Optimization and Evaluation of an Olfactory Stimulator for fMRI Studies

doi:10.11938/cjmr20172574

Abstract

Abstract: An automatically-controlled olfactometer that can be used in the magnetic resonance imaging environment was designed and built in this study. The overall system design was in accordance with the general requirements of stimulator and aimed to show improvement over an existing olfactometer in the laboratory. The device included two parts:the control system and the gas transportation system. The control system used LabVIEW platform-based software and adopted a virtual apparatus scheme. It was capable of providing man-machine interaction controlling stimulus sequence and gas paths according to the applications. The gas delivery system consisted of 4 variable gas paths and 1 constant gas path, through which clean air was transmitted to three gas-washing bottles filled with liquids having different odors. The fluctuation of gas flow measured by a Honeywell AWM43600 airflow sensor was within 0.3%, and the switching response time between different branches was about 1.07 s. Founctional magnetic resonance imaging (fMRI) experiments on olfaction were performed on 8 subjects with the stimulation device, providing odors of ethanol, pyridine and isoamyl acetate. The fMRI results demonstrated thalamus, amygdala, piriform cortex, orbital frontal cortex activations upon olfactory stimulation. It was concluded that the olfactometer built can deliver quantitative olfactory stimulus and meet the requirements for olfactory fMRI experiments.

Key words: fMRI, olfactory stimulator

CLC Number:

LIU Wei, WANG Hui, WANG Er-lei, CHEN Guang-qiang, YANG Xiao-dong. Optimization and Evaluation of an Olfactory Stimulator for fMRI Studies[J]. Chinese Journal of Magnetic Resonance, 2017, 34(4): 519-527.

References

[1]DOTY R L.Clinical studies of olfaction[J].Chem Senses.2005,30(Suppl 1):i207-i209. [2]HENKIN R I,LEVY L M.Functional MRI of congenital hyposmia:brain activation to odors and imagination of odors and tastes[J].J Comput Assist Tomogr.2002,26(1):39-61. [3]ATTEMS J,WALKER L,JELLINGER K A.Olfactory bulb involvement in neurodegenerative diseases[J].Acta Neuropathol.2014,127(4):459-475. [4]MURPHY C,CERF-DUCASTEL B,CALHOUN-HANEY R,et al.ERP,fMRI and functional connectivity studies of brain response to odor in normal aging and Alzheimer's disease[J].Chem Senses.2005,30(Suppl 1):i170-i171. [5]BURGHART-MESSTECHNIK CORPORATION.Olfactometer OL022[EB/OL].http://www.burghart-mt.de/index.php?p1=produkte&p2=olfaktometrie&p3=omi_m [6]SOBEL N,PRABHAKARAN V,DESMOND J E,et al.A method for functional magnetic resonance imaging of olfaction[J].J Neurosci Methods.1997,78(1,2):115-123. [7]VIGOUROUX M,BERTRAND B,FARGET V,et al.A stimulation method using odors suitable for PET and fMRI studies with recording of physiological and behavioral signals[J].J Neurosci Methods.2005,142(1):35-44. [8]JOHNSON B N,SOBEL N.Methods for building an olfactometer with known concentration outcomes[J].J Neurosci Methods.2007,160(2):231-245. [9]LUNDSTROM J N,GORDON A R,ALDEN E C,et al.Methods for building an inexpensive computer-controlled olfactometer for temporally-precise experiments[J].Int J Psychophysiol.2010,78(2):179-189. [10]SOMMER J U,MABOSHE W,GRIEBE M,et al.A mobile olfactometer for fMRI-studies[J].J Neurosci Methods.2012,209(1):189-194. [11]BESTGEN A,SCHULZE P,KUCHINKE L,et al.An extension of olfactometry methods:An expandable,fully automated,mobile,MRI-compatible olfactometer[J].J Neurosci Methods.2016,261:85-96. [12]有慧.嗅觉系统结构和功能MR成像研究[D].北京:中国协和医科大学,2007. [13]WANG X G,Zhu Z W,XV Y J,et al.Advances in automatic stimulation devices for functional magnetic resonance imaging[J].China Medical Devices,2013,28(1):1-8.王骁冠,祝祯伟,徐雅洁,等.功能磁共振成像自动刺激装置研究进展[J].中国医疗设备.2013,28(1):1-8. [14]王骁冠.一种用于fMRI的嗅觉刺激装置设计与验证[D].长春:中国科学院长春光学精密机械与物理研究所,2014. [15]WU J.L,ZHANG Q,ZHANG J W,et al.Functional MRI study on regional brain responses to pleasant and unpleasant odors[J].Chinese Journal of Medical Imaging Technology,2006,22(1):2-6.伍建林,张清,张竞文,等.愉快及非愉快气体激活相应脑区的功能磁共振成像实验研究[J].中国医学影像技术.2006,22(1):2-6. [16]NI M F,WU J L,ZHANG Q,et al.Functional MRI research of smoker's responses to smoking olfactory cue[J].Chinese Journal of Medical Imaging Technology,2010.26(2):238-242.倪鸣飞,伍建林,张清,等.功能磁共振成像观察吸烟成瘾者对香烟的嗅觉诱导反应[J].中国医学影像技术.2010,26(2):238-242. [17]POELLINGER A,THOMAS R,LIO P,et al.Activation and habituation in olfaction-An fMRI study[J].Neuroimage.2001,13(4):547-560.