1
|
Nguyen QA, Klein PM, Xie C, Benthall KN, Iafrati J, Homidan J, Bendor JT, Dudok B, Farrell JS, Gschwind T, Porter CL, Keravala A, Dodson GS, Soltesz I. Acetylcholine receptor based chemogenetics engineered for neuronal inhibition and seizure control assessed in mice. Nat Commun 2024; 15:601. [PMID: 38238329 PMCID: PMC10796428 DOI: 10.1038/s41467-024-44853-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 01/09/2024] [Indexed: 01/22/2024] Open
Abstract
Epilepsy is a prevalent disorder involving neuronal network hyperexcitability, yet existing therapeutic strategies often fail to provide optimal patient outcomes. Chemogenetic approaches, where exogenous receptors are expressed in defined brain areas and specifically activated by selective agonists, are appealing methods to constrain overactive neuronal activity. We developed BARNI (Bradanicline- and Acetylcholine-activated Receptor for Neuronal Inhibition), an engineered channel comprised of the α7 nicotinic acetylcholine receptor ligand-binding domain coupled to an α1 glycine receptor anion pore domain. Here we demonstrate that BARNI activation by the clinical stage α7 nicotinic acetylcholine receptor-selective agonist bradanicline effectively suppressed targeted neuronal activity, and controlled both acute and chronic seizures in male mice. Our results provide evidence for the use of an inhibitory acetylcholine-based engineered channel activatable by both exogenous and endogenous agonists as a potential therapeutic approach to treating epilepsy.
Collapse
Affiliation(s)
- Quynh-Anh Nguyen
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA.
| | - Peter M Klein
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA.
| | - Cheng Xie
- CODA Biotherapeutics, 240 East Grand Ave., South San Francisco, CA, 94080, USA
| | - Katelyn N Benthall
- CODA Biotherapeutics, 240 East Grand Ave., South San Francisco, CA, 94080, USA
| | - Jillian Iafrati
- CODA Biotherapeutics, 240 East Grand Ave., South San Francisco, CA, 94080, USA
| | - Jesslyn Homidan
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
| | - Jacob T Bendor
- CODA Biotherapeutics, 240 East Grand Ave., South San Francisco, CA, 94080, USA
| | - Barna Dudok
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
- Department of Neurology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jordan S Farrell
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
| | - Tilo Gschwind
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
| | - Charlotte L Porter
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
| | - Annahita Keravala
- CODA Biotherapeutics, 240 East Grand Ave., South San Francisco, CA, 94080, USA
| | - G Steven Dodson
- CODA Biotherapeutics, 240 East Grand Ave., South San Francisco, CA, 94080, USA
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
| |
Collapse
|
2
|
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.
Collapse
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.
| |
Collapse
|
3
|
Zhang C, Kwan P. The Concept of Drug-Resistant Epileptogenic Zone. Front Neurol 2019; 10:558. [PMID: 31214106 PMCID: PMC6555267 DOI: 10.3389/fneur.2019.00558] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 05/09/2019] [Indexed: 12/01/2022] Open
Abstract
Resective surgery is the most effective way to treat drug-resistant epilepsy. Despite extensive pre-surgical evaluation, only 30–70% patients would become seizure-free after surgery. New approaches and strategies are needed to improve the outcome of epilepsy surgery. It is commonly observed in clinical practice that antiepileptic drugs (AEDs) could maintain seizure freedom in a large proportion of patients after surgery, who were uncontrolled before the operation. In some patients cessation of AEDs leads to seizure recurrence which, in most cases, can be controlled by resuming AEDs. These observations suggest that the surgery has converted the epilepsy from drug-resistant to drug-responsive, implying that the operation has removed the brain tissue accounting for pharmacoresistance, rather than the pathological substrate of epilepsy (at least not completely). Based on these observations, it is hypothesized that there is a drug-resistant epileptogenic zone (DREZ) which overlaps with the epileptogenic zone (EZ), and has both epileptogenic and drug-resistant properties. DREZ is necessary and sufficient to cause drug-resistant epilepsy, and its remove would render the epilepsy drug-responsive. Testing the hypothesis requires the development of new methods to define the DREZ, which may be used to guide surgical planning when the epileptogenic zone cannot be completely excised. This concept can also help understand the mechanisms of drug-resistant epilepsy, leading to new therapeutic strategies.
