Unveiling the functional connectivity of astrocytic networks with AstroNet, a graph reconstruction algorithm coupled to image processing.

Astrocytes form extensive networks with diverse calcium activity, yet the organization and connectivity of these networks across brain regions remain largely unknown. To address this, we developed AstroNet, a data-driven algorithm that uses two-photon calcium imaging to map temporal correlations in astrocyte activation. By organizing individual astrocyte activation events chronologically, our method reconstructs functional networks and extracts local astrocyte correlations.

Upregulation of astroglial connexin 30 impairs hippocampal synaptic activity and recognition memory.

Astrocytes crucially contribute to synaptic physiology and information processing. One of their key characteristics is to express high levels of connexins (Cxs), the gap junction-forming protein. Among them, Cx30 displays specific properties since it is postnatally expressed and dynamically upregulated by neuronal activity and modulates cognitive processes by shaping synaptic and network activities, as recently shown in knockout mice.

Prostaglandin D Controls Local Blood Flow and Sleep-Promoting Neurons in the VLPO via Astrocyte-Derived Adenosine.

Prostaglandin D (PGD) is one of the most potent endogenous sleep-promoting molecules. However, the cellular and molecular mechanisms of the PGD-induced activation of sleep-promoting neurons in the ventrolateral preoptic nucleus (VLPO), the major nonrapid eye movement (NREM)-sleep center, still remains unclear. We here show that PGD receptors (DP) are not only expressed in the leptomeninges but also in astrocytes from the VLPO.