Sweet taste and nutrient value subdivide rewarding dopaminergic neurons in Drosophila.

ABSTRACT: Dopaminergic neurons provide reward learning signals in mammals and insects [1-4]. Recent work in Drosophila has demonstrated that water-reinforcing dopaminergic neurons are different to those for nutritious sugars [5]. Here, we tested whether the sweet taste and nutrient properties of sugar reinforcement further subdivide the fly reward system. We found that dopaminergic neurons expressing the OAMB octopamine receptor [6] specifically convey the short-term reinforcing effects of sweet taste [4]. These dopaminergic neurons project to the ?'2 and ?4 regions of the mushroom body lobes. In contrast, nutrient-dependent long-term memory requires different dopaminergic neurons that project to the ?5b regions, and it can be artificially reinforced by those projecting to the ? lobe and adjacent ?1 region. Surprisingly, whereas artificial implantation and expression of short-term memory occur in satiated flies, formation and expression of artificial long-term memory require flies to be hungry. These studies suggest that short-term and long-term sugar memories have different physiological constraints. They also demonstrate further functional heterogeneity within the rewarding dopaminergic neuron population.

SUBMITTER: Huetteroth W 

PROVIDER: S-EPMC4372253 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature