The Corticostriatal Circuit: Order Flashcards
classical conditioning
development of a physiological response to a cue for a reward.
- a passive form of learning
Pavlov’s dogs
one of the first studies of classical conditioning: food could be predicted by some other stimulus
laying out pavlov’s dogs study
- food was the primary reinforcer, salivating was the unconditioned reflex
- food was the primary reinforce and the bell was the secondary reinforcer (paired together), salivating was the unconditioned reflex
- the bell become the secondary reinforcer, bringing about the salivating as the conditioned response
classical conditiong and fear conditioning
fear learning is a negative form of classical conditioning
STUDY: monkeys trained to expect juice with cue
studies dopamine and reward
1. when unpredicted reward occurs, dopamine immediately after
2. when cue and predicted award, shift in dopamine from reward to cue
3. when predicted reward doesn’t occur, there’s dopamine release after cue but then a dip in dopamine when the reward is left out
primary reinforcer pathway
(ex. eating can trigger the release of dopamine)
BLA, HF, VTA (by way of primary enforcer) –> VS –> lateral hypothalamus, ventral pallidum (to lateral hypothalamus & NBM)
secondary reinforcer pathway
(paired with primary reinforcer)
BLA, HF, Ventral tegmental area (by way of secondary reinforcer) –> VS –> LH, VP (to LH & NBM)
primary reinforcers
food, drugs, alcohol, sex
STUDY: milkshake
(studied response to drinking milkshake if dehydrated and given water)
Finds: magnitude of VS activation positively connected with subjective exposure
what are the pathways of signaling for primary reinforcers
opioid signaling in hedonic hotspot
STUDY: favorite foods
*remember ugly pic of fav soup
Finds: direct neural activity in VS when viewing images of your favorite foods
STUDY: sex as a primary enforcer
(viewed porn in a scanner)
Finds: strong VS activation in men and women when viewing porn
*differs only in hypothalamus related to medial preoptic area between men & women (dimorphism)
primary reinforcer uniquely in humans
music (intrinsically rewarding)
humor
secondary reinforcers
visual cues: pictures of food (makes you salivate)
cigarette smokers: activation (craving)
STUDY: bong & cannabis
higher VS activation leading to higher vmPFC activation
(many had financial incentives)
higher VS and midbrain VTA activity in anticipation of winning money
STUDY: non-alcoholic beer
Finds: greater activation of VS even flavor activates the VS
- found dopamine release
uses of PET
can be used to see dopamine signaling
operant conditioning
goal-directed plans, working for a reward. motivation satisfied by action
(ex. it requires a specific behavioral response to get food)
operant conditioning pathway (need a plan)
dlPFC –> vmPFC –> VS
(vmPFC integrates bottom-up sensory interoceptive, contextual input with motivational states, leading to internal and external subjective awareness)
operant conditioning pathway (execution of plan)
VS –> Substantia Nigra –> DS –> DP –> vaN/ vlN of thalamus –> motor cortices
operant conditioning pathway (plan being executed correctly?)
(Monitoring)
VS –> SN –> DS –> dlPFC
operant conditioning pathway (error detection)
VS –> VP –> dmN –> dlPFC & vmPFC (to dACC and dlPFC)
operant conditioning pathway (if output/ goal is successful)
input planning –> VS –> output (action/ behavior) –> goal achieved –> VTA (dopamine release) (to VS)
operant conditioning pathway (goal not achieved by plan, no dopamine release)
new input –> VS –> dACC (back to new input) & new output
STUDY: dopamine with PET
more effort = more dopamine
release in vmPFC and striatum
STUDY: dopamine with fMRI
as it became harder (more effort required) –> more activity in the VS gate and more functional connectivity between VS and motor cortex
STUDY: cue, delay, target, winning money (MIDT, money incentive delay task)
delay: more activation of vmPFC in this anticipation, VS and VTA
–> engaged most in anticipation of forthcoming reward
what does VS and vmPFC activation mean?
indicates how pleasant/ enjoyable participants find substances (“hedonic hot spots”)
STUDY: shopping study
(asked participants to look at common items, ex. chocolate, and decide if they should buy them. gave them $25 and said they would ship the items to their homes – to mimic real-world behavior)
ACTIVATION:
preference – vs activation when shown product & price (especially during purchase)
price differential – vmPFC activation during price (especially when purchased)
purchase – insula activation during choice (especially when didn’t purchase)
STUDY: music
(brought favorite music) PET and bold fMRI data
FIND: greater dopamine and VS activation (more activated when we find something more pleasant)
STUDY: buying new music
magnitude of activation tracks how much you’re willing to pay to have a song
STUDY: humor
greater VS activity when find something funny
STUDY: social reciprocity
(present with a choice, either maintain both your earnings and maintain trust or increase your earnings and break the trust)
learn who is and isn’t trustworthy
FIND: VS gate activity and vmPFC increased when someone is generous and kind to us
STUDY: social reciprocity (response following the end of the game)
greater VS activation to faces of trustworthy partners
lower VS activation to faces of untrustworthy partners
(building patterns of association)
what is the impact of a positive social exchange on the corticostriatal circuit?
happy expressions & interactions –> BS activation
STUDY: pleasure in the suffering of others
(Red socks vs. Yankees, sports rivalries)
FIND: activity in the striatum and putamen with the success of their team and failure of the opposing team
activity in dACC with loss of your team
Understanding impulsivity
(think of the graphs here)
greater impulsivity = greater VS activity & lower dlPFC and dACC regions & reduced functional connectivity between VS and prefrontal regions
STUDY: impulsivity & delaying gratification
In children: ability to delay gratification in childhood can predict more success and less impulsivity
*caveat 1: when neglected child, taking most accessible option (Not waiting for second marshmallow) is the safest
caveat 2: depends on someones trustworthiness (higher trustworthiness = higher likelihood of waiting)
STUDY: effort & reward
(squeezing an inflated ball or pressing a button with pinky)
- greater effort required to obtain reward = greater dopamine release and cmPFC release (DA projects to vmPFC)
- correlated with greater activity in motor cortex
STUDY: shopping
(presented with image of item, wait, told price of item, wait, do you want to buy?, wait)
- greater VS activation for products purchased vs. those not purchased
STUDY: couples study
(couples separated in 2 fMRI scans simultaneously could communicate and send love notes)
- processing compliments, especially from a significant other –> greater VS and vmPFC activation
