Dopamine manipulations drive changes in information sampling in healthy volunteers

Background: Information sampling is the cognitive process of accumulating information before committing to a decision. Patients across numerous disorders show decreased information sampling relative to controls. Aims: Here, we used the Beads and the Best Choice Tasks to study the role of dopamine signaling in information sampling. Methods: Participants were given placebo, amisulpride, or ropinirole in each session, in a double-blind cross-over design. Results: We found that ropinirole (agonist) increased the number of beads drawn in the Beads Task specifically when participants faced a loss, and decreased the rank of the chosen option in the Best Choice Task. Conclusions: These effects are likely driven by a combination of effects at presynaptic D₂ receptors, which affect dopamine release, and post-synaptic D₂ receptors. Increased D₂ relative to D₁ receptor activation in the striatum leads to increased sampling in the loss condition in the Beads Task. It also leads to choice of a poorer ranked option in the Best Choice Task. Decreased D₂ relative to D₁ receptor activation leads to decreased sampling in the Beads Task in the loss condition.