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Abstract:
A classical model of human attention holds that two main components of externally directed attention – stimulus-driven reorienting and executive control – rely on independent neural systems. However, questioning full independency, more recent network-based approaches to human brain function highlight the role of a common set of regions, often referred to as saliency or central executive network, in a huge variety of cognitive tasks involving externally directed attention. Furthermore, a common feature of these tasks is down-regulation of activity in the default mode network, which is upregulated when attention is directed internally. Finally, activation patterns diverge in temporo-parietal junction (TPJ), with increases during stimulus-driven, but decreases during executive control of attention. We explicitly addressed this question of specificity vs. commonality of neural networks related to stimulus-driven reorienting and executive control of attention in a task that independently manipulates both functions and probes for subjectively experienced fluctuations of attention (i.e. mind-wandering). In a large sample (n = 282), reorienting was induced through invalid spatial cueing and executive control through flanker-target conflict while fMRI data were acquired. Results revealed a strong overlap of activations related to both attention functions in cingulo-opercular and fronto-parietal regions. Furthermore, activity in left anterior insula (AI) showed super-additive increases of activity during concurrent demand of both functions. Furthermore, the neural activation pattern in TPJ showed an anterior vs. posterior distinction, with reorienting related activation in anterior TPJ, but joint downregulation during concurrent demand of both functions in posterior TPJ – a region that was upregulated during subjective reports of mind-wandering. This dissociation was replicated in resting state functional connectivity analysis, embedding the anterior TPJ peak into the cingulo-opercular salience network, and posterior TPJ into the default mode network. Finally, task-based functional connectivity indicated inhibitory coupling between posterior TPJ and AI during concurrent attention demands. These results demonstrate involvement of domain-general brain networks in different attentional functions and a central role of anterior insula in regulating these networks.
Implications of these findings for the relationship between lower-level domain general and higher-level socio-cognitive and socio-affective functions will be discussed. Furthermore, in light of mental training-induced changes in the investigated attentional, socio-affective, and socio-cognitive functions, we will discuss their involvement in different types of contemplative practice.