Collapse
Affiliation(s)
- Chunbo Zhang
- School of Pharmacy, Nanchang University, Nanchang, China
| | - Patrick Kwan
- Department of Neuroscience, Alfred Hospital, Monash University, Melbourne, VIC, Australia.,Departments of Medicine and Neurology, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| |
Collapse
|
4
|
Li L, Bragin A, Staba R, Engel J. Unit firing and oscillations at seizure onset in epileptic rodents. Neurobiol Dis 2019; 127:382-389. [PMID: 30928646 DOI: 10.1016/j.nbd.2019.03.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 03/04/2019] [Accepted: 03/26/2019] [Indexed: 01/27/2023] Open
Abstract
Epileptic seizures result from a variety of pathophysiological processes, evidenced by different electrographic ictal onset patterns, as seen on direct brain recordings. The two most common electrographic patterns of focal ictal onset in patients are hypersynchronous (HYP) and low-voltage fast (LVF). Whereas LVF ictal onsets were believed to result from disinhibition; based on similarities with absence seizures, focal HYP ictal onsets were believed to result from increased synchronizing inhibition. Recent findings, however, suggest the differences between these seizure onset types are more complicated and, in some cases, the opposite of these concepts are true. The following review presents evidence that a reduction of tonic inhibition on small pathologically interconnected neuron (PIN) clusters generating pathological high-frequency oscillations (pHFOs), which reflect abnormal synchronously bursting neurons may be the cause of HYP ictal onsets. Increased inhibition preceding LVF ictal onsets are discussed in other reviews in this issue. We postulate that neuronal cell loss following epileptogenic insults can result in structural reorganization, giving rise to small PIN clusters, which generate pHFOs. These clusters have a heterogeneous distribution and are spatially stable over time. Studies have demonstrated that a transient reduction in tonic inhibition causes these clusters to increase in size. This could result in consolidation and synchronization of pHFOs until a critical mass leads to propagation of HYP ictal discharges. Viewed within a network neuroscience framework, local disturbances such as PIN clusters are likely to contribute to large-scale brain network alterations: a better understanding of these epileptogenic networks promises to elucidate mechanisms of ictogenesis, epileptogenesis, and certain comorbidities of epilepsy.
Collapse
Affiliation(s)
- Lin Li
- Department of Neurology, University of California, Los Angeles, CA, USA
| | - Anatol Bragin
- Department of Neurology, University of California, Los Angeles, CA, USA; Brain Research Institute, University of California, Los Angeles, CA, USA
| | - Richard Staba
- Department of Neurology, University of California, Los Angeles, CA, USA
| | - Jerome Engel
- Department of Neurology, University of California, Los Angeles, CA, USA; Brain Research Institute, University of California, Los Angeles, CA, USA; Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
| |
Collapse
|
5
|
Engel J, Bragin A, Staba R. Nonictal EEG biomarkers for diagnosis and treatment. Epilepsia Open 2018; 3:120-126. [PMID: 30564770 PMCID: PMC6293068 DOI: 10.1002/epi4.12233] [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] [Accepted: 05/02/2018] [Indexed: 12/11/2022] Open
Abstract
There are no reliable nonictal biomarkers for epilepsy, electroencephalography (EEG) or otherwise, but efforts to identify biomarkers that would predict the development of epilepsy after a potential epileptogenic insult, diagnose the existence of epilepsy, or assess the effects of antiseizure or antiepileptogenic interventions are relying heavily on electrophysiology. The most promising EEG biomarkers to date are pathologic high‐frequency oscillations (pHFOs), brief EEG events in the range of 100 to 600 Hz, which are believed to reflect summated action potentials from synchronously bursting neurons. Studies of patients with epilepsy, and experimental animal models, have been based primarily on direct brain recording, which makes pHFOs potentially useful for localizing the epileptogenic zone for surgical resection, but application for other diagnostic and therapeutic purposes is limited. Consequently, recent efforts have involved identification of HFOs recorded with scalp electrodes, and with magnetoencephalography, which may reflect the same pathophysiologic mechanisms as pHFOs recorded directly from the brain. The search is also on for other EEG changes that might serve as epilepsy biomarkers, and candidates include arcuate rhythms, which may reflect repetitive pHFOs, reduction in theta rhythm, which correlates with epileptogenesis in several rodent models of epilepsy, and shortened sleep spindles that correlate with ictogenesis.
Collapse
Affiliation(s)
- Jerome Engel
- Department of NeurologyUniversity of California Los AngelesLos AngelesCaliforniaU.S.A.
