长期高海拔暴露影响移居者空间工作记忆--来自时域和频域分析的证据

Long-term exposure to high altitude affects spatial working memory in migrants - evidence from time and frequency domain analysis

长期高海拔暴露影响空间工作记忆。以往研究主要集中于分析时域脑电成分,而非关注频域上不同频段的神经振荡。为探究长期高海拔暴露影响空间工作记忆的时间动态特征与神经振荡过程,本研究采用n-back任务结合事件相关电位技术记录生长在低海拔地区、成年后移居高海拔地区满3年的20名健康年轻人(高海拔组)和从未到过高海拔的21名年轻人(低海拔组)的脑电数据,并进行时域与频域分析。结果显示,与低海拔组相比,高海拔组反应时更长,在2-back条件下正确率更低;在2-back条件下,高海拔组的P2波幅更正,晚期正电位(late positive potential, LPP)波幅更负;早期delta频段(1~4 Hz,160~300 ms)的能量值更大,晚期delta频段(1~4 Hz, 450~650 ms)、theta频段(4~8 Hz, 450~650 ms)的能量值更小。以上结果表明,长期高海拔暴露影响移居者空间工作记忆能力,主要体现为后期匹配阶段注意资源不足,反应抑制能力与信息维持能力降低,从而损害空间工作记忆能力。

Long-term exposure to high altitude affects spatial working memory. Previous studies have focused on the analysis of electroencephalogram(EEG) components in time domain rather than in frequency domain. To explore the influence of long-term high altitude exposure on time dynamic characteristics and neural oscillation process of the spatial working memory, n-back task combined with the technology of event related potential recording was performed on 20 young migrants who grew at low altitude before the age of 18 and moved to high altitude more than three years ago, and 21 young people who had never been to the high altitude. EEG data were recorded, and the time domain and frequency domain analyses were performed. The results showed that the response time was longer and the accuracy rate was lower under the 2-back condition in the high altitude group compared with those in low altitude group. The late positive potential(LPP) amplitude was more negative, P2 amplitude was more positive in the 2-back condition, and the power value of early delta frequency band(1–4 Hz, 160–300 ms) was larger, while the power values of late delta frequency band(1–4 Hz, 450–650 ms) and theta frequency band(4–8 Hz, 450–650 ms) were smaller in the high altitude group compared with those in low altitude group. The results suggested that long-term exposure to high altitude affected the spatial working memory ability of the migrants, which was reflected in the lack of attention resources in the later matching stage, decreased response inhibition ability and information maintenance ability, and thus resulted in impaired spatial working memory.