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Penner C, Minxha J, Chandravadia N, Mamelak AN, Rutishauser U. Properties and hemispheric differences of theta oscillations in the human hippocampus. Hippocampus 2022; 32:335-341. [PMID: 35231153 PMCID: PMC9067167 DOI: 10.1002/hipo.23412] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 02/15/2022] [Accepted: 02/16/2022] [Indexed: 11/11/2022]
Abstract
The left and right primate hippocampi (LH and RH) are thought to support distinct functions, but little is known about differences between the hemispheres at the neuronal level. We recorded single-neuron and local field potentials from the human hippocampus in epilepsy patients implanted with depth electrodes. We detected theta-frequency bouts of oscillatory activity while patients performed a visual recognition memory task. Theta appeared in bouts of 3.16 cycles, with sawtooth-shaped oscillations that had a prolonged downswing period. Outside the seizure onset zone, the average frequency of theta bouts was higher in the RH compared to the LH (6.0 vs. 5.3 Hz). LH theta bouts had lower amplitudes and a higher prevalence compared to the RH (26% vs. 21% of total time). Additionally, the RH contained a population of thin spiking visually tuned neurons that were not present in the LH. These data show that human theta appears in short oscillatory bouts whose properties vary between hemispheres, thereby revealing neurophysiological properties of the hippocampus that differ between the hemispheres.
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Affiliation(s)
- Cooper Penner
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Juri Minxha
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, California, USA
- Center for Theoretical Neuroscience, College of Physicians and Surgeons, Columbia University, New York, New York, USA
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Nand Chandravadia
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Adam N Mamelak
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Ueli Rutishauser
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, California, USA
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, California, USA
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
- Department of Biomedical Sciences, Center for Neural Science and Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
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2
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Aykan S, Puglia MH, Kalaycıoğlu C, Pelphrey KA, Tuncalı T, Nalçacı E. Right Anterior Theta Hypersynchrony as a Quantitative Measure Associated with Autistic Traits and K-Cl Cotransporter KCC2 Polymorphism. J Autism Dev Disord 2022; 52:61-72. [PMID: 33635423 DOI: 10.1007/s10803-021-04924-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/10/2021] [Indexed: 10/22/2022]
Abstract
Our aim was to use theta coherence as a quantitative trait to investigate the relation of the polymorphisms in NKCC1 (rs3087889) and KCC2 (rs9074) channel protein genes to autistic traits (AQ) in neurotypicals. Coherence values for candidate connection regions were calculated from eyes-closed resting EEGs in two independent groups. Hypersynchrony within the right anterior region was related to AQ in both groups (p < 0.05), and variability in this hypersynchrony was related to the rs9074 polymorphism in the total group (p < 0.05). In conclusion, theta hypersynchrony within the right anterior region during eyes-closed rest can be considered a quantitative measure for autistic traits. Replicating our findings in two independent populations with different backgrounds strengthens the validity of the current study.
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Affiliation(s)
- Simge Aykan
- Department of Physiology, Ankara University School of Medicine, Ankara, Turkey.
| | - Meghan H Puglia
- Department of Neurology, University of Virginia, Charlottesville, VA, USA
- Department of Psychology, University of Virginia, Charlottesville, VA, USA
| | - Canan Kalaycıoğlu
- Department of Physiology, Ankara University School of Medicine, Ankara, Turkey
| | - Kevin A Pelphrey
- Department of Neurology, University of Virginia, Charlottesville, VA, USA
| | - Timur Tuncalı
- Department of Medical Genetics, Ankara University School of Medicine, Ankara, Turkey
| | - Erhan Nalçacı
- Department of Physiology, Ankara University School of Medicine, Ankara, Turkey
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3
