OPPOSING MODULATION OF SOCIAL INTERACTION AND FOOD INTAKE BY NEUROTENSIN VS SOMATOSTATIN NEURONS IN THE LATERAL SEPTUM

Social behaviors, whether conflictual or cooperative, are essential for survival and reproduction. However, the neural circuit mechanisms that regulate different social behaviors are still not well understood. The lateral septum (LS), a key brain region, plays a role in regulating aggression and feeding behaviors. We previously showed that somatostatin-expressing (Sst) neurons in the LS promote food-seeking (Carus-Cadavieco et al., Nature 2017).
We investigated how lateral septum Sst- and neurotensin-expressing (Nts-) neurons control social interaction and feeding by combining optogenetics, chemogenetics, and calcium imaging in freely behaving mice. Furthermore, we performed whole-cell patch-clamp recordings to reveal the connectivity between these two neuronal populations.
Based on the calcium imaging data, we clustered Nts and Sst cells according to their distinct coding patterns for food and social interactions, as well as their responses to same-sex and opposite-sex intruders. Optogenetic activation of Nts cells resulted in increased social interaction. At the same time, opto- or chemogenetic activation of Nts cells decreased food intake.
Conversely, optogenetic activation of Sst cells in the lateral septum reduced social interactions. Both Nts and Sst neurons exhibited position-related firing; however, Sst neurons showed greater place field stability. Furthermore, whole-cell patch-clamp recordings confirmed a functional connection from LS-Nts to LS-Sst neurons.
In summary, our findings indicate that Sst- and Nts-expressing neuronal populations in the LS act in a complementary manner to regulate distinct aspects of innate behaviors.
We gratefully acknowledge support by DFG Walter Benjamin Programme to D.K. (project number: 551841466) and DFG SFB1089 and EXC2030-CECAD to T.K..