9319449 Bishop Recent studies have shown that cells within the brain do not always respond in the same way to a particular stimulus. One factor which determines how brain cells respond is chemicals that are released from special fibers that modulate ongoing signaling. One of these chemicals is called serotonin. The intent of this study is to determine the anatomical organization and physiological effects of serotonin on cells located in the mammalian cerebellum, which is a part of the brain that is essential for coordinating movement. Deficiencies in levels of serotonin have been implicated in several movement disorders. We must first define the basic organization and mechanisms of action of serotonin in cerebellar circuits before we can understand how deficiencies can cause disorganization of movement. ***