- Brain Research InstituteUniversity of California Los AngelesLos AngelesCaliforniaU.S.A.
- Neurobiology and Psychiatry and Biobehavioral SciencesDavid Geffen School of Medicine at UCLALos AngelesCaliforniaU.S.A.
| | - Anatol Bragin
- Department of NeurologyUniversity of California Los AngelesLos AngelesCaliforniaU.S.A.
- Brain Research InstituteUniversity of California Los AngelesLos AngelesCaliforniaU.S.A.
| | - Richard Staba
- Department of NeurologyUniversity of California Los AngelesLos AngelesCaliforniaU.S.A.
| |
Collapse
|
6
|
Exploring human epileptic activity at the single-neuron level. Epilepsy Behav 2016; 58:11-7. [PMID: 26994366 DOI: 10.1016/j.yebeh.2016.02.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 02/09/2016] [Accepted: 02/10/2016] [Indexed: 11/21/2022]
Abstract
Today, localization of the seizure focus heavily relies on EEG monitoring (scalp or intracranial). However, current technology enables much finer resolutions. The activity of hundreds of single neurons in the human brain can now be simultaneously explored before, during, and after a seizure or in association with an interictal discharge. This technology opens up new horizons to understanding epilepsy at a completely new level. This review therefore begins with a brief description of the basis of the technology, the microelectrodes, and the setup for their implantation in patients with epilepsy. Using these electrodes, recent studies provide novel insights into both the time domain and firing patterns of epileptic activity of single neurons. In the time domain, seizure-related activity may occur even minutes before seizure onset (in its current, EEG-based definition). Seizure-related neuronal interactions exhibit complex heterogeneous dynamics. In the seizure-onset zone, changes in firing patterns correlate with cell loss; in the penumbra, neurons maintain their spike stereotypy during a seizure. Hence, investigation of the extracellular electrical activity is expected to provide a better understanding of the mechanisms underlying the disease; it may, in the future, serve for a more accurate localization of the seizure focus; and it may also be employed to predict the occurrence of seizures prior to their behavioral manifestation in order to administer automatic therapeutic interventions.
Collapse
|
7
|
Weiss SA, Alvarado-Rojas C, Bragin A, Behnke E, Fields T, Fried I, Engel J, Staba R. Ictal onset patterns of local field potentials, high frequency oscillations, and unit activity in human mesial temporal lobe epilepsy. Epilepsia 2016; 57:111-21. [PMID: 26611159 PMCID: PMC4862409 DOI: 10.1111/epi.13251] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/13/2015] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To characterize local field potentials, high frequency oscillations, and single unit firing patterns in microelectrode recordings of human limbic onset seizures. METHODS Wide bandwidth local field potential recordings were acquired from microelectrodes implanted in mesial temporal structures during spontaneous seizures from six patients with mesial temporal lobe epilepsy. RESULTS In the seizure onset zone, distinct epileptiform discharges were evident in the local field potential prior to the time of seizure onset in the intracranial EEG. In all three seizures with hypersynchronous (HYP) seizure onset, fast ripples with incrementally increasing power accompanied epileptiform discharges during the transition to the ictal state (p < 0.01). In a single low voltage fast (LVF) onset seizure a triad of evolving HYP LFP discharges, increased single unit activity, and fast ripples of incrementally increasing power were identified ~20 s prior to seizure onset (p < 0.01). In addition, incrementally increasing fast ripples occurred after seizure onset just prior to the transition to LVF activity (p < 0.01). HYP onset was associated with an increase in fast ripple and ripple rate (p < 0.05) and commonly each HYP discharge had a superimposed ripple followed by a fast ripple. Putative excitatory and inhibitory single units could be distinguished during limbic seizure onset, and heterogeneous shifts in firing rate were observed during LVF activity. SIGNIFICANCE Epileptiform activity is detected by microelectrodes before it is detected by depth macroelectrodes, and the one clinically identified LVF ictal onset was a HYP onset at the local level. Patterns of incrementally increasing fast ripple power are consistent with observations in rats with experimental hippocampal epilepsy, suggesting that limbic seizures arise when small clusters of synchronously bursting neurons increase in size, coalesce, and reach a critical mass for propagation.
