Overview of the procedure used to perform trans-cranial ultrasoundexposures using a standard stereotaxic positioning system. Step 1: Askin incision is made to expose the skull surface, and a metal pointer isused to locate the bregma and lambda sutures. Step 2: An ultrasound couplingchamber is placed over the skull with a thin layer of ultrasound gel betweenthe chamber and skull. The chamber is filled with degassed water. Step 3:The metal pointer is replaced with a focused ultrasound transducer whosefocus is now aligned with bregma. The rat brain atlas is used to determinethe appropriate distance to move the ultrasound focus to a targeted regionin the brain.