Astrocytes Supply Presynaptic Terminals with a Sweet Incentive to Make Connections.

Glial cells shape neural circuits by secreting cues that contribute to the spatiotemporal control of connectivity. A new study in Neuron from Farhy-Tselnicker et al. (2017) shows that the astrocyte-secreted heparan sulfate proteoglycan GPC4 acts on presynaptic terminals to indirectly regulate AMPA receptor clustering and active synapse formation.