A decrease in brain activation associated with driving when listening to someone speak

Abstract

Behavioral studies have shown that engaging in a secondary task, such as talking on a cellular telephone, disrupts driving performance. This study used functional magnetic resonance imaging (fMRI) to investigate the impact of concurrent auditory language comprehension on the brain activity associated with a simulated driving task. Participants steered a vehicle along a curving virtual road, either undisturbed or while listening to spoken sentences that they judged as true or false. The dual-task condition produced a significant deterioration in driving accuracy caused by the processing of the auditory sentences. At the same time, the parietal lobe activation associated with spatial processing in the undisturbed driving task decreased by 37% when participants concurrently listened to sentences. The findings show that language comprehension performed concurrently with driving draws mental resources away from the driving and produces deterioration in driving performance, even when it does not require holding or dialing a phone.

Figure 1

Screen capture of the display for the driving simulation. Participants steered the vehicle with a computer mouse or track-ball held in their right hand under two conditions; one in which they focused attention on the driving task alone, and one in which they also judged whether auditorily presented sentences describing world knowledge were true or false. Blocks of the driving alone and driving while listening conditions were 60-s in duration and were alternated with 24-s fixation baseline intervals.

Figure 2

Whole-brain voxel-wise random effects statistical parameter maps of each condition contrasted with the fixation baseline thresholded at p < .0001 with an 81-voxel extent threshold (resulting in a cluster-level threshold of p < .05 after correction for multiple comparisons). Similar areas of activation are present in both conditions but with additional language-related activity in temporal and inferior frontal areas (yellow ovals).

Figure 3

Whole-brain voxel-wise random effects statistical parameter maps of direct contrasts between the two conditions thresholded at p < .0001 with a 81-voxel extent threshold (resulting in a cluster level threshold of p < .05 after correction for multiple comparisons). The top panel indicates that parietal and superior extrastriate activation decreases with the addition of a sentence listening task (blue circle). The bottom panel shows that the addition of a sentence listening task results in activation in temporal and prefrontal language areas (yellow ovals).

Figure 4

The percentage change in signal intensity for five functional groupings (networks) of cortical areas. The component regions of each network are those specified in Table 3. The driving-related activation in spatial processing areas significantly decreases with the addition of the sentence listening task. The addition of the sentence listening task significantly increases language area activation. Error bars show the standard error of the mean.