Co-modulatory spectral changes in independent brain processes are correlated with task performance.
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).
Brain Research Center, University System of Taiwan, Hsinchu, Taiwan.
Shang-Wen
SW
Chuang
Li-Wei
LW
Ko
Yuan-Pin
YP
Lin
Ruey-Song
RS
Huang
Tzyy-Ping
TP
Jung
Chin-Teng
CT
Lin
D000293:Adolescent; D000328:Adult; D001334:Automobile Driving; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D025341:Principal Component Analysis; D012815:Signal Processing, Computer-Assisted; D012894:Sleep Stages / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology*; D055815:Young Adult