Collapse
Affiliation(s)
- Shennan Aibel Weiss
- Department of Neurology, University of California Los Angeles, Los Angeles, California, U.S.A
| | - Catalina Alvarado-Rojas
- Department of Neurology, University of California Los Angeles, Los Angeles, California, U.S.A
| | - Anatol Bragin
- Department of Neurology, University of California Los Angeles, Los Angeles, California, U.S.A
| | - Eric Behnke
- Department of Neurology, University of California Los Angeles, Los Angeles, California, U.S.A
- Department of Neurosurgery, University of California Los Angeles, Los Angeles, California, U.S.A
| | - Tony Fields
- Department of Neurology, University of California Los Angeles, Los Angeles, California, U.S.A
- Department of Neurosurgery, University of California Los Angeles, Los Angeles, California, U.S.A
| | - Itzhak Fried
- Department of Neurology, University of California Los Angeles, Los Angeles, California, U.S.A
- Department of Neurosurgery, University of California Los Angeles, Los Angeles, California, U.S.A
| | - Jerome Engel
- Department of Neurology, University of California Los Angeles, Los Angeles, California, U.S.A
- Department of Neurobiology, University of California Los Angeles, Los Angeles, California, U.S.A
- Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, California, U.S.A
- the Brain Research Institute David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, U.S.A
| | - Richard Staba
- Department of Neurology, University of California Los Angeles, Los Angeles, California, U.S.A
| |
Collapse
|
8
|
Buzsáki G. Hippocampal sharp wave-ripple: A cognitive biomarker for episodic memory and planning. Hippocampus 2015; 25:1073-188. [PMID: 26135716 PMCID: PMC4648295 DOI: 10.1002/hipo.22488] [Citation(s) in RCA: 926] [Impact Index Per Article: 102.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 06/30/2015] [Indexed: 12/23/2022]
Abstract
Sharp wave ripples (SPW-Rs) represent the most synchronous population pattern in the mammalian brain. Their excitatory output affects a wide area of the cortex and several subcortical nuclei. SPW-Rs occur during "off-line" states of the brain, associated with consummatory behaviors and non-REM sleep, and are influenced by numerous neurotransmitters and neuromodulators. They arise from the excitatory recurrent system of the CA3 region and the SPW-induced excitation brings about a fast network oscillation (ripple) in CA1. The spike content of SPW-Rs is temporally and spatially coordinated by a consortium of interneurons to replay fragments of waking neuronal sequences in a compressed format. SPW-Rs assist in transferring this compressed hippocampal representation to distributed circuits to support memory consolidation; selective disruption of SPW-Rs interferes with memory. Recently acquired and pre-existing information are combined during SPW-R replay to influence decisions, plan actions and, potentially, allow for creative thoughts. In addition to the widely studied contribution to memory, SPW-Rs may also affect endocrine function via activation of hypothalamic circuits. Alteration of the physiological mechanisms supporting SPW-Rs leads to their pathological conversion, "p-ripples," which are a marker of epileptogenic tissue and can be observed in rodent models of schizophrenia and Alzheimer's Disease. Mechanisms for SPW-R genesis and function are discussed in this review.
Collapse
Affiliation(s)
- György Buzsáki
- The Neuroscience Institute, School of Medicine and Center for Neural Science, New York University, New York, New York
| |
Collapse
|
9
|
Cerebellar Directed Optogenetic Intervention Inhibits Spontaneous Hippocampal Seizures in a Mouse Model of Temporal Lobe Epilepsy. eNeuro 2014; 1. [PMID: 25599088 PMCID: PMC4293636 DOI: 10.1523/eneuro.0005-14.2014] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Epilepsy is a condition of spontaneous recurrent seizures. Current treatment options for epilepsy can have major negative side effects and for many patients fail to control seizures. We detected seizures on-line and tested a new selective intervention using a mouse model of temporal lobe epilepsy. Krook-Magnuson et al. report a bidirectional functional connectivity between the hippocampus and the cerebellum in a mouse model of temporal lobe epilepsy, and demonstrate that cerebellar directed on-demand optogenetic intervention can stop seizures recorded from the hippocampus. ![]()
Temporal lobe epilepsy is often medically refractory and new targets for intervention are needed. We used a mouse model of temporal lobe epilepsy, on-line seizure detection, and responsive optogenetic intervention to investigate the potential for cerebellar control of spontaneous temporal lobe seizures. Cerebellar targeted intervention inhibited spontaneous temporal lobe seizures during the chronic phase of the disorder. We further report that the direction of modulation as well as the location of intervention within the cerebellum can affect the outcome of intervention. Specifically, on-demand optogenetic excitation or inhibition of parvalbumin-expressing neurons, including Purkinje cells, in the lateral or midline cerebellum results in a decrease in seizure duration. In contrast, a consistent reduction in spontaneous seizure frequency occurs uniquely with on-demand optogenetic excitation of the midline cerebellum, and was not seen with intervention directly targeting the hippocampal formation. These findings demonstrate that the cerebellum is a powerful modulator of temporal lobe epilepsy, and that intervention targeting the cerebellum as a potential therapy for epilepsy should be revisited.
