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Bischoff H, Kovach C, Kumar S, Bruss J, Tranel D, Khalsa SS. Sensing, feeling and regulating: investigating the association of focal brain damage with voluntary respiratory and motor control. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230251. [PMID: 39005040 DOI: 10.1098/rstb.2023.0251] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 03/26/2024] [Indexed: 07/16/2024] Open
Abstract
Breathing is a complex, vital function that can be modulated to influence physical and mental well-being. However, the role of cortical and subcortical brain regions in voluntary control of human respiration is underexplored. Here we investigated the influence of damage to human frontal, temporal or limbic regions on the sensation and regulation of breathing patterns. Participants performed a respiratory regulation task across regular and irregular frequencies ranging from 6 to 60 breaths per minute (bpm), with a counterbalanced hand motor control task. Interoceptive and affective states induced by each condition were assessed via questionnaire, and autonomic signals were indexed via skin conductance. Participants with focal lesions to the bilateral frontal lobe, right insula/basal ganglia and left medial temporal lobe showed reduced performance relative to individually matched healthy comparisons during the breathing and motor tasks. They also reported significantly higher anxiety during the 60 bpm regular and irregular breathing trials, with anxiety correlating with difficulty in rapid breathing specifically within this group. This study demonstrates that damage to frontal, temporal or limbic regions is associated with abnormal voluntary respiratory and motor regulation and tachypnoea-related anxiety, highlighting the role of the forebrain in affective and motor responses during breathing. This article is part of the theme issue 'Sensing and feeling: an integrative approach to sensory processing and emotional experience'.
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Affiliation(s)
- Henrik Bischoff
- Department of Psychology, University of Stockholm, 10691 Stockholm, Sweden
- Department of Psychology, Carl-von-Ossietzky University Oldenburg, 26129 Oldenburg, Germany
| | - Christopher Kovach
- Department of Neurosurgery, University of Iowa, Iowa City, IA 52242, USA
- Department of Neurosurgery, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Sukbhinder Kumar
- Department of Neurosurgery, University of Iowa, Iowa City, IA 52242, USA
| | - Joel Bruss
- Departments of Pediatrics, Neurology, and Psychiatry, University of Iowa, Iowa City, IA 52242, USA
| | - Daniel Tranel
- Departments of Neurology and Psychological and Brain Sciences, University of Iowa, Iowa City, IA 52242, USA
| | - Sahib S Khalsa
- Laureate Institute for Brain Research, Tulsa, OK 74136, USA
- Oxley College of Health Sciences, University of Tulsa, Tulsa, OK 74119, USA
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
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Lam HW, Patodia S, Zeicu C, Lim YM, Mrzyglod A, Scott C, Oliveira J, De Tisi J, Legouhy A, Zhang H, Koepp M, Diehl B, Thom M. Quantitative cellular pathology of the amygdala in temporal lobe epilepsy and correlation with magnetic resonance imaging volumetry, tissue microstructure, and sudden unexpected death in epilepsy risk factors. Epilepsia 2024; 65:2368-2385. [PMID: 38837385 DOI: 10.1111/epi.18033] [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] [Received: 02/19/2024] [Revised: 05/18/2024] [Accepted: 05/20/2024] [Indexed: 06/07/2024]
Abstract
OBJECTIVE Amygdala enlargement can occur in temporal lobe epilepsy, and increased amygdala volume is also reported in sudden unexpected death in epilepsy (SUDEP). Apnea can be induced by amygdala stimulation, and postconvulsive central apnea (PCCA) and generalized seizures are both known SUDEP risk factors. Neurite orientation dispersion and density imaging (NODDI) has recently provided additional information on altered amygdala microstructure in SUDEP. In a series of 24 surgical temporal lobe epilepsy cases, our aim was to quantify amygdala cellular pathology parameters that could predict enlargement, NODDI changes, and ictal respiratory dysfunction. METHODS Using whole slide scanning automated quantitative image analysis methods, parallel evaluation of myelin, axons, dendrites, oligodendroglia, microglia, astroglia, neurons, serotonergic networks, mTOR-pathway activation (pS6) and phosphorylated tau (pTau; AT8, AT100, PHF) in amygdala, periamygdala cortex, and white matter regions of interest were compared with preoperative magnetic resonance imaging data on amygdala size, and in 13 cases with NODDI and evidence of ictal-associated apnea. RESULTS We observed significantly higher glial labeling (Iba1, glial fibrillary acidic protein, Olig2) in amygdala regions compared to cortex and a strong positive correlation between Olig2 and Iba1 in the amygdala. Larger amygdala volumes correlated with lower microtubule-associated protein (MAP2), whereas higher NODDI orientation dispersion index correlated with lower Olig2 cell densities. In the three cases with recorded PCCA, higher MAP2 and pS6-235 expression was noted than in those without. pTau did not correlate with SUDEP risk factors, including seizure frequency. SIGNIFICANCE Histological quantitation of amygdala microstructure can shed light on enlargement and diffusion imaging alterations in epilepsy to explore possible mechanisms of amygdala dysfunction, including mTOR pathway activation, that in turn may increase the risk for SUDEP.
