Hippocampal ripples and their coordinated dialogue with the default mode network during recent and remote recollection
Yitzhak Norman, Omri Raccah, Su Liu, Josef Parvizi, R. Malach
Neuron July 16, 2021 DOI: 10.1016/j.neuron.2021.06.020 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational study Peer reviewed |
|---|---|
| Population | Humans |
| Topics | Default mode network |
| Key findings | Hippocampal ripple rate increased significantly before recall of autobiographical and semantic memories, and ripple patterns showed specificity for memory type and a semantization effect with memory age. |
Abstract
SUMMARY Hippocampal ripples are prominent synchronization events generated by hippocampal neuronal assemblies. To date, ripples have been primarily associated with navigational memory in rodents and shortterm episodic recollections in humans. Here, we uncover different profiles of ripple activity in the human hippocampus during the retrieval of recent and remote autobiographical events and semantic facts. We found that the ripple rate increased significantly before reported recall compared to control conditions. Patterns of ripple activity across multiple hippocampal sites demonstrated remarkable specificity for memory type. Intriguingly, these ripple patterns revealed a semantization dimension, in which patterns associated with autobiographical contents become similar to those of semantic memory as a function of memory age. Finally, widely distributed sites across the neocortex exhibited ripple-coupled activations during recollection, with the strongest activation found within the default mode network. Our results thus reveal a key role for hippocampal ripples in orchestrating hippocampal-cortical communication across large-scale networks involved in conscious recollection.
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
Cited by 4
- The default mode network: where spontaneous thought meets memory consolidation. Current Opinion in Behavioral Sciences February 1, 2026
- CONSCIOUSNESS AND SLEEP Neuron April 29, 2024
- Causal evidence for the processing of bodily self in the anterior precuneus. Neuron August 16, 2023
- Local neuronal relational structures underlying the contents of human conscious experience Neuroscience of Consciousness September 3, 2021