Making sense of astrocytic calcium signals - from acquisition to interpretation

Astrocytes functionally interact with neurons and with other brain cells. Although not electrically excitable, astrocytes display a complex repertoire of intracellular Ca²⁺ signalling that evolves in space and time within single astrocytes and across astrocytic networks. Decoding the physiological meaning of these dynamic changes in astrocytic Ca²⁺ activity has remained a major challenge. This Review describes experimental preparations and methods for recording and studying Ca²⁺ activity in astrocytes, focusing on the analysis of Ca²⁺ signalling events in single astrocytes and in astrocytic networks. The limitations of existing experimental approaches and ongoing technical and conceptual challenges in the interpretation of astrocytic Ca²⁺ events and their spatio-temporal patterns are also discussed.