Is Handedness Associated with the Depth of the Olfactory Sulcus?

Zang, Yunpeng; Whitcroft, Katie L; Glöckler, Carmina; Hummel, Thomas

BACKGROUND Structural and functional asymmetry is frequent in biological systems. The aim of the present study was to examine whether there is a relation between handedness and the depth of the olfactory sulcus (OS) and reinvestigate whether there is a lateralization of OS depth. METHODS Forty-two healthy volunteers (mean age 24.1 years; 23 right-handed and 19 left-handed) participated. The subjects' brains were scanned using magnetic resonance imaging to assess OS depth. Normal olfactory function was ascertained using the Sniffin' Sticks odor identification test. RESULTS There was no significant difference in OS depth between right- and left-handed participants (right-handed mean: right OS depth = 11.3 mm, left OS = 10.6 mm; left-handed mean: right OS = 11.3 mm, left OS = 11.0 mm). Across all subjects, OS depth was significantly larger on the right side compared to the left. CONCLUSION Handedness has no major influence on OS depth. The present study confirmed that the right OS is deeper compared to the left OS, possibly indicating a right-sided lateralization of the olfactory system. IMPLICATIONS The depth of the right OS is larger than that of the left OS. No major effect of handedness was observed.