Download "Dissociable dopaminergic control of saccadic target selection and its implications for reward modulation"

To investigate mechanisms by which reward modulates target
selection, we studied the behavioral effects of perturbing dopaminergic
activity within the frontal eye field (FEF) of monkeys performing
a saccadic choice task and simulated the effects using a plausible
cortical network. We found that manipulation of FEF activity either
by blocking D1 receptors (D1Rs) or by stimulating D2 receptors
(D2Rs) increased the tendency to choose targets in the response field
of the affected site. However, the D1R manipulation decreased the
tendency to repeat choices on subsequent trials, whereas the D2R
manipulation increased that tendency. Moreover, the amount of
shift in target selection resulting from the two manipulations correlated
in opposite ways with the baseline stochasticity of choice
behavior. Our network simulation results suggest that D1Rs influence
target selection mainly through their effects on the strength of inputs
to the FEF and on recurrent connectivity, whereas D2Rs influence the
excitability of FEF output neurons. Altogether, these results reveal
dissociable dopaminergic mechanisms influencing target selection
and suggest how reward can influence adaptive choice behavior via
prefrontal dopamine.