51
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Khalil R, Abo Elfetoh N, Moftah MZ, Khedr EM. Acquired equivalence associative learning in GTC epileptic patients: experimental and computational study. Front Cell Neurosci 2015; 9:418. [PMID: 26578883 PMCID: PMC4621864 DOI: 10.3389/fncel.2015.00418] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 10/02/2015] [Indexed: 12/24/2022] Open
Abstract
Previous cognitive behavioral studies based on Acquired Equivalence Associative learning Task (AEALT) showed a strong relation between hippocampus and basal ganglia in associative learning. However, experimental behavioral studies of patients with Generalized Tonic Clonic (GTC) epilepsy remained sparse. The aim of the present study is to integrate a classical behavioral cognitive analysis with a computational model approach to investigate cognitive associative learning impairments in patients with GTC epilepsy. We measured the accuracy of associative learning response performance in five GTC epileptic patients and five control subjects by using AEALT, all subjects were matched in age and gender. We ran the task using E-Prime, a neuropsychological software program, and SPSS for data statistical analysis. We tested whether GTC epileptic patients would have different learning performance than normal subjects, based on the degree and the location of impairment either in basal ganglia and/or hippocampus. With the number of patients that was available, our behavioral analysis showed no remarkable differences in learning performance of GTC patients as compared to their control subjects, both in the transfer and acquisition phases. In parallel, our simulation results confirmed strong connection and interaction between hippocampus and basal ganglia in our GTC and their control subjects. Nevertheless, the differences in neural firing rate of the connectionist model and weight update of basal ganglia were not significantly different between GTC and control subjects. Therefore, the behavioral analysis and the simulation data provided the same result, thus indicating that the computational model is likely to predict cognitive outcomes.
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Affiliation(s)
- Radwa Khalil
- Department of Cognitive Biology, Otto-von-Guericke Universität Magdeburg, Germany ; Department of Developmental Physiology, Institute of Physiology, Otto-von-Guericke Universität Magdeburg, Germany ; IMN - Institut des Maladies Neurodégénératives, University of Bordeaux Bordeaux, France
| | - Noha Abo Elfetoh
- Department of Neurology, Faculty of Medicine, Assiut University Assiut, Egypt
| | - Marie Z Moftah
- Department of Zoology, Faculty of Science, Alexandria University Alexandria, Egypt
| | - Eman M Khedr
- Department of Neurology, Faculty of Medicine, Assiut University Assiut, Egypt
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52
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Abstract
The challenges to individuals with epilepsy extend far beyond the seizures. Co-morbidities in epilepsy are very common and are often more problematic to individuals than the seizures themselves. In this review, the pathophysiological mechanisms of cognitive impairment are discussed. While aetiology of the epilepsy has a significant influence on cognition, there is increasing evidence that prolonged or recurrent seizures can cause or exacerbate cognitive impairment. Alterations in signalling pathways and neuronal network function play a major role in both the pathophysiology of epilepsy and the epilepsy comorbidities. However, the biological underpinnings of cognitive impairment can be distinct from the pathophysiological processes that cause seizures.
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53
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Sun H, Juul HM, Jensen FE. Models of hypoxia and ischemia-induced seizures. J Neurosci Methods 2015; 260:252-60. [PMID: 26434705 DOI: 10.1016/j.jneumeth.2015.09.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 09/22/2015] [Indexed: 01/19/2023]
Abstract
Despite greater understanding and improved management, seizures continue to be a major problem in childhood. Neonatal seizures are often refractory to conventional antiepileptic drugs, and can result in later life epilepsy and cognitive deficits, conditions for which there are no specific treatments. Hypoxic and/or ischemic encephalopathy (HIE) is the most common cause for neonatal seizures, and accounts for more than two-thirds of neonatal seizure cases. A better understanding of the cellular and molecular mechanisms is essential for identifying new therapeutic strategies that control the neonatal seizures and its cognitive consequences. This heavily relies on animal models that play a critical role in discovering novel mechanisms underlying both epileptogenesis and associated cognitive impairments. To date, a number of animal models have provided a tremendous amount of information regarding the pathophysiology of HIE-induced neonatal seizures. This review provides an overview on the most important features of the main animal models of HIE-induced seizures. In particular, we focus on the methodology of seizure induction and the characterizations of post-HIE injury consequences. These aspects of HIE-induced seizure models are discussed in the light of the suitability of these models in studying human HIE-induced seizures.
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Affiliation(s)
- Hongyu Sun
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Halvor M Juul
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Frances E Jensen
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.