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Affiliation(s)
- Hou Wang Lam
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
| | - Smriti Patodia
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
| | - Claudia Zeicu
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
| | - Yau Mun Lim
- Division of Neuropathology, UCL Queen Square Institute of Neurology and National Hospital for Neurology and Neurosurgery, University College Hospitals NHS Foundation Trust, London, UK
| | - Alicja Mrzyglod
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
| | - Catherine Scott
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
- Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, University College Hospitals NHS Foundation Trust, London, UK
| | - Joana Oliveira
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
- Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, University College Hospitals NHS Foundation Trust, London, UK
| | - Jane De Tisi
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
| | - Antoine Legouhy
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, UK
| | - Hui Zhang
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, UK
| | - Matthias Koepp
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
| | - Beate Diehl
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
- Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, University College Hospitals NHS Foundation Trust, London, UK
| | - Maria Thom
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
- Division of Neuropathology, UCL Queen Square Institute of Neurology and National Hospital for Neurology and Neurosurgery, University College Hospitals NHS Foundation Trust, London, UK
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Roy B, Ogren JA, Allen LA, Diehl B, Sankar R, Lhatoo SD, Kumar R, Harper RM. Brain gray matter changes in children at risk for sudden unexpected death in epilepsy. Pediatr Res 2024:10.1038/s41390-024-03295-0. [PMID: 38992155 DOI: 10.1038/s41390-024-03295-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 04/24/2024] [Accepted: 05/15/2024] [Indexed: 07/13/2024]
Abstract
BACKGROUND Potential failing adult brain sites, stratified by risk, mediating Sudden Unexpected Death in Epilepsy (SUDEP) have been described, but are unknown in children. METHODS We examined regional brain volumes using T1-weighted MRI images in 21 children with epilepsy at high SUDEP risk and 62 healthy children, together with SUDEP risk scores, calculated from focal seizure frequency. Gray matter tissue type was partitioned, maps normalized, smoothed, and compared between groups (SPM12; ANCOVA; covariates, age, sex, and BMI). Partial correlations between regional volumes and seizure frequency were examined (SPM12, covariates, age, sex, and BMI); 67% were at high risk for SUDEP. RESULTS The cerebellar cortex, hippocampus, amygdala, putamen, cingulate, thalamus, and para-hippocampal gyrus showed increased gray matter volumes in epilepsy, and decreased volumes in the posterior thalamus, lingual gyrus, and temporal cortices. The cingulate, insula, and putamen showed significant positive relationships with focal seizure frequency indices using whole-brain voxel-by-voxel partial correlations. Tissue volume changes in selected sites differed in direction from adults; particularly, cerebellar sites, key for hypotensive recovery, increased rather than adult declines. CONCLUSION The volume increases may represent expansion by inflammatory or other processes that, with sustained repetitive seizure discharge, lead to tissue volume declines described earlier in adults. IMPACT Children with epilepsy, who are at risk for Sudden Unexplained Death, show changes in brain volume that often differ in direction of change from adults at risk for SUDEP. Sites of volume change play significant roles in mediating breathing and blood pressure, and include areas that serve recovery from prolonged apnea and marked loss of blood pressure. The extent of volume changes correlated with focal seizure frequency. Although the underlying processes contributing to regional volume changes remain speculative, regions of tissue swelling in pediatric brain areas may represent transitory conditions that later lead to tissue loss in the adult condition.