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Saboo KV, Balzekas I, Kremen V, Varatharajah Y, Kucewicz M, Iyer RK, Worrell GA. Leveraging electrophysiologic correlates of word encoding to map seizure onset zone in focal epilepsy: Task-dependent changes in epileptiform activity, spectral features, and functional connectivity. Epilepsia 2021; 62:2627-2639. [PMID: 34536230 DOI: 10.1111/epi.17067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 08/31/2021] [Accepted: 09/01/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Verbal memory dysfunction is common in focal, drug-resistant epilepsy (DRE). Unfortunately, surgical removal of seizure-generating brain tissue can be associated with further memory decline. Therefore, localization of both the circuits generating seizures and those underlying cognitive functions is critical in presurgical evaluations for patients who may be candidates for resective surgery. We used intracranial electroencephalographic (iEEG) recordings during a verbal memory task to investigate word encoding in focal epilepsy. We hypothesized that engagement in a memory task would exaggerate local iEEG feature differences between the seizure onset zone (SOZ) and neighboring tissue as compared to wakeful rest ("nontask"). METHODS Ten participants undergoing presurgical iEEG evaluation for DRE performed a free recall verbal memory task. We evaluated three iEEG features in SOZ and non-SOZ electrodes during successful word encoding and compared them with nontask recordings: interictal epileptiform spike (IES) rates, power in band (PIB), and relative entropy (REN; a functional connectivity measure). RESULTS We found a complex pattern of PIB and REN changes in SOZ and non-SOZ electrodes during successful word encoding compared to nontask. Successful word encoding was associated with a reduction in local electrographic functional connectivity (increased REN), which was most exaggerated in temporal lobe SOZ. The IES rates were reduced during task, but only in the non-SOZ electrodes. Compared with nontask, REN features during task yielded marginal improvements in SOZ classification. SIGNIFICANCE Previous studies have supported REN as a biomarker for epileptic brain. We show that REN differences between SOZ and non-SOZ are enhanced during a verbal memory task. We also show that IESs are reduced during task in non-SOZ, but not in SOZ. These findings support the hypothesis that SOZ and non-SOZ respond differently to task and warrant further exploration into the use of cognitive tasks to identify functioning memory circuits and localize SOZ.
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Affiliation(s)
- Krishnakant V Saboo
- Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois, USA.,Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.,Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic School of Medicine and Mayo Clinic Medical Scientist Training Program, Mayo Clinic, Rochester, Minnesota, USA
| | - Irena Balzekas
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.,Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic School of Medicine and Mayo Clinic Medical Scientist Training Program, Mayo Clinic, Rochester, Minnesota, USA
| | - Vaclav Kremen
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.,Czech Institute of Informatics, Robotics, and Cybernetics, Czech Technical University in Prague, Prague, Czech Republic
| | - Yogatheesan Varatharajah
- Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois, USA.,Department of Bioengineering, University of Illinois, Urbana, Illinois, USA
| | - Michal Kucewicz
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.,Faculty of Electronics, Telecommunications, and Informatics, Multimedia Systems Department, BioTechMed Center, Gdansk University of Technology, Gdansk, Poland.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Ravishankar K Iyer
- Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois, USA
| | - Gregory A Worrell
- Bioelectronics, Neurophysiology, and Engineering Laboratory, Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
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Pototskiy E, Dellinger JR, Bumgarner S, Patel J, Sherrerd-Smith W, Musto AE. Brain injuries can set up an epileptogenic neuronal network. Neurosci Biobehav Rev 2021; 129:351-366. [PMID: 34384843 DOI: 10.1016/j.neubiorev.2021.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 08/01/2021] [Indexed: 10/20/2022]
Abstract
Development of epilepsy or epileptogenesis promotes recurrent seizures. As of today, there are no effective prophylactic therapies to prevent the onset of epilepsy. Contributing to this deficiency of preventive therapy is the lack of clarity in fundamental neurobiological mechanisms underlying epileptogenesis and lack of reliable biomarkers to identify patients at risk for developing epilepsy. This limits the development of prophylactic therapies in epilepsy. Here, neural network dysfunctions reflected by oscillopathies and microepileptiform activities, including neuronal hyperexcitability and hypersynchrony, drawn from both clinical and experimental epilepsy models, have been reviewed. This review suggests that epileptogenesis reflects a progressive and dynamic dysfunction of specific neuronal networks which recruit further interconnected groups of neurons, with this resultant pathological network mediating seizure occurrence, recurrence, and progression. In the future, combining spatial and temporal resolution of neuronal non-invasive recordings from patients at risk of developing epilepsy, together with analytics and computational tools, may contribute to determining whether the brain is undergoing epileptogenesis in asymptomatic patients following brain injury.
