Left dorsolateral prefrontal cortex supports context-dependent prioritisation of off-task thought

Abstract

When environments lack compelling goals, humans often let their minds wander to thoughts with greater personal relevance; however, we currently do not understand how this context-dependent prioritisation process operates. Dorsolateral prefrontal cortex (DLPFC) maintains goal representations in a context-dependent manner. Here, we show this region is involved in prioritising off-task thought in an analogous way. In a whole brain analysis we established that neural activity in DLPFC is high both when ‘on-task’ under demanding conditions and ‘off-task’ in a non-demanding task. Furthermore, individuals who increase off-task thought when external demands decrease, show lower correlation between neural signals linked to external tasks and lateral regions of the DMN within DLPFC, as well as less cortical grey matter in regions sensitive to these external task relevant signals. We conclude humans prioritise daydreaming when environmental demands decrease by aligning cognition with their personal goals using DLPFC.

Neurocognitive patterns dissociating semantic processing from executive control are linked to more detailed off-task mental time travel

“…Consequently, individual variation in these underlying features will determine the ease with which certain thought patterns are generated or maintained. Consistent with this view, studies highlight attention and control systems as important in the prioritisation and maintenance of patterns of thought in a context-appropriate manner 14,15 . In contrast, activity patterns within regions allied to the default mode network (DMN), are associated with features of experience that are closely tied to the nature of the representations of the thoughts themselves [16][17][18][19][20] .…”

“…It is important to consider how these individual differences translate into momentary patterns of neural activity. In this context, it is worth noting that we have recently shown that that neural signals in both the dorsal left pre-frontal cortex, and the posterior cortex are linked to momentary differences in off-task content, and levels of subject detail respectively 15 . These regions are both highlighted by our analysis as members of the neural network linked to semantic processing, and to reports of experiences which emphasise off-task episodes with a high degree of subject detail (See also Kam and colleagues 42 for a conceptually similar conclusion).…”

Missing the forest because of the trees: Slower alternations during binocular rivalry are associated with lower levels of visual detail during ongoing thought

“…Our recent work on the macrostructural organisation of the cortex suggests that the DMN is functionally and spatially isolated from sensory and motor systems . Perhaps the apparent contribution of the DMN to greater focus on external information with greater detail (Sormaz et al, 2018;Turnbull et al, 2019a;Turnbull et al, 2019b), or, during efficient task performance (e.g. Esterman et al, 2012;Vatansever et al, 2017), arises when there is a particularly strong representation of bottom up sensory signals in the DMN.…”

“…Sometimes our thoughts become focused on personal experiences rather than events in the external environment, or any task being performed (Seli et al, 2018;Schooler, 2006, 2015). Research suggests states of off-task thought are linked to systems important for attentional focus, including both dorsal and ventral attention networks (Hasenkamp et al, 2012;Turnbull et al, 2019a;Turnbull et al, 2019b). Experience can also fluctuate in the level of details with which events in the external environment are processed.…”

“…Our study sought to extend our understanding of naturally occurring changes in ongoing experience, by linking them to both changes in the structural organisation of the cortex, as well as to indices of the top-down influence on vision as estimated from binocular rivalry alternations. Specifically, we analysed data from a large cohort of individuals for whom we had extensively described the contents of their ongoing experience in a laboratory task (for prior publications see Ho et al, 2019;Sormaz et al, 2018;Turnbull et al, 2019a;Turnbull et al, 2019b;Wang et al, 2018) and for whom we also acquired measures of binocular rivalry using a similar paradigm to our prior study (see Baker et al, 2015). These individuals also had measures of structural connectivity provided by diffusion tensor imaging (DTI), which has highlighted neural processes linked to both binocular rivalry (Genç et al, 2011) and to patterns of ongoing thought in a prior study .…”