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Affiliation(s)
- Bhaswati Roy
- Department of Anesthesiology and Perioperative Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Jennifer A Ogren
- Department of Neurobiology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Luke A Allen
- Department of Clinical and Experimental Epilepsy, University College London Institute of Neurology, London, UK
| | - Beate Diehl
- Department of Clinical and Experimental Epilepsy, University College London Institute of Neurology, London, UK
| | - Raman Sankar
- Department of Neurology and Pediatrics, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Samden D Lhatoo
- Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Rajesh Kumar
- Department of Anesthesiology and Perioperative Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA.
- Brain Research Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA.
- Department of Radiological Sciences, University of California Los Angeles, Los Angeles, CA, 90095, USA.
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, 90095, USA.
| | - Ronald M Harper
- Department of Neurobiology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
- Brain Research Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA
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Lacuey N, Talavera B, Magana-Tellez O, Mancera-Páez O, Hupp N, Luo X, Hampson JP, Hampson J, Rani RS, Ochoa-Urrea M, Alamoudi OA, Melius S, Pati S, Gavvala J, Tandon N, Mosher JC, Lhatoo SD. Ictal Central Apnea Is Predictive of Mesial Temporal Seizure Onset: An Intracranial Investigation. Ann Neurol 2024; 95:998-1008. [PMID: 38400804 PMCID: PMC11061876 DOI: 10.1002/ana.26888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 12/27/2023] [Accepted: 01/23/2024] [Indexed: 02/26/2024]
Abstract
OBJECTIVE Ictal central apnea (ICA) is a semiological sign of focal epilepsy, associated with temporal and frontal lobe seizures. In this study, using qualitative and quantitative approaches, we aimed to assess the localizational value of ICA. We also aimed to compare ICA clinical utility in relation to other seizure semiological features of focal epilepsy. METHODS We analyzed seizures in patients with medically refractory focal epilepsy undergoing intracranial stereotactic electroencephalographic (SEEG) evaluations with simultaneous multimodal cardiorespiratory monitoring. A total of 179 seizures in 72 patients with reliable artifact-free respiratory signal were analyzed. RESULTS ICA was seen in 55 of 179 (30.7%) seizures. Presence of ICA predicted a mesial temporal seizure onset compared to those without ICA (odds ratio = 3.8, 95% confidence interval = 1.3-11.6, p = 0.01). ICA specificity was 0.82. ICA onset was correlated with increased high-frequency broadband gamma (60-150Hz) activity in specific mesial or basal temporal regions, including amygdala, hippocampus, and fusiform and lingual gyri. Based on our results, ICA has an almost 4-fold greater association with mesial temporal seizure onset zones compared to those without ICA and is highly specific for mesial temporal seizure onset zones. As evidence of symptomatogenic areas, onset-synchronous increase in high gamma activity in mesial or basal temporal structures was seen in early onset ICA, likely representing anatomical substrates for ICA generation. INTERPRETATION ICA recognition may help anatomoelectroclinical localization of clinical seizure onset to specific mesial and basal temporal brain regions, and the inclusion of these regions in SEEG evaluations may help accurately pinpoint seizure onset zones for resection. ANN NEUROL 2024;95:998-1008.
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Affiliation(s)
- Nuria Lacuey
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, Texas, USA
| | - Blanca Talavera
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, Texas, USA
| | - Oman Magana-Tellez
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, Texas, USA
| | - Oscar Mancera-Páez
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, Texas, USA
| | - Norma Hupp
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, Texas, USA
| | - Xi Luo
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, Texas, USA
- Department of Biostatistics and Data Science, University of Texas Health Science Center (UTHealth), School of Public Health, Houston, Texas, USA
| | - Johnson P. Hampson
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, Texas, USA
| | - Jaison Hampson
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, Texas, USA
| | - R. Sandhya Rani
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, Texas, USA
| | - Manuela Ochoa-Urrea
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, Texas, USA
- Memorial Hermann, Texas Medical Center, Houston, TX, USA
| | - Omar A. Alamoudi
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, Texas, USA
- Biomedical Engineering Program, Faculty of Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Stephen Melius
