Axonal control of striatal dopamine transmission: Direct drivers and diverse gates

Striatal dopamine (DA) transmission regulates motivation and action selection through the basal ganglia. Disruptions to DA signaling underlie a variety of common psychomotor disorders, including addiction disorders and Parkinson's disease. However, we require a better knowledge of the mechanisms that govern striatal DA transmission if we are to understand DA function and dysfunction fully. Activity in DA neurons has long been assumed to be the principal driver of striatal DA release, and for DA neurons this activity spans a broad range of firing frequencies, from tonic low frequencies to phasic bursts at higher frequencies. Current hypotheses suggest that phasic DA neuron activity encodes reward predictions, learning and/or salience. But how distinct modes of activity are reported to the striatum will depend on how DA axons and their presynaptic zones translate this, or other activity, in to DA release.