Misha B. Ahrens1, Baljit S. Khakh2 and Kira E. Poskanzer3 1Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, USA 2Department of Physiology and Department of Neurobiology, University of California Los Angeles, Los Angeles, California 90095, USA 3Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, California 94143, USA Correspondence: ahrensmjanelia.hhmi.org; bkhakhmednet.ucla.edu; kira.poskanzerucsf.edu

Astrocytes are predominant glial cells that tile the central nervous system and participate in well-established functional and morphological interactions with neurons, blood vessels, and other glia. These ubiquitous cells display rich intracellular Ca2+ signaling, which has now been studied for over 30 years. In this review, we provide a summary and perspective of recent progress concerning the study of astrocyte intracellular Ca2+ signaling as well as discussion of its potential functions. Progress has occurred in the areas of imaging, silencing, activating, and analyzing astrocyte Ca2+ signals. These insights have collectively permitted exploration of the relationships of astrocyte Ca2+ signals to neural circuit function and behavior in a variety of species. We summarize these aspects along with a framework for mechanistically interpreting behavioral studies to identify directly causal effects. We finish by providing a perspective on new avenues of research concerning astrocyte Ca2+ signaling.