前庭刺激对选择注意影响的事件相关电位研究

目的应用事件相关电位(ERPs)技术观察线性改变前庭刺激时晚期选择注意加工的动态变化.方法33名被试者进行了匀角速度旋转(10°/s)和4种水平匀角加速度旋转刺激,角加速度分别为0.6°/s2、0.8°/s2、1.0°/s2和1.2°/s2.前庭刺激时被试者完成相同的等概率听觉认知任务.听觉刺激为1000 ms随机间隔的中文数字2到9,任务要求被试者听到奇数(靶信号)快速按键,听到偶数(非靶信号)不按键.结果与对照和4种水平匀角加速度旋转相比,匀速旋转时非靶信号ERPs的N2幅值在前中央脑区显著降低,靶信号ERPs的N2幅值在F4、Fz和T4电极位置显著降低.与对照相比,匀速旋转时靶信号ERPs的P3潜伏期显著缩短.4种角加速度水平,靶信号ERPs的P3潜伏期在0.8°/s2和1.0°/s2刺激时较长,在0.6°/s2和1.2°/s2时较短.结论匀速旋转对晚期选择注意加工有激活作用,相对于匀速旋转,匀角加速度旋转对选择注意加工有抑制作用,这种抑制作用有几个层次.

An Event-related Potentials Study on Selective Attention Modulated by Vestibular Stimulation

Objective: To explore the dynamic change of the late attentional selection process under linearly varied vestibular stimuli using event-related potentials (ERPs) technique. Method: Thirty-three subjects participated in the experiment. They were exposed to vestibular stimulation of constant angular velocity rotation (10 degrees/s) and four levels of constant angular acceleration rotation, the acceleration was 0.6 degrees/s2, 0.8 degrees/s2, 1.0 degrees/s2, 1.2 degrees/s2 respectively. The same auditory go/no-go cognitive task was done during the stimulation. The task involved verbally given Chinese digit number from two to nine with 1000 ms random interval. Subjects were asked to push the button for the odd numbers (target) and withhold to the even numbers (non-target). Result: Compared with control and different level of constant angular acceleration rotation, the N2 amplitude of non-target ERPs (NT-ERPs) decreased significantly over anterior-central scalp during 10 degrees/s constant rotation, but the N2 amplitude of target ERPs (T-ERPs) reduced significantly only at F4, F(Z) and T4 sites. The P3 latency of T-ERPs decreased significantly in 10 degrees/s constant rotation in contrast with control. Under four different acceleration level, the P3 latency of T-ERPs was relatively longer in 0.8 degrees/s2 and 1.0 degrees/s2, but shorter in 0.6 degrees/s2 and 1.2 degrees/s2. Conclusion: Constant angular velocity rotation had an activating effect on late attentional selection process. In contrast to the activation effect of constant angular velocity rotation, constant angular acceleration had an inhibition effect on the cognitive processes and this inhibition effect may have several levels.