Abstract
Sustaining attention over prolonged periods of time is a critical task frequently demanded by our environment. Whether while driving a car or while scanning luggage, failures to detect relevant information can be life threatening. These failures could have multiple underlying sources. To investigate the temporal and spatial characteristics of neural activity underlying these failures, 13 participants performed a continuous temporal expectancy task while simultaneously recording both EEG and fMRI. Each participant completed two tasks. In both tasks, participants monitored a stream of flickering faces and cars (15Hz) for 3.5 minutes. Standard images were presented for 800 ms while targets, requiring a face vs. car discrimination, were presented for 1100 ms. Auditory stimuli (vowel or consonant) were presented, half of which coincided with the presentation of a visual target. In the single task blocks participants only responded to the visual targets, however in the dual task blocks participants responded to both auditory and visual targets. Visual target detection accuracy was better in the single task condition (M=.51) than in the dual task condition (M=.39, F(1,12)=10.8, p < .01). There was an overall decline in performance as a function of time within each block (F(8,96)=44.9, p< .001). Analysis of the EEG data revealed an increase in occipital alpha activity in the 4 seconds preceding a missed visual target, compared to the 4 seconds preceding a target that was correctly identified (mean difference=.56 μV2, F(1,12)=10.4, p< .001). Analysis of the fMRI data revealed that correctly identified targets evoked an increase in activity in dorsal attentional control regions (anterior cingulate cortex, bi-lateral IPS) whereas missed targets corresponded with an increase in activity in the default mode network (precuneus, frontal pole, lateral parietal inferior gyri). These results reveal the underlying neural dynamics of sustained and dual task failures of performance.
Meeting abstract presented at VSS 2016