It is increasingly apparent that synapses are tripartite structures. In addition to the pre- and postsynaptic terminal, the astrocyte (a sub-type of glial cell) acts as a third element that wraps around the synaptic structure to control synapse formation and function. The goal of my laboratory is to identify the mechanisms by which astrocytes regulate synaptic transmission, neuronal circuits and their critical role in controlling behavior. Our recent studies also focus on the roles of these glial cells in disorders of the nervous system.