Collapse
|
10
|
Abstract
Limbic epilepsy refers to a condition that consists of epileptic seizures that originate in or preferentially involve the limbic system. The majority of cases are medically refractory, necessitating surgical resection when possible. However, even resection of structures thought to be responsible for seizure generation may not leave a patient seizure free. While mesial temporal lobe limbic structures are centrally involved, there is growing evidence that the epileptogenic network consists of a broader area, involving structures outside of the temporal lobe and the limbic system. Information on structural, functional, and metabolic connectivity in patients with limbic epilepsy is available from a large body of studies employing methods such as MRI, EEG, MEG, fMRI, PET, and SPECT scanning, implicating the involvement of various brain regions in the epileptogenic network. To date, there are no consistent and conclusive findings to define the exact boundaries of this network, but it is possible that in the future studies of network connectivity in the individual patient may allow more tailored treatment and prognosis in terms of surgical resection.
Collapse
|
11
|
On-demand optogenetic control of spontaneous seizures in temporal lobe epilepsy. Nat Commun 2013; 4:1376. [PMID: 23340416 PMCID: PMC3562457 DOI: 10.1038/ncomms2376] [Citation(s) in RCA: 419] [Impact Index Per Article: 38.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 12/12/2012] [Indexed: 01/19/2023] Open
Abstract
Temporal lobe epilepsy is the most common type of epilepsy in adults, is often medically refractory, and due to broad actions and long-time scales, current systemic treatments have major negative side-effects. However, temporal lobe seizures tend to arise from discrete regions before overt clinical behaviour, making temporally and spatially specific treatment theoretically possible. Here we report the arrest of spontaneous seizures using a real-time, closed-loop, response system and in vivo optogenetics in a mouse model of temporal lobe epilepsy. Either optogenetic inhibition of excitatory principal cells, or activation of a subpopulation of GABAergic cells representing <5% of hippocampal neurons, stops seizures rapidly upon light application. These results demonstrate that spontaneous temporal lobe seizures can be detected and terminated by modulating specific cell populations in a spatially restricted manner. A clinical approach built on these principles may overcome many of the side-effects of currently available treatment options. Temporal lobe epilepsy in adults does not always respond to treatment. Krook-Magnuson and colleagues use optogenetics to inhibit and activate excitatory and inhibitory neurons, respectively, in a mouse model of temporal lobe epilepsy, and find that they can stop seizures on a moment-to-moment basis.
Collapse
|
12
|
Memarian N, Thompson PM, Engel J, Staba RJ. Quantitative analysis of structural neuroimaging of mesial temporal lobe epilepsy. ACTA ACUST UNITED AC 2013; 5. [PMID: 24319498 DOI: 10.2217/iim.13.28] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mesial temporal lobe epilepsy (MTLE) is the most common of the surgically remediable drug-resistant epilepsies. MRI is the primary diagnostic tool to detect anatomical abnormalities and, when combined with EEG, can more accurately identify an epileptogenic lesion, which is often hippocampal sclerosis in cases of MTLE. As structural imaging technology has advanced the surgical treatment of MTLE and other lesional epilepsies, so too have the analysis techniques that are used to measure different structural attributes of the brain. These techniques, which are reviewed here and have been used chiefly in basic research of epilepsy and in studies of MTLE, have identified different types and the extent of anatomical abnormalities that can extend beyond the affected hippocampus. These results suggest that structural imaging and sophisticated imaging analysis could provide important information to identify networks capable of generating spontaneous seizures and ultimately help guide surgical therapy that improves postsurgical seizure-freedom outcomes.
Collapse
Affiliation(s)
- Negar Memarian
- Department of Neurology, Reed, Neurological Research Center, Suite, 2155, University of California, 710 Westwood Plaza, Los Angeles, CA 90095, USA
| | | | | | | |
Collapse
|