Two tales of how expectation of reward modulates behavior

• A common framework for reward-modulated perception and vocal behavior.
• Both behaviors involve the cortico-basal ganglia pathway.
• Reward modulates the readout process in perceptual decision making.
• Social context modulates neural variability via dopamine-dependent mechanisms.

Expectation of reward modulates many types of behaviors. Here we highlight two lines of research on reward-modulated perceptual decision making in primates and social context-modulated singing in songbirds, respectively. These two seemingly distinct behaviors are both known to involve cortico-basal ganglia-thalamic circuits. The underlying computations may be conceptualized using a simple, common framework. We summarize and compare our current knowledge of the two fields to motivate new experiments for each field, with the goal of finding general principles for how the brain implements reward-modulated behavior.