1. A system to reduce artifact in a signal acquired from a subject, the system comprising: a sensing assembly adapted to acquire a signal from a subject indicative of the subject's brain activity; a stimulation assembly adapted to stimulate one or more neurons of the subject; and a timing controller programmed to control the time the sensing assembly is powered to acquire the signal such that the sensing assembly is powered at a substantially different time than the time when the stimulation assembly stimulates the subject and that the sensing assembly is not powered to acquire the signal during the time the stimulation assembly stimulates the subject, wherein the acquisition time and the stimulation time are variable based upon the subject's predicted susceptibility to having a seizure.