Infrequent increases in stimulus intensity may interrupt central executive functioning during Rapid Eye Movement sleep.

This study examines the extent to which infrequent changes in the intensity of an auditory stimulus can interrupt the functioning of the central executive during natural sleep. In the waking, conscious state, highly relevant but unattended stimulus input may elicit a positive-going event-related potential, P3a, peaking at about 250 ms. P3a is presumed to reflect the interruption of the central executive controlling ongoing cognitive activities, resulting in potential awareness of stimulus input. In this study, both an increment and decrement in the intensity of a frequently occurring standard stimulus elicited a P3a during wakefulness. During Rapid Eye Movement sleep, only the increment continued to do so. Detection of an increase in the intensity of a standard stimulus is thought to be carried out by two separate systems, the transient detector system (responsible for the detection of transient energy) and the change detection system. By contrast, detection of a decrease in intensity is carried out only by the change detection system. This suggests that interruption of central executive functioning during Rapid Eye Movement is largely a consequence of sufficient output of the auditory transient detector rather than the change detector system. During stage 2, neither the decrement nor the increment was able to elicit a P3a. This is consistent with a deactivation of the central executive and a profound state of unconsciousness.