45

What has been observed in skilled musicians such as pianists and violinists?

A) They have increased brain volume
B) They have increased brain mass
C) They have increased area of the motor cortex that corresponds to hand control
D) all of the above

Question 46

Skilled musicians and violinists display changes in their _______________________ relative to amateurs.

A) motor cortices
B) auditory cortices
C) hippocampi
D) all of the above

Question 47

Consider figure 3.20. In the text Next to each finding
-________________ rats are raised in cages with other rats and no toys

A) social
B) enriched
C) enriched
D) deprived
Enriched

Question 48

Consider figure 3.20. In the text Next to each finding
-________________ rats are raised in cages with other rats, toys, and maze training

A) social
B) enriched
C) enriched
D) deprived
Enriched

Question 49

Consider figure 3.20. In the text Next to each finding
-________________ largest cerebral cortex at the point when the experiment was concluded

A) social
B) enriched
C) enriched
D) deprived
Enriched

Question 50

Consider figure 3.20. In the text Next to each finding
-________________ neurons that were packed most closely together at conclusion of experiment

A) social
B) enriched
C) enriched
D) deprived
Enriched

Question 51

Consider figure 3.20. In the text Next to each finding
-________________ most synapses at the conclusion of experiment

A) social
B) enriched
C) enriched
D) deprived
Enriched

Question 52

What type of environment early in life will lead to decreased neuron density in the adult rodent brain?

A) an environment filled with toys and social interactions
B) an environment filled with social interactions but no toys
C) an environment with few toys and no social interactions
D) the early environment has no effect on neuron density later in life

Question 53

You are studying two different rodent brains. One of them has an increased mass but decreased neuron density. This animal most likely experienced __________________________ early in life.

A) an environment filled with toys and social interactions
B) an environment filled with social interactions but no toys
C) an environment with few toys and no social interactions
D) an environment with only siblings present in the cage

Question 54

Consider figure 3.20. In the text The rats raised in an enriched environment had heavier brains and their neurons were spaced farther apart. What is taking up the extra space and adding mass to the enriched brains?

Question 55

Human brains seem to respond to enrichment in much the same way as rodent brains. Propose a hypothesis as to the specific human behaviors (infant and parent) that contribute to proper brain development.

Question 56

Which brain regions have been observed to display experience-dependent plasticity?

A) cerebellum
B) hippocampus
C) motor cortex
D) all of the above

Question 57

What is true of experience-dependent plasticity in the brain?

A) It has been observed in many different brain regions
B) it occurs mainly in motor cortex and sensory cortices
C) it is generally caused by injuries
D) all of the above

Question 58

An experiment is performed that removes a certain region of the hippocampus. The behavior of the animal is then observed and deficits are recorded. This is an example of a ______________________ experiment.

Question 59

An experiment is performed that over-expresses a protein known to be involved in LTP. The LTP is exaggerated. This is an example of a ______________________ experiment.

Question 60

In order to show a causal relationship between two events, it must be established that event one is both _______________ and _______________ in producing event two.

A) necessary; effective
B) necessary; sufficient
C) related to; associated with
D) sufficient; effective

Question 61

Chapter 3 gives a number of examples of how animals have been used to understand principles of neuronal signaling that apply to all creatures, including humans. Outline 5 examples of experiments that use animals and describe the hypothesis, results and conclusion for each.

Question 62

Chapter 3 gives a number of examples of how animals have been used in research. Do you believe that this use of animals is justified? Construct an argument using examples from the reading.

Question 63

Chapter 3 briefly discusses drugs that are being developed in order to increase the ability to establish LTP. When might this be helpful in terms of increasing health and improving quality of life?

Question 64

Drugs are currently in development that make it more difficult to establish LTP. What types of situations can you imagine where it would be beneficial to NOT have the ability to strengthen synaptic connections?