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Verzhbinsky IA, Rubin DB, Kajfez S, Bu Y, Kelemen JN, Kapitonava A, Williams ZM, Hochberg LR, Cash SS, Halgren E. Co-occurring ripple oscillations facilitate neuronal interactions between cortical locations in humans. Proc Natl Acad Sci U S A 2024; 121:e2312204121. [PMID: 38157452 PMCID: PMC10769862 DOI: 10.1073/pnas.2312204121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 11/05/2023] [Indexed: 01/03/2024] Open
Abstract
How the human cortex integrates ("binds") information encoded by spatially distributed neurons remains largely unknown. One hypothesis suggests that synchronous bursts of high-frequency oscillations ("ripples") contribute to binding by facilitating integration of neuronal firing across different cortical locations. While studies have demonstrated that ripples modulate local activity in the cortex, it is not known whether their co-occurrence coordinates neural firing across larger distances. We tested this hypothesis using local field-potentials and single-unit firing from four 96-channel microelectrode arrays in the supragranular cortex of 3 patients. Neurons in co-rippling locations showed increased short-latency co-firing, prediction of each other's firing, and co-participation in neural assemblies. Effects were similar for putative pyramidal and interneurons, during non-rapid eye movement sleep and waking, in temporal and Rolandic cortices, and at distances up to 16 mm (the longest tested). Increased co-prediction during co-ripples was maintained when firing-rate changes were equated, indicating that it was not secondary to non-oscillatory activation. Co-rippling enhanced prediction was strongly modulated by ripple phase, supporting the most common posited mechanism for binding-by-synchrony. Co-ripple enhanced prediction is reciprocal, synergistic with local upstates, and further enhanced when multiple sites co-ripple, supporting re-entrant facilitation. Together, these results support the hypothesis that trans-cortical co-occurring ripples increase the integration of neuronal firing of neurons in different cortical locations and do so in part through phase-modulation rather than unstructured activation.
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Affiliation(s)
- Ilya A. Verzhbinsky
- Neurosciences Graduate Program, University of California San Diego, La Jolla, CA92093
- Medical Scientist Training Program, University of California San Diego, La Jolla, CA92093
| | - Daniel B. Rubin
- Department of Neurology, Center for Neurotechnology and Neurorecovery, Massachusetts General Hospital, Boston, MA02114
| | - Sophie Kajfez
- Department of Radiology, University of California San Diego, La Jolla, CA92093
| | - Yiting Bu
- Department of Neurosciences, University of California San Diego, La Jolla, CA92093
| | - Jessica N. Kelemen
- Department of Neurology, Center for Neurotechnology and Neurorecovery, Massachusetts General Hospital, Boston, MA02114
| | - Anastasia Kapitonava
- Department of Neurology, Center for Neurotechnology and Neurorecovery, Massachusetts General Hospital, Boston, MA02114
| | - Ziv M. Williams
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA02114
| | - Leigh R. Hochberg
- Department of Neurology, Center for Neurotechnology and Neurorecovery, Massachusetts General Hospital, Boston, MA02114
- Center for Neurorestoration and Neurotechnology, Department of Veterans Affairs, Providence, RI02908
- Carney Institute for Brain Science and School of Engineering, Brown University, Providence, RI02912
| | - Sydney S. Cash
- Department of Neurology, Center for Neurotechnology and Neurorecovery, Massachusetts General Hospital, Boston, MA02114
| | - Eric Halgren
- Department of Radiology, University of California San Diego, La Jolla, CA92093
- Department of Neurosciences, University of California San Diego, La Jolla, CA92093
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Verzhbinsky IA, Rubin DB, Kajfez S, Bu Y, Kelemen JN, Kapitonava A, Williams ZM, Hochberg LR, Cash SS, Halgren E. Co-occurring ripple oscillations facilitate neuronal interactions between cortical locations in humans. bioRxiv 2023:2023.05.20.541588. [PMID: 37292943 PMCID: PMC10245779 DOI: 10.1101/2023.05.20.541588] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Synchronous bursts of high frequency oscillations ('ripples') are hypothesized to contribute to binding by facilitating integration of neuronal firing across cortical locations. We tested this hypothesis using local field-potentials and single-unit firing from four 96-channel microelectrode arrays in supragranular cortex of 3 patients. Neurons in co-rippling locations showed increased short-latency co-firing, prediction of each-other's firing, and co-participation in neural assemblies. Effects were similar for putative pyramidal and interneurons, during NREM sleep and waking, in temporal and Rolandic cortices, and at distances up to 16mm. Increased co-prediction during co-ripples was maintained when firing-rate changes were equated, and were strongly modulated by ripple phase. Co-ripple enhanced prediction is reciprocal, synergistic with local upstates, and further enhanced when multiple sites co-ripple. Together, these results support the hypothesis that trans-cortical co-ripples increase the integration of neuronal firing of neurons in different cortical locations, and do so in part through phase-modulation rather than unstructured activation.
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Affiliation(s)
- Ilya A. Verzhbinsky
- Neurosciences Graduate Program, University of California San Diego, La Jolla, CA 92093, USA
- Medical Scientist Training Program, University of California San Diego, La Jolla, CA 92093, USA
| | - Daniel B. Rubin
- Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
- Harvard Medical School, Boston, MA 02114, USA
| | - Sophie Kajfez
- Department of Radiology, University of California San Diego, La Jolla, CA 92093, USA
| | - Yiting Bu
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Jessica N. Kelemen
- Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Anastasia Kapitonava
- Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Ziv M. Williams
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA 02114
- Program in Neuroscience, Harvard-MIT Program in Health Sciences and Technology, Harvard Medical School, Boston, MA 02115
| | - Leigh R. Hochberg
- Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
- Harvard Medical School, Boston, MA 02114, USA
- Center for Neurorestoration and Neurotechnology, Department of Veterans Affairs, Providence, RI 02908, USA
- Carney Institute for Brain Science and School of Engineering, Brown University, Providence, RI 02912, USA
| | - Sydney S. Cash
- Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
- Harvard Medical School, Boston, MA 02114, USA
| | - Eric Halgren
- Department of Radiology, University of California San Diego, La Jolla, CA 92093, USA
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA
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Dickey CW, Verzhbinsky IA, Jiang X, Rosen BQ, Kajfez S, Eskandar EN, Gonzalez-Martinez J, Cash SS, Halgren E. Cortical Ripples during NREM Sleep and Waking in Humans. J Neurosci 2022; 42:7931-7946. [PMID: 36041852 PMCID: PMC9617618 DOI: 10.1523/jneurosci.0742-22.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 07/19/2022] [Accepted: 07/22/2022] [Indexed: 11/21/2022] Open
Abstract
Hippocampal ripples index the reconstruction of spatiotemporal neuronal firing patterns essential for the consolidation of memories in the cortex during non-rapid eye movement sleep (NREM). Recently, cortical ripples in humans have been shown to enfold the replay of neuron firing patterns during cued recall. Here, using intracranial recordings from 18 patients (12 female), we show that cortical ripples also occur during NREM in humans, with similar density, oscillation frequency (∼90 Hz), duration, and amplitude to waking. Ripples occurred in all cortical regions with similar characteristics, unrelated to putative hippocampal connectivity, and were less dense and robust in higher association areas. Putative pyramidal and interneuron spiking phase-locked to cortical ripples during NREM, with phase delays consistent with ripple generation through pyramidal-interneuron feedback. Cortical ripples were smaller in amplitude than hippocampal ripples but were similar in density, frequency, and duration. Cortical ripples during NREM typically occurred just before the upstate peak, often during spindles. Upstates and spindles have previously been associated with memory consolidation, and we found that cortical ripples grouped cofiring between units within the window of spike timing-dependent plasticity. Thus, human NREM cortical ripples are as follows: ubiquitous and stereotyped with a tightly focused oscillation frequency; similar to hippocampal ripples; associated with upstates and spindles; and associated with unit cofiring. These properties are consistent with cortical ripples possibly contributing to memory consolidation and other functions during NREM in humans.SIGNIFICANCE STATEMENT In rodents, hippocampal ripples organize replay during sleep to promote memory consolidation in the cortex, where ripples also occur. However, evidence for cortical ripples in human sleep is limited, and their anatomic distribution and physiological properties are unexplored. Here, using human intracranial recordings, we demonstrate that ripples occur throughout the cortex during waking and sleep with highly stereotyped characteristics. During sleep, cortical ripples tend to occur during spindles on the down-to-upstate transition, and thus participate in a sequence of sleep waves that is important for consolidation. Furthermore, cortical ripples organize single-unit spiking with timing optimal to facilitate plasticity. Therefore, cortical ripples in humans possess essential physiological properties to support memory and other cognitive functions.
