NOW vs LATER brain circuits: implications for obesity and addiction.

Balancing behaviors that provide a reward NOW versus behaviors that provide an advantage LATER is critical for survival. We propose a model in which dopamine (DA) can favor NOW processes through phasic signaling in reward circuits or LATER processes through tonic signaling in control circuits. At the same time, through its modulation of the orbitofrontal cortex, which processes salience attribution, DA also enables shifting from NOW to LATER, while its modulation of the insula, which processes interoceptive information, influences the probability of selecting NOW vs LATER actions on the basis of an individual's physiological state. Disruptions along these circuits contribute to diverse pathologies, including obesity and addiction.