Measurement of Frontal Cortex Brain Activity Attributable to the Driving Workload and Increased Attention

Functional magnetic resonance imaging (fMRI) and functional near-infrared spectroscopy (fNIRS) were used to measure subjects’ cerebral blood flow in order to investigate higher-order human brain function activity associated with cognition and attention while operating a vehicle. As a first step, the effects of the fundamental driving environment on brain activity was investigated on the basis of fMRI measurements, with simultaneous measurement of the frontal region by fNIRS. The experiments involved the presentation of visual stimuli by video clips and the execution of simple individual tasks corresponding to steering wheel and pedal operations. As a second step, a driving simulator was used to reproduce narrow road driving and car-following driving situations requiring cognition and attention. Drivers’ mental activity under these conditions involving different levels of attention was measured by fNIRS. The results showed that the level of activity in the lateral frontal region rose as the relative difficulty of the tasks increased based on subjective evaluations. In addition, under the narrow road driving condition, greater activation in the prefrontal region attributable to increased attention was found in a comparison with the results for ordinary driving tasks.