Hippocampal Sharp-Wave Ripples Influence Selective Activation of the Default Mode Network
Raphael Kaplan, Mohit H. Adhikari, Rikkert Hindriks, Dante Mantini, Yusuke Murayama, Nikos K. Logothetis, Gustavo Deco
Current Biology February 20, 2016 DOI: 10.1016/j.cub.2016.01.017 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational study Peer reviewed |
|---|---|
| Population | Anesthetized monkeys |
| Topics | Default mode network |
| Keywords | Hippocampal formation Mode computer interface Functional connectivity |
| Citations | 127 |
| Key findings | Hippocampal ripples are followed by a dramatic increase in DMN fMRI signal, but not after other hippocampal events or in other resting-state networks. |
Abstract
The default mode network (DMN) is a commonly observed resting-state network (RSN) that includes medial temporal, parietal, and prefrontal regions involved in episodic memory [1-3]. The behavioral relevance of endogenous DMN activity remains elusive, despite an emerging literature correlating resting fMRI fluctuations with memory performance [4, 5]-particularly in DMN regions [6-8]. Mechanistic support for the DMN's role in memory consolidation might come from investigation of large deflections (sharp-waves) in the hippocampal local field potential that co-occur with high-frequency (>80 Hz) oscillations called ripples-both during sleep [9, 10] and awake deliberative periods [11-13]. Ripples are ideally suited for memory consolidation [14, 15], since the reactivation of hippocampal place cell ensembles occurs during ripples [16-19]. Moreover, the number of ripples after learning predicts subsequent memory performance in rodents [20-22] and humans [23], whereas electrical stimulation of the hippocampus after learning interferes with memory consolidation [24-26]. A recent study in macaques showed diffuse fMRI neocortical activation and subcortical deactivation specifically after ripples [27]. Yet it is unclear whether ripples and other hippocampal neural events influence endogenous fluctuations in specific RSNs-like the DMN-unitarily. Here, we examine fMRI datasets from anesthetized monkeys with simultaneous hippocampal electrophysiology recordings, where we observe a dramatic increase in the DMN fMRI signal following ripples, but not following other hippocampal electrophysiological events. Crucially, we find increases in ongoing DMN activity after ripples, but not in other RSNs. Our results relate endogenous DMN fluctuations to hippocampal ripples, thereby linking network-level resting fMRI fluctuations with behaviorally relevant circuit-level neural dynamics.
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 | |
| 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 | |
| Psilocybin triggers an activity-dependent rewiring of large-scale cortical networks Mice | 2025 | Experimental study in mice |
Citations in the library
Cited by 6
- The default mode network: where the idiosyncratic self meets the shared social world Nature Reviews Neuroscience January 22, 2021
- The default mode network: where spontaneous thought meets memory consolidation. Current Opinion in Behavioral Sciences February 1, 2026
- Replay, the default mode network and the cascaded memory systems model Nature Reviews Neuroscience August 15, 2022
- Hippocampal ripples and their coordinated dialogue with the default mode network during recent and remote recollection Neuron July 16, 2021
- Does Consciousness Disappear in Dreamless Sleep? Trends in Cognitive Sciences December 1, 2016
and 1 more in the library