Space wandering in the rodent default mode network.
Trang-Anh Estelle Nghiem, Byeongwook Lee, Tzu-Hao Harry Chao, Nicholas K Branigan, Percy K Mistry, Yen-Yu Ian Shih, Vinod Menon
bioRxiv September 1, 2023 preprint DOI: 10.1101/2023.08.31.555793 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational study |
|---|---|
| Population | Awake, freely exploring rats |
| Topics | Default mode network |
| Key findings | The authors report that core DMN nodes show a hierarchical functional organization during spatial exploration, are more strongly coupled with each other than with the anterior insula, and encode movement kinematics like linear and angular velocity. They argue that higher linear velocity relates to enhanced DMN activity, greater DMN synchronization, and increased DMN-anterior insula anticorrelation, challenging the idea of the DMN as a "task-negative" network. |
Abstract
The default mode network (DMN) is a large-scale brain network known to be suppressed during a wide range of cognitive tasks. However, our comprehension of its role in naturalistic and unconstrained behaviors has remained elusive because most research on the DMN has been conducted within the restrictive confines of MRI scanners. Here we use multisite GCaMP fiber photometry with simultaneous videography to probe DMN function in awake, freely exploring rats. We examined neural dynamics in three core DMN nodes- the retrosplenial cortex, cingulate cortex, and prelimbic cortex- as well as the anterior insula node of the salience network, and their association with the rats' spatial exploration behaviors. We found that DMN nodes displayed a hierarchical functional organization during spatial exploration, characterized by stronger coupling with each other than with the anterior insula. Crucially, these DMN nodes encoded the kinematics of spatial exploration, including linear and angular velocity. Additionally, we identified latent brain states that encoded distinct patterns of time-varying exploration behaviors and discovered that higher linear velocity was associated with enhanced DMN activity, heightened synchronization among DMN nodes, and increased anticorrelation between the DMN and anterior insula. Our findings highlight the involvement of the DMN in collectively and dynamically encoding spatial exploration in a real-world setting. Our findings challenge the notion that the DMN is primarily a "task-negative" network disengaged from the external world. By illuminating the DMN's role in naturalistic behaviors, our study underscores the importance of investigating brain network function in ecologically valid contexts.
Comparable studies
Other preclinical and animal studies on default mode network, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Rat brains also have a default mode network Rats | 2012 | Observational study | |
| Large-scale topology and the default mode network in the mouse connectome Mouse brain | 2014 | Observational study | |
| Hippocampal Sharp-Wave Ripples Influence Selective Activation of the Default Mode Network Anesthetized monkeys | 2016 | Observational study | |
| Psilocybin-induced default mode network hypoconnectivity is blunted in alcohol-dependent rats Healthy rats and a rat model of alcohol relapse | 2023 | Randomized, placebo-controlled crossover pharmaco-fMRI study | |
| Altered functional connectivity within the default mode network in two animal models with opposing episodic memories Rats (control, LPS-challenged, and footshock-exposed groups) | 2018 | Animal model study |
Citations in the library
Cites 12
- 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
- 20 years of the default mode network: A review and synthesis Neuron May 10, 2023
- Rat brains also have a default mode network Proceedings of the National Academy of Sciences February 21, 2012
and 7 more in the library