Single-Cell Resolution of Individual Variation in Hypothalamic Neurons Allows Targeted Manipulation Affecting Social Motivation

One great challenge in neuroscience is connecting molecular and cellular phenotypes to behavioral consequences. Using social motivation as a test case, we propose that individual behavioral trait variation can be leveraged to identify novel components of social reward circuits in the brain. Specifically, we hypothesized that either proportion or molecular features of distinct neuron classes in the hypothalamus can predict individual differences in social motivation. To test this, we generated high-precision single-nucleus RNA-sequencing profiles of >120,000 neurons from the hypothalamus and adjacent thalamus from 36 mice assessed for social motivation, balancing across sex and an autism-associated mutation genotype. Analysis of IEG patterns revealed that PVN Agtr1a+ neurons negatively predict social behavior. Consistent with this, FDA-approved AGTR1A antagonists increase social orienting. Next, analyzing neuronal subtype proportions as predictors of social behavior, we identified multiple neuronal populations whose relative abundance correlated with individual differences in social reward-seeking, particularly the Nxph4+ neurons of the posterior and lateral hypothalamus. Subsequent chemogenetic inhibition of these suppressed multiple aspects of social motivation. This work establishes a proof-of-principle for a new approach using single-cellsingle cell genomics to identify neural substrates for behavior and identifies cellular determinants of social motivation, which suggest therapeutic avenues for disorders with social deficits.