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54
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Stafstrom CE, Benke TA. Autism and Epilepsy: Exploring the Relationship Using Experimental Models. Epilepsy Curr 2015; 15:206-10. [PMID: 26316869 PMCID: PMC4532234 DOI: 10.5698/1535-7511-15.4.206] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The common co-occurrence of autism and epilepsy suggests that certain neurobiological mechanisms are shared between these disorders. In particular, the profusion of novel genetic mutations being discovered in autism and epilepsy points to abnormalities in synapse formation and function that alter the balance between neuronal excitation and inhibition. Animal models can be informative in sorting out the medical and behavioral complexities in autism and epilepsy and the relationship between them. As mechanistic information accrues, it is anticipated that mutation- and pathway-specific targeted treatments can be developed.
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Affiliation(s)
- Carl E. Stafstrom
- Division of Pediatric Neurology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Tim A. Benke
- Division of Pediatric Neurology, University of Colorado, School of Medicine, Children's Hospital Colorado, Aurora, CO
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55
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Holmes GL, Tian C, Hernan AE, Flynn S, Camp D, Barry J. Alterations in sociability and functional brain connectivity caused by early-life seizures are prevented by bumetanide. Neurobiol Dis 2015; 77:204-19. [PMID: 25766676 PMCID: PMC4682568 DOI: 10.1016/j.nbd.2015.02.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Revised: 12/29/2014] [Accepted: 02/13/2015] [Indexed: 01/02/2023] Open
Abstract
There is a well-described association between infantile epilepsy and pervasive cognitive and behavioral deficits, including a high incidence of autism spectrum disorders. Despite the robustness of the relationship between early-life seizures and the development of autism, the pathophysiological mechanism by which this occurs has not been explored. As a result of increasing evidence that autism is a disorder of brain connectivity we hypothesized that early-life seizures would interrupt normal brain connectivity during brain maturation and result in an autistic phenotype. Normal rat pups underwent recurrent flurothyl-induced seizures from postnatal (P)days 5-14 and then tested, along with controls, for developmental alterations of development brain oscillatory activity from P18-P25. Specifically we wished to understand how normal changes in rhythmicity in and between brain regions change as a function of age and if this rhythmicity is altered or interrupted by early life seizures. In rat pups with early-life seizures, field recordings from dorsal and ventral hippocampus and prefrontal cortex demonstrated marked increase in coherence as well as a decrease in voltage correlation at all bandwidths compared to controls while there were minimal differences in total power and relative power spectral densities. Rats with early-life seizures had resulting impairment in the sociability and social novelty tests but demonstrated no evidence of increased activity or generalized anxiety as measured in the open field. In addition, rats with early-life seizures had lower seizure thresholds than controls, indicating long-standing alterations in the excitatory/inhibition balance. Bumetanide, a pharmacological agent that blocks the activity of NKCC1 and induces a significant shift of ECl toward more hyperpolarized values, administration at the time of the seizures precluded the subsequent abnormalities in coherence and voltage correlation and resulted in normal sociability and seizure threshold. Taken together these findings indicate that early-life seizures alter the development of oscillations and result in autistic-like behaviors. The altered communication between these brain regions could reflect the physiological underpinnings underlying social cognitive deficits seen in autism spectrum disorders.
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Affiliation(s)
- Gregory L Holmes
- Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, VT05405, USA.
| | - Chengju Tian
- Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, VT05405, USA
| | - Amanda E Hernan
- Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, VT05405, USA
| | - Sean Flynn
- Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, VT05405, USA
| | - Devon Camp
- Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, VT05405, USA
| | - Jeremy Barry
- Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, VT05405, USA
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56
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Bernard PB, Castano AM, Beitzel CS, Carlson VB, Benke TA. Behavioral changes following a single episode of early-life seizures support the latent development of an autistic phenotype. Epilepsy Behav 2015; 44:78-85. [PMID: 25659043 PMCID: PMC4405461 DOI: 10.1016/j.yebeh.2015.01.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 01/06/2015] [Accepted: 01/07/2015] [Indexed: 01/23/2023]
Abstract
We probed the developmental and behavioral consequences of a single episode of kainic acid-induced early-life seizures (KA-ELS) in the rat on postnatal day 7. Correlates of developmental trajectory were not altered, demonstrating that long-term consequences following KA-ELS are not initiated by secondary causes, such as malnourishment or alterations in maternal care. We report reduced marble burying in adult rats, suggestive of restricted interests, a trait common to experimental and clinical autism. We did not detect increased repetitive grooming during habituated cage behavior. However, we did detect reduced grooming in adult KA-ELS rats in the presence of an unfamiliar rat, supporting altered social anxiety following KA-ELS. Reanalysis of a social approach task further indicated abnormal social interactions. Taken together with previous physiological and behavioral data, these data support the hypothesis that KA-ELS lead to a latent autistic phenotype in adult rats not attributable to other early alterations in development.
