Intramodal attentional processing during a monotonous car driving simulation: an EEG study
The present study aimed at monitoring attentional processes in an intramodal (visual) setting during a monotonous car driving simulation by means of the EEG. Two different conditions were included in the study. Condition C1 consisted in watching a grey screen on which sometimes a red light appeared. Subjects had to react to this stimulus by pressing a foot pedal. Condition C2 consisted in actively driving a simulated car by performing a lane change task additionally to the first visual task. The whole session lasted approximately three hours. The EEG results revealed a main effect of condition showing a reduced parieto-occipital alpha band activity for C2 and a main effect of reaction time with a reduced frontal alpha band activity for short reaction times. No interaction between condition and reaction time was found. Thus, for a demanding dual task with intramodal stimulus competition, a short reaction time requires the strong activation of executive frontal cortices as shown by a strong alpha desynchronisation. In contrast, a previous study (Schubert et al., 2008) involving an intermodal (auditory-visual) distribution of attention showed that fast reactions to auditory stimuli are accompanied by increased alpha oscillations over parieto-occipital cortices. Considering these results we can conclude that the relation between brain rhythms and reaction times can be interpreted only in its specific context, i.e., both (low and high) alpha states are reasonable correlates of an efficient sensory- motor coupling leading to fast reactions.