Analyses of vestibular cortical responses with Dipole-tracing method and functional near infrared

开发了一种评估前庭刺激对应的大脑功能定位的系统。在该系统中，在冷空气和热气刺激前庭引起眩晕的过程中，同时记录和分析脑电(EEG)和功能近红外光谱(FNIRS)，并在冷热刺激2~4min后观察两种血流的特征反应，以氧化血红蛋白为评价指标。一种是单纯性的大脑顶叶和颞叶血流增加，另一种是额叶血流的两相反应，先是前庭刺激后血流减少，然后当受试者感到眩晕时增加。这些显著的血流反应在大脑中非常广泛的区域观察到，如中央前回、额顶盖、额极、中央后回、边缘上回、顶上小叶和颞上回，前庭刺激时的脑电反应频谱分析显示θ波爆发，θ波对应的功率谱增加，提示脑电活动的增加可能与前庭刺激引起的眩晕相对应。这些结果表明，同时记录fNIR和EEG可以根据眩晕检测大脑皮质的活动，为外周性眩晕的诊断和治疗提供了非常有用的临床信息。

A system to evaluate functional localization in the brain corresponding to the vestibular stimulation was developed. In this system, a electro-encephalogram (EEG) and a functional near infrared spectroscopy (fNIRS) were simultaneously recorded and analyzed during vertigo elicited by the vestibular stimulations, which were made by the cold and hot air.Two characteristic responses of blood flow, evaluated by the oxidized hemoglobin, were observed after the cold and warm caloric stimulation for two to four minutes. One was simple increase of the blood flow, observed in the parietal and temporal area of the brain, the other was two phase response of the blood flow in the frontal area, in which at first the blood flow decreased just after the vestibular stimulation and then it increased when the test subject felt vertigo.These remarkable blood flow responses were observed in very wide area in the brain, such as precentral gyrus, frontoparietal operculum, frontal pole, postcentral gyrus, supramarginal gyrus, superior parietal lobule and superior temporal gyrus, the localization of which almost corresponded to those of the previous reports evaluated by other methods.The EEG responses during the vestibular stimulation indicated a burst of θ-wave and increase of the power spectrum corresponding to the θ-wave by the frequency analysis, which might suggest that the increase of brain activity according to the vertigo elicited by the vestibular stimulation.These results indicated that the simultaneous recording of the fNIRS and EEG could detect the activity of the cerebral cortex according to the vertigo and that our method could provide very useful clinical information for diagnosis and treatment of the peripheral vertiginous diseases.