Your Attention Please: Neural Networks, Individual Differences, and Clinical Implications of Attentional Control in the Human Brain

Our brains ability to direct our attention requires paradoxical processing. We must be able to focus and maintain our attention without allowing external stimuli to lure us off task. Yet, we must also be able to shift our attention flexibly to switch tasks in response to relevant cues. Unitary accounts of attention maintain that these abilities rely on similar or identical neurocognitive mechanisms, while fractionated models propose that these are dissociable processes. Here, we investigated the relationship between sustained attention and task switching both behaviourally and at the level of the brain. We conducted a confirmatory factor analysis of participants performance on several cognitive switching and sustained attention tasks and found that the observed pattern of performance is consistent with two separate but related factors. We then extended these findings using neuroimaging methods. A multivariate, data-driven analysis of brain activity revealed that sustained attention and task switching are also associated with distinct patterns of activation across the brain. Behavioural performance on each type of task correlated with activity in non-overlapping frontoparietal areas. As participants reaction time increased over time on a task of sustained attention, they recruited a set of right-lateralized regions associated with stimuli-related processing. Concurrently, when participants showed greater differences in reaction time between switch trials and repeat trials, they recruited areas associated with enhanced goal-directed processing in both hemispheres. Our results provide compelling evidence for the dissociation of sustained attention and task switching, both in terms of behavioural performance and patterns of brain activity. We review these findings in the context of existing models of attention and discuss possible clinical implications.