差分回归分析技术在嗅觉磁共振功能成像研究中的价值

Value of differential regression analysis technique in the research on brain olfaction functional magnetic resonance imaging

目的:差分回归分析技术适用于生理学相关函数未知的复杂脑高级功能的功能磁共振成像研究,实验应用差分回归分析技术观察人脑嗅觉活动时相关中枢的动态激活区。方法:实验于2005-11/2006-01完成。选择对13例右利手、无嗅觉障碍的健康志愿者进行嗅觉刺激功能磁共振成像实验。①实验方法:刺激方式采用组块设计,先给予30次Scan(S)刺激,再给予第二次刺激15次S,之间有55次S作为控制任务;每位被试先给予愉快气体(乙酸戊酯),间隔足够长时间后,再给非愉快气体(吡啶)。采用GE Signa 1.5T echospeed MR/i磁共振成像系统进行功能图像扫描。②数据分析:在AFNI平台上,数据经头动校正、空间标准化、空间平滑等处理后,再用差分回归分析技术进行数据处理和分析获得嗅觉实验脑激活图。阈值P=0.005。结果:11例受试者的数据进入结果分析。①嗅觉实验激活脑区(双侧皆有)为海马、眶额回、丘脑背内侧核、扣带回的背侧及喙、杏仁核、前额叶及额内侧回、颞叶、岛叶、枕叶、脑干和小脑,各脑区反应时间均较刺激时间有不同程度的延后。②愉快气体与非愉快气体激活的脑区无显著差异(P>0.005),均以右侧大脑半球激活明显(P<0.005)。结论:差分回归分析技术是嗅觉等复杂的脑功能研究可行的实验分析方法,人脑嗅觉刺激是复杂的延迟反应过程,右侧大脑半球为嗅觉"优势半球"。

AIM： Differential regression analysis technique is suitable for the research of functional magnetic resonance imaging （fMRI） of physiology-associated complex brain functions. In this study, the dynamic activation region of related center under olfaction activity was observed using differential regression analysis technique. METHODS： The experiment was performed from November 2005 to January 2006. Thirteen right-handed healthy volunteers without olfaction impediment were selected for the olfaction study by functional magnetic resonance imaging. ①BIock method was used as stimulation pattern. The subjects were stimulated with Scan （S） for 30 times, followed by S for 15 times, between which there was S for 55 times as control. Before stimulation, every subject was given amyl acetate （pleasant gas）, then pyridine （unpleasant gas） after enough interval. The functional image scanning was performed using GE Signa 1.5T echospeed MR/l system. ②The raw fMRI data were disposed by DRA at AFNI-fMRI software base including realignment, normalization and smooth （P =0.005）. RESULTS： All 11 subjects were involved in the result analysis. ①The activation areas of the olfaction fMRI （two sides） were hippocampus, gyrus front-orbitale, dorsal medial nucleus of thalamus, the dorsal anterior cingulate cortex and the rostral anterior cingulate cortex, amygdala, prefrontal lobe, interior-frontal lobe, temporal lobe, insular lobe, occipital lobe, brain stem and cerebellum. The reaction time of each area was delayed compared with stimulation time. ②As for the activation areas, there was no significant difference between that induced by pleasant and unpleasant gases （P 〉 0.005）. Moreover, compared to left hemisphere, the activation areas in right hemisphere were more remarkable （P 〈 0.005）. CONCLUSION： Differential regression analysis technique can be used as an effective method for the complicated olfactory and other fMRI research. The sensory and cognitive process of olfaction is a kind of complicated chronic reaction, and right hemisphere is the dominant hemisphere of olfaction.