Abstract
Default Mode Network (DMN) has been called a “task-negative” network which deactivates during engaging extrinsic tasks. But the behavior is more nuanced. We analyse the DMN during three different tasks (visual, affect and language; n=54) and find inter trial variability which gets amiss when analysed using General Linear Model (GLM). The region also shows significant across subjects variations which limits the use of Inter Subject Correlation (ISC) method to detect correlated deactivations during the task. We introduce Temporal Synchronization Analysis (TSA), a family of methods that can help detect inter-trial (IT-TSA) and inter-subject (IS-TSA) synchronization across the brain. We find that DMN is weakly synchronized across trials and subjects, challenging the notion of task negative behavior. Our study suggests the role of DMN as an active component associated with self-referential, autobiographical processes which are deactivated differentially and non linearly across trials and subjects in the presence of extrinsic processes.
Competing Interest Statement
The authors have declared no competing interest.