A dimmer switch for reward: the vagus sets the gain.

The vagus nerve, among its various functions, carries gut nutrient signals to brain reward circuits. In a recent study, Onimus and colleagues have shown it is more than a simple relay: vagal integrity is required for maintaining dopamine release and the circuit structure of the mesolimbic system to mount reward responses. These findings reveal the vagus as a tonic gatekeeper of motivation and reward.