The demonstration that astrocytes, the brain's most abundant cell type, participate in the formation of inhibitory synapses in the cortex suggests an important role for these cells in some neurological disorders. Astrocytes, named for their star-like shape, are ubiquitous brain cells known for regulating excitatory synapse formation through cells. Recent studies have shown that astrocytes also play a role in forming inhibitory synapses, but the key players and underlying mechanisms have remained unknown until now.