Z轴和偏心旋转对人体听觉认知过程的影响

Effects of Z-axis and off-vertical axis rotation on human auditory cognitive processing

目的采用事件相关电位方法（ERP）研究刺激耳石器和水平半规管对人听觉认知活动的不同影响。方法17名受试者进行了相同梯形刺激曲线的Z轴和偏心50cm旋转。旋转过程分为各持续150S的3段：10°／s匀速旋转、0．6°／s^2的匀角加速度旋转和0．6°／s^2减加速度旋转。在旋转过程中，受试者按要求完成听力认知任务，即等概率中文阿拉伯数字语音信号2～9，听到奇数（靶信号）用按键进行反应，听到偶数（非靶信号）不按键。记录试验期间的脑电图，并对记录作了处理。结果偏心匀速旋转时ERP的N1和P2波幅低于对照，N2和P3潜伏期相对于对照减慢，非靶信号ERP的额区和颞区P2潜伏期相对于对照和Z轴旋转延长。偏心加速度或负加速度旋转时相对于Z轴旋转，反应时缩短。偏心和Z轴加速度旋转时相对于对照ERP的N1和P2波幅降低。偏心加速度旋转相对于Z轴旋转ERP的N1和P3潜伏期减慢，P2潜伏期和靶信号ERP的N2潜伏期加快。偏心和Z轴负加速度旋转时相对于对照靶信号ERP的P3峰值波幅降低，靶信号ERP的N1和P3潜伏期减慢，偏心负加速度旋转时非靶信号ERP的P3潜伏期快于Z轴旋转。结论偏心匀速旋转单纯刺激耳石感受器对听觉脑认知过程产生抑制作用；偏心加速度旋转同时刺激耳石和半规管时对脑认知过程的抑制作用减弱，可能与前庭感受器向中枢传人冲动增强有关。

Objective To explore the effects of otolith and semicircular canal stimuli on human auditory cognitive processing by means of event-related potentials （ERP）. Methods Seventeen college students served as subjects. They underwent Z-axis and 50 cm off-vertical axis rotation with same trapezoid stimuli curve respectively as follows： 150 s constant 10°/s rotation, 150 s constant 0. 6°/s^2 acceleration and then 150 s 0. 6°/s^2 deceleration. Subjects were asked to perform the auditory cognitive tasks during the rotation. The go/no-go 2 to 9 Arabic numbers in Chinese pronunciation with about 1 s interval were presented to the subjects through headphone and the subjects were asked to respond as quickly as possible to the odd numbers （target signal） and withhold to the even numbers （non-target signal）. EEGs of subjects were recorded during the experiment and the recordings were treated. Results As compared with control, the N1 and P2 amplitudes of ERP wave were decreased and the N2 and P3 latencies were lengthened during off-vertical axis constant 10°/s rotation. The frontal and temporal P2 latencies induced by non-target signal were longer than that in control and Z-axis constant 10°/s rotation. Compared with Z-axis acceleration and deceleration, the reaction time was shortened during off-vertical axis constant angular acceleration and deceleration. The N1 and P2 amplitudes decreased in Z-axis and off-vertical axis acceleration as compared with control. In contrast to Z-axis acceleration, the N1 and P3 latencies were lengthened while P2 and N2 latencies induced by target signal were shortened during off-vertical axis acceleration. Compared with control, the P3 amplitudes induced by target signal were decreased while N1 and P3 latency induced by target signals were lengthened during Z-axis and off-vertical axis deceleration. The P3 latency Induced by non-target signal during off-vertical axis rotation was shorter than that during Z-axis deceleration, Candusions It was suggested that off-vertical axis constant 10°/s rotation simply stimulated the otolith organ, so as exerted inhibition effect on the cogni- tive processing. Off-vertical axis acceleration and deceleration rotation stimulated both otolith organ and horizontal semicircular canal, the attenuation of inhibition effect may be caused by the increasing central afferent impulses from vestibular system.