Hippocampal sharp wave‐ripple: A cognitive biomarker for episodic memory and planning

By György Buzsáki. 2015

1,553 citations recorded by the source corpus.

Sharp wave ripples (SPW‐Rs) represent the most synchronous population pattern in the mammalian brain. Their excitatory output affects a wide area of the cortex and several subcortical nuclei. SPW‐Rs occur during “off‐line” states of the brain, associated with consummatory behaviors and non‐REM sleep, and are influenced by numerous neurotransmitters and neuromodulators. They arise from the excitatory recurrent system of the CA3 region and the SPW‐induced excitation brings about a fast network oscillation (ripple) in CA1. The spike content of SPW‐Rs is temporally and spatially coordinated by a consortium of interneurons to replay fragments of waking neuronal sequences in a compressed format. SPW‐Rs assist in transferring this compressed hippocampal representation to distributed circuits to support memory consolidation; selective disruption of SPW‐Rs interferes with memory. Recently acquired and pre‐existing information are combined during SPW‐R replay to influence decisions, plan actions and, potentially, allow for creative thoughts. In addition to the widely studied contribution to memory, SPW‐Rs may also affect endocrine function via activation of hypothalamic circuits. Alteration of the physiological mechanisms supporting SPW‐Rs leads to their pathological conversion, “p‐ripples,” which are a marker of epileptogenic tissue and can be observed in rodent models of schizophrenia and Alzheimer's Disease. Mechanisms for SPW‐R genesis and function are discussed in this review. © 2015 The Authors Hippocampus Published by Wiley Periodicals, Inc.

Subfields: Cellular and Molecular Neuroscience, Cognitive Neuroscience

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Cellular and Molecular Neuroscience

In Cognitive Neuroscience

Citations in the corpus

Replay in Deep Learning: Current Approaches and Missing Biological Elements (2021, neutral): “Specifically, the Deep Q-Network (DQN) (Mnih et al., 2013, 2015) performed experience replay using a sliding window approach where a uniformly selected set of previous transitions was replayed to the agent.”
Distinct hippocampal-cortical memory representations for experiences associated with movement versus immobility (2017, positive): “Location specific activity in the hippocampus is interrupted intermittently by sharp-wave ripple (SWR) events, during which hippocampal activity transiently switches to expressing representations corresponding to episodes of past experience or potential future scenarios (Buzsáki, 2015).”
Post-learning hippocampal dynamics promote preferential retention of rewarding events (2016, neutral): “One important factor to consider is that SWRs are sometimes isolated events, but they can also occur in clusters (Papatheodoropoulos, 2010; for a review, see Buzsáki, 2015).”
The content of hippocampal “replay” (2018, background): “Recently, several excellent reviews have been published which explore the brain’s spatial representation network (Moser et al., 2015) and hippocampal ripples (Buzs aki, 2015).”
Human Replay Spontaneously Reorganizes Experience (2019, background): “, 2016), and they coincide with an increase in source-localized hippocampal power in ripple frequency (Buzsáki, 2015).”
High-density, long-lasting, and multi-region electrophysiological recordings using polymer electrode arrays (2018, positive): “The SWR (Buzsaki, 2015) is an event of synchronous hippocampal population firing known to influence activity across the majority of the brain (Logothetis et al., 2012).”
Hippocampal Offline Reactivation Consolidates Recently Formed Cell Assembly Patterns during Sharp Wave-Ripples (2016, background): “Offline reactivation is most prominent during sharp wave-ripple (SWR; 125–250 Hz) oscillatory events (Wilson and McNaughton, 1994; Buzsáki, 2015a) in which conditions indeed promote Hebbian synaptic plasticity (Sadowski et al., 2016).”
Memory engrams: Recalling the past and imagining the future (2020, background): “Post-encoding reactivation or replay of hippocampal place cell firing, especially during slow-wave sleep (SWS) (87, 88), is thought to be important for memory consolidation (89-92).”
Cellular and Systems Consolidation of Declarative Memory (2017, background): “Perhaps these two types of replay represent different mechanisms, or perhaps the delay is caused by the time that is needed for the information to travel across the cortex (Buzsaki 2015; Genzel and Robertson 2015).”
Replay Comes of Age. (2017, background): “Several recent reviews have covered similar ground, including some shorter reviews (Carr et al. 2011, O’Neill et al. 2010) and a very comprehensive review of related and overlapping phenomena in the local hippocampal electroencelphalogram (EEG) (Buzsaki 2015).”
Hippocampal replays under the scrutiny of reinforcement learning models. (2018, background): “These last around 50 to 120 ms, during which the local field potential strongly oscillates around 200 Hz (Buzsáki et al. 1992; Buzsáki 2015).”
Learning Structures: Predictive Representations, Replay, and Generalization (2020, background): “Rodent electrophysiology shows that while animals rest, or eat, there are brief high-frequency network oscillations in the hippocampus known as ripples [47], accompanied by neural activity patterns that sweep trajectories of place cells forwards and backwards at compressed time-scale [48,49].”
Bidirectional Interaction of Hippocampal Ripples and Cortical Slow Waves Leads to Coordinated Spiking Activity During NREM Sleep. (2020, background): “Anatomically, the existence of connections from hippocampus to PFC is well established — CA1/subiculum connections to PFC were independently described in mice (Parent et al. 2009), rhesus monkey (Averbeck and Seo 2008, Barbas and Blatt 1995, Goldman-Rakic et al. 1984), cats (Cavada et al. 1983, Irle”
Echoes of Pink Noise: A Hypothesized Mechanism for Enhancing Sleep-Dependent Memory Consolidation with Auditory Stimulation (2025, unknown): “Finally, SW-Rs are brief high-frequency bursts primarily observed in the hippocampus (Buzsáki 2015; Vaz et al. 2019).”