The Influence of Ultradian Autonomic Rhythms, as Indexed by the Nasal Cycle, on Unilateral Olfactory Thresholds

Abstract

Cyclic side-to-side variations in the autonomic tone of the nasal mucosae produce corresponding changes in nasal patency. This 90 minute to 4 hour “nasal cycle” is correlated with a number of ultradian rhythms, including asymmetries in left:right cerebral EEG activity and differential performance on visual/spatial psychological tasks (Eccles, 1978; Klein et al., 1986; Werntz et al., 1984). Several authors have proposed that the nasal cycle is part of an overall physiological rhythm known as the Basic Rest-Activity Cycle (BRAC). Thus, relatively greater airflow through the left nasal chamber is associated with the ‘REST’ phase of the BRAG and relatively greater airflow through the right nasal chamber is associated with the ‘ACTIVITY’ phase of the BRAC. During the ‘REST’ phase of the BRAC there is a preponderance of right hemispheric EEG activity, a spatial cognitive mode, and a parasympathetic predominance in the stomach, intestines, and other unpaired body organs. During the ‘ACTIVITY’ phase of the BRAG, greater left EEG hemispheric activity, a verbal cognitive mode, and sympathetic predominance in unpaired organs occurs (Kennedy et al., 1986).