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

为了确定人类对气味的嗅觉功能是否在左右鼻孔和大脑半球具有类似于听力功能的优势，使用两个37通道的鱿鱼系统(Magne^&lt；TM&gt；，Bti Co.)，对所有受试者记录了60秒对宜人气味(草莓精华)和不愉快气味(异戊酸)的脑磁图(MEGS)。被文物污染的巨型炸弹被肉眼检查拒收。研究了7名脑磁图显示低水平伪影的受试者。用离散傅里叶变换的方法计算气味刺激时左右半球θ，α-1、α-2、β和γ频段的功率谱密度，在气味刺激时，θ，α-1、α-2和Megs-2频段在右侧鼻孔刺激时占主导地位。然而，在刺激左鼻孔时，左右半球之间没有观察到任何频段的功率谱密度的差异。伴随着难闻气味，刺激左侧鼻孔时，θ，α-1和β频段的功率谱密度在右侧大脑半球占优势。在刺激右鼻孔时，左右半球各频段的功率谱密度没有差异。这些结果表明，无论气味是愉快的还是令人不快的，嗅觉功能在右半球都占主导地位。然而，目前尚不清楚为什么右鼻孔对令人愉快的气味更敏感，而左鼻孔对不愉快的气味更敏感。

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.