No Effects of Handedness on Passive Processing of Olfactory Stimuli: An FMRI Study Katrin Lübke & Marie Gottschlich & Johannes Gerber & Bettina M. Pause & Thomas Hummel Received: 30 September 2011 / Accepted: 21 December 2011 / Published online: 10 January 2012 # Springer Science+Business Media, LLC 2012 Abstract The study aimed to investigate possible differ- ences in lateralized olfactory processing in left- and right- handed subjects using a functional MRI paradigm. Twenty- four (14 female, 10 male) right-handers and 24 (14 female, 10 male) left-handers participated; their mean age was 24.0 years, all were in excellent health with no indication of any major nasal or other health problems. The rose-like odor phenyl ethyl alcohol and the smell of rotten eggs (H 2 S) were used for relatively specific olfactory activation in a block design using a 1.5-T MR scanner. Results indicated no major differences in lateralized olfactory activation between left- and right-handers. This suggests that in simple olfactory tasks, handedness does not seem to play a substantial role in the processing of olfactory information. Keywords Olfaction . Smell . Hemisphere . Lateralization Introduction Olfactory stimuli are processed to some degree ipsilaterally to the stimulated nostril which is different from other sensory systems (Doty et al. 1997; Lascano et al. 2010). However, similar to other systems, effects of handedness should be expected (Bryden and Steenhuis 1991). Lateralized differences in olfactory sensitivity in relation to the subjects' handedness have been reported in a number of psychophysical experiments. Frye et al. (1992) showed for 2-butanone odor detection thresholds that right-handers (RH; n 0 37) were slightly more sensitive on the left side of the nose, whereas left-handers (LH; n 0 38) were more sen- sitive on the right side. However, other research showed the contrary (Youngentoub et al. 1982), with LH being more sensitive on the left side whereas RH (n 0 10) had lower n- butanol odor thresholds on the right side. Two other studies did not find differences for phenyl ethyl alcohol (PEA) detection thresholds between LH and RH (Betchen and Doty 1998; Zatorre and Jones-Gotman 1990). When investigating more demanding olfactory tasks, Zatorre and Jones-Gotman (1990) reported that, other than with detection thresholds, odors are in general better dis- criminated when presented to the right nostril, this phenome- non being not significantly influenced by the subjects' handedness. In contrast, Hummel et al. (1998) reported the presence of such an influence. The current study aimed to investigate effects of handed- ness on functional odor processing in order to clarify the role of handedness in olfaction. Using a functional magnetic resonance imaging (fMRI) paradigm allowed us to regard differences between LH and RH in olfaction at the most basic level, independently of olfactory performance. Prelimi- nary work by Yousem and co-workers, who studied responses from 16 RH and 3 LH subjects, showed striking differences K. Lübke : B. M. Pause Institute for Experimental Psychology, Department for Biological Psychology and Social Psychology, Heinrich-Heine-University of Düsseldorf, Düsseldorf, Germany K. Lübke : M. Gottschlich : T. Hummel (*) Smell & Taste Clinic, Department of Otorhinolaryngology, University of Dresden Medical School, Fetscherstrasse 74, 01307 Dresden, Germany e-mail: thummel@mail.zih.tu-dresden.de J. Gerber Department of Neuroradiology, University of Dresden Medical School, Dresden, Germany Chem. Percept. (2012) 5:22–26 DOI 10.1007/s12078-011-9115-3