corticostriatal behavior & function

describe the study that showed a response bias to ambiguous stimuli

participants were presented with a circle with dots for eyes and a short vertical dash as the nose with no mouth

• they were then presented a long mouth or short mouth for 100 ms

• asked to respond if it was a short or long mouth

• however only some of the correct responses are reward as well as a disproportionate reward ratio where the long mouth is 3x rewarded

• overtime accurately identify the mouth that is rewarded more and falsely identify the short mouth as the long

  • implicitly learn that one stimuli is more associated with reward and more likely to respond with that stimuli: response bias

what becomes activated when presented with a greater rewarded stimulus (long mouth over short mouth)?

more activation in VS and OFC

what areas are active/responsive to the delivery of the reward to the lower reward stimulus?

activation in caudate and ACC

what is reinforced that create habitual patterns of behavior?

both the reward and the whole plan of action that resulted in the reward

describe the loop on how are actions generated and reinforced

VS modulates dopamine projection in midbrain (SN) --project→ DS → DP —trigger→ motor cortices that generate movement

describe the loop on how plans are reinforced

VS modulates dopamine projection in midbrain (SN) --project→ DS → dlPFC

describe the loop on how alternate plans are formed after a plan is not achieved

dACC recruits dlPFC to form alternative plans

what areas are activated during anticipation of sugar tea over salt tea?

VS

what areas are activated during anticipation of receiving vs actual delivery?

VS

what areas were activated during the milkshake study that required subjective evaluation of the milkshake?

VS, vmPFC, and OFC

VS is associated with __ __, while the OFC/vmPFC is more associated with __ __

VS is associated with anticipatory cues, while the OFC/vmPFC is more associated with evaluation of reward

what activated brain area in response to food images predicted the amount of BMI gain during first semester of college?

VS

describe VS response to attractiveness

more activated when responding to attractive stimuli

decrease in activity when responding to less attractive stimuli

describe activity in cocaine infusion study

nucleus accumbens, globus pallidus, and VTA increase

amygdala decrease

difference in brain activity during craving response of a drug vs rush response of a drug

more VS activity during craving

drug cues recruit what responses in the brain>

VS, vmPFC, OFC

anticipation is associated with __, while the experience is associated with __

DS, VS

describe the anticipation & expected value study

• participants first see a cue

• delay

• participant presses a button when target appears on the screen as quickly as they can and they earn a reward ($$)

• the amount of time the target is on the screen is based on their past performance to induce errors

• different shapes are used to refer to whether the upcoming trial may be a gain trial, loss trial, or neutral trial

• lines in the cue are used to indicate the magnitude of the possible loss or reward

• found MFC, VS, and midbrain activity with a larger response when it is more probable to receive a reward

describe the guessing game study

• participants told they had a deck of cards with no face cards

• shown the back of a card and told that when the card is flipped over to guess whether it will be higher or less than 5

• if they guess right they win money and positive feedback arrow but if they are incorrect they get a negative feedback arrow

• activation across striatal circuit, less VS because less anticipation, more in caudal and putamen

describe the results of the trust game study

trustworthiness of individuals you’re socially interacting with are modifying VS gate from motivated behavior & interacting with people who are more trustworthy, more sharing of resources elicit more VS response

what is predictive of purchasing a product in the shopping study?

VS response: larger response more likely to buy and vice versa

describe impulsivity

characterized by inclination to initiate behavior without adequate forethought as to the consequences

describe delay discounting

given two similar rewards, humans show a preference for one that arrives sooner rather than later and discount the value of the later reward

describe how the VS correlates with delay discounting

immediate reward is chosen over delayed reward the greater the response they have in the VS