- Memorial Hermann, Texas Medical Center, Houston, TX, USA
| | - Sandipan Pati
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, Texas, USA
| | - Jay Gavvala
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, Texas, USA
| | - Nitin Tandon
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, Texas, USA
| | - John C. Mosher
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, Texas, USA
| | - Samden D. Lhatoo
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, Texas, USA
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Bischoff H, Kovach C, Kumar S, Bruss J, Tranel D, Khalsa SS. Sensing, Feeling, and Regulating: Investigating the Association of Focal Brain Damage with Voluntary Respiratory and Motor Control. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.16.562254. [PMID: 37905134 PMCID: PMC10614780 DOI: 10.1101/2023.10.16.562254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Breathing is a complex, vital function that can be modulated to influence physical and mental well-being. However, the role of cortical and subcortical brain regions in voluntary control of human respiration is underexplored. Here we investigated the influence of damage to human frontal, temporal, or limbic regions on the sensation and regulation of breathing patterns. Participants performed a respiratory regulation task across regular and irregular frequencies ranging from 6 to 60 breaths per minute (bpm), with a counterbalanced hand motor control task. Interoceptive and affective states induced by each condition were assessed via questionnaire and autonomic signals were indexed via skin conductance. Participants with focal lesions to the bilateral frontal lobe, right insula/basal ganglia, and left medial temporal lobe showed reduced performance than individually matched healthy comparisons during the breathing and motor tasks. They also reported significantly higher anxiety during the 60-bpm regular and irregular breathing trials, with anxiety correlating with difficulty in rapid breathing specifically within this group. This study demonstrates that damage to frontal, temporal, or limbic regions is associated with abnormal voluntary respiratory and motor regulation and tachypnea-related anxiety, highlighting the role of the forebrain in affective and motor responses during breathing. Highlights Impaired human respiratory regulation is associated with cortical/subcortical brain lesionsFrontolimbic/temporal regions contribute to rhythmic breathing and hand motor controlFrontolimbic/temporal damage is associated with anxiety during tachypnea/irregular breathingThe human forebrain is vital for affective and interoceptive experiences during breathing.
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Brodovskaya A, Sun H, Adotevi N, Wenker IC, Mitchell KE, Clements RT, Kapur J. Neuronal plasticity contributes to postictal death. Prog Neurobiol 2023; 231:102531. [PMID: 37778436 PMCID: PMC10842614 DOI: 10.1016/j.pneurobio.2023.102531] [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] [Received: 03/30/2023] [Revised: 08/07/2023] [Accepted: 09/25/2023] [Indexed: 10/03/2023]
Abstract
Repeated generalized tonic-clonic seizures (GTCSs) are the most critical risk factor for sudden unexpected death in epilepsy (SUDEP). GTCSs can cause fatal apnea. We investigated neuronal plasticity mechanisms that precipitate postictal apnea and seizure-induced death. Repeated seizures worsened behavior, precipitated apnea, and enlarged active neuronal circuits, recruiting more neurons in such brainstem nuclei as periaqueductal gray (PAG) and dorsal raphe, indicative of brainstem plasticity. Seizure-activated neurons are more excitable and have enhanced AMPA-mediated excitatory transmission after a seizure. Global deletion of the GluA1 subunit of AMPA receptors abolishes postictal apnea and seizure-induced death. Treatment with a drug that blocks Ca2+-permeable AMPA receptors also renders mice apnea-free with five-fold better survival than untreated mice. Repeated seizures traffic the GluA1 subunit-containing AMPA receptors to synapses, and blocking this mechanism decreases the probability of postictal apnea and seizure-induced death.
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Affiliation(s)
| | - Huayu Sun
- Department of Neurology, University of Virginia, Charlottesville, VA 22908, USA
| | - Nadia Adotevi
- Department of Neurology, University of Virginia, Charlottesville, VA 22908, USA
| | - Ian C Wenker
- Department of Anesthesiology, University of Virginia, Charlottesville, VA 22908, USA
| | - Keri E Mitchell
- Department of Chemistry, University of Virginia, Charlottesville, VA 22908, USA
| | - Rachel T Clements
- Department of Neuroscience, University of Virginia, Charlottesville, VA 22908, USA
| | - Jaideep Kapur
- Department of Neurology, University of Virginia, Charlottesville, VA 22908, USA; UVA Brain Institute, University of Virginia, Charlottesville, VA 22908, USA.
