Astrocyte ensembles manipulated with AstroLight tune cue-motivated behavior

Astrocyte regulation of behavioral outputs: the versatile roles of calcium

Behavior arises from coordinated brain-wide neural and glial networks, enabling organisms to perceive, interpret, and respond to stimuli. Astrocytes play an important role in shaping behavioral output, yet the underlying molecular mechanisms are not fully understood. Astrocytes respond to intrinsic and extrinsic cues with calcium (Ca2+) fluctuations, which are highly heterogeneous across spatio-temporal scales, contexts, and brain regions. This heterogeneity allows astrocytes to exert dynamic regulatory effects on neuronal function but has made it challenging to understand the precise mechanisms and pathways linking astrocytic Ca2+ to specific behavioral outcomes, and the functional relevance of these signals remains unclear. Here, we review recent literature uncovering roles for astrocytic Ca2+ signaling in a wide array of behaviors, including cognitive, homeostatic, and affective focusing on its physiological roles, and potential pathological implications. We specifically highlight how different types of astrocytic Ca2+ signals are linked to distinct behavioral outcomes and discuss limitations and unanswered questions that remain to be addressed.

ASTROCYTES AND ALCOHOL THROUGHOUT THE LIFESPAN

Evidence for involvement of astrocytes in several neurodegenerative disorders and in drug addiction has been emerging over the last two decades, but only in recent years have astrocytes been investigated for their roles in alcohol use disorder (AUD). As a result, there is a need to evaluate existing preclinical literature supporting involvement of astrocytes in the effects of alcohol exposure. Here we review emerging evidence about responses of astrocytes to alcohol, and the contributions of astrocytes to the development of AUD. We review studies of single-cell RNA sequencing with a focus on alcohol and astrocyte heterogeneity, astrocyte reactivity, and the role of astrocytes in remodeling the extracellular matrix. Effects of alcohol on astrocyte-modulated synaptic transmission are also discussed emphasizing studies never reviewed before. Since astrocytes play essential roles in brain development, we review recent research on the role of astrocytes in fetal alcohol spectrum disorders (FASD) which may also shed light on fetal development of psychiatric disorders that have a high prevalence in individuals affected by FASD. Finally, this review highlights gaps in knowledge about astrocyte biology and alcohol that need further research. Particularly, the dire need to identify astrocyte subpopulations and molecules that are susceptible to alcohol exposure and may be targets for therapeutic intervention.