The study investigates the integration of past events in hippocampal astrocytes, which are typically thought to lack central integration. The researchers found that astrocytic calcium signals in the hippocampus of adult mice can be conditionally integrated from distal processes to the soma, reflecting past neuronal and behavioral events on a timescale of seconds. Salient past events, such as pupil dilations, facilitate this propagation. Optogenetic activation of the locus coeruleus (LC), a key regulator of arousal, reproduces centripetal propagation, while pharmacological inhibition of α1-adrenergic receptors reduces it. This suggests that astrocytes are computational units that integrate calcium signals upon behaviorally relevant events, with noradrenaline release from the LC playing a crucial role in this process. The findings highlight a principle of spatiotemporal integration of salient past events within astrocytes in awake, behaving animals.The study investigates the integration of past events in hippocampal astrocytes, which are typically thought to lack central integration. The researchers found that astrocytic calcium signals in the hippocampus of adult mice can be conditionally integrated from distal processes to the soma, reflecting past neuronal and behavioral events on a timescale of seconds. Salient past events, such as pupil dilations, facilitate this propagation. Optogenetic activation of the locus coeruleus (LC), a key regulator of arousal, reproduces centripetal propagation, while pharmacological inhibition of α1-adrenergic receptors reduces it. This suggests that astrocytes are computational units that integrate calcium signals upon behaviorally relevant events, with noradrenaline release from the LC playing a crucial role in this process. The findings highlight a principle of spatiotemporal integration of salient past events within astrocytes in awake, behaving animals.