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Harmata GI, Rhone AE, Kovach CK, Kumar S, Mowla MR, Sainju RK, Nagahama Y, Oya H, Gehlbach BK, Ciliberto MA, Mueller RN, Kawasaki H, Pattinson KT, Simonyan K, Davenport PW, Howard MA, Steinschneider M, Chan AC, Richerson GB, Wemmie JA, Dlouhy BJ. Failure to breathe persists without air hunger or alarm following amygdala seizures. JCI Insight 2023; 8:e172423. [PMID: 37788112 PMCID: PMC10721319 DOI: 10.1172/jci.insight.172423] [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] [Received: 05/24/2023] [Accepted: 09/29/2023] [Indexed: 10/05/2023] Open
Abstract
Postictal apnea is thought to be a major cause of sudden unexpected death in epilepsy (SUDEP). However, the mechanisms underlying postictal apnea are unknown. To understand causes of postictal apnea, we used a multimodal approach to study brain mechanisms of breathing control in 20 patients (ranging from pediatric to adult) undergoing intracranial electroencephalography for intractable epilepsy. Our results indicate that amygdala seizures can cause postictal apnea. Moreover, we identified a distinct region within the amygdala where electrical stimulation was sufficient to reproduce prolonged breathing loss persisting well beyond the end of stimulation. The persistent apnea was resistant to rising CO2 levels, and air hunger failed to occur, suggesting impaired CO2 chemosensitivity. Using es-fMRI, a potentially novel approach combining electrical stimulation with functional MRI, we found that amygdala stimulation altered blood oxygen level-dependent (BOLD) activity in the pons/medulla and ventral insula. Together, these findings suggest that seizure activity in a focal subregion of the amygdala is sufficient to suppress breathing and air hunger for prolonged periods of time in the postictal period, likely via brainstem and insula sites involved in chemosensation and interoception. They further provide insights into SUDEP, may help identify those at greatest risk, and may lead to treatments to prevent SUDEP.
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Affiliation(s)
- Gail I.S. Harmata
- Department of Neurosurgery
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
- Interdisciplinary Graduate Program in Neuroscience
- Pharmacological Sciences Training Program
- Department of Psychiatry
| | | | | | | | | | | | | | - Hiroyuki Oya
- Department of Neurosurgery
- Iowa Neuroscience Institute
| | | | | | - Rashmi N. Mueller
- Department of Neurosurgery
- Department of Anesthesia, University of Iowa, Iowa City, Iowa, USA
| | | | - Kyle T.S. Pattinson
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Kristina Simonyan
- Department of Otolaryngology–Head and Neck Surgery, Massachusetts Eye and Ear and Harvard Medical School, Boston, Massachusetts, USA
| | - Paul W. Davenport
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, USA
| | - Matthew A. Howard
- Department of Neurosurgery
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
| | | | | | - George B. Richerson
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
- Interdisciplinary Graduate Program in Neuroscience
- Department of Neurology
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA
- Department of Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - John A. Wemmie
- Department of Neurosurgery
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
- Interdisciplinary Graduate Program in Neuroscience
- Department of Psychiatry
- Department of Internal Medicine
- Department of Neurology, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - Brian J. Dlouhy
- Department of Neurosurgery
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
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Khan MA, Dev S, Kumari M, Mahak F, Umair A, Rasool M, Kumari A, Payal F, Panta U, Deepa F, Varrassi G, Khatri M, Kumar S. Respiratory Dysfunction in Epileptic Encephalopathies: Insights and Challenges. Cureus 2023; 15:e46216. [PMID: 37905295 PMCID: PMC10613478 DOI: 10.7759/cureus.46216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 09/29/2023] [Indexed: 11/02/2023] Open
Abstract
Epileptic encephalopathies constitute a group of severe epileptic disorders characterized by intractable seizures and cognitive regression. Beyond the hallmark neurological manifestations, these disorders frequently exhibit associated respiratory dysfunction, which is increasingly recognized as a critical aspect of their pathophysiology. Respiratory abnormalities in epileptic encephalopathies encompass a spectrum of manifestations, ranging from subtle alterations in breathing patterns to life-threatening events such as apneas and hypoventilation. These respiratory disturbances often occur during seizures, the interictal period, or even persist chronically, leading to significant morbidity and mortality. We explore the varied clinical presentations and their implications on patient outcomes, emphasizing the need for heightened awareness among clinicians. This review unravels the intricate mechanisms linking epilepsy and respiratory dysfunction. GABAergic and glutamatergic imbalances, alterations in central respiratory centers, and abnormal autonomic control are among the key factors contributing to respiratory disturbances in these patients. We elucidate the neurobiological intricacies that underlie these processes and their relevance to therapeutic interventions. Accurate diagnosis of respiratory dysfunction in epileptic encephalopathies is often hindered by its diverse clinical phenotypes and the absence of routine screening protocols. We scrutinize the diagnostic hurdles, highlighting the necessity of comprehensive respiratory assessments in managing these patients. Timely recognition of respiratory issues may guide treatment decisions and mitigate complications. Management of respiratory dysfunction in epileptic encephalopathies is complex and necessitates a multidisciplinary approach. We explore various therapeutic modalities, including antiepileptic drugs (AEDs), ventilatory support, and novel interventions like neuromodulation techniques. The review emphasizes the individualized nature of treatment strategies tailored to each patient's specific needs. In conclusion, this narrative review offers a comprehensive overview of respiratory dysfunction in epileptic encephalopathies, shedding light on its clinical importance, underlying mechanisms, diagnostic challenges, and therapeutic considerations. By addressing these insights and challenges, we hope to inspire further research and innovation to enhance the care and outcomes of patients with epileptic encephalopathies.