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Affiliation(s)
- Paul B Bernard
- Department of Pediatrics, University of Colorado, School of Medicine, USA
| | - Anna M Castano
- Department of Pediatrics, University of Colorado, School of Medicine, USA
| | - Christy S Beitzel
- Department of Neuroscience Graduate Program, University of Colorado, School of Medicine, USA
| | - Vivian B Carlson
- Department of Pediatrics, University of Colorado, School of Medicine, USA
| | - Tim A Benke
- Department of Pediatrics, University of Colorado, School of Medicine, USA; Department of Neuroscience Graduate Program, University of Colorado, School of Medicine, USA; Department of Neurology, University of Colorado, School of Medicine, USA; Department of Pharmacology, University of Colorado, School of Medicine, USA; Department of Otolaryngology, University of Colorado, School of Medicine, USA.
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57
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Early influences: seizures during infancy influence behavior in young adult mice. Epilepsy Curr 2015; 14:353-4. [PMID: 25678873 DOI: 10.5698/1535-7597-14.6.353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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58
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Pitcher MR, Herrera JA, Buffington SA, Kochukov MY, Merritt JK, Fisher AR, Schanen NC, Costa-Mattioli M, Neul JL. Rett syndrome like phenotypes in the R255X Mecp2 mutant mouse are rescued by MECP2 transgene. Hum Mol Genet 2015; 24:2662-72. [PMID: 25634563 DOI: 10.1093/hmg/ddv030] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 01/26/2015] [Indexed: 01/26/2023] Open
Abstract
Rett syndrome (RTT) is a severe neurodevelopmental disorder that is usually caused by mutations in Methyl-CpG-binding Protein 2 (MECP2). Four of the eight common disease causing mutations in MECP2 are nonsense mutations and are responsible for over 35% of all cases of RTT. A strategy to overcome disease-causing nonsense mutations is treatment with nonsense mutation suppressing drugs that allow expression of full-length proteins from mutated genes with premature in-frame stop codons. To determine if this strategy is useful in RTT, we characterized a new mouse model containing a knock-in nonsense mutation (p.R255X) in the Mecp2 locus (Mecp2(R255X)). To determine whether the truncated gene product acts as a dominant negative allele and if RTT-like phenotypes could be rescued by expression of wild-type protein, we genetically introduced an extra copy of MECP2 via an MECP2 transgene. The addition of MECP2 transgene to Mecp2(R255X) mice abolished the phenotypic abnormalities and resulted in near complete rescue. Expression of MECP2 transgene Mecp2(R255X) allele also rescued mTORC1 signaling abnormalities discovered in mice with loss of function and overexpression of Mecp2. Finally, we treated Mecp2(R255X) embryonic fibroblasts with the nonsense mutation suppressing drug gentamicin and we were able to induce expression of full-length MeCP2 from the mutant p.R255X allele. These data provide proof of concept that the p.R255X mutation of MECP2 is amenable to the nonsense suppression therapeutic strategy and provide guidelines for the extent of rescue that can be expected by re-expressing MeCP2 protein.
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Affiliation(s)
- Meagan R Pitcher
- Interdepartmental Program in Translational Biology and Molecular Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - José A Herrera
- Interdepartmental Program in Translational Biology and Molecular Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | | | - Mikhail Y Kochukov
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Jonathan K Merritt
- Interdepartmental Program in Translational Biology and Molecular Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Amanda R Fisher
- Department of Biological Sciences, University of Delaware, Newark, DE, USA and
| | | | | | - Jeffrey L Neul
- Interdepartmental Program in Translational Biology and Molecular Medicine, Department of Pediatrics, Section of Neurology, Baylor College of Medicine, Houston, TX, USA, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA,
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59
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Kang SK, Kadam SD. Neonatal Seizures: Impact on Neurodevelopmental Outcomes. Front Pediatr 2015; 3:101. [PMID: 26636052 PMCID: PMC4655485 DOI: 10.3389/fped.2015.00101] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 11/05/2015] [Indexed: 11/24/2022] Open
Abstract
Neonatal period is the most vulnerable time for the occurrence of seizures, and neonatal seizures often pose a clinical challenge both for their acute management and frequency of associated long-term co-morbidities. Etiologies of neonatal seizures are known to play a primary role in the anti-epileptic drug responsiveness and the long-term sequelae. Recent studies have suggested that burden of acute recurrent seizures in neonates may also impact chronic outcomes independent of the etiology. However, not many studies, either clinical or pre-clinical, have addressed the long-term outcomes of neonatal seizures in an etiology-specific manner. In this review, we briefly review the available clinical and pre-clinical research for long-term outcomes following neonatal seizures. As the most frequent cause of acquired neonatal seizures, we focus on the studies evaluating long-term effects of HIE-seizures with the goal to evaluate (1) what parameters evaluated during acute stages of neonatal seizures can reliably be used to predict long-term outcomes? and (2) what available clinical and pre-clinical data are available help determine importance of etiology vs. seizure burdens in long-term sequelae.
