Lateralized dominance of the nasal cycle is not reflected in the Olfactory Bulb volumes and cerebral activations

Abstract Background- Nasal cycle (NC) is a rhythmic change of lateralized nasal airflow mediated by the autonomous nervous system. Previous studies reported the dependence of NC dominance on handedness and hemispheric cerebral activity. Objective- We aimed to investigate firstly, the possible lateralized effect of NC dominance on olfactory bulb volume: the first cerebral region processing olfactory information, and secondly, the association of NC dominance with the lateralized cerebral dominance in terms of olfactory processing. Methods- Thirty- five subjects (22 women, mean age 26 ± 3 years) participated in the study. NC dominance was ascertained using a portable rhino-flowmeter, the “Nasal Holter” for a duration of 24 h, out of which 22 subjects had right-dominant NC and 13 subjects had left-sided dominance. Structural and functional brain measurements were assessed using a 3T MR scanner (Siemens). Vanillin odor was presented during functional scans using a computer-controlled olfactometer. Results and Conclusions- NC dominance was found to be independent of the lateralization of olfactory bulb volumes. Also, cerebral activations were found independent of the NC during odor perception. NC dominance is not associated with lateralized structural or functional differences in the cerebral olfactory system.