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Affiliation(s)
- Muhammad Ali Khan
- Medicine, Shaikh Khalifa Bin Zayed Al-Nahyan Medical and Dental College, Lahore, PAK
| | - Shah Dev
- Medicine, Jinnah Sindh Medical University, Karachi, PAK
| | - Maneesha Kumari
- Medicine, Peoples University of Medical and Health Sciences for Women, Shaheed Benazirabad, PAK
| | - Fnu Mahak
- Medicine, Jinnah Postgraduate Medical Center, Karachi, PAK
| | - Ahmed Umair
- Medicine, Fatima Memorial College of Medicine and Dentistry, Lahore, PAK
| | - Maham Rasool
- Medicine, King Edward Medical University (KEMU), Lahore, PAK
| | - Aneesha Kumari
- Medicine, Shaheed Mohtarma Benazir Bhutto Medical University, Larkana, PAK
| | - Fnu Payal
- Medicine, Shaheed Mohtarma Benazir Bhutto Medical University, Larkana, PAK
| | - Uttam Panta
- Medicine, Chitwan Medical College, Bharatpur, NPL
| | - Fnu Deepa
- Medicine, Ghulam Muhammad Mahar Medical College, Sukkur, PAK
| | | | - Mahima Khatri
- Medicine and Surgery, Dow University of Health Sciences, Karachi, PAK
| | - Satesh Kumar
- Medicine and Surgery, Shaheed Mohtarma Benazir Bhutto Medical College, Karachi, PAK
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Talavera B, Chaitanya G, Hupp N, Pati S, Hampson JP, Luo X, Hampson J, Vakilna YS, Rani MRS, Noor R, Mosher JC, Tandon N, Lhatoo SD, Lacuey N. Stimulation-induced respiratory enhancement in corticothalamic regions. Epilepsia 2023; 64:1925-1938. [PMID: 37119434 DOI: 10.1111/epi.17635] [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] [Received: 01/23/2023] [Revised: 04/26/2023] [Accepted: 04/27/2023] [Indexed: 05/01/2023]
Abstract
OBJECTIVE We aimed to identify corticothalamic areas and electrical stimulation paradigms that optimally enhance breathing. METHODS Twenty-nine patients with medically intractable epilepsy were prospectively recruited in an epilepsy monitoring unit while undergoing stereoelectroencephalographic evaluation. Direct electrical stimulation in cortical and thalamic regions was carried out using low (<1 Hz) and high (≥10 Hz) frequencies, and low (<5 mA) and high (≥5 mA) current intensities, with pulse width of .1 ms. Electrocardiography, arterial oxygen saturation (SpO2 ), end-tidal carbon dioxide (ETCO2 ), oronasal airflow, and abdominal and thoracic plethysmography were monitored continuously during stimulations. Airflow signal was used to estimate breathing rate, tidal volume, and minute ventilation (MV) changes during stimulation, compared to baseline. RESULTS Electrical stimulation increased MV in the amygdala, anterior cingulate, anterior insula, temporal pole, and thalamus, with an average increase in MV of 20.8% ± 28.9% (range = 0.2%-165.6%) in 19 patients. MV changes were associated with SpO2 and ETCO2 changes (p < .001). Effects on respiration were parameter and site dependent. Within amygdala, low-frequency stimulation of the medial region produced 78.49% greater MV change (p < .001) compared to high-frequency stimulation. Longer stimulation produced greater MV changes (an increase of 4.47% in MV for every additional 10 s, p = .04). SIGNIFICANCE Stimulation of amygdala, anterior cingulate gyrus, anterior insula, temporal pole, and thalamus, using certain stimulation paradigms, enhances respiration. