We are interested in 4 disease conditions: Epilepsy, Alzheimer, Traumatic Brain Injury and Brain tumors. These may seem unrelated but share common changes in brain support cells named astrocytes and alterations in the brains vasculature. Astrocytes become reactive under all these disease conditions and change their homeostatic role to support normal brain function. They normally regulate blood flow but retractions of their processes impair blood flow and cause a break down of the blood brain brain barrier. We use mouse models in conjunction with live imaging and electrophysiology.