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Exam 2: Dopamine and Principles of Learning

Terms in this set (16)

Living in Boulder, snow is a way of life. You and your roommate got a steal on a cheap apartment right above the place where all the sand trucks load up before and during every snowstorm, making a piercing BEEP! every time they back up to the loading dock. You notice that over time, the beeping make you more anxious and more likely to get up and shut the window, while in contrast your roommate is like, "huh, I don't even notice anymore!" You are displaying _______ while your roommate is displaying ____________ to the auditory stimulus.

a) sensitization; habituation
b) habituation; sensitization
c) habituation; sensory adaptation
d) conditioning; opponent processing
e) siphon extension; gill withdrawal reflex
a) sensitization; habituation
What is the general goal of opponent processes, whether it is regarding behavior or neurobiological situations?

a) Biological systems strive to maintain homeostasis; "B" processes are adaptations that work to bring unexpected changes ("a" processes) back to normal
b) Like a "fight or flight" response, opponent processes prepare the organism to defend against an opponent
c) Animals have to learn which process - "a" or "b" - is most salient, and then use that information to guide their responding
d) Over learning, the goal is to generate enough "a" process to counteract innate "b" processes
e) Generate a more exciable "up state" that is more conducive to learning and attention
a) Biological systems strive to maintain homeostasis; "B" processes are adaptations that work to bring unexpected changes ("a" processes) back to normal
For your experiment, you want to know how animals learn about the relationship between cues (CS) and salient outcomes (US), so you set up two CS-US associations: CS(A) is a tone 5-second tone where a food pellet is delivered precisely at then end of each tone, whereas CS(B) is a 5-sec light presentation followed by a one-sec gap before the delivery of an annoying-puff to the face. In these experiments, CS(A) is a(n) ______________ and CS(B) is a(n) _________________

a) delay conditioning design; trace conditioning design
b) conditioned cue; conditioned inhibitor
c) "a" process; "b" process
d) V; delta-V
e) sensitized cue; habituated cue
a) delay conditioning design; trace conditioning design
Which of the following is most likely to establish an inhibitory relationship for Cue X?

a) Every time you present Cue A, the animal gets 5 pellets, but when you present A and X together, the animal gets 2 pellets
b) When the animal gets Cue A, it gets 3 pellets, but when it gets Cue X it gets no pellets
c) When the animal get Cue A, it gets 2 pellets, but when A and X are presented together, the animal gets 5 pellets
d) The animal receives Cue A and gets no pellets, but when it gets Cue X, it also receives no pellets
e) Pellets are distributed completely at random, so the animal is just as likely to receive pellets when Cue X is on as when it's off
a) Every time you present Cue A, the animal gets 5 pellets, but when you present A and X together, the animal gets 2 pellets
You are interested in proving that dopamine release in the insula cortex is necessary for learning about cue-reward associations. How should you set up your experiment to test this idea?

a) In a TH::Cre rat, infuse a cre-dependent AAV coding for halorhodopsin into the VTA, and present optical silencing of terminals over the terminals in the insula during conditioning
b) In a Vgat::cre mouse, infuse a cre-dependent AAV coding for channelrhodopsin into the VTA, and stimulate the VTA with light during conditioning
c) In one group of animals, bilaterally inhibit the insula with halorhodopsin during conditioning, while in another group of animals, bilaterally inhibit the VTA with halorhodopsin
d) In a Vglut::Cre rat, infuse an AAV coding for a fluorescent tracer into the insula, and then optically silence terminals in the VTA during conditioning
e) In a Vgat::cre mouse, infuse cre-dependent AAV-NpHR into both insula and VTA, optically inhibit the VTA during conditioning
a) In a TH::Cre rat, infuse a cre-dependent AAV coding for halorhodopsin into the VTA, and present optical silencing of terminals over the terminals in the insula during conditioning
You have designed an experiment as follows until the animal has learned this extremely well:
Cue A --> 3 pelletsCue B --> 3 pellets
On the day of test, you introduce a novel Cue X such that the compound cue is delivered:
ABX --> 3 pellets
According to the Rescorla-Wagner model, what do you anticipate the animal will learn about Cue X if it is later presented alone (i.e., what is V(x))?

