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Question

Dopamine Signal in Reward Uncertainty

Answer 1

Coding of reward uncertainty is distinct from reward prediction error highest sustained activation for CS with P=0.5 - when there is a chance but not certainty, dopamine neurons fire at a steady rate

Answer 2

happens through short and long term modification of synaptic transmission in the striatum. These changes can lead to optimised prediction of rewards following occasion until prediction errors no longer occur. transmitted in the striatum, a part of the brain. These changes help the brain better predict rewards over time until there are no more mistakes in predicting those rewards. | remember prediction error

Answer 3

Dopamine neurons do not respond to proportional size of rewards but to size of errors in reward prediction

Answer 4

measured dopamine release in the VMS and DLS daily 1h sessions of r 3 weeks active key (cocaine) and nonactive key (nothing) phasic dopamine release in the VMS during early self-administration and diminished in amplitude for week 2 and 3 phasic dopamine in DLS not present in early self-administration but appears in week 2 and 3 (progressively emerges) recreational to habitual use development of phasic dopamine in DLS depends on VMS motivational addiction to behavioral addiction

Answer 5

lOFC - value assignment mOFC - value comparison ACC - action value comparison

Answer 6

value related vs motor related which option is preferred, which action is selected

Answer 7

vmPFC vs MCC lesions stimulus vs action value card deck vs wrist movement associations and learned and relearned (contingencies were changed)

Answer 8

Action selection and action specification occur simultaneously and behaviour is a constant competition for most relevant action - sensory info is not collected to have a complete picture of environment but in an action dependent manner

Answer 9

Competition between potential actions via biasing by inputs from different sources - by lPFC: topdown control, based on task rules - by basal ganglia controls action based on expected reward - by parietal activity: decision making factors cells with different movement preferences mutually inhibit each other

Answer 10

set of loops spanning over central sulcus, each loop processes info relating to separate aspect of movement smell a cup of coffee (sensory cortex) knowing its lunchtime (PFC)

Answer 11

 Top-Down Control: higher brain areas, such as PFC, generate priority signals that guide attention. These signals bias the sensory cortices to process certain stimuli over others.  Sensory Filtering: Attention acts as a filter at the level of the sensory cortices, allowing only a subset of sensory signals to reach higher levels of processing. This selective processing is influenced by goals, expectations, and relevance.  The posterior sensory brain structures (visual or auditory cortices) are directly influenced by attention signals that filter incoming sensory data based on salience and relevance. - neurons in sensory areas modulate firing depending on how attention is allocated LIP is thought to contain a salience map

Answer 12

 Value Based Decision Making: Attention is not the initial filter, instead it arises from the processes involved in value-based decision making. =basal ganglia  State Estimation: The brain first estimates the most appropriate state for the current situation. This state estimation process involved learned associations and current goals, integrating sensory and other data.  Basal Ganglia assess and assign value to different potential states, effectively deciding which state should dominate. This dominant state then influences what the sensory cortices should prioritize and process.

Answer 13

cooperation of learned associations between inputs outputs and prior knowledge each state is a template for a particular situation and dictates what to attend to

Answer 14

pp observe motion of two balls moving from different starting points and different speeds towards a finish line, after short time ball disappears, pp have to predict - received feedback on performance or no feedback - error rate was kept 37% - or x on 26% of trials results - experiment 1 inhibition of habenula = disinhibition of VTA - correct trials, increased dopamine response, facilitating learning - less inhibition of VTA which inhibit aMCC so no ERN but excitation of VS and putamen (reward) error trials, opposite effect decreased dopamine response impairs learning =ERN can reflect either omission of reward OR higher uncertainty during errors Experiment 2 correct trials with x had similar activation patterns to error trials error trials with x lower habenula activity less inhibition of VTA which inhibits aMCC so no ERN MCC activated by error with negative feedback, = error monitoring

Answer 15

occurs 50-100ms post error ERN indicates a worse than expected result anti learning function disinhibition of aMCC - feedback signal error detection and internal error monitoring -by informative feedback :( - action outcome associations

Answer 16

What to do? - based on external sensory information about objects and internal information about current needs How to do? - based on external sensory information: info about spatial relationships among objects relative to configuration of own body

Answer 17

depression of dopamine system leads to disinhibition of MCC which elicits ERN - ERN also reflects emotional response to errors due to connection to limbic regions (amygdala) - leads to behavioural adjustment due to updates action outcome associations