ABSTRACT
The rationale for using ERs intraoperatively is very simple: all naturally occurring external stimuli detected by the sense organs, such as sounds and lights, are transmitted to the brain in the form of electrical signals through various sensory neural pathways. If these pathways are structurally and functionally intact, the signals reaching the brain give rise to certain patterns of activity. Thus, like the natural stimuli, the delivery of experimental stimuli, such as tones or electrical pulses, and the simultaneous observation of the resulting patterns of activity provide an instantaneous display of the status of the sensory neural structures intervening between the stimulation and recording sites.