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Affiliation(s)
- Charles W Dickey
- Neurosciences Graduate Program, University of California San Diego, La Jolla, California 92093
- Medical Scientist Training Program, University of California San Diego, La Jolla, California 92093
| | - Ilya A Verzhbinsky
- Neurosciences Graduate Program, University of California San Diego, La Jolla, California 92093
- Medical Scientist Training Program, University of California San Diego, La Jolla, California 92093
| | - Xi Jiang
- Neurosciences Graduate Program, University of California San Diego, La Jolla, California 92093
| | - Burke Q Rosen
- Neurosciences Graduate Program, University of California San Diego, La Jolla, California 92093
| | - Sophie Kajfez
- Department of Radiology, University of California San Diego, La Jolla, California 92093
| | - Emad N Eskandar
- Department of Neurological Surgery, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Jorge Gonzalez-Martinez
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Sydney S Cash
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114
| | - Eric Halgren
- Department of Radiology, University of California San Diego, La Jolla, California 92093
- Department of Neurosciences, University of California San Diego, La Jolla, California 92093
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Dickey CW, Verzhbinsky IA, Jiang X, Rosen BQ, Kajfez S, Stedelin B, Shih JJ, Ben-Haim S, Raslan AM, Eskandar EN, Gonzalez-Martinez J, Cash SS, Halgren E. Widespread ripples synchronize human cortical activity during sleep, waking, and memory recall. Proc Natl Acad Sci U S A 2022; 119:e2107797119. [PMID: 35867767 PMCID: PMC9282280 DOI: 10.1073/pnas.2107797119] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 05/02/2022] [Indexed: 12/02/2022] Open
Abstract
Declarative memory encoding, consolidation, and retrieval require the integration of elements encoded in widespread cortical locations. The mechanism whereby such "binding" of different components of mental events into unified representations occurs is unknown. The "binding-by-synchrony" theory proposes that distributed encoding areas are bound by synchronous oscillations enabling enhanced communication. However, evidence for such oscillations is sparse. Brief high-frequency oscillations ("ripples") occur in the hippocampus and cortex and help organize memory recall and consolidation. Here, using intracranial recordings in humans, we report that these ∼70-ms-duration, 90-Hz ripples often couple (within ±500 ms), co-occur (≥ 25-ms overlap), and, crucially, phase-lock (have consistent phase lags) between widely distributed focal cortical locations during both sleep and waking, even between hemispheres. Cortical ripple co-occurrence is facilitated through activation across multiple sites, and phase locking increases with more cortical sites corippling. Ripples in all cortical areas co-occur with hippocampal ripples but do not phase-lock with them, further suggesting that cortico-cortical synchrony is mediated by cortico-cortical connections. Ripple phase lags vary across sleep nights, consistent with participation in different networks. During waking, we show that hippocampo-cortical and cortico-cortical coripples increase preceding successful delayed memory recall, when binding between the cue and response is essential. Ripples increase and phase-modulate unit firing, and coripples increase high-frequency correlations between areas, suggesting synchronized unit spiking facilitating information exchange. co-occurrence, phase synchrony, and high-frequency correlation are maintained with little decrement over very long distances (25 cm). Hippocampo-cortico-cortical coripples appear to possess the essential properties necessary to support binding by synchrony during memory retrieval and perhaps generally in cognition.
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Affiliation(s)
- Charles W. Dickey
- Neurosciences Graduate Program, University of California San Diego, La Jolla, CA 92093
- Medical Scientist Training Program, University of California San Diego, La Jolla, CA 92093
| | - Ilya A. Verzhbinsky
- Neurosciences Graduate Program, University of California San Diego, La Jolla, CA 92093
- Medical Scientist Training Program, University of California San Diego, La Jolla, CA 92093
| | - Xi Jiang
- Neurosciences Graduate Program, University of California San Diego, La Jolla, CA 92093
| | - Burke Q. Rosen
- Neurosciences Graduate Program, University of California San Diego, La Jolla, CA 92093
| | - Sophie Kajfez
- Department of Radiology, University of California San Diego, La Jolla, CA 92093
| | - Brittany Stedelin
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239
| | - Jerry J. Shih
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093
| | - Sharona Ben-Haim
- Department of Neurological Surgery, University of California San Diego, La Jolla, CA 92093
| | - Ahmed M. Raslan
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239
| | - Emad N. Eskandar
- Department of Neurological Surgery, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY 10461
| | | | - Sydney S. Cash
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114
| | - Eric Halgren
- Department of Radiology, University of California San Diego, La Jolla, CA 92093
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093
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