Effects of repetitive stimulation and reduced sensory input on cortical alertness

Abstract

This study was designed to investigate the effects of repetitive stimulation and reduced sensory input on cortical alertness. Two groups of subjects relaxed for 26.6 min during two conditions of repetitive auditory stimulation, while a control group was tested for the same period of time but with no stimulation. Continuous measures of cortical alertness were obtained from quantified EEG output in the 8–13, 4–8, and 2–4 Hz frequency ranges. Tonic skin conductance level and spontaneous fluctuations in skin conductance were also measured. There were no group differences in either the electrodermal measures or EEG output in the 4–8 and 2–4 Hz ranges. With regard to 8–13 Hz activity, however, EEG output fell in the control group but remained constant in the repetitive stimulation groups. These results do not support the Pavlovian contention that repetitive stimulation leads to a more rapid decline in cortical alertness than do conditions of reduced sensory input.