Sustaining attention to simple tasks: a meta-analytic review of the neural mechanisms of vigilant attention

Abstract

Maintaining attention for more than a few seconds is essential for mastering everyday life. Yet, our ability to stay focused on a particular task is limited, resulting in well-known performance decrements with increasing time on task. Intriguingly, such decrements are even more likely if the task is cognitively simple and repetitive. The attentional function that enables our prolonged engagement in intellectually unchallenging, uninteresting activities has been termed vigilant attention. Here we synthesized what we have learned from functional neuroimaging about the mechanisms of this essential mental faculty. To this end, a quantitative meta-analysis of pertinent neuroimaging studies was performed, including supplementary analyses of moderating factors. Furthermore, we reviewed the available evidence on neural time-on-task effects, additionally considering information obtained from patients with focal brain damage. Integrating the results of both meta-analysis and review, we identified a set of mainly right-lateralized brain regions that may form the core network subserving vigilant attention in humans, including dorsomedial, mid- and ventrolateral prefrontal cortex, anterior insula, parietal areas (intraparietal sulcus, temporoparietal junction), and subcortical structures (cerebellar vermis, thalamus, putamen, midbrain). We discuss the potential functional roles of different nodes of this network as well as implications of our findings for a theoretical account of vigilant attention. It is conjectured that sustaining attention is a multicomponent, nonunitary mental faculty, involving a mixture of (a) sustained/recurrent processes subserving task-set/arousal maintenance and (b) transient processes subserving the target-driven reorienting of attention. Finally, limitations of previous studies are considered and suggestions for future research are provided.

Figure 1

Foci of brain activity with significant convergence across all 67 experiments included in the meta-analysis (cluster-level p < .05, family-wise error–corrected for multiple comparisons; cluster-forming threshold p < .001 at voxel level). Brain sections show foci of significant convergence overlaid on the template brain with maps of cytoarchitectonically defined areas as included in the SPM Anatomy Toolbox 1.7 (Eickhoff et al., 2005). Coordinates refer to Montreal Neurological Institute (MNI) space and follow the neurological convention (left = left). DMPFC = dorsomedial prefrontal cortex (including pre-supplementary motor area); dPMC/vPMC = dorsal/ventral premotor cortex; IFJ = inferior frontal junction; Ins = anterior insula; IPS = intraparietal sulcus (including adjacent inferior parietal lobule); MLPFC = midlateral prefrontal cortex; MOG = middle occipital gyrus; TOJ/TPJ = temporo-occipital/temporoparietal junction.

Figure 2

Foci of brain activity that show significantly stronger across-experiment convergence with increasing duration of uninterrupted maintenance of vigilant attention.

Figure 3

Foci of brain activity with significantly stronger convergence in experiments involving an overt (yellow) or no overt (blue) motor response to target stimuli.

Figure 4

Foci of brain activity with significantly stronger convergence in experiments involving detection (yellow) or discrimination (blue) tasks.

Figure 5

Foci of brain activity with significantly stronger convergence in experiments with temporally predictable (yellow) or unpredictable (blue) stimulus occurrence.

Figure 6

Simplified hierarchical model of the putative functions and interrelations of cortical core nodes of the brain network involved in vigilant attention (see text for details). Solid lines denote top-down signaling; broken lines denote bottom-up signaling; dotted lines denote within-level signaling. Abbreviations: aIns = anterior insula; aMCC/dmPFC = anterior midcingulate cortex; IFJ = inferior frontal junction; I-O = Input–Output; IPS = intraparietal sulcus; MLPFC = midlateral prefrontal cortex; TPJ = temporoparietal junction.