Basolateral amygdala astrocytes encode anxiety states

The basolateral amygdala (BLA) has been implicated in threat detection and the generation of anxiety states. While previous experiments have demonstrated the important role of BLA principal neurons in driving anxiety-related behaviors, population-level recordings suggest that principal neurons encode exploratory states rather than anxiety per se. This discrepancy raises the question of whether anxiety is indeed represented within the BLA. Here, using simultaneous in vivo calcium recordings in BLA astrocytes and principal neurons, we find that, in contrast to neurons, astrocyte activity provides a stable and scalable representation of anxiety states across an array of behavioral tasks. We show that driving BLA astrocyte activity increases anxiety-related behaviors and identify noradrenaline acting on α1 adrenoreceptors as responsible for endogenous astrocyte activation and subsequent modulation of anxiety. Our results shed light on a specialized encoding property of BLA astrocytes and establish these cells as key computational elements of anxiety circuits.