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Affiliation(s)
- Seok Kyu Kang
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger , Baltimore, MD , USA
| | - Shilpa D Kadam
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger , Baltimore, MD , USA ; Department of Neurology, Johns Hopkins University School of Medicine , Baltimore, MD , USA
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60
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McMahon JJ, Yu W, Yang J, Feng H, Helm M, McMahon E, Zhu X, Shin D, Huang Y. Seizure-dependent mTOR activation in 5-HT neurons promotes autism-like behaviors in mice. Neurobiol Dis 2014; 73:296-306. [PMID: 25315683 DOI: 10.1016/j.nbd.2014.10.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/23/2014] [Accepted: 10/01/2014] [Indexed: 11/15/2022] Open
Abstract
Epilepsy and autism spectrum disorder (ASD) are common comorbidities of one another. Despite the prevalent correlation between the two disorders, few studies have been able to elucidate a mechanistic link. We demonstrate that forebrain specific Tsc1 deletion in mice causes epilepsy and autism-like behaviors, concomitant with disruption of 5-HT neurotransmission. We find that epileptiform activity propagates to the raphe nuclei, resulting in seizure-dependent hyperactivation of mTOR in 5-HT neurons. To dissect whether mTOR hyperactivity in 5-HT neurons alone was sufficient to recapitulate an autism-like phenotype we utilized Tsc1flox/flox;Slc6a4-cre mice, in which mTOR is restrictively hyperactivated in 5-HT neurons. Tsc1flox/flox;Slc6a4-cre mice displayed alterations of the 5-HT system and autism-like behaviors, without causing epilepsy. Rapamycin treatment in these mice was sufficient to rescue the phenotype. We conclude that the spread of seizure activity to the brainstem is capable of promoting hyperactivation of mTOR in the raphe nuclei, which in turn promotes autism-like behaviors. Thus our study provides a novel mechanism describing how epilepsy can contribute to the development of autism-like behaviors, suggesting new therapeutic strategies for autism.
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Affiliation(s)
- John J McMahon
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA
| | - Wilson Yu
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA
| | - Jun Yang
- Center for Cardiovascular Sciences, Albany Medical College, Albany, NY 12208, USA
| | - Haihua Feng
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA
| | - Meghan Helm
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA
| | - Elizabeth McMahon
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA
| | - Xinjun Zhu
- Center for Cardiovascular Sciences, Albany Medical College, Albany, NY 12208, USA
| | - Damian Shin
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA
| | - Yunfei Huang
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA.
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61
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Bernard PB, Benke TA. Early life seizures: evidence for chronic deficits linked to autism and intellectual disability across species and models. Exp Neurol 2014; 263:72-8. [PMID: 25284323 DOI: 10.1016/j.expneurol.2014.09.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 09/02/2014] [Accepted: 09/16/2014] [Indexed: 11/08/2022]
Abstract
Recent work in Exp Neurol by Lugo et al. (2014b) demonstrated chronic alterations in sociability, learning and memory following multiple early life seizures (ELS) in a mouse model. This work adds to the growing body of evidence supporting the detrimental nature of ELS on the developing brain to contribute to aspects of an autistic phenotype with intellectual disability. Review of the face validity of behavioral testing and the construct validity of the models used informs the predictive ability and thus the utility of these models to translate underlying molecular and cellular mechanisms into future human studies.
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Affiliation(s)
- Paul B Bernard
- Department of Pediatrics, University of Colorado, School of Medicine, USA
| | - Tim A Benke
- Department of Pediatrics, University of Colorado, School of Medicine, USA; Neuroscience Graduate Program, University of Colorado, School of Medicine, USA; Department of Neurology, University of Colorado, School of Medicine, USA; Department of Pharmacology, University of Colorado, School of Medicine, USA; Department of Otolaryngology, University of Colorado, School of Medicine, USA.
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