Brain Research Center, University System of Taiwan, Hsinchu, Taiwan.
Neuroimage. 2012 Sep;62(3):1469-77. doi: 10.1016/j.neuroimage.2012.05.035. Epub 2012 May 24.
This study investigates the independent modulators that mediate the power spectra of electrophysiological processes, measured by electroencephalogram (EEG), in a sustained-attention experiment. EEG and behavioral data were collected during 1-2 hour virtual-reality based driving experiments in which subjects were instructed to maintain their cruising position and compensate for randomly induced drift using the steering wheel. Independent component analysis (ICA) applied to 30-channel EEG data separated the recorded EEG signals into a sum of maximally temporally independent components (ICs) for each of 30 subjects. Logarithmic spectra of resultant IC activities were then decomposed by principal component analysis, followed by ICA, to find spectrally fixed and temporally independent modulators (IM). Across subjects, the spectral ICA consistently found four performance-related independent modulators: delta, delta-theta, alpha, and beta modulators that multiplicatively affected the spectra of spatially distinct IC processes when the participants experienced waves of alternating alertness and drowsiness during long-hour simulated driving. The activation of the delta-theta modulator increased monotonically as subjects' task performances decreased. Furthermore, the time courses of the theta-beta modulator were highly correlated with concurrent changes in driving errors across subjects (r=0.77±0.13).
本研究调查了在持续注意力实验中，通过脑电图（EEG）测量的电生理过程的功率谱的独立调制器。在基于虚拟现实的 1-2 小时驾驶实验中，收集了 EEG 和行为数据，在该实验中，要求受试者保持巡航位置，并使用方向盘补偿随机诱导的漂移。应用于 30 通道 EEG 数据的独立成分分析（ICA）将记录的 EEG 信号分解为 30 位受试者各自的最大时间独立成分（IC）的总和。然后通过主成分分析对所得 IC 活动的对数谱进行分解，随后进行 ICA，以找到频谱固定且时间独立的调制器（IM）。在所有受试者中，频谱 ICA 一致地发现了四个与性能相关的独立调制器：当参与者在长时间模拟驾驶过程中经历交替警觉和困倦的浪潮时，它们会对空间上不同的 IC 过程的频谱产生乘法影响的 delta、delta-theta、alpha 和 beta 调制器。delta-theta 调制器的激活随着受试者任务表现的下降而单调增加。此外，theta-beta 调制器的时间历程与受试者之间的驾驶误差的并发变化高度相关（r=0.77±0.13）。
