Theta and Alpha Oscillations in Attentional Interaction during Distracted Driving

Abstract

Performing multiple tasks simultaneously usually affects the behavioral performance as compared with executing the single task. Moreover, processing multiple tasks simultaneously often involve more cognitive demands. Two visual tasks, lane-keeping task and mental calculation, were utilized to assess the brain dynamics through 32-channel electroencephalogram (EEG) recorded from 14 participants. A 400-ms stimulus onset asynchrony (SOA) factor was used to induce distinct levels of attentional requirements. In the dual-task conditions, the deteriorated behavior reflected the divided attention and the overlapping brain resources used. The frontal, parietal and occipital components were decomposed by independent component analysis (ICA) algorithm. The event- and response-related theta and alpha oscillations in selected brain regions were investigated first. The increased theta oscillation in frontal component and decreased alpha oscillations in parietal and occipital components reflect the cognitive demands and attentional requirements as executing the designed tasks. Furthermore, time-varying interactive over-additive (O-Add), additive (Add) and under-additive (U-Add) activations were explored and summarized through the comparison between the summation of the elicited spectral perturbations in two single-task conditions and the spectral perturbations in the dual task. Add and U-Add activations were observed while executing the dual tasks. U-Add theta and alpha activations dominated the posterior region in dual-task situations. Our results show that both deteriorated behaviors and interactive brain activations should be comprehensively considered for evaluating workload or attentional interaction precisely.

Keywords: alpha; dual-task; electroencephalogram (EEG); independent component analysis (ICA); interactive attention; stimulus onset asynchrony (SOA); theta.

Figure 1

The scenarios of the single- and dual-task conditions. The participants had to cruise in the third lane throughout the experiment. (A) The participants were required to cruise the third lane in the whole experiment. (B) Only the lane deviation was displayed in the single-task driving condition. (C) Only the mathematic equation was displayed in the single-task math condition. (D) Both the lane deviation and mathematic equation were simultaneously displayed. (E) The mathematic equation appeared 400 ms before the lane deviation. (F) The lane deviation appeared 400 ms before the mental equation.

Figure 2

(A) Histograms of the reaction times (RTs; distributions of red bars) and solution times (STs; distributions of blue bars). The short RTs indicate that the participants had a high level of alertness throughout the experiment. (B) The averaged RTs of the driving task (red bars) and the STs of the math task (blue bars) in each condition. The STs were significantly different between the single- and dual-task conditions (p < 0.05), but the RTs were not significantly different between the single- and dual-task conditions.

Figure 3

(A,B) The event-related spectral perturbation (ERSP) plots in the frontal, parietal and occipital components show the time-frequency results during the performance of the lane-deviation or mental calculation task. (C,D) The performance-related changes in the theta and alpha frequencies in the frontal, parietal and occipital components. The epochs with quick RTs or STs are depicted in the bottom of each sub-figure. The red and blue dotted lines indicate the onset of lane deviation and mental calculation, respectively. The red and blue solid lines indicate the onset of turning the steering wheel and the button-press response, respectively.

Figure 4

(A–C) The mean ERSP plots in the frontal, parietal and occipital components show the time-frequency results during the performance of the dual-task conditions. (D–F) The performance-related changes in the theta and alpha frequencies in the frontal, parietal and occipital areas. The epochs with quick STs are depicted in the bottom of each sub-figure. The red and blue dotted lines indicate the onset of lane deviation and mental calculation, respectively. The red and blue solid lines indicate the onset of turning the steering wheel and the button-press response, respectively.

Figure 5

The dynamics of the theta and alpha oscillations. (A) The theta activations (B) and alpha activations. The green, yellowish brown and pink lines indicate the recorded oscillations during the dual conditions: simultaneous (D&M), calculation first (M/D) and deviation first (D/M), respectively. The black lines represent the interactive activations, which are the sum of the activations while executing the two tasks individually.