1. A method performed by an implantable medical device to treat a medical condition in a patient having a brain, a vagus nerve, a trigeminal nerve, and a glossopharyngeal nerve, the method comprising: applying a first electrical signal to a portion of at least one of the vagus nerve, the trigeminal nerve, and the glossopharyngeal nerve of the patient, the first electrical signal comprising a series of microbursts, a number of pulses per microburst, an interpulse interval, an interburst period between successive microbursts in the series of microbursts, and a microburst duration, the interburst period is at least 100 milliseconds, the number of pulses per microburst is from 2 pulses to about 15 pulses, and the microburst duration is less than about 1 second, at least one of the interpulse interval, the microburst duration, and the interburst period is selectable to enhance nerve evoked potentials in the brain of the patient; discontinuing applying the first electrical signal; and applying a second electrical burst signal to the portion of at least one of the vagus nerve, the trigeminal nerve, and the glossopharyngeal nerve; wherein the second electrical burst signal comprises more than 50 pulses per burst or a burst duration of at least 7 seconds.