Cortical Representation to Odorant Stimulation: Statistical Non-parametric Mapping of Low Resolution Electromagnetic Tomography (LORETA)

J Korean Neurol Assoc > Volume 22(4); 2004 > Article

Journal of the Korean Neurological Association 2004;22(4): 334-339.

방향성 후각 자극에 의한 대뇌 피질의 활성: Low Resolution Electromagnetic Tomography (LORETA)를 이용한 비모수 통계 지도

정기영, 김재문 이일근 김지현 주은연 홍승봉 변홍식 이주형

성균관대학교 의과대학 신경과학교실, 영상의학과*, 충남대학교 의과대학 신경과학교실†, 건국대학교 의과대학 신경과학교실‡, GNR Community ㈜중앙연구소§

Cortical Representation to Odorant Stimulation: Statistical Non-parametric Mapping of Low Resolution Electromagnetic Tomography (LORETA)

Ki-Young Jung

Departments of Neurology and Radiology*, Sungkyunkwan University School of Medicine, Seoul; Department of Neurology, Chungnam National University College of Medicine†, Daejeon; Department of Neurology, Kunkuk University, College of Medicine‡, Seoul; Research Laboratory, GNR Community, Ltd.§, Seoul, Korea

Abstract

Background: Although olfactory stimulation has been known to produce effects on human mood and cognition, the specific EEG patterns of activity was reported diversely. The purpose of this study was to investigate EEG changes by odorant using low resolution electromagnetic tomography (LORETA) in young healthy subjects.
Methods: The EEG's of nineteen (10 males, 9 females) non-smoking right-handed college students were recorded after odorant stimulation. A nineteen-channel EEG was recorded referenced to linked ears before and during olfactory stimulation. Olfactory stimulation was presented with lavender essential oil by blotter method. The LORETA power was computed from ten 2-s epochs, separately for the different EEG frequencies. The power values were logarithmically transformed and paired sample t-tests were done for each voxel and frequency band (1.5-30 Hz). Statistical results were displayed 3-dimensionally on the standard brain template.
Results: All subjects experienced positive feelings (relaxed and pleasant) by olfactory stimulation with lavender oil (p<0.01). The LORETA power of theta and alpha band was increased in the dorsolateral and medial frontal areas, predominantly in the posterior cingulate gyri. The alpha LORETA power was also increased in bilateral orbitofrontal regions and the left perisylvian region including the insular cortex. Beta power was increased in the posterior cingulated gyri and mesial temporal region, predominantly on the left side.
Conclusions: These results suggest that olfaction associated with emotional feeling might induce brain electrical power changes not only in the limbic system but also in the neocortex with lateralization to the dominant hemisphere.Key Words: Olfactory stimulation, Emotion, Electroencephalograhy, Low resolution electromagnetic tomography, Statistical non-parametric mapping