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Default Mode Network activation at task switches reflects mental task-set structure

Ashley X. Zhou, John Duncan, Daniel J Mitchell

preprint DOI: 10.1101/2024.07.08.602546 (opens in new tab)

Study at a glance

AI-extracted from the abstract
Characteristics fMRI study
Topics Default mode network
Key points Core DMN activation at task switches depends on the order in which groups of tasks were learned, not on the number of currently relevant tasks.

Abstract

Abstract Recent findings challenge traditional views of the Default Mode Network (DMN) as purely task-negative or self-oriented, showing increased DMN activity during demanding switches between externally-focused tasks (Crittenden et al., 2015; Smith et al., 2018; Zhou et al., 2024). However, it is unclear what modulates the DMN at switches, with transitions within a stimulus domain activating DMN regions in some studies but not others. Differences in the number of tasks suggest that complexity or structure of the set of tasks may be important. In this fMRI study, we examined whether the DMN’s response to task switches depends on the complexity of the active set of tasks, manipulated by the number of tasks in a run, or abstract task groupings based on instructional order. Core DMN activation at task switches was unaffected by the number of currently relevant tasks. Instead, it depended on the order in which groups of tasks had been learnt. Multivariate decoding revealed that Core DMN hierarchically represents individual tasks, task domains, and higher-order task groupings based on instruction order. We suggest that, as the complexity of instructions increases, rules are increasingly organized into higher-level chunks, and Core DMN activity is highest at switches between chunks.

Comparable studies

Other experimental studies on default mode network, most cited first.

Study Year Design Participants
Functional connectivity of default mode network components: Correlation, anticorrelation, and causality Healthy subjects 2008 Observational study using resting-state fMRI and seed correlation analysis
Patterns of Brain Activity Supporting Autobiographical Memory, Prospection, and Theory of Mind, and Their Relationship to the Default Mode Network Healthy subjects 2009 Experimental study using fMRI
Dynamic reconfiguration of the default mode network during narrative comprehension Human subjects 2016 Experimental study
Broadband Cortical Desynchronization Underlies the Human Psychedelic State Healthy human participants 2013 Experimental study
The brain on art: intense aesthetic experience activates the default mode network Human observers 2012 Observational study with fMRI and behavioral analysis

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