Fois, G. R. | bioRxiv Science

bioRxiv2026

tVTA controls dual dopaminergic inputs to the external Globus Pallidus

Midbrain dopamine (DA) neurons critically regulate basal ganglia function through their widespread projections. While the nigrostriatal pathway is well characterized and represents the dominant source of DA in the basal ganglia, other nuclei such as the external Globus Pallidus (GPe) also receive dopaminergic innervation, yet no consensus exists about its precise anatomical origin. In addition, the GABAergic tail of the ventral tegmental area (tVTA) provides a major inhibitory input to midbrain DA neurons, but its influence over DA pathways to the GPe remains unknown. In the rat, we combined retrograde tracing, immunohistochemistry, and ex vivo electrophysiology to identify distinct populations of DA neurons in the substantia nigra pars compacta (SNc) and ventral tegmental area (VTA) that project to the GPe and display distinct electrophysiological properties. Using optogenetics and electrophysiology, we also demonstrate that these GPe-projecting DA neurons receive powerful inhibitory input from the tVTA. Together, our findings define both the origin and inhibitory control of dopaminergic innervation to the GPe, revealing a previously unrecognized disynaptic circuit (tVTA[->]DA[->]GPe) that refines our understanding of basal ganglia circuit function.

neuroscience↗

bioRxiv2022

The ventral striatum contributes to energy balance

Accumulating evidence points to dysregulations of common brain systems in eating disorders (ED), the Nucleus Accumbens (NAc) in particular. However, to which extent alterations in NAc activity contribute to ED-like dimensions remains unclear. Using chemogenetic manipulations of dopamine D1 receptor-expressing and D2-expressing neuronal subpopulations of the NAc in male mice, we assessed their respective roles in incentive processes, food intake and the balance between feeding and exercise-mediated energy expenditure. We found that D1-neurons facilitate effort for a food reward but decreased food intake, while D2-neurons have opposite effects. The anorexigenic influence of D1-neurons was accompanied by increased voluntary exercise while the orexigenic effect of D2-neurons was concomitant with decreased running, congruent with D2-neurons being more active than D1-neurons during feeding while it is the opposite during running. Chronic manipulations of each subpopulations had limited effects on energy balance. However, repeated activation of D1-neurons combined with inhibition of D2-neurons biased behavior toward activity-related energy expenditure leading to weight/fat loss, whilst the opposite manipulations favored energy intake and hence weight/fat gain. Strikingly, concomitant activation of D1-neurons and inhibition of D2-neurons precipitated weight loss in anorexia models. These results suggest that dysregulations of NAc dopaminoceptive neurons might be at the core of EDs.

neuroscience↗