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Affiliation(s)
- Esther Pototskiy
- Department of Anatomy & Pathology, Eastern Virginia Medical School, Department of Pathology, Norfolk, Virginia, USA; College of Sciences, Old Dominion University, Norfolk, Virginia
| | - Joshua Ryan Dellinger
- Department of Anatomy & Pathology, Eastern Virginia Medical School, Department of Pathology, Norfolk, Virginia, USA
| | - Stuart Bumgarner
- Department of Anatomy & Pathology, Eastern Virginia Medical School, Department of Pathology, Norfolk, Virginia, USA
| | - Jay Patel
- Department of Anatomy & Pathology, Eastern Virginia Medical School, Department of Pathology, Norfolk, Virginia, USA
| | - William Sherrerd-Smith
- Department of Anatomy & Pathology, Eastern Virginia Medical School, Department of Pathology, Norfolk, Virginia, USA
| | - Alberto E Musto
- Department of Anatomy & Pathology, Eastern Virginia Medical School, Department of Pathology, Norfolk, Virginia, USA; Department of Neurology, Eastern Virginia Medical School, Department of Pathology, Norfolk, Virginia, USA.
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Johnson EL, Kam JWY, Tzovara A, Knight RT. Insights into human cognition from intracranial EEG: A review of audition, memory, internal cognition, and causality. J Neural Eng 2020; 17:051001. [PMID: 32916678 PMCID: PMC7731730 DOI: 10.1088/1741-2552/abb7a5] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
By recording neural activity directly from the human brain, researchers gain unprecedented insight into how neurocognitive processes unfold in real time. We first briefly discuss how intracranial electroencephalography (iEEG) recordings, performed for clinical practice, are used to study human cognition with the spatiotemporal and single-trial precision traditionally limited to non-human animal research. We then delineate how studies using iEEG have informed our understanding of issues fundamental to human cognition: auditory prediction, working and episodic memory, and internal cognition. We also discuss the potential of iEEG to infer causality through the manipulation or 'engineering' of neurocognitive processes via spatiotemporally precise electrical stimulation. We close by highlighting limitations of iEEG, potential of burgeoning techniques to further increase spatiotemporal precision, and implications for future research using intracranial approaches to understand, restore, and enhance human cognition.
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Affiliation(s)
- Elizabeth L Johnson
- Helen Wills Neuroscience Institute, University of California, Berkeley, United States of America
- Life-Span Cognitive Neuroscience Program, Institute of Gerontology, Wayne State University, United States of America
| | - Julia W Y Kam
- Helen Wills Neuroscience Institute, University of California, Berkeley, United States of America
- Department of Psychology, University of Calgary, Canada
- Hotchkiss Brain Institute, University of Calgary, Canada
| | - Athina Tzovara
- Helen Wills Neuroscience Institute, University of California, Berkeley, United States of America
- Institute for Computer Science, University of Bern, Switzerland
- Sleep Wake Epilepsy Center | NeuroTec, Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Robert T Knight
- Helen Wills Neuroscience Institute, University of California, Berkeley, United States of America
- Department of Psychology, University of California, Berkeley, United States of America
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Efficiency of Repetitive Transcranial Direct Current Stimulation of the Dorsolateral Prefrontal Cortex in Disorders of Consciousness: A Randomized Sham-Controlled Study. Neural Plast 2019; 2019:7089543. [PMID: 31308848 PMCID: PMC6594311 DOI: 10.1155/2019/7089543] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 04/26/2019] [Accepted: 05/23/2019] [Indexed: 12/20/2022] Open
Abstract
Conventional transcranial direct current stimulation (tDCS) targeting the left dorsolateral prefrontal cortex (DLPFC) could improve arousal in disorders of consciousness (DOC). However, the comparative effectiveness of anodal stimulation of the left DLPFC and the electrophysiological effect of tDCS are yet to be determined. In this randomized sham-controlled design, patients were separated into three groups (left/right anodal tDCS, sham). Data on the clinical assessments and EEG were collected at baseline and after 2 weeks of tDCS. The outcome at 3-month follow-up was evaluated using the Glasgow Outcome Scale-Extended. Results showed that sessions of the left tDCS facilitated the excitability of the prefrontal cortex, whereas only one patient had a positive outcome. Targeting the right DLPFC was less effective, merely leading to activation of the stimulation site, with no effect on the state of arousal. Moreover, sham stimulation had minimal or no effect on any of the outcomes. These results provide evidence for a hemispheric asymmetry of tDCS effects in patients with DOC. Left anodal tDCS might be more effective for modulating cortical excitability compared to tDCS on the right DLPFC. However, future studies with large sample sizes are needed to confirm these findings. This trial is registered with NCT03809936.
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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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