Heterogeneous pericoerulear neurons tune arousal and exploratory behaviours

As the primary source of noradrenaline in the brain, the locus coeruleus (LC) regulates arousal, avoidance and stress responses^1,2. However, how local neuromodulatory inputs control LC function remains unresolved. Here we identify a population of transcriptionally, spatially and functionally diverse GABAergic (γ-aminobutyric acid-producing) neurons in the LC dendritic field that receive distant inputs and modulate modes of LC firing to control global arousal levels and arousal-related processing and behaviours. We define peri-LC anatomy using viral tracing and combine single-cell RNA sequencing with spatial transcriptomics to molecularly define both LC noradrenaline-producing and peri-LC cell types. We identify several neuronal cell types that underlie peri-LC functional diversity using a series of complementary neural circuit approaches in behaving mice. Our findings indicate that LC and peri-LC neurons are transcriptionally, functionally and anatomically heterogenous neuronal populations that modulate arousal and avoidance states. Defining the molecular, cellular and functional diversity of the LC and peri-LC provides a roadmap for understanding the neurobiological basis of arousal, motivation and neuropsychiatric disorders.