Weak Task Synchronization of Default Mode Network in Task Based Paradigms
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort |
|---|---|
| Sample size | 223 |
| Population | Human subjects from four publicly available fMRI datasets |
| Topics | Default mode network |
| Key findings | The default mode network exhibits large variability across subjects, trials, and regions, with low synchronization, challenging its characterization as a uniformly task-negative network. |
Abstract
Abstract Default mode network (DMN) are the areas of the brain that get deactivated upon the presentation of externally focused, attention demanding tasks. Interestingly, these areas are consistently deactivated irrespective of the nature of the task. Recent evidence shows that the behavior of the DMN may be more nuanced than what was earlier believed. We wanted to investigate the dynamics of DMN further and utilized novel statistical approaches to study the same. We analysed four publicly available datasets (total 223 subjects) across seven tasks related to different cognitive modalities and found out that there is a large amount of variability in the presumed task-negative network across subjects, trials and regions. We designed a method called Inter Trial Temporal Synchronization Analysis (IT-TSA) and Inter Subject TSA (IS-TSA) to analyse variability across trials and subjects respectively. We found out that all task-negative regions and even weak task-positive regions have low synchronization across trials and subjects. We hypothesize that the DMN variability might be more due to neural differences rather than structural or HRF variations. We also investigated the use of non GLM technique like the Inter Subject Correlation (ISC) and found that it may only be suitable to study tightly synchronized task-positive regions. Our study challenges the understanding of DMN as a task-negative region and advances the findings that DMN acts as an active component associated with a unique set of self-referential, autobiographical processes which are deactivated differentially and non linearly across trials and subjects in the presence of extrinsic processes. Highlights Default Mode Network is weakly synchronized across trials and subjects in task paradigms. Inter Subject Correlation is not suited to detect task-based activations in DMN. Synchronization Analysis reveals temporal structure in fMRI data.
Comparable studies
Other observational and cohort studies on default mode network, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| A default mode of brain function Normal adult human brain | 2001 | Observational study | |
| Resting-State Functional Connectivity Reflects Structural Connectivity in the Default Mode Network Healthy subjects | 2008 | Observational cohort | |
| Meditation experience is associated with increased cortical thickness Participants with extensive Insight meditation experience and matched controls | 2005 | Observational cohort | n = 20 |
| Meditation experience is associated with differences in default mode network activity and connectivity Experienced meditators and matched meditation-naive controls | 2011 | Observational cohort | |
| The precuneus/posterior cingulate cortex plays a pivotal role in the default mode network: Evidence from a partial correlation network analysis Healthy subjects | 2008 | Observational study |
Citations in the library
Cites 6
- A default mode of brain function Proceedings of the National Academy of Sciences January 16, 2001
- The Brain's Default Mode Network Annual Review of Neuroscience May 4, 2015
- Experience sampling during fMRI reveals default network and executive system contributions to mind wandering. Proceedings of the National Academy of Sciences May 26, 2009
- Dynamic reconfiguration of the default mode network during narrative comprehension Nature Communications July 18, 2016
- Contributions of default mode network stability and deactivation to adolescent task engagement Scientific Reports December 21, 2018
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