a) Animal will treat Cue X as an inhibitor because the outcome was less than what it expected
b) Animal will show no conditioning to Cue X because of blocking
c) Animal will show excitatory conditioning to Cue X because it is contingently paired with 2 pellets
d) Animal will be unable to attend to Cue X because attention is a limited resource
e) Animal will learn that Cue X overshadows Cues A and B because A and B are old and X is novel
a) Animal will treat Cue X as an inhibitor because the outcome was less than what it expected
In question 6, I used a colloquial term "learned extremely well" to talk about the first phase of the experiment. In terms of conditioning modeling, what does this mean more formally?
Note: Canvas won't let me put greek letters in the answers, so a reminder:
λ = lambda
∑ = sum of
α = alpha
β = beta
Δ = delta

a) lambda is equal to sum of all present V's
b) lambda is equal to delta-V
c) alpha-V is equal to beta-V
d) all Vs have converged to zero
e) delta-V is now equal to sum of all present V's
a) lambda is equal to sum of all present V's
You conduct a new experiment where (note this is a little different from the one in Question 6):
PHASE 1
Cue A --> 2 pelletCue B --> 2 pellet
Assuming they have learned this first phase perfectly, the rats then move on to the next phase, where you introduce a novel Cue C:
PHASE 2
ABC --> 2 pellets
In these animals, you have infused GRABDA into the nucleus accumbens, and an optical fiber with the tip in the same location (NAc) for fiber photometry.
What data do you predict will will obtain during the cue presentations for the Cue A alone (phase 1) compared to the first time the rats encounter compound cue ABC (phase 2) at the time of cue presentation?

a) The GRABDA signal will be larger for ABC than for A alone
b) GRABDA signals for Cue A alone will be the same as for ABC
c) GRABDA signal for Cue A is less than ABC because of a negative prediction error
d) Using GRABDA, during Cue A will silence dopamine transmission, leading to a negative (aversive) signal to ABC
e) You cannot predict anything about cue signal from the information provided (none of the above)
!= e
You repeat the same experiment as in Question 8; again:
PHASE 1
Cue A --> 2 pelletCue B --> 2 pellet
Assuming they have learned this first phase perfectly, the rats then move on to the next phase, where you introduce a novel Cue C:
PHASE 2
ABC --> 2 pellets
In these animals, you have infused GRABDA into the nucleus accumbens, and an optical fiber with the tip in the same location (NAc) for fiber photometry.
However, now you compared the GRABDA data at the time of reward receipt. Compare your anticipated GRABDA effect at the time of reward receipt at the very end of Phase 1 for Cue A (when it is ell-learned) and the first trial of the ABC compound in Phase 2.

a) There should be no change in GRABDA signal for the Cue A outcome, but a negative loss in fluorescence for the rewards after ABC
b) The GRABDA signal for both Cue A and Cues ABC will be identical because they are both the same reward
c) GRABDA will be greater for ABC than A alone because of summation
d) GRABDA will optogenetically suppress dopamine at both rewards, leading to loss of motivated behaviors for the cues
e) You cannot predict anything about reward signal from the information provided (none of the above)
a) There should be no change in GRABDA signal for the Cue A outcome, but a negative loss in fluorescence for the rewards after ABC
In the famous Schultz, Dayan, and Montegue (1997) paper, how did they explain the phenomenon that midbrain VTA/SNc neurons that used to fire more during juice rewards stopped firing when the a visual predicted the same reward?

a) Dopamine neurons encode a prediction error, not reward. So when the cue predicted the juice, it was no longer surprising (no prediction error)
b) The juice became less rewarding over time because of a "b" process and was no longer enjoyed
c) The electrode lost sensitivity and was unable to record activity for rewards after already detecting firing for the preceding cue
d) The lack of firing during a reward receipt in this case is a negative prediction error
e) Dopamine neurons prefer conditioned stimuli (CS) over unconditioned stimuli (US), so the firing reflects this innate preference
a) Dopamine neurons encode a prediction error, not reward. So when the cue predicted the juice, it was no longer surprising (no prediction error)
*Click ALL that apply*
Which of the following options are ways to observe changes in activity in dopamine neurons?

a) increase in fluorescence in GRABDA-expressing neurons in the NAc
b) an increase in the number of dots in a raster plot of recorded dopamine neurons
c) a taller height of a histogram of recorded phototagged ChR2-expressing neurons in a TH::cre rat
d) phototagging and recording the histogram of ChR2-expressing neurons in a Vgat::cre mouse
e) using a 2-photon miniendoscope to see increases in GCaMP fluorescence in the VTA of a standard rat
...
In a DAT::cre mouse (same as the type used by Cohen et al from the readings), you have expressed ChR2 in the VTA using a cre-dependent vector AAV-DIO-ChR2-EYFP. You then optically stimulated a mesolimbic neuron in the VTA which has changed the activity in a neuron the direct pathway. Which of the following provides a valid description the pathway you have manipulated in this experiment?

a) You have stimulated a dopamine neuron that projects to a D1R neuron in the NAc
b) You have stimulated a GABA neuron that projects to a D1R-expressing neuron in the PFC
c) You have stimulated a dopamine neuron that projects to a D2R-expressing neuron in the striatum
d) While you have shown a connection between the VTA and NAc, you cannot know whether these involve dopamine release or D1R/D2R cells specifically
e) You have stimulated a dopamine cell that projects to a D2R-expressing cell in the NAc
a) You have stimulated a dopamine neuron that projects to a D1R neuron in the NAc
Targets of dopamine release, such as those in the NAc or PFC, can express ______________ receptors, but dopamine neurons themselves can express _________ receptors

a) D1-like and D2-like; D2-like
b) D1-like; D1-like and D2-like
c) dopamine; GABA
d) dopamine; tyrosine hydroxylase
e) direct pathway; indirect pathway
!= d
You have obtained a D2::GFP reporter mouse which means that every cell that expresses a D2 receptor glows green with fluorescence. You observe one of these neurons in a slice dish, and then flow into the chamber some dopamine. What will likely happen on the intracellular side of the neuron in this case?

a) dopamine binding will trigger activity of a G(i) subunit and decrease cellular excitability via adenylyl cyclase activity
b) dopamine binding will trigger activity of a G(s) subunit and increase cellular excitability via adenylyl cyclase activity
c) dopamine binding will open sodium channels to depolarize the cell
d) dopamine binding will open potassium channels to hyperpolarize the cell
e) it's not possible to know without first knowing whether this is occurring in a direct pathway or an indirect pathway neuron
a) dopamine binding will trigger activity of a G(i) subunit and decrease cellular excitability via adenylyl cyclase activity
Based on properties of the D1 receptors, which of the following is most likely to be true?

a) a D1R-positive neuron can be observed in the dorsal striatum of a D1::cre mouse
b) A D1R neuron will always be also positive for tyrosine hydroxylase, the enzyme that is necessary for dopamine synthesis
c) activation of a D1R neuron via optogenetics will trigger avoidance behaviors
d) D1R neurons cannot receive input from SNc, which is an exclusively D2R-targeting pathway
e) D1R neurons will likely also express D3 and D4 subtypes of receptors
a) a D1R-positive neuron can be observed in the dorsal striatum of a D1::cre mouse
The neural pathway from the midbrain to the nucleus accumbens constitutes the __________ and the neuronal pathway back to the midbrain that first synapses onto the subthalamic nucleus is the ______________.

a) mesolimbic pathway; indirect pathway
b) direct pathway; indirect pathway
c) mesolimbic pathway; nigrostriatal pathway
d) dopaminergic pathway; noradrenergic pathway
e) direct pathway; imesolimbic pathway
!=b
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