Influence of physical parameters of sound on the sensory gating effects of N40 in rats.

Sensory gating is the ability of the brain to modulate its sensitivity to incoming stimuli. The N40 component of the auditory evoked potential, evaluated with the paired click paradigm, was used to probe the gating effect in rats. The physical characteristics of the first and second sounds (S1 and S2), such as frequency, duration, and intensity, were altered in three experiments in this study. Changes in the physical characteristics of the paired click influenced the gating effect. If the two clicks remained identical, physical characteristics of the stimuli has minimal effects on gating, but if S1 was more salient than S2, gating was stronger and the opposite if S1 was fainter than S2. The greater the physical difference between S1 and S2, the more the gating effect was affected.