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Herweg NA, Solomon EA, Kahana MJ. Theta Oscillations in Human Memory. Trends Cogn Sci 2020; 24:208-227. [PMID: 32029359 PMCID: PMC8310425 DOI: 10.1016/j.tics.2019.12.006] [Citation(s) in RCA: 195] [Impact Index Per Article: 48.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 12/05/2019] [Accepted: 12/10/2019] [Indexed: 11/21/2022]
Abstract
Theta frequency (4-8 Hz) fluctuations of the local field potential have long been implicated in learning and memory. Human studies of episodic memory, however, have provided mixed evidence for theta's role in successful learning and remembering. Re-evaluating these conflicting findings leads us to conclude that: (i) successful memory is associated both with increased narrow-band theta oscillations and a broad-band tilt of the power spectrum; (ii) theta oscillations specifically support associative memory, whereas the spectral tilt reflects a general index of activation; and (iii) different cognitive contrasts (generalized versus specific to memory), recording techniques (invasive versus noninvasive), and referencing schemes (local versus global) alter the balance between the two phenomena to make one or the other more easily detectable.
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Affiliation(s)
- Nora A Herweg
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
| | - Ethan A Solomon
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael J Kahana
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA.
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52
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Zioga I, Harrison PM, Pearce MT, Bhattacharya J, Di Bernardi Luft C. From learning to creativity: Identifying the behavioural and neural correlates of learning to predict human judgements of musical creativity. Neuroimage 2020; 206:116311. [DOI: 10.1016/j.neuroimage.2019.116311] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 10/18/2019] [Accepted: 10/22/2019] [Indexed: 10/25/2022] Open
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53
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A Neural Chronometry of Memory Recall. Trends Cogn Sci 2019; 23:1071-1085. [DOI: 10.1016/j.tics.2019.09.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 09/13/2019] [Accepted: 09/25/2019] [Indexed: 12/23/2022]
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54
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Kunz L, Maidenbaum S, Chen D, Wang L, Jacobs J, Axmacher N. Mesoscopic Neural Representations in Spatial Navigation. Trends Cogn Sci 2019; 23:615-630. [PMID: 31130396 PMCID: PMC6601347 DOI: 10.1016/j.tics.2019.04.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 04/24/2019] [Accepted: 04/24/2019] [Indexed: 01/21/2023]
Abstract
Recent evidence suggests that mesoscopic neural oscillations measured via intracranial electroencephalography exhibit spatial representations, which were previously only observed at the micro- and macroscopic level of brain organization. Specifically, theta (and gamma) oscillations correlate with movement, speed, distance, specific locations, and goal proximity to boundaries. In entorhinal cortex (EC), they exhibit hexadirectional modulation, which is putatively linked to grid cell activity. Understanding this mesoscopic neural code is crucial because information represented by oscillatory power and phase may complement the information content at other levels of brain organization. Mesoscopic neural oscillations help bridge the gap between single-neuron and macroscopic brain signals of spatial navigation and may provide a mechanistic basis for novel biomarkers and therapeutic targets to treat diseases causing spatial disorientation.
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Affiliation(s)
- Lukas Kunz
- Epilepsy Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany.
| | - Shachar Maidenbaum
- Department of Biomedical Engineering, Columbia University, New York City, NY, USA.
| | - Dong Chen
- CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China
| | - Liang Wang
- CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China; CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai, China; Department of Psychology, University of Chinese Academy of Sciences, Beijing, China.
| | - Joshua Jacobs
- Department of Biomedical Engineering, Columbia University, New York City, NY, USA.
| | - Nikolai Axmacher
- Department of Neuropsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, Bochum, Germany.
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55
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Kunz L, Wang L, Lachner-Piza D, Zhang H, Brandt A, Dümpelmann M, Reinacher PC, Coenen VA, Chen D, Wang WX, Zhou W, Liang S, Grewe P, Bien CG, Bierbrauer A, Navarro Schröder T, Schulze-Bonhage A, Axmacher N. Hippocampal theta phases organize the reactivation of large-scale electrophysiological representations during goal-directed navigation. SCIENCE ADVANCES 2019; 5:eaav8192. [PMID: 31281882 PMCID: PMC6609163 DOI: 10.1126/sciadv.aav8192] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 05/24/2019] [Indexed: 05/11/2023]
Abstract
Humans are adept in simultaneously following multiple goals, but the neural mechanisms for maintaining specific goals and distinguishing them from other goals are incompletely understood. For short time scales, working memory studies suggest that multiple mental contents are maintained by theta-coupled reactivation, but evidence for similar mechanisms during complex behaviors such as goal-directed navigation is scarce. We examined intracranial electroencephalography recordings of epilepsy patients performing an object-location memory task in a virtual environment. We report that large-scale electrophysiological representations of objects that cue for specific goal locations are dynamically reactivated during goal-directed navigation. Reactivation of different cue representations occurred at stimulus-specific hippocampal theta phases. Locking to more distinct theta phases predicted better memory performance, identifying hippocampal theta phase coding as a mechanism for separating competing goals. Our findings suggest shared neural mechanisms between working memory and goal-directed navigation and provide new insights into the functions of the hippocampal theta rhythm.
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Affiliation(s)
- Lukas Kunz
- Epilepsy Center, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
- Corresponding author. (L.K.); (N.A.)
| | - Liang Wang
- CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China
- CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Daniel Lachner-Piza
- Epilepsy Center, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Hui Zhang
- Department of Neuropsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, Bochum, Germany
| | - Armin Brandt
- Epilepsy Center, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Matthias Dümpelmann
- Epilepsy Center, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Peter C. Reinacher
- University Medical Center, Stereotactic and Functional Neurosurgery, Freiburg im Breisgau, Germany
| | - Volker A. Coenen
- University Medical Center, Stereotactic and Functional Neurosurgery, Freiburg im Breisgau, Germany
| | - Dong Chen
- School of Systems Science, Beijing Normal University, Beijing, China
| | - Wen-Xu Wang
- School of Systems Science, Beijing Normal University, Beijing, China
| | - Wenjing Zhou
- Department of Epilepsy Center, Tsinghua University Yuquan Hospital, Beijing, China
| | - Shuli Liang
- Department of Neurosurgery, First Affiliated Hospital of General Hospital of PLA, Beijing, China
| | - Philip Grewe
- Bethel Epilepsy Centre, Krankenhaus Mara, Bielefeld, Germany
| | | | - Anne Bierbrauer
- Department of Neuropsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, Bochum, Germany
| | - Tobias Navarro Schröder
- Kavli Institute for Systems Neuroscience, Centre for Neural Computation, The Egil and Pauline Braathen and Fred Kavli Centre for Cortical Microcircuits, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Andreas Schulze-Bonhage
- Epilepsy Center, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Nikolai Axmacher
- Department of Neuropsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, Bochum, Germany
- Corresponding author. (L.K.); (N.A.)
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56
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Frauscher B, von Ellenrieder N, Zelmann R, Doležalová I, Minotti L, Olivier A, Hall J, Hoffmann D, Nguyen DK, Kahane P, Dubeau F, Gotman J. Atlas of the normal intracranial electroencephalogram: neurophysiological awake activity in different cortical areas. Brain 2019; 141:1130-1144. [PMID: 29506200 DOI: 10.1093/brain/awy035] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 01/01/2018] [Indexed: 11/13/2022] Open
Abstract
In contrast to scalp EEG, our knowledge of the normal physiological intracranial EEG activity is scarce. This multicentre study provides an atlas of normal intracranial EEG of the human brain during wakefulness. Here we present the results of power spectra analysis during wakefulness. Intracranial electrodes are placed in or on the brain of epilepsy patients when candidates for surgical treatment and non-invasive approaches failed to sufficiently localize the epileptic focus. Electrode contacts are usually in cortical regions showing epileptic activity, but some are placed in normal regions, at distance from the epileptogenic zone or lesion. Intracranial EEG channels defined using strict criteria as very likely to be in healthy brain regions were selected from three tertiary epilepsy centres. All contacts were localized in a common stereotactic space allowing the accumulation and superposition of results from many subjects. Sixty-second artefact-free sections during wakefulness were selected. Power spectra were calculated for 38 brain regions, and compared to a set of channels with no spectral peaks in order to identify significant peaks in the different regions. A total of 1785 channels with normal brain activity from 106 patients were identified. There were on average 2.7 channels per cm3 of cortical grey matter. The number of contacts per brain region averaged 47 (range 6-178). We found significant differences in the spectral density distributions across the different brain lobes, with beta activity in the frontal lobe (20-24 Hz), a clear alpha peak in the occipital lobe (9.25-10.25 Hz), intermediate alpha (8.25-9.25 Hz) and beta (17-20 Hz) frequencies in the parietal lobe, and lower alpha (7.75-8.25 Hz) and delta (0.75-2.25 Hz) peaks in the temporal lobe. Some cortical regions showed a specific electrophysiological signature: peaks present in >60% of channels were found in the precentral gyrus (lateral: peak frequency range, 20-24 Hz; mesial: 24-30 Hz), opercular part of the inferior frontal gyrus (20-24 Hz), cuneus (7.75-8.75 Hz), and hippocampus (0.75-1.25 Hz). Eight per cent of all analysed channels had more than one spectral peak; these channels were mostly recording from sensory and motor regions. Alpha activity was not present throughout the occipital lobe, and some cortical regions showed peaks in delta activity during wakefulness. This is the first atlas of normal intracranial EEG activity; it includes dense coverage of all cortical regions in a common stereotactic space, enabling direct comparisons of EEG across subjects. This atlas provides a normative baseline against which clinical EEGs and experimental results can be compared. It is provided as an open web resource (https://mni-open-ieegatlas. RESEARCH mcgill.ca).
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Affiliation(s)
- Birgit Frauscher
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada.,Department of Medicine and Center for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
| | | | - Rina Zelmann
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada.,Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Irena Doležalová
- Brno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University Brno, Czech Republic
| | - Lorella Minotti
- Department of Neurology, Grenoble-Alpes University Hospital and Grenoble-Alpes University, Grenoble, France
| | - André Olivier
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Jeffery Hall
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Dominique Hoffmann
- Department of Neurology, Grenoble-Alpes University Hospital and Grenoble-Alpes University, Grenoble, France
| | - Dang Khoa Nguyen
- Centre hospitalier de l'Université de Montréal - Hôpital Notre-Dame, Montréal, Québec, Canada
| | - Philippe Kahane
- Department of Neurology, Grenoble-Alpes University Hospital and Grenoble-Alpes University, Grenoble, France
| | - François Dubeau
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Jean Gotman
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
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57
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Ruzich E, Crespo‐García M, Dalal SS, Schneiderman JF. Characterizing hippocampal dynamics with MEG: A systematic review and evidence-based guidelines. Hum Brain Mapp 2019; 40:1353-1375. [PMID: 30378210 PMCID: PMC6456020 DOI: 10.1002/hbm.24445] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 10/12/2018] [Accepted: 10/16/2018] [Indexed: 12/12/2022] Open
Abstract
The hippocampus, a hub of activity for a variety of important cognitive processes, is a target of increasing interest for researchers and clinicians. Magnetoencephalography (MEG) is an attractive technique for imaging spectro-temporal aspects of function, for example, neural oscillations and network timing, especially in shallow cortical structures. However, the decrease in MEG signal-to-noise ratio as a function of source depth implies that the utility of MEG for investigations of deeper brain structures, including the hippocampus, is less clear. To determine whether MEG can be used to detect and localize activity from the hippocampus, we executed a systematic review of the existing literature and found successful detection of oscillatory neural activity originating in the hippocampus with MEG. Prerequisites are the use of established experimental paradigms, adequate coregistration, forward modeling, analysis methods, optimization of signal-to-noise ratios, and protocol trial designs that maximize contrast for hippocampal activity while minimizing those from other brain regions. While localizing activity to specific sub-structures within the hippocampus has not been achieved, we provide recommendations for improving the reliability of such endeavors.
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Affiliation(s)
- Emily Ruzich
- Department of Clinical Neurophysiology and MedTech West, Institute of Neuroscience and PhysiologySahlgrenska Academy & the University of GothenburgGothenburgSweden
| | | | - Sarang S. Dalal
- Center of Functionally Integrative NeuroscienceAarhus UniversityAarhus CDenmark
| | - Justin F. Schneiderman
- Department of Clinical Neurophysiology and MedTech West, Institute of Neuroscience and PhysiologySahlgrenska Academy & the University of GothenburgGothenburgSweden
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58
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Moxon KA, Shahlaie K, Girgis F, Saez I, Kennedy J, Gurkoff GG. From adagio to allegretto: The changing tempo of theta frequencies in epilepsy and its relation to interneuron function. Neurobiol Dis 2019; 129:169-181. [PMID: 30798003 DOI: 10.1016/j.nbd.2019.02.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 02/06/2019] [Accepted: 02/20/2019] [Indexed: 12/29/2022] Open
Abstract
Despite decades of research, our understanding of epilepsy, including how seizures are generated and propagate, is incomplete. However, there is growing recognition that epilepsy is more than just the occurrence of seizures, with patients often experiencing comorbid deficits in cognition that are poorly understood. In addition, the available therapies for treatment of epilepsy, from pharmaceutical treatment to surgical resection and seizure prevention devices, often exacerbate deficits in cognitive function. In this review, we discuss the hypothesis that seizure generation and cognitive deficits have a similar pathological source characterized by, but not limited to, deficits in theta oscillations and their influence on interneurons. We present a new framework that describes oscillatory states in epilepsy as alternating between hyper- and hypo-synchrony rather than solely the spontaneous transition to hyper-excitability characterized by the seizures. This framework suggests that as neural oscillations, specifically in the theta range, vary their tempo from a slowed almost adagio tempo during interictal periods to faster, more rhythmic allegretto tempo preictally, they impact the function of interneurons, modulating their ability to control seizures and their role in cognitive processing. This slow wave oscillatory framework may help explain why current therapies that work to reduce hyper-excitability do not completely eliminate seizures and often lead to exacerbated cognitive deficits.
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Affiliation(s)
- Karen A Moxon
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, United States of America.
| | - Kiarash Shahlaie
- Department of Neurological Surgery, University of California Davis, Sacramento, CA 95817, United States of America; Center for Neuroscience, University of California Davis, Davis, CA 95618, United States of America
| | - Fady Girgis
- Department of Neurological Surgery, University of California Davis, Sacramento, CA 95817, United States of America
| | - Ignacio Saez
- Department of Neurological Surgery, University of California Davis, Sacramento, CA 95817, United States of America; Center for Neuroscience, University of California Davis, Davis, CA 95618, United States of America
| | - Jeffrey Kennedy
- Department of Neurology, University of California Davis, Sacramento, CA 95817, United States of America
| | - Gene G Gurkoff
- Department of Neurological Surgery, University of California Davis, Sacramento, CA 95817, United States of America; Center for Neuroscience, University of California Davis, Davis, CA 95618, United States of America
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59
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Mankin EA, Thurley K, Chenani A, Haas OV, Debs L, Henke J, Galinato M, Leutgeb JK, Leutgeb S, Leibold C. The hippocampal code for space in Mongolian gerbils. Hippocampus 2019; 29:787-801. [PMID: 30746805 DOI: 10.1002/hipo.23075] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 12/07/2018] [Accepted: 01/15/2019] [Indexed: 11/11/2022]
Abstract
Large parts of our knowledge about the physiology of the hippocampus in the intact brain are derived from studies in rats and mice. While many of those findings fit well to the limited data available from humans and primates, there are also marked differences, for example, in hippocampal oscillation frequencies and in the persistence of theta oscillations. To test whether the distinct sensory specializations of the visual and auditory system of primates play a key role in explaining these differences, we recorded basic hippocampal physiological properties in Mongolian gerbils, a rodent species with high visual acuity, and good low-frequency hearing, similar to humans. We found that gerbils show only minor differences to rats regarding hippocampal place field activity, theta properties (frequency, persistence, phase precession, theta compression), and sharp wave ripple events. The only major difference between rats and gerbils was a considerably higher degree of head direction selectivity of gerbil place fields, which may be explained by their visual system being able to better resolve distant cues. Thus, differences in sensory specializations between rodent species only affect hippocampal circuit dynamics to a minor extent, which implies that differences to other mammalian lineages, such as bats and primates, cannot be solely explained by specialization in the auditory or visual system.
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Affiliation(s)
- Emily A Mankin
- Neurobiology Section and Center for Neural Circuits and Behavior, University of California, San Diego, La Jolla, California.,Department of Neurosurgery, David Geffen School of Medicine and Semel Institute For Neuroscience and Human Behavior, University of California, Los Angeles, California
| | - Kay Thurley
- Department Biologie II, Ludwig-Maximilians-Universität München, Martinsried, Germany.,Bernstein Center for Computational Neuroscience Munich, Martinsried, Germany
| | - Alireza Chenani
- Department Biologie II, Ludwig-Maximilians-Universität München, Martinsried, Germany.,Bernstein Center for Computational Neuroscience Munich, Martinsried, Germany
| | - Olivia V Haas
- Department Biologie II, Ludwig-Maximilians-Universität München, Martinsried, Germany.,Bernstein Center for Computational Neuroscience Munich, Martinsried, Germany
| | - Luca Debs
- Neurobiology Section and Center for Neural Circuits and Behavior, University of California, San Diego, La Jolla, California
| | - Josephine Henke
- Department Biologie II, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Melissa Galinato
- Neurobiology Section and Center for Neural Circuits and Behavior, University of California, San Diego, La Jolla, California
| | - Jill K Leutgeb
- Neurobiology Section and Center for Neural Circuits and Behavior, University of California, San Diego, La Jolla, California
| | - Stefan Leutgeb
- Neurobiology Section and Center for Neural Circuits and Behavior, University of California, San Diego, La Jolla, California.,Kavli Institute for Brain and Mind, University of California, San Diego, La Jolla, California
| | - Christian Leibold
- Department Biologie II, Ludwig-Maximilians-Universität München, Martinsried, Germany.,Bernstein Center for Computational Neuroscience Munich, Martinsried, Germany
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60
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Abstract
The hippocampal theta rhythm is critical for learning and memory. New research demonstrates that theta oscillations in freely moving humans are similar in frequency and function to those observed in rodents and are modulated by movement speed and exploratory behavior.
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Affiliation(s)
- Michael A Yassa
- 309 Qureshey Research Laboratory, University of California, Irvine, Irvine, CA 92697-3800, USA.
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61
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Izadi A, Pevzner A, Lee DJ, Ekstrom AD, Shahlaie K, Gurkoff GG. Medial septal stimulation increases seizure threshold and improves cognition in epileptic rats. Brain Stimul 2019; 12:735-742. [PMID: 30733144 DOI: 10.1016/j.brs.2019.01.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 01/07/2019] [Accepted: 01/10/2019] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Temporal lobe epilepsy is most prevalent among focal epilepsies, and nearly one-third of patients are refractory to pharmacological intervention. Persistent cognitive and neurobehavioral comorbidities also occur due to the recurrent nature of seizures and medication-related side effects. HYPOTHESIS Electrical neuromodulation is an effective strategy to reduce seizures both in animal models and clinically, but its efficacy to modulate cognition remains unclear. We hypothesized that theta frequency stimulation of the medial septum would increase septohippocampal oscillations, increase seizure threshold, and improve spatial learning in a rat model of pilocarpine-induced epilepsy. METHODS Sham and pilocarpine rats were implanted with electrodes in the medial septum, hippocampus and prefrontal cortex. EEG was assessed days prior to and following stimulation. Sham and pilocarpine-treated rats received either no stimulation, continuous (throughout each behavior), or pre-task (one minute prior to each behavior) 7.7 Hz septal stimulation during the Barnes maze spatial navigation test and also during assessment of flurothyl-induced seizures. RESULTS Both continuous and pre-task stimulation prevented epilepsy-associated reductions in theta oscillations over time. Additionally, both stimulation paradigms significantly improved spatial navigation in the Barnes maze, reducing latency and improving search strategy. Moreover, stimulation led to significant increases in seizure threshold in pilocarpine-treated rats. There was no evidence of cognitive enhancement or increased seizure threshold in stimulated sham rats. CONCLUSION These findings have profound implications as theta stimulation of the septum represents a single frequency and target that has the potential to both improve cognition and reduce seizures for patients with refractory epilepsy.
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Affiliation(s)
- Ali Izadi
- Department of Neurological Surgery, University of California, Davis, USA; Center for Neuroscience, University of California, Davis, USA
| | - Aleksandr Pevzner
- Department of Neurological Surgery, University of California, Davis, USA
| | - Darrin J Lee
- Department of Neurological Surgery, University of California, Davis, USA
| | - Arne D Ekstrom
- Center for Neuroscience, University of California, Davis, USA
| | - Kiarash Shahlaie
- Department of Neurological Surgery, University of California, Davis, USA; Center for Neuroscience, University of California, Davis, USA
| | - Gene G Gurkoff
- Department of Neurological Surgery, University of California, Davis, USA; Center for Neuroscience, University of California, Davis, USA.
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62
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Izadi A, Ondek K, Schedlbauer A, Keselman I, Shahlaie K, Gurkoff G. Clinically indicated electrical stimulation strategies to treat patients with medically refractory epilepsy. Epilepsia Open 2018; 3:198-209. [PMID: 30564779 PMCID: PMC6293066 DOI: 10.1002/epi4.12276] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/11/2018] [Indexed: 12/25/2022] Open
Abstract
Focal epilepsies represent approximately half of all diagnoses, and more than one-third of these patients are refractory to pharmacologic treatment. Although resection can result in seizure freedom, many patients do not meet surgical criteria, as seizures may be multifocal in origin or have a focus in an eloquent region of the brain. For these individuals, several U.S. Food and Drug Administration (FDA)-approved electrical stimulation paradigms serve as alternative options, including vagus nerve stimulation, responsive neurostimulation, and stimulation of the anterior nucleus of the thalamus. All of these are safe, flexible, and lead to progressive seizure control over time when used as an adjunctive therapy to antiepileptic drugs. Focal epilepsies frequently involve significant comorbidities such as cognitive decline. Similar to antiepilepsy medications and surgical resection, current stimulation targets and parameters have yet to address cognitive impairments directly, with patients reporting persistent comorbidities associated with focal epilepsy despite a significant reduction in the number of their seizures. Although low-frequency theta oscillations of the septohippocampal network are critical for modulating cellular activity and, in turn, cognitive processing, the coordination of neural excitability is also imperative for preventing seizures. In this review, we summarize current FDA-approved electrical stimulation paradigms and propose that theta oscillations of the medial septal nucleus represent a novel neuromodulation target for concurrent seizure reduction and cognitive improvement in epilepsy. Ultimately, further advancements in clinical neurostimulation strategies will allow for the efficient treatment of both seizures and comorbidities, thereby improving overall quality of life for patients with epilepsy.
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Affiliation(s)
- Ali Izadi
- Department of Neurological SurgeryUniversity of CaliforniaDavisCalifornia,U.S.A.
| | - Katelynn Ondek
- Department of Neurological SurgeryUniversity of CaliforniaDavisCalifornia,U.S.A.,Center for NeuroscienceUniversity of CaliforniaDavisCalifornia,U.S.A.
| | - Amber Schedlbauer
- Department of Neurological SurgeryUniversity of CaliforniaDavisCalifornia,U.S.A.
| | - Inna Keselman
- Department of Neurological SurgeryUniversity of CaliforniaDavisCalifornia,U.S.A.,Department of NeurologyUniversity of CaliforniaDavisCaliforniaU.S.A.
| | - Kiarash Shahlaie
- Department of Neurological SurgeryUniversity of CaliforniaDavisCalifornia,U.S.A.,Center for NeuroscienceUniversity of CaliforniaDavisCalifornia,U.S.A.
| | - Gene Gurkoff
- Department of Neurological SurgeryUniversity of CaliforniaDavisCalifornia,U.S.A.,Center for NeuroscienceUniversity of CaliforniaDavisCalifornia,U.S.A.
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63
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Hexadirectional Modulation of Theta Power in Human Entorhinal Cortex during Spatial Navigation. Curr Biol 2018; 28:3310-3315.e4. [PMID: 30318350 DOI: 10.1016/j.cub.2018.08.029] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 07/26/2018] [Accepted: 08/14/2018] [Indexed: 12/23/2022]
Abstract
Grid cells and theta oscillations are fundamental components of the brain's navigation system. Grid cells provide animals [1, 2] and humans [3, 4] with a spatial map of the environment by exhibiting multiple firing fields arranged in a regular grid of equilateral triangles. This unique firing pattern presumably constitutes the neural basis for path integration [5-8] and may also enable navigation in visual and conceptual spaces [9-12]. Theta frequency oscillations are a prominent mesoscopic network phenomenon during navigation in both rodents and humans [13, 14] and encode movement speed [15-17], distance traveled [18], and proximity to spatial boundaries [19]. Whether theta oscillations may also carry a grid-like signal remains elusive, however. Capitalizing on previous fMRI studies revealing a macroscopic proxy of sum grid cell activity in human entorhinal cortex (EC) [20-22], we examined intracranial EEG recordings from the EC of epilepsy patients (n = 9) performing a virtual navigation task. We found that the power of theta oscillations (4-8 Hz) exhibits 6-fold rotational modulation by movement direction, reminiscent of grid cell-like representations detected using fMRI. Modulation of theta power was specific to 6-fold rotational symmetry and to the EC. Hexadirectional modulation of theta power by movement direction only emerged during fast movements, stabilized over the course of the experiment, and showed sensitivity to the environmental boundary. Our results suggest that oscillatory power in the theta frequency range carries an imprint of sum grid cell activity potentially enabled by a common grid orientation of neighboring grid cells [23].
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64
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Chung SW, Sullivan CM, Rogasch NC, Hoy KE, Bailey NW, Cash RFH, Fitzgerald PB. The effects of individualised intermittent theta burst stimulation in the prefrontal cortex: A TMS-EEG study. Hum Brain Mapp 2018; 40:608-627. [PMID: 30251765 DOI: 10.1002/hbm.24398] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 08/08/2018] [Accepted: 09/04/2018] [Indexed: 01/08/2023] Open
Abstract
Recent studies have highlighted variability in response to theta burst stimulation (TBS) in humans. TBS paradigm was originally developed in rodents to mimic gamma bursts coupled with theta rhythms, and was shown to elicit long-term potentiation. The protocol was subsequently adapted for humans using standardised frequencies of stimulation. However, each individual has different rhythmic firing pattern. The present study sought to explore whether individualised intermittent TBS (Ind iTBS) could outperform the effects of two other iTBS variants. Twenty healthy volunteers received iTBS over left prefrontal cortex using 30 Hz at 6 Hz, 50 Hz at 5 Hz, or individualised frequency in separate sessions. Ind iTBS was determined using theta-gamma coupling during the 3-back task. Concurrent use of transcranial magnetic stimulation and electroencephalography (TMS-EEG) was used to track changes in cortical plasticity. We also utilised mood ratings using a visual analogue scale and assessed working memory via the 3-back task before and after stimulation. No group-level effect was observed following either 30 or 50 Hz iTBS in TMS-EEG. Ind iTBS significantly increased the amplitude of the TMS-evoked P60, and decreased N100 and P200 amplitudes. A significant positive correlation between neurophysiological change and change in mood rating was also observed. Improved accuracy in the 3-back task was observed following both 50 Hz and Ind iTBS conditions. These findings highlight the critical importance of frequency in the parameter space of iTBS. Tailored stimulation parameters appear more efficacious than standard paradigms in neurophysiological and mood changes. This novel approach presents a promising option and benefits may extend to clinical applications.
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Affiliation(s)
- Sung Wook Chung
- Monash Alfred Psychiatry Research Centre, Monash University, Central Clinical School and The Alfred, Melbourne, Australia
| | - Caley M Sullivan
- Monash Alfred Psychiatry Research Centre, Monash University, Central Clinical School and The Alfred, Melbourne, Australia
| | - Nigel C Rogasch
- Brain and Mental Health Laboratory, School of Psychological Sciences and Monash Biomedical Imaging, Monash Institute of Cognitive and Clinical Neuroscience, Monash University, Melbourne, Australia
| | - Kate E Hoy
- Monash Alfred Psychiatry Research Centre, Monash University, Central Clinical School and The Alfred, Melbourne, Australia
| | - Neil W Bailey
- Monash Alfred Psychiatry Research Centre, Monash University, Central Clinical School and The Alfred, Melbourne, Australia
| | - Robin F H Cash
- Monash Alfred Psychiatry Research Centre, Monash University, Central Clinical School and The Alfred, Melbourne, Australia
| | - Paul B Fitzgerald
- Monash Alfred Psychiatry Research Centre, Monash University, Central Clinical School and The Alfred, Melbourne, Australia.,Epworth Clinic, Epworth Healthcare, Melbourne, Australia
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65
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Park JL, Dudchenko PA, Donaldson DI. Navigation in Real-World Environments: New Opportunities Afforded by Advances in Mobile Brain Imaging. Front Hum Neurosci 2018; 12:361. [PMID: 30254578 PMCID: PMC6141718 DOI: 10.3389/fnhum.2018.00361] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 08/23/2018] [Indexed: 12/29/2022] Open
Abstract
A central question in neuroscience and psychology is how the mammalian brain represents the outside world and enables interaction with it. Significant progress on this question has been made in the domain of spatial cognition, where a consistent network of brain regions that represent external space has been identified in both humans and rodents. In rodents, much of the work to date has been done in situations where the animal is free to move about naturally. By contrast, the majority of work carried out to date in humans is static, due to limitations imposed by traditional laboratory based imaging techniques. In recent years, significant progress has been made in bridging the gap between animal and human work by employing virtual reality (VR) technology to simulate aspects of real-world navigation. Despite this progress, the VR studies often fail to fully simulate important aspects of real-world navigation, where information derived from self-motion is integrated with representations of environmental features and task goals. In the current review article, we provide a brief overview of animal and human imaging work to date, focusing on commonalties and differences in findings across species. Following on from this we discuss VR studies of spatial cognition, outlining limitations and developments, before introducing mobile brain imaging techniques and describe technical challenges and solutions for real-world recording. Finally, we discuss how these advances in mobile brain imaging technology, provide an unprecedented opportunity to illuminate how the brain represents complex multifaceted information during naturalistic navigation.
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Affiliation(s)
- Joanne L Park
- Department of Psychology, Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom
| | - Paul A Dudchenko
- Department of Psychology, Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom
| | - David I Donaldson
- Department of Psychology, Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom
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66
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Wohlgemuth MJ, Yu C, Moss CF. 3D Hippocampal Place Field Dynamics in Free-Flying Echolocating Bats. Front Cell Neurosci 2018; 12:270. [PMID: 30190673 PMCID: PMC6115611 DOI: 10.3389/fncel.2018.00270] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 08/02/2018] [Indexed: 12/20/2022] Open
Abstract
A large body of laboratory research has investigated the process by which environmental cues are acquired and used for spatial navigation in rodents; however, the key to differentiating between species specializations and general principles lies in comparative research. Rodent research has focused on a class of neurons in the hippocampus implicated in the representation of allocentric space - termed place cells - and the process by which these representations form. One class of models of hippocampal place field formation depends on continuous theta, a low frequency brain oscillation that is prevalent in crawling rodents. Comparative studies of hippocampal activity in echolocating bats have reported many findings that parallel the rodent literature, but also describe noteworthy species differences, especially with respect to theta rhythm. Here, we first discuss studies of the bat hippocampal formation and point to gaps in our knowledge, which motivate our new lines of inquiry. We present data from the free-flying laryngeal echolocating big brown bat, which shows 3-D place cells without continuous theta, similar to reports from the lingual echolocating Egyptian fruit bat. We also report findings, which demonstrate that the animal's control over echolocation call rate (sensory sampling) influences place field tuning. These results motivate future comparative research on hippocampal function in the context of natural sensory-guided behaviors.
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Affiliation(s)
- Melville J. Wohlgemuth
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, United States
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67
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Boudewyn M, Carter C. I must have missed that: Alpha-band oscillations track attention to spoken language. Neuropsychologia 2018; 117:148-155. [DOI: 10.1016/j.neuropsychologia.2018.05.024] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 05/17/2018] [Accepted: 05/25/2018] [Indexed: 11/26/2022]
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68
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Herweg NA, Kahana MJ. Spatial Representations in the Human Brain. Front Hum Neurosci 2018; 12:297. [PMID: 30104966 PMCID: PMC6078001 DOI: 10.3389/fnhum.2018.00297] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 07/06/2018] [Indexed: 11/13/2022] Open
Abstract
While extensive research on the neurophysiology of spatial memory has been carried out in rodents, memory research in humans had traditionally focused on more abstract, language-based tasks. Recent studies have begun to address this gap using virtual navigation tasks in combination with electrophysiological recordings in humans. These studies suggest that the human medial temporal lobe (MTL) is equipped with a population of place and grid cells similar to that previously observed in the rodent brain. Furthermore, theta oscillations have been linked to spatial navigation and, more specifically, to the encoding and retrieval of spatial information. While some studies suggest a single navigational theta rhythm which is of lower frequency in humans than rodents, other studies advocate for the existence of two functionally distinct delta-theta frequency bands involved in both spatial and episodic memory. Despite the general consensus between rodent and human electrophysiology, behavioral work in humans does not unequivocally support the use of a metric Euclidean map for navigation. Formal models of navigational behavior, which specifically consider the spatial scale of the environment and complementary learning mechanisms, may help to better understand different navigational strategies and their neurophysiological mechanisms. Finally, the functional overlap of spatial and declarative memory in the MTL calls for a unified theory of MTL function. Such a theory will critically rely upon linking task-related phenomena at multiple temporal and spatial scales. Understanding how single cell responses relate to ongoing theta oscillations during both the encoding and retrieval of spatial and non-spatial associations appears to be key toward developing a more mechanistic understanding of memory processes in the MTL.
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Affiliation(s)
- Nora A. Herweg
- Computational Memory Lab, Department of Psychology, University of Pennsylvania, Philadelphia, PA, United States
| | - Michael J. Kahana
- Computational Memory Lab, Department of Psychology, University of Pennsylvania, Philadelphia, PA, United States
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69
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Watrous AJ, Miller J, Qasim SE, Fried I, Jacobs J. Phase-tuned neuronal firing encodes human contextual representations for navigational goals. eLife 2018; 7:32554. [PMID: 29932417 PMCID: PMC6040884 DOI: 10.7554/elife.32554] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 06/21/2018] [Indexed: 12/03/2022] Open
Abstract
We previously demonstrated that the phase of oscillations modulates neural activity representing categorical information using human intracranial recordings and high-frequency activity from local field potentials (Watrous et al., 2015b). We extend these findings here using human single-neuron recordings during a virtual navigation task. We identify neurons in the medial temporal lobe with firing-rate modulations for specific navigational goals, as well as for navigational planning and goal arrival. Going beyond this work, using a novel oscillation detection algorithm, we identify phase-locked neural firing that encodes information about a person’s prospective navigational goal in the absence of firing rate changes. These results provide evidence for navigational planning and contextual accounts of human MTL function at the single-neuron level. More generally, our findings identify phase-coded neuronal firing as a component of the human neural code.
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Affiliation(s)
- Andrew J Watrous
- Department of Biomedical Engineering, Columbia University, New York, United States.,Department of Neurology, Dell Medical School, University of Texas at Austin, Austin, Texas, United States.,Seton Brain and Spine Institute, Austin, Texas, United States
| | - Jonathan Miller
- Department of Biomedical Engineering, Columbia University, New York, United States
| | - Salman E Qasim
- Department of Biomedical Engineering, Columbia University, New York, United States
| | - Itzhak Fried
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States.,Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, United States.,Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.,Department of Neurosurgery, Tel-Aviv Medical Center, Tel-Aviv, Israel
| | - Joshua Jacobs
- Department of Biomedical Engineering, Columbia University, New York, United States
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70
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Miller J, Watrous AJ, Tsitsiklis M, Lee SA, Sheth SA, Schevon CA, Smith EH, Sperling MR, Sharan A, Asadi-Pooya AA, Worrell GA, Meisenhelter S, Inman CS, Davis KA, Lega B, Wanda PA, Das SR, Stein JM, Gorniak R, Jacobs J. Lateralized hippocampal oscillations underlie distinct aspects of human spatial memory and navigation. Nat Commun 2018; 9:2423. [PMID: 29930307 PMCID: PMC6013427 DOI: 10.1038/s41467-018-04847-9] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 05/29/2018] [Indexed: 12/29/2022] Open
Abstract
The hippocampus plays a vital role in various aspects of cognition including both memory and spatial navigation. To understand electrophysiologically how the hippocampus supports these processes, we recorded intracranial electroencephalographic activity from 46 neurosurgical patients as they performed a spatial memory task. We measure signals from multiple brain regions, including both left and right hippocampi, and we use spectral analysis to identify oscillatory patterns related to memory encoding and navigation. We show that in the left but not right hippocampus, the amplitude of oscillations in the 1–3-Hz “low theta” band increases when viewing subsequently remembered object–location pairs. In contrast, in the right but not left hippocampus, low-theta activity increases during periods of navigation. The frequencies of these hippocampal signals are slower than task-related signals in the neocortex. These results suggest that the human brain includes multiple lateralized oscillatory networks that support different aspects of cognition. Theta oscillations are implicated in memory formation. Here, the authors show that low-theta oscillations in the hippocampus are differentially modulated between each hemisphere, with oscillations in the left increasing when successfully learning object–location pairs and in the right during spatial navigation.
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Affiliation(s)
- Jonathan Miller
- Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, Mail Code 8904, 1210 Amsterdam Avenue, New York, NY, 10027, USA
| | - Andrew J Watrous
- Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, Mail Code 8904, 1210 Amsterdam Avenue, New York, NY, 10027, USA
| | - Melina Tsitsiklis
- Doctoral Program in Neurobiology and Behavior, Columbia University, New York, 10027, NY, USA
| | - Sang Ah Lee
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Korea
| | - Sameer A Sheth
- Department of Neurosurgery, Baylor College of Medicine, Houston, 77030, TX, USA
| | - Catherine A Schevon
- Department of Neurology, Columbia University Medical Center, New York, 10032, NY, USA
| | - Elliot H Smith
- Department of Neurological Surgery, Columbia University Medical Center, New York, 10032, NY, USA
| | - Michael R Sperling
- Department of Neurology, Thomas Jefferson University, Philadelphia, 19107, PA, USA
| | - Ashwini Sharan
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, 19107, PA, USA
| | - Ali Akbar Asadi-Pooya
- Department of Neurology, Thomas Jefferson University, Philadelphia, 19107, PA, USA.,Shiraz Neurosciences Research Center, Shiraz University of Medical Sciences, Shiraz, 71348, Iran
| | | | - Stephen Meisenhelter
- Department of Neurology, Geisel School of Medicine at Dartmouth, Lebanon, 03756, NH, USA
| | - Cory S Inman
- Emory University School of Medicine, Atlanta, 30322, GA, USA
| | - Kathryn A Davis
- Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, 19104, PA, USA
| | - Bradley Lega
- University of Texas-Southwestern, Dallas, 75390, TX, USA
| | - Paul A Wanda
- Department of Psychology, University of Pennsylvania, Philadelphia, 19104, PA, USA
| | - Sandhitsu R Das
- Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, 19104, PA, USA
| | - Joel M Stein
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, 19104, PA, USA
| | - Richard Gorniak
- Department of Radiology, Thomas Jefferson University, Philadelphia, 19107, PA, USA
| | - Joshua Jacobs
- Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, Mail Code 8904, 1210 Amsterdam Avenue, New York, NY, 10027, USA.
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71
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Pu Y, Cheyne DO, Cornwell BR, Johnson BW. Non-invasive Investigation of Human Hippocampal Rhythms Using Magnetoencephalography: A Review. Front Neurosci 2018; 12:273. [PMID: 29755314 PMCID: PMC5932174 DOI: 10.3389/fnins.2018.00273] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 04/09/2018] [Indexed: 02/06/2023] Open
Abstract
Hippocampal rhythms are believed to support crucial cognitive processes including memory, navigation, and language. Due to the location of the hippocampus deep in the brain, studying hippocampal rhythms using non-invasive magnetoencephalography (MEG) recordings has generally been assumed to be methodologically challenging. However, with the advent of whole-head MEG systems in the 1990s and development of advanced source localization techniques, simulation and empirical studies have provided evidence that human hippocampal signals can be sensed by MEG and reliably reconstructed by source localization algorithms. This paper systematically reviews simulation studies and empirical evidence of the current capacities and limitations of MEG “deep source imaging” of the human hippocampus. Overall, these studies confirm that MEG provides a unique avenue to investigate human hippocampal rhythms in cognition, and can bridge the gap between animal studies and human hippocampal research, as well as elucidate the functional role and the behavioral correlates of human hippocampal oscillations.
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Affiliation(s)
- Yi Pu
- ARC Centre of Excellence in Cognition and its Disorders, Macquarie University, Sydney, NSW, Australia.,Department of Cognitive Science, Macquarie University, Sydney, NSW, Australia
| | - Douglas O Cheyne
- Program in Neurosciences and Mental Health, Hospital for Sick Children Research Institute, Toronto, ON, Canada.,Department of Medical Imaging, University of Toronto, Toronto, ON, Canada
| | - Brian R Cornwell
- Brain and Psychological Sciences Research Centre, Swinburne University of Technology, Melbourne, VIC, Australia
| | - Blake W Johnson
- ARC Centre of Excellence in Cognition and its Disorders, Macquarie University, Sydney, NSW, Australia.,Department of Cognitive Science, Macquarie University, Sydney, NSW, Australia
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72
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Seewoo BJ, Etherington SJ, Feindel KW, Rodger J. Combined rTMS/fMRI Studies: An Overlooked Resource in Animal Models. Front Neurosci 2018; 12:180. [PMID: 29628873 PMCID: PMC5876299 DOI: 10.3389/fnins.2018.00180] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 03/06/2018] [Indexed: 12/11/2022] Open
Abstract
Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive neuromodulation technique, which has brain network-level effects in healthy individuals and is also used to treat many neurological and psychiatric conditions in which brain connectivity is believed to be abnormal. Despite the fact that rTMS is being used in a clinical setting and animal studies are increasingly identifying potential cellular and molecular mechanisms, little is known about how these mechanisms relate to clinical changes. This knowledge gap is amplified by non-overlapping approaches used in preclinical and clinical rTMS studies: preclinical studies are mostly invasive, using cellular and molecular approaches, while clinical studies are non-invasive, including functional magnetic resonance imaging (fMRI), TMS electroencephalography (EEG), positron emission tomography (PET), and behavioral measures. A non-invasive method is therefore needed in rodents to link our understanding of cellular and molecular changes to functional connectivity changes that are clinically relevant. fMRI is the technique of choice for examining both short and long term functional connectivity changes in large-scale networks and is becoming increasingly popular in animal research because of its high translatability, but, to date, there have been no reports of animal rTMS studies using this technique. This review summarizes the main studies combining different rTMS protocols with fMRI in humans, in both healthy and patient populations, providing a foundation for the design of equivalent studies in animals. We discuss the challenges of combining these two methods in animals and highlight considerations important for acquiring clinically-relevant information from combined rTMS/fMRI studies in animals. We believe that combining rTMS and fMRI in animal models will generate new knowledge in the following ways: functional connectivity changes can be explored in greater detail through complementary invasive procedures, clarifying mechanism and improving the therapeutic application of rTMS, as well as improving interpretation of fMRI data. And, in a more general context, a robust comparative approach will refine the use of animal models of specific neuropsychiatric conditions.
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Affiliation(s)
- Bhedita J Seewoo
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, Perth, WA, Australia.,Centre for Microscopy, Characterization and Analysis, Research Infrastructure Centers, The University of Western Australia, Perth, WA, Australia
| | - Sarah J Etherington
- School of Veterinary and Life Sciences, Murdoch University, Perth, WA, Australia
| | - Kirk W Feindel
- Centre for Microscopy, Characterization and Analysis, Research Infrastructure Centers, The University of Western Australia, Perth, WA, Australia.,School of Biomedical Sciences, University of Western Australia, Perth, WA, Australia
| | - Jennifer Rodger
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, Perth, WA, Australia.,Brain Plasticity Group, Perron Institute for Neurological and Translational Research, Perth, WA, Australia
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73
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M Aghajan Z, Schuette P, Fields TA, Tran ME, Siddiqui SM, Hasulak NR, Tcheng TK, Eliashiv D, Mankin EA, Stern J, Fried I, Suthana N. Theta Oscillations in the Human Medial Temporal Lobe during Real-World Ambulatory Movement. Curr Biol 2017; 27:3743-3751.e3. [PMID: 29199073 DOI: 10.1016/j.cub.2017.10.062] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 09/21/2017] [Accepted: 10/25/2017] [Indexed: 01/24/2023]
Abstract
The theta rhythm-a slow (6-12 Hz) oscillatory component of the local field potential-plays a critical role in spatial navigation and memory by coordinating the activity of neuronal ensembles within the medial temporal lobe (MTL). Although theta has been extensively studied in freely moving rodents, its presence in humans has been elusive and primarily investigated in stationary subjects. Here we used a unique clinical opportunity to examine theta within the human MTL during untethered, real-world ambulatory movement. We recorded intracranial electroencephalographic activity from participants chronically implanted with the wireless NeuroPace responsive neurostimulator (RNS) and tracked their motion with sub-millimeter precision. Our data revealed that movement-related theta oscillations indeed exist in humans, such that theta power is significantly higher during movement than immobility. Unlike in rodents, however, theta occurs in short bouts, with average durations of ∼400 ms, which are more prevalent during fast versus slow movements. In a rare opportunity to study a congenitally blind participant, we found that both the prevalence and duration of theta bouts were increased relative to the sighted participants. These results provide critical support for conserved neurobiological characteristics of theta oscillations during ambulatory spatial navigation, while highlighting some fundamental differences across species in these oscillations between humans and rodents.
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Affiliation(s)
- Zahra M Aghajan
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Peter Schuette
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Tony A Fields
- Department of Neurology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Michelle E Tran
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Sameed M Siddiqui
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | | | | | - Dawn Eliashiv
- Department of Neurology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Emily A Mankin
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - John Stern
- Department of Neurology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Itzhak Fried
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Functional Neurosurgery Unit, Tel Aviv Medical Center, Tel Aviv 64361, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Nanthia Suthana
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Psychology, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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74
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Geng K, Shin DC, Song D, Hampson RE, Deadwyler SA, Berger TW, Marmarelis VZ. Mechanism-Based and Input-Output Modeling of the Key Neuronal Connections and Signal Transformations in the CA3-CA1 Regions of the Hippocampus. Neural Comput 2017; 30:149-183. [PMID: 29064783 DOI: 10.1162/neco_a_01031] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
This letter examines the results of input-output (nonparametric) modeling based on the analysis of data generated by a mechanism-based (parametric) model of CA3-CA1 neuronal connections in the hippocampus. The motivation is to obtain biological insight into the interpretation of such input-output (Volterra-equivalent) models estimated from synthetic data. The insights obtained may be subsequently used to interpretat input-output models extracted from actual experimental data. Specifically, we found that a simplified parametric model may serve as a useful tool to study the signal transformations in the hippocampal CA3-CA1 regions. Input-output modeling of model-based synthetic data show that GABAergic interneurons are responsible for regulating neuronal excitation, controlling the precision of spike timing, and maintaining network oscillations, in a manner consistent with previous studies. The input-output model obtained from real data exhibits intriguing similarities with its synthetic-data counterpart, demonstrating the importance of a dynamic resonance in the system/model response around 2 Hz to 3 Hz. Using the input-output model from real data as a guide, we may be able to amend the parametric model by incorporating more mechanisms in order to yield better-matching input-output model. The approach we present can also be applied to the study of other neural systems and pathways.
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Affiliation(s)
- Kunling Geng
- Department of Biomedical Engineering and the Biomedical Simulations Resource Center at the University of Southern California, Los Angeles, CA, 90089, U.S.A.
| | - Dae C Shin
- Department of Biomedical Engineering and the Biomedical Simulations Resource Center at the University of Southern California, Los Angeles, CA, 90089, U.S.A.
| | - Dong Song
- Department of Biomedical Engineering and the Biomedical Simulations Resource Center at the University of Southern California, Los Angeles, CA, 90089, U.S.A.
| | - Robert E Hampson
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, 27157, U.S.A.
| | - Samuel A Deadwyler
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, 27157, U.S.A.
| | - Theodore W Berger
- Department of Biomedical Engineering and the Biomedical Simulations Resource Center at the University of Southern California, Los Angeles, CA, 90089, U.S.A.
| | - Vasilis Z Marmarelis
- Department of Biomedical Engineering and the Biomedical Simulations Resource Center at the University of Southern California, Los Angeles, CA, 90089, U.S.A.
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75
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Human hippocampal theta power indicates movement onset and distance travelled. Proc Natl Acad Sci U S A 2017; 114:12297-12302. [PMID: 29078334 DOI: 10.1073/pnas.1708716114] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Theta frequency oscillations in the 6- to 10-Hz range dominate the rodent hippocampal local field potential during translational movement, suggesting that theta encodes self-motion. Increases in theta power have also been identified in the human hippocampus during both real and virtual movement but appear as transient bursts in distinct high- and low-frequency bands, and it is not yet clear how these bursts relate to the sustained oscillation observed in rodents. Here, we examine depth electrode recordings from the temporal lobe of 13 presurgical epilepsy patients performing a self-paced spatial memory task in a virtual environment. In contrast to previous studies, we focus on movement-onset periods that incorporate both initial acceleration and an immediately preceding stationary interval associated with prominent theta oscillations in the rodent hippocampal formation. We demonstrate that movement-onset periods are associated with a significant increase in both low (2-5 Hz)- and high (6-9 Hz)-frequency theta power in the human hippocampus. Similar increases in low- and high-frequency theta power are seen across lateral temporal lobe recording sites and persist throughout the remainder of movement in both regions. In addition, we show that movement-related theta power is greater both before and during longer paths, directly implicating human hippocampal theta in the encoding of translational movement. These findings strengthen the connection between studies of theta-band activity in rodents and humans and offer additional insight into the neural mechanisms of spatial navigation.
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76
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Lin JJ, Rugg MD, Das S, Stein J, Rizzuto DS, Kahana MJ, Lega BC. Theta band power increases in the posterior hippocampus predict successful episodic memory encoding in humans. Hippocampus 2017; 27:1040-1053. [PMID: 28608960 DOI: 10.1002/hipo.22751] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 06/07/2017] [Accepted: 06/08/2017] [Indexed: 12/23/2022]
Abstract
Functional differences in the anterior and posterior hippocampus during episodic memory processing have not been examined in human electrophysiological data. This is in spite of strong evidence for such differences in rodent data, including greater place cell specificity in the dorsal hippocampus, greater sensitivity to the aversive or motivational content of memories in ventral regions, connectivity analyses identifying preferential ventral hippocampal connections with the amygdala, and gene expression analyses identifying a dorsal-ventral gradient. We asked if memory-related oscillatory patterns observed in human hippocampal recordings, including the gamma band and slow-theta (2.5-5 Hz) subsequent memory effects, would exhibit differences along the longitudinal axis and between hemispheres. We took advantage of a new dataset of stereo electroencephalography patients with simultaneous, robotically targeted anterior, and posterior hippocampal electrodes to directly compare oscillatory subsequent memory effects during item encoding. This same data set allowed us to examine left-right connectivity and hemispheric differences in hippocampal oscillatory patterns. Our data suggest that a power increase during successful item encoding in the 2.5-5 Hz slow-theta frequency range preferentially occurs in the posterior hippocampus during the first 1,000 ms after item presentation, while a gamma band power increase is stronger in the dominant hemisphere. This dominant-nondominant pattern in the gamma range appears to reverse during item retrieval, however. Intrahippocampal phase coherence was found to be stronger during successful item encoding. Our phase coherence data are also consistent with existing reports of a traveling wave for theta oscillations propagating along the septotemporal (longitudinal) axis of the human hippocampus. We examine how our findings fit with theories of functional specialization along the hippocampal axis.
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Affiliation(s)
- Jui-Jui Lin
- Department of Neurological Surgery, University of Texas, Southwestern Medical Center, Dallas, Texas, 75390
| | - Michael D Rugg
- Center for Vital Longevity, University of Texas at Dallas, Dallas, Texas, 75390
| | - Sandhitsu Das
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, 19104
| | - Joel Stein
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, 19104
| | - Daniel S Rizzuto
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania, 19104
| | - Michael J Kahana
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania, 19104
| | - Bradley C Lega
- Department of Neurological Surgery, University of Texas, Southwestern Medical Center, Dallas, Texas, 75390
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77
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Lega B, Germi J, Rugg M. Modulation of Oscillatory Power and Connectivity in the Human Posterior Cingulate Cortex Supports the Encoding and Retrieval of Episodic Memories. J Cogn Neurosci 2017; 29:1415-1432. [PMID: 28387588 DOI: 10.1162/jocn_a_01133] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Existing data from noninvasive studies have led researchers to posit that the posterior cingulate cortex (PCC) supports mnemonic processes: It exhibits degeneration in memory disorders, and fMRI investigations have demonstrated memory-related activation principally during the retrieval of memory items. Despite these data, the role of the PCC in episodic memory has received only limited treatment using the spatial and temporal precision of intracranial EEG, with previous analyses focused on item retrieval. Using data gathered from 21 human participants who underwent stereo-EEG for seizure localization, we characterized oscillatory patterns in the PCC during the encoding and retrieval of episodic memories. We identified a subsequent memory effect during item encoding characterized by increased gamma band oscillatory power and a low-frequency power desynchronization. Fourteen participants had stereotactic electrodes located simultaneously in the hippocampus and PCC, and with these unique data, we describe connectivity changes between these structures that predict successful item encoding and that precede item retrieval. Oscillatory power during retrieval matched the pattern we observed during encoding, with low-frequency (below 15 Hz) desynchronization and a gamma band (especially high gamma, 70-180 Hz) power increase. Encoding is characterized by synchrony between the hippocampus and PCC, centered at 3 Hz, consistent with other observations of properties of this oscillation akin to those for rodent theta activity. We discuss our findings in light of existing theories of episodic memory processing, including the information via desynchronization hypothesis and retrieved context theory, and examine how our data fit with existing theories for the functional role of the PCC. These include a postulated role for the PCC in modulating internally directed attention and for representing or integrating contextual information for memory items.
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Affiliation(s)
| | - James Germi
- University of Texas-Southwestern Medical Center
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78
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Communication between Brain Areas Based on Nested Oscillations. eNeuro 2017; 4:eN-TNC-0153-16. [PMID: 28374013 PMCID: PMC5367085 DOI: 10.1523/eneuro.0153-16.2017] [Citation(s) in RCA: 145] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 01/25/2017] [Accepted: 02/14/2017] [Indexed: 12/02/2022] Open
Abstract
Unraveling how brain regions communicate is crucial for understanding how the brain processes external and internal information. Neuronal oscillations within and across brain regions have been proposed to play a crucial role in this process. Two main hypotheses have been suggested for routing of information based on oscillations, namely communication through coherence and gating by inhibition. Here, we propose a framework unifying these two hypotheses that is based on recent empirical findings. We discuss a theory in which communication between two regions is established by phase synchronization of oscillations at lower frequencies (<25 Hz), which serve as temporal reference frame for information carried by high-frequency activity (>40 Hz). Our framework, consistent with numerous recent empirical findings, posits that cross-frequency interactions are essential for understanding how large-scale cognitive and perceptual networks operate.
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79
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Kaplan R, Bush D, Bisby JA, Horner AJ, Meyer SS, Burgess N. Medial Prefrontal-Medial Temporal Theta Phase Coupling in Dynamic Spatial Imagery. J Cogn Neurosci 2017; 29:507-519. [PMID: 27779906 PMCID: PMC5321531 DOI: 10.1162/jocn_a_01064] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Hippocampal-medial prefrontal interactions are thought to play a crucial role in mental simulation. Notably, the frontal midline/medial pFC (mPFC) theta rhythm in humans has been linked to introspective thought and working memory. In parallel, theta rhythms have been proposed to coordinate processing in the medial temporal cortex, retrosplenial cortex (RSc), and parietal cortex during the movement of viewpoint in imagery, extending their association with physical movement in rodent models. Here, we used noninvasive whole-head MEG to investigate theta oscillatory power and phase-locking during the 18-sec postencoding delay period of a spatial working memory task, in which participants imagined previously learned object sequences either on a blank background (object maintenance), from a first-person viewpoint in a scene (static imagery), or moving along a path past the objects (dynamic imagery). We found increases in 4- to 7-Hz theta power in mPFC when comparing the delay period with a preencoding baseline. We then examined whether the mPFC theta rhythm was phase-coupled with ongoing theta oscillations elsewhere in the brain. The same mPFC region showed significantly higher theta phase coupling with the posterior medial temporal lobe/RSc for dynamic imagery versus either object maintenance or static imagery. mPFC theta phase coupling was not observed with any other brain region. These results implicate oscillatory coupling between mPFC and medial temporal lobe/RSc theta rhythms in the dynamic mental exploration of imagined scenes.
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Affiliation(s)
- Raphael Kaplan
- University College London
- Universitat Pompeu Fabra, Barcelona, Spain
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80
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Bohbot VD, Copara MS, Gotman J, Ekstrom AD. Low-frequency theta oscillations in the human hippocampus during real-world and virtual navigation. Nat Commun 2017; 8:14415. [PMID: 28195129 PMCID: PMC5316881 DOI: 10.1038/ncomms14415] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 12/28/2016] [Indexed: 11/09/2022] Open
Abstract
Low-Frequency Oscillations (LFO) in the range of 7-9 Hz, or theta rhythm, has been recorded in rodents ambulating in the real world. However, intra-hippocampus EEG recordings during virtual navigation in humans have consistently reported LFO that appear to predominate around 3-4 Hz. Here we report clear evidence of 7-9 Hz rhythmicity in raw intra-hippocampus EEG traces during real as well as virtual movement. Oscillations typically occur at a lower frequency in virtual than real world navigation. This study highlights the possibility that human and rodent hippocampal EEG activity are not as different as previously reported and this difference may arise, in part, due to the lack of actual movement in previous human navigation studies, which were virtual.
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Affiliation(s)
- Véronique D Bohbot
- Douglas Institute, Department of Psychiatry, McGill University, 6875 boulevard LaSalle, Verdun, Quebec, Canada H4H 1R3
| | - Milagros S Copara
- Neuroscience Graduate Group, University of California, Davis, 1 Shields Avenue, Davis, California 95616, USA
| | - Jean Gotman
- Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4
| | - Arne D Ekstrom
- Neuroscience Graduate Group, University of California, Davis, 1 Shields Avenue, Davis, California 95616, USA.,Center for Neuroscience, University of California, Davis, 1 Shields Avenue, Davis, California 95618, USA.,Department of Psychology, University of California, Davis, 1 Shields Avenue, Davis, California 95618, USA
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81
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Hacker CD, Snyder AZ, Pahwa M, Corbetta M, Leuthardt EC. Frequency-specific electrophysiologic correlates of resting state fMRI networks. Neuroimage 2017; 149:446-457. [PMID: 28159686 PMCID: PMC5745814 DOI: 10.1016/j.neuroimage.2017.01.054] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 01/12/2017] [Accepted: 01/22/2017] [Indexed: 11/29/2022] Open
Abstract
Resting state functional MRI (R-fMRI) studies have shown that slow (< 0.1 Hz), intrinsic fluctuations of the blood oxygen level dependent (BOLD) signal are temporally correlated within hierarchically organized functional systems known as resting state networks (RSNs) (Doucet et al., 2011). Most broadly, this hierarchy exhibits a dichotomy between two opposed systems (Fox et al., 2005). One system engages with the environment and includes the visual, auditory, and sensorimotor (SMN) networks as well as the dorsal attention network (DAN), which controls spatial attention. The other system includes the default mode network (DMN) and the fronto-parietal control system (FPC), RSNs that instantiate episodic memory and executive control, respectively. Here, we test the hypothesis, based on the spectral specificity of electrophysiologic responses to perceptual vs. memory tasks (Klimesch, 1999; Pfurtscheller and Lopes da Silva, 1999), that these two large-scale neural systems also manifest frequency specificity in the resting state. We measured the spatial correspondence between electrocorticographic (ECoG) band-limited power (BLP) and R-fMRI correlation patterns in awake, resting, human subjects. Our results show that, while gamma BLP correspondence was common throughout the brain, theta (4–8 Hz) BLP correspondence was stronger in the DMN and FPC, whereas alpha (8–12 Hz) correspondence was stronger in the SMN and DAN. Thus, the human brain, at rest, exhibits frequency specific electrophysiology, respecting both the spectral structure of task responses and the hierarchical organization of RSNs.
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Affiliation(s)
- Carl D Hacker
- Department of Neurosurgery, Washington University School of Medicine, Campus Box 8225, United States.
| | - Abraham Z Snyder
- Department of Radiology, Washington University School of Medicine, Campus Box 8225, United States; Department of Neurology, Washington University School of Medicine, Campus Box 8225, United States
| | - Mrinal Pahwa
- Department of Neurosurgery, Washington University School of Medicine, Campus Box 8225, United States
| | - Maurizio Corbetta
- Department of Neurology, Washington University School of Medicine, Campus Box 8225, United States
| | - Eric C Leuthardt
- Department of Neurosurgery, Washington University School of Medicine, Campus Box 8225, United States
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Lee DJ, Izadi A, Melnik M, Seidl S, Echeverri A, Shahlaie K, Gurkoff GG. Stimulation of the medial septum improves performance in spatial learning following pilocarpine-induced status epilepticus. Epilepsy Res 2017; 130:53-63. [PMID: 28152425 DOI: 10.1016/j.eplepsyres.2017.01.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 12/22/2016] [Accepted: 01/09/2017] [Indexed: 01/20/2023]
Abstract
Temporal lobe epilepsy often leads to hippocampal sclerosis and persistent cognitive deficits, including difficulty with learning and memory. Hippocampal theta oscillations are critical in optimizing hippocampal function and facilitating plasticity. We hypothesized that pilocarpine-induced status epilepticus would disrupt oscillations and behavioral performance and that electrical neuromodulation to entrain theta would improve cognition specifically in injured rats. Rats received a pilocarpine (n=30) or saline injection (n=27) and unilateral bi-polar electrodes were implanted into the medial septum and hippocampus the following day. Hippocampal and septal theta were recorded in a Plexiglas box over the first week following implantation. Control and pilocarpine-treated rats were split into stimulation (continuous 7.7Hz, 80μA, 1ms pulse width) and non-stimulation groups for behavioral analysis. Continuous stimulation was initiated one-minute prior to and throughout an object exploration task (post-injury day seven) and again for each of six trials on the Barnes maze (post-injury days 12-14). There was a significant reduction in hippocampal theta power (p<0.05) and percentage of time oscillating in theta (p<0.05). In addition there was a significant decrease in object exploration in rats post-pilocarpine (p<0.05) and an impairment in spatial learning. Specifically, pilocarpine-treated rats were more likely to use random search strategies (p<0.001) and had an increase in latency to find the hidden platform (p<0.05) on the Barnes maze. Stimulation of the medial septum at 7.7Hz in pilocarpine-treated rats resulted in performance similar to shams in both the object recognition and Barnes maze tasks. Stimulation of sham rats resulted in impaired object exploration (p<0.05) with no difference in Barnes maze latency or strategy. In conclusion, pilocarpine-induced seizures diminished hippocampal oscillations and impaired performance in both an object exploration and a spatial memory task in pilocarpine-treated rats. Theta stimulation at 7.7Hz improved behavioral outcome on the Barnes maze task; this improvement in function was not related to a general cognitive enhancement, as shams did not benefit from stimulation. Therefore, stimulation of the medial septum represents an exciting target to improve behavioral outcome in patients with epilepsy.
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Affiliation(s)
- Darrin J Lee
- Department of Neurological Surgery, UC Davis School of Medicine, 4860 Y Street, Suite 3740, Sacramento, CA 95817, United States
| | - Ali Izadi
- Department of Neurological Surgery, UC Davis School of Medicine, 4860 Y Street, Suite 3740, Sacramento, CA 95817, United States; Center for Neuroscience, University of California, 1544 Newton Court, Davis, CA 95618, United States.
| | - Mikhail Melnik
- Department of Neurological Surgery, UC Davis School of Medicine, 4860 Y Street, Suite 3740, Sacramento, CA 95817, United States.
| | - Stacey Seidl
- Department of Neurological Surgery, UC Davis School of Medicine, 4860 Y Street, Suite 3740, Sacramento, CA 95817, United States; Center for Neuroscience, University of California, 1544 Newton Court, Davis, CA 95618, United States.
| | - Angela Echeverri
- Department of Neurological Surgery, UC Davis School of Medicine, 4860 Y Street, Suite 3740, Sacramento, CA 95817, United States.
| | - Kiarash Shahlaie
- Department of Neurological Surgery, UC Davis School of Medicine, 4860 Y Street, Suite 3740, Sacramento, CA 95817, United States; Center for Neuroscience, University of California, 1544 Newton Court, Davis, CA 95618, United States.
| | - Gene G Gurkoff
- Department of Neurological Surgery, UC Davis School of Medicine, 4860 Y Street, Suite 3740, Sacramento, CA 95817, United States; Center for Neuroscience, University of California, 1544 Newton Court, Davis, CA 95618, United States.
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Spatial Mnemonic Encoding: Theta Power Decreases and Medial Temporal Lobe BOLD Increases Co-Occur during the Usage of the Method of Loci. eNeuro 2017; 3:eN-NWR-0184-16. [PMID: 28101523 PMCID: PMC5223054 DOI: 10.1523/eneuro.0184-16.2016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 11/03/2016] [Accepted: 11/04/2016] [Indexed: 01/13/2023] Open
Abstract
The method of loci is one, if not the most, efficient mnemonic encoding strategy. This spatial mnemonic combines the core cognitive processes commonly linked to medial temporal lobe (MTL) activity: spatial and associative memory processes. During such processes, fMRI studies consistently demonstrate MTL activity, while electrophysiological studies have emphasized the important role of theta oscillations (3-8 Hz) in the MTL. However, it is still unknown whether increases or decreases in theta power co-occur with increased BOLD signal in the MTL during memory encoding. To investigate this question, we recorded EEG and fMRI separately, while human participants used the spatial method of loci or the pegword method, a similarly associative but nonspatial mnemonic. The more effective spatial mnemonic induced a pronounced theta power decrease source localized to the left MTL compared with the nonspatial associative mnemonic strategy. This effect was mirrored by BOLD signal increases in the MTL. Successful encoding, irrespective of the strategy used, elicited decreases in left temporal theta power and increases in MTL BOLD activity. This pattern of results suggests a negative relationship between theta power and BOLD signal changes in the MTL during memory encoding and spatial processing. The findings extend the well known negative relation of alpha/beta oscillations and BOLD signals in the cortex to theta oscillations in the MTL.
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84
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Duarte IC, Castelhano J, Sales F, Castelo-Branco M. The anterior versus posterior hippocampal oscillations debate in human spatial navigation: evidence from an electrocorticographic case study. Brain Behav 2016; 6:e00507. [PMID: 27688937 PMCID: PMC5036430 DOI: 10.1002/brb3.507] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 04/16/2016] [Accepted: 04/30/2016] [Indexed: 01/30/2023] Open
Abstract
INTRODUCTION Hippocampal oscillations have been regularly described as playing a dominant role in spatial memory and navigation in rodents. In humans, the relative role of anterior versus posterior rhythms during navigational memory is not established. METHODS Here, we tested this hypothesis using direct brain ECoG recordings in the anterior and posterior hippocampus of a patient, in a navigational task requiring spatial memory. We assessed multiple oscillatory bands during encoding and retrieval phases. RESULTS We found navigation related 1-3.5 Hz activity during retrieval, both in the anterior and posterior hippocampus. Activity between 4 and 8 Hz was identified during both encoding and retrieval, only in the anterior hippocampus. CONCLUSIONS Our findings are consistent with the view that an anterior/posterior functional gradient is present in the hippocampus, and involves two distinct neuronal networks, supporting either encoding or retrieval processes. Although this is a single case scenario, these findings suggest that neural oscillations during spatial navigation do vary across hippocampal subregions, as a function of encoding versus retrieval processes during the mnemonic process. In this single case study, the results point to the presence of a dual involvement of multiple frequency bands across hippocampal subregions during encoding and retrieval. Although these results need generalization, they provide a new perspective on distinct physiological properties of the anterior and posterior hippocampus in human spatial navigation during encoding and retrieval.
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Affiliation(s)
- Isabel C Duarte
- Brain Imaging Network ICNAS Coimbra Portugal; Institute for Biomedical Imaging and Life Sciences CNC.IBILI University of Coimbra Coimbra Portugal
| | - João Castelhano
- Brain Imaging Network ICNAS Coimbra Portugal; Institute for Biomedical Imaging and Life Sciences CNC.IBILI University of Coimbra Coimbra Portugal
| | | | - Miguel Castelo-Branco
- Brain Imaging Network ICNAS Coimbra Portugal; Institute for Biomedical Imaging and Life Sciences CNC.IBILI University of Coimbra Coimbra Portugal
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85
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Crespo-García M, Zeiller M, Leupold C, Kreiselmeyer G, Rampp S, Hamer HM, Dalal SS. Slow-theta power decreases during item-place encoding predict spatial accuracy of subsequent context recall. Neuroimage 2016; 142:533-543. [PMID: 27521743 DOI: 10.1016/j.neuroimage.2016.08.021] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 07/26/2016] [Accepted: 08/09/2016] [Indexed: 12/31/2022] Open
Abstract
Human hippocampal theta oscillations play a key role in accurate spatial coding. Associative encoding involves similar hippocampal networks but, paradoxically, is also characterized by theta power decreases. Here, we investigated how theta activity relates to associative encoding of place contexts resulting in accurate navigation. Using MEG, we found that slow-theta (2-5Hz) power negatively correlated with subsequent spatial accuracy for virtual contextual locations in posterior hippocampus and other cortical structures involved in spatial cognition. A rare opportunity to simultaneously record MEG and intracranial EEG in an epilepsy patient provided crucial insights: during power decreases, slow-theta in right anterior hippocampus and left inferior frontal gyrus phase-led the left temporal cortex and predicted spatial accuracy. Our findings indicate that decreased slow-theta activity reflects local and long-range neural mechanisms that encode accurate spatial contexts, and strengthens the view that local suppression of low-frequency activity is essential for more efficient processing of detailed information.
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Affiliation(s)
- Maité Crespo-García
- Department of Psychology, University of Konstanz, 78464 Konstanz, Germany; Zukunftskolleg, University of Konstanz, 78464 Konstanz, Germany.
| | - Monika Zeiller
- Department of Psychology, University of Konstanz, 78464 Konstanz, Germany
| | - Claudia Leupold
- Department of Neurosurgery, Epilepsy Center, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Gernot Kreiselmeyer
- Department of Neurology, Epilepsy Center, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Stefan Rampp
- Department of Neurosurgery, Epilepsy Center, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Hajo M Hamer
- Department of Neurology, Epilepsy Center, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Sarang S Dalal
- Department of Psychology, University of Konstanz, 78464 Konstanz, Germany; Zukunftskolleg, University of Konstanz, 78464 Konstanz, Germany
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86
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Qasim SE, Jacobs J. Human Hippocampal Theta Oscillations during Movement without Visual Cues. Neuron 2016; 89:1121-1123. [PMID: 26985718 DOI: 10.1016/j.neuron.2016.03.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The hippocampus exhibits theta oscillations when animals navigate. Vass et al. (2016) discovered that theta oscillations are also present when humans are moved through a virtual environment without sensory feedback, indicating that theta oscillations have a general role in spatial cognition beyond sensorimotor processing.
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Affiliation(s)
- Salman E Qasim
- Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
| | - Joshua Jacobs
- Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA.
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87
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Gips B, van der Eerden JPJM, Jensen O. A biologically plausible mechanism for neuronal coding organized by the phase of alpha oscillations. Eur J Neurosci 2016; 44:2147-61. [PMID: 27320148 PMCID: PMC5129495 DOI: 10.1111/ejn.13318] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 06/15/2016] [Accepted: 06/17/2016] [Indexed: 01/18/2023]
Abstract
The visual system receives a wealth of sensory information of which only little is relevant for behaviour. We present a mechanism in which alpha oscillations serve to prioritize different components of visual information. By way of simulated neuronal networks, we show that inhibitory modulation in the alpha range (~ 10 Hz) can serve to temporally segment the visual information to prevent information overload. Coupled excitatory and inhibitory neurons generate a gamma rhythm in which information is segmented and sorted according to excitability in each alpha cycle. Further details are coded by distributed neuronal firing patterns within each gamma cycle. The network model produces coupling between alpha phase and gamma (40–100 Hz) amplitude in the simulated local field potential similar to that observed experimentally in human and animal recordings.
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Affiliation(s)
- Bart Gips
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Kapittelweg 29, 6525 EN, Nijmegen, The Netherlands
| | - Jan P J M van der Eerden
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Kapittelweg 29, 6525 EN, Nijmegen, The Netherlands
| | - Ole Jensen
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Kapittelweg 29, 6525 EN, Nijmegen, The Netherlands
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88
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Pevzner A, Izadi A, Lee DJ, Shahlaie K, Gurkoff GG. Making Waves in the Brain: What Are Oscillations, and Why Modulating Them Makes Sense for Brain Injury. Front Syst Neurosci 2016; 10:30. [PMID: 27092062 PMCID: PMC4823270 DOI: 10.3389/fnsys.2016.00030] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 03/22/2016] [Indexed: 01/19/2023] Open
Abstract
Traumatic brain injury (TBI) can result in persistent cognitive, behavioral and emotional deficits. However, the vast majority of patients are not chronically hospitalized; rather they have to manage their disabilities once they are discharged to home. Promoting recovery to pre-injury level is important from a patient care as well as a societal perspective. Electrical neuromodulation is one approach that has shown promise in alleviating symptoms associated with neurological disorders such as in Parkinson’s disease (PD) and epilepsy. Consistent with this perspective, both animal and clinical studies have revealed that TBI alters physiological oscillatory rhythms. More recently several studies demonstrated that low frequency stimulation improves cognitive outcome in models of TBI. Specifically, stimulation of the septohippocampal circuit in the theta frequency entrained oscillations and improved spatial learning following TBI. In order to evaluate the potential of electrical deep brain stimulation for clinical translation we review the basic neurophysiology of oscillations, their role in cognition and how they are changed post-TBI. Furthermore, we highlight several factors for future pre-clinical and clinical studies to consider, with the hope that it will promote a hypothesis driven approach to subsequent experimental designs and ultimately successful translation to improve outcome in patients with TBI.
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Affiliation(s)
- Aleksandr Pevzner
- Department of Neurological Surgery, University of California-DavisSacramento, CA, USA; Center for Neuroscience, University of California-DavisSacramento, CA, USA
| | - Ali Izadi
- Department of Neurological Surgery, University of California-DavisSacramento, CA, USA; Center for Neuroscience, University of California-DavisSacramento, CA, USA
| | - Darrin J Lee
- Department of Neurological Surgery, University of California-DavisSacramento, CA, USA; Center for Neuroscience, University of California-DavisSacramento, CA, USA
| | - Kiarash Shahlaie
- Department of Neurological Surgery, University of California-DavisSacramento, CA, USA; Center for Neuroscience, University of California-DavisSacramento, CA, USA
| | - Gene G Gurkoff
- Department of Neurological Surgery, University of California-DavisSacramento, CA, USA; Center for Neuroscience, University of California-DavisSacramento, CA, USA
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89
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Abstract
The hippocampal local field potential (LFP) shows three major types of rhythms: theta, sharp wave-ripples and gamma. These rhythms are defined by their frequencies, they have behavioural correlates in several species including rats and humans, and they have been proposed to carry out distinct functions in hippocampal memory processing. However, recent findings have challenged traditional views on these behavioural functions. In this Review, I discuss our current understanding of the origins and the mnemonic functions of hippocampal theta, sharp wave-ripples and gamma rhythms on the basis of findings from rodent studies. In addition, I present an updated synthesis of their roles and interactions within the hippocampal network.
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Affiliation(s)
- Laura Lee Colgin
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, Austin, Texas 78712, USA
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90
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Kay K, Sosa M, Chung JE, Karlsson MP, Larkin MC, Frank LM. A hippocampal network for spatial coding during immobility and sleep. Nature 2016; 531:185-90. [PMID: 26934224 PMCID: PMC5037107 DOI: 10.1038/nature17144] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 01/13/2016] [Indexed: 12/11/2022]
Abstract
How does an animal know where it is when it stops moving? Hippocampal place cells fire at discrete locations as subjects traverse space, thereby providing an explicit neural code for current location during locomotion. In contrast, during awake immobility, the hippocampus is thought to be dominated by neural firing representing past and possible future experience. The question of whether and how the hippocampus constructs a representation of current location in the absence of locomotion has stood unresolved. Here we report that a distinct population of hippocampal neurons, located in the CA2 subregion, signals current location during immobility, and furthermore does so in association with a previously unidentified hippocampus-wide network pattern. In addition, signaling of location persists into brief periods of desynchronization prevalent in slow-wave sleep. The hippocampus thus generates a distinct representation of current location during immobility, pointing to mnemonic processing specific to experience occurring in the absence of locomotion.
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Affiliation(s)
- Kenneth Kay
- UCSF Center for Integrative Neuroscience and Department of Physiology, University of California San Francisco, California 94158, USA
| | - Marielena Sosa
- UCSF Center for Integrative Neuroscience and Department of Physiology, University of California San Francisco, California 94158, USA
| | - Jason E Chung
- UCSF Center for Integrative Neuroscience and Department of Physiology, University of California San Francisco, California 94158, USA
| | - Mattias P Karlsson
- UCSF Center for Integrative Neuroscience and Department of Physiology, University of California San Francisco, California 94158, USA
| | - Margaret C Larkin
- UCSF Center for Integrative Neuroscience and Department of Physiology, University of California San Francisco, California 94158, USA
| | - Loren M Frank
- UCSF Center for Integrative Neuroscience and Department of Physiology, University of California San Francisco, California 94158, USA.,Howard Hughes Medical Institute, University of California San Francisco, California 94158, USA
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91
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Lega B, Burke J, Jacobs J, Kahana MJ. Slow-Theta-to-Gamma Phase-Amplitude Coupling in Human Hippocampus Supports the Formation of New Episodic Memories. Cereb Cortex 2016; 26:268-278. [PMID: 25316340 PMCID: PMC4677977 DOI: 10.1093/cercor/bhu232] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Phase-amplitude coupling (PAC) has been proposed as a neural mechanism for coordinating information processing across brain regions. Here we sought to characterize PAC in the human hippocampus, and in temporal and frontal cortices, during the formation of new episodic memories. Intracranial recordings taken as 56 neurosurgical patients studied and recalled lists of words revealed significant hippocampal PAC, with slow-theta activity (2.5-5 Hz) modulating gamma band activity (34-130 Hz). Furthermore, a significant number of hippocampal electrodes exhibited greater PAC during successful than unsuccessful encoding, with the gamma activity at these sites coupled to the trough of the slow-theta oscillation. These same conditions facilitate LTP in animal models, providing a possible mechanism of action for this effect in human memory. Uniquely in the hippocampus, phase preference during item encoding exhibited a biphasic pattern. Overall, our findings help translate between the patterns identified during basic memory tasks in animals and those present during complex human memory encoding. We discuss the unique properties of human hippocampal PAC and how our findings relate to influential theories of information processing based on theta-gamma interactions.
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Affiliation(s)
- Bradley Lega
- Department of Neurosurgery, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - John Burke
- Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joshua Jacobs
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, USA
| | - Michael J. Kahana
- Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104, USA
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92
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Sosa M, Gillespie AK, Frank LM. Neural Activity Patterns Underlying Spatial Coding in the Hippocampus. Curr Top Behav Neurosci 2016; 37:43-100. [PMID: 27885550 DOI: 10.1007/7854_2016_462] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The hippocampus is well known as a central site for memory processing-critical for storing and later retrieving the experiences events of daily life so they can be used to shape future behavior. Much of what we know about the physiology underlying hippocampal function comes from spatial navigation studies in rodents, which have allowed great strides in understanding how the hippocampus represents experience at the cellular level. However, it remains a challenge to reconcile our knowledge of spatial encoding in the hippocampus with its demonstrated role in memory-dependent tasks in both humans and other animals. Moreover, our understanding of how networks of neurons coordinate their activity within and across hippocampal subregions to enable the encoding, consolidation, and retrieval of memories is incomplete. In this chapter, we explore how information may be represented at the cellular level and processed via coordinated patterns of activity throughout the subregions of the hippocampal network.
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Affiliation(s)
- Marielena Sosa
- Kavli Institute for Fundamental Neuroscience and Department of Physiology, University of California, San Francisco, USA
| | | | - Loren M Frank
- Kavli Institute for Fundamental Neuroscience and Department of Physiology, University of California, San Francisco, USA. .,Howard Hughes Medical Institute, Maryland, USA.
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93
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Abstract
The hippocampal theta oscillation is strongly correlated with behaviors such as memory and spatial navigation, but we do not understand its specific functional role. One hint of theta's function came from the discovery in rodents that theta oscillations are traveling waves that allow parts of the hippocampus to simultaneously exhibit separate oscillatory phases. Because hippocampal theta oscillations in humans have different properties compared with rodents, we examined these signals directly using multielectrode recordings from neurosurgical patients. Our findings confirm that human hippocampal theta oscillations are traveling waves, but also show that these oscillations appear at a broader range of frequencies compared with rodents. Human traveling waves showed a distinctive pattern of spatial propagation such that there is a consistent phase spread across the hippocampus regardless of the oscillations' frequency. This suggests that traveling theta oscillations are important functionally in humans because they coordinate phase coding throughout the hippocampus in a consistent manner. Significance statement: We show for the first time in humans that hippocampal theta oscillations are traveling waves, moving along the length of the hippocampus in a posterior-anterior direction. The existence of these traveling theta waves is important for understanding hippocampal neural coding because they cause neurons at separate positions in the hippocampus to experience different theta phases simultaneously. The theta phase that a neuron measures is a key factor in how that cell represents behavioral information. Therefore, the existence of traveling theta waves indicates that, to fully understand how a hippocampal neuron represents information, it is vital to also account for that cell's location in addition to conventional measures of neural activity.
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94
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Leszczyński M, Fell J, Axmacher N. Rhythmic Working Memory Activation in the Human Hippocampus. Cell Rep 2015; 13:1272-1282. [DOI: 10.1016/j.celrep.2015.09.081] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 08/18/2015] [Accepted: 09/25/2015] [Indexed: 10/22/2022] Open
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95
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Rabiller G, He JW, Nishijima Y, Wong A, Liu J. Perturbation of Brain Oscillations after Ischemic Stroke: A Potential Biomarker for Post-Stroke Function and Therapy. Int J Mol Sci 2015; 16:25605-40. [PMID: 26516838 PMCID: PMC4632818 DOI: 10.3390/ijms161025605] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 10/06/2015] [Accepted: 10/15/2015] [Indexed: 01/08/2023] Open
Abstract
Brain waves resonate from the generators of electrical current and propagate across brain regions with oscillation frequencies ranging from 0.05 to 500 Hz. The commonly observed oscillatory waves recorded by an electroencephalogram (EEG) in normal adult humans can be grouped into five main categories according to the frequency and amplitude, namely δ (1-4 Hz, 20-200 μV), θ (4-8 Hz, 10 μV), α (8-12 Hz, 20-200 μV), β (12-30 Hz, 5-10 μV), and γ (30-80 Hz, low amplitude). Emerging evidence from experimental and human studies suggests that groups of function and behavior seem to be specifically associated with the presence of each oscillation band, although the complex relationship between oscillation frequency and function, as well as the interaction between brain oscillations, are far from clear. Changes of brain oscillation patterns have long been implicated in the diseases of the central nervous system including ischemic stroke, in which the reduction of cerebral blood flow as well as the progression of tissue damage have direct spatiotemporal effects on the power of several oscillatory bands and their interactions. This review summarizes the current knowledge in behavior and function associated with each brain oscillation, and also in the specific changes in brain electrical activities that correspond to the molecular events and functional alterations observed after experimental and human stroke. We provide the basis of the generations of brain oscillations and potential cellular and molecular mechanisms underlying stroke-induced perturbation. We will also discuss the implications of using brain oscillation patterns as biomarkers for the prediction of stroke outcome and therapeutic efficacy.
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Affiliation(s)
- Gratianne Rabiller
- Department of Neurological Surgery, University of California at San Francisco and Department of Veterans Affairs Medical Center, 1700 Owens Street, San Francisco, CA 94158, USA.
- UCSF and SFVAMC, San Francisco, CA 94158, USA.
- Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux 33000, France.
- CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux 33000, France.
| | - Ji-Wei He
- Department of Neurological Surgery, University of California at San Francisco and Department of Veterans Affairs Medical Center, 1700 Owens Street, San Francisco, CA 94158, USA.
- UCSF and SFVAMC, San Francisco, CA 94158, USA.
| | - Yasuo Nishijima
- Department of Neurological Surgery, University of California at San Francisco and Department of Veterans Affairs Medical Center, 1700 Owens Street, San Francisco, CA 94158, USA.
- UCSF and SFVAMC, San Francisco, CA 94158, USA.
- Department of Neurosurgery, Tohoku University Graduate School of Medicine 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan.
| | - Aaron Wong
- Department of Neurological Surgery, University of California at San Francisco and Department of Veterans Affairs Medical Center, 1700 Owens Street, San Francisco, CA 94158, USA.
- UCSF and SFVAMC, San Francisco, CA 94158, USA.
- Rice University, 6100 Main St, Houston, TX 77005, USA.
| | - Jialing Liu
- Department of Neurological Surgery, University of California at San Francisco and Department of Veterans Affairs Medical Center, 1700 Owens Street, San Francisco, CA 94158, USA.
- UCSF and SFVAMC, San Francisco, CA 94158, USA.
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96
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From Parallel Mathematical Description of Action to Unparalleled Outcome of Abstraction: A Comparative Analysis. ARCHIVES OF NEUROSCIENCE 2015. [DOI: 10.5812/archneurosci.22573] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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97
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Halgren E, Kaestner E, Marinkovic K, Cash SS, Wang C, Schomer DL, Madsen JR, Ulbert I. Laminar profile of spontaneous and evoked theta: Rhythmic modulation of cortical processing during word integration. Neuropsychologia 2015; 76:108-24. [PMID: 25801916 PMCID: PMC4575841 DOI: 10.1016/j.neuropsychologia.2015.03.021] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 03/18/2015] [Accepted: 03/18/2015] [Indexed: 01/01/2023]
Abstract
Theta may play a central role during language understanding and other extended cognitive processing, providing an envelope for widespread integration of participating cortical areas. We used linear microelectrode arrays in epileptics to define the circuits generating theta in inferotemporal, perirhinal, entorhinal, prefrontal and anterior cingulate cortices. In all locations, theta was generated by excitatory current sinks in middle layers which receive predominantly feedforward inputs, alternating with sinks in superficial layers which receive mainly feedback/associative inputs. Baseline and event-related theta were generated by indistinguishable laminar profiles of transmembrane currents and unit-firing. Word presentation could reset theta phase, permitting theta to contribute to late event-related potentials, even when theta power decreases relative to baseline. Limited recordings during sentence reading are consistent with rhythmic theta activity entrained by a given word modulating the neural background for the following word. These findings show that theta occurs spontaneously, and can be momentarily suppressed, reset and synchronized by words. Theta represents an alternation between feedforward/divergent and associative/convergent processing modes that may temporally organize sustained processing and optimize the timing of memory formation. We suggest that words are initially encoded via a ventral feedforward stream which is lexicosemantic in the anteroventral temporal lobe; its arrival may trigger a widespread theta rhythm which integrates the word within a larger context.
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Affiliation(s)
- Eric Halgren
- Departments of Radiology and Neurosciences, University of California at San Diego, La Jolla, CA 92069, USA.
| | - Erik Kaestner
- Interdepartmental Neurosciences Program, University of California at San Diego, La Jolla, CA 92069, USA
| | - Ksenija Marinkovic
- Department of Psychology, San Diego State University, San Diego, CA, USA
| | - Sydney S Cash
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | - Chunmao Wang
- Departments of Radiology and Neurosciences, University of California at San Diego, La Jolla, CA 92069, USA; Interdepartmental Neurosciences Program, University of California at San Diego, La Jolla, CA 92069, USA; Department of Psychology, San Diego State University, San Diego, CA, USA; Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA; Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Department of Neurosurgery, Children's Hospital, Harvard Medical School, Boston, MA, USA; Institute of Cognitive Neuroscience and Psychology, Research Center for Natural Sciences, Hungarian Academy of Sciences, Budapest-1117, Hungary
| | - Donald L Schomer
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Joseph R Madsen
- Department of Neurosurgery, Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Istvan Ulbert
- Institute of Cognitive Neuroscience and Psychology, Research Center for Natural Sciences, Hungarian Academy of Sciences, Budapest-1117, Hungary
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98
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Caplan JB, Bottomley M, Kang P, Dixon RA. Distinguishing rhythmic from non-rhythmic brain activity during rest in healthy neurocognitive aging. Neuroimage 2015; 112:341-352. [PMID: 25769279 DOI: 10.1016/j.neuroimage.2015.03.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 02/10/2015] [Accepted: 03/01/2015] [Indexed: 10/23/2022] Open
Abstract
Rhythmic brain activity at low frequencies (<12Hz) during rest are thought to increase in neurodegenerative disease, but findings in healthy neurocognitive aging are mixed. Here we address two reasons conventional spectral analyses may have led to inconsistent results. First, spectral-power measures are compared to a baseline condition; when resting activity is the signal of interest, it is unclear what the baseline should be. Second, conventional methods do not clearly differentiate power due to rhythmic versus non-rhythmic activity. The Better OSCillation detection method (BOSC; Caplan et al., 2001; Whitten et al., 2011) avoids these problems by using the signal's own spectral characteristics as a reference to detect elevations in power lasting a few cycles. We recorded electroencephalographic (EEG) signal during rest, alternating eyes open and closed, in healthy younger (18-25 years) and older (60-74 years) participants. Topographic plots suggested the conventional and BOSC analyses measured different sources of activity, particularly at frequencies, like delta (1-4Hz), at which rhythms are sporadic; topographies were more similar in the 8-12Hz alpha band. There was little theta-band activity meeting the BOSC method's criteria, suggesting prior findings of theta power in healthy aging may reflect non-rhythmic signal. In contrast, delta oscillations were present at higher levels than theta in both age groups. In summary, applying strict and standardized criteria for rhythmicity, slow rhythms appear present in the resting brain at delta and alpha, but not theta frequencies, and appear unchanged in healthy aging.
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Affiliation(s)
- Jeremy B Caplan
- Psychology Department, Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada.
| | - Monica Bottomley
- Psychology Department, Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Pardeep Kang
- Psychology Department, Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Roger A Dixon
- Psychology Department, Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
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99
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Jensen MP, Adachi T, Hakimian S. Brain Oscillations, Hypnosis, and Hypnotizability. AMERICAN JOURNAL OF CLINICAL HYPNOSIS 2015; 57:230-253. [PMID: 25792761 DOI: 10.1080/00029157.2014.976786] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
In this article, we summarize the state-of-science knowledge regarding the associations between hypnosis and brain oscillations. Brain oscillations represent the combined electrical activity of neuronal assemblies, and are usually measured as specific frequencies representing slower (delta, theta, alpha) and faster (beta, gamma) oscillations. Hypnosis has been most closely linked to power in the theta band and changes in gamma activity. These oscillations are thought to play a critical role in both the recording and recall of declarative memory and emotional limbic circuits. Here we propose that it is this role that may be the mechanistic link between theta (and perhaps gamma) oscillations and hypnosis; specifically that theta oscillations may facilitate, and that changes in gamma activity observed with hypnosis may underlie, some hypnotic responses. If these hypotheses are supported, they have important implications for both understanding the effects of hypnosis, and for enhancing response to hypnotic treatments.
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100
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Thalamic pathways underlying prefrontal cortex–medial temporal lobe oscillatory interactions. Trends Neurosci 2015; 38:3-12. [DOI: 10.1016/j.tins.2014.09.007] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 09/29/2014] [Accepted: 09/30/2014] [Indexed: 12/15/2022]
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