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

A Turnbull,M Sormaz,E Jefferies,C Murphy,J Smallwood,T Karapanagiotidis,B Bernhardt,R M Leech,H T Wang,X Wang,D Vatansever,N S P Ho,D S Margulies

doi:10.1038/s41467-019-11764-y

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.

Highlights

When environments lack compelling goals, humans often let their minds wander to thoughts with greater personal relevance; we currently do not understand how this contextdependent prioritisation process operates
To create conditions varying the requirement for external attention, we used a paradigm, which alternated between a higher demand condition in which task-relevant information is maintained in working memory (1-back) and a condition with no equivalent requirement (0-back, Fig. 1)
Our study combined multiple neuroimaging methods to demonstrate a role for left Dorsolateral prefrontal cortex (DLPFC) in the prioritisation of personally relevant information in situations of low demands

Summary

Introduction

When environments lack compelling goals, humans often let their minds wander to thoughts with greater personal relevance; we currently do not understand how this contextdependent prioritisation process operates. It has been argued that this apparent contradiction could be reconciled by assuming a general role of control processes that maximises the fit between patterns of ongoing experience and the demands imposed by the external environment[1] This view, known as the context regulation hypothesis, predicts a common control process underpins both the act of reducing off-task thought when external demands are high, and increasing thoughts about personally relevant information when the environment lacks a compelling goal. Based on prior neuroimaging studies, the process of goal-motivated prioritisation may depend upon regions that make up the ventral attention, or salience, network[15] This network includes regions of dorsolateral frontal (Brodmann Area, BA, 9/46) and parietal cortex (BA 40), the anterior cingulate (BA 24 and 32), as well as structures including the anterior insula. We examine (a) whether a common neural region is involved in both the prioritisation of off-task thought when task demands are low and the facilitation of on-task thought when environmental demands are increased, and (b) the neural mechanisms that help individuals focus attention on personally relevant information under these circumstances

Methods

Results

Conclusion