Discrete Fourier transform analysis of nostril and cerebrum hemisphere dominance to pleasant and unpleasant odors as assessed by magnetoencephalography.

2001 Fiscal Year Final Research Report Summary

• Project/Area Number: 12671691
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Otorhinolaryngology
• Research Institution: Fukuoka University
• Principal Investigator: KATO Toshihiko School of Medicine, Fukuoka University Professor, 医学部, 教授 (80078766)
• Co-Investigator(Kenkyū-buntansha): KAKIGI Ryusuke Okazaki National Research Institute for Physiological Science, Professor, 生理学研究所, 教授 (10145196) ; HARADA Mirofumi School of Medicine, Fukuoka University Associate Professor, 医学部, 助教授 (00299562) ; SHIRAISHI Kimio Kyushu Institute of Design, Fukuoka University Associate Prof., 助教授 (90187518)
• Project Period (FY): 2000 – 2001
• Keywords: dominance / hemisphere / nostril / olfactory / magnetoencephalography

Research Abstract

To determine whether human olfactory function to odors has dominance in the right or left nostrils and cerebrum hemispheres similar to hearing function, magnetoencephalograms (MEGs) to a pleasant odor (strawberry essence) and an unpleasant odor (isovalcric acid) were recorded for 60 seconds hi ll participants with use of two 37-channel SQUID systems (Magne^<TM>, Bti Co.). MEGs contaminated by artifacts were rejected by visual inspection. The seven subjects whose MEGs showed low levels of artifacts were studied. The power spectrum densities of the θ, α 1, α 2, β, and γ, frequency bands in the right and left hemispheres during odor stimulation of each nositril were calculated on the basis of a 50-second portion of the MEGs by means of discrete Fourier transform analysis.
With the pleasant odor, the power spectrum densities of the θ, α1, and α2 frequency bands showed dominance in the right hemisphere during right-nostril stimulation. No difference, however, was observed between the right and left hemispheres in the power spectrum densities of any frequency band during left-nostril stimulation. With the unpleasant odor, the power spectrum densities of the θ, α1, and β frequency bands showed dominance in the right hemisphere in response to left-nostril stimulation. No difference was observed between the power spectrum densities of any frequency band between the right and left hemispheres during right-nostril stimulation.
These results suggest that olfactory function had dominance in the right hemisphere regardless of whether the odor was pleasant or unpleasant. However, it remains unclear why the right nostril odor was more sensitive to the pleasant odor and the left nostril more sensitive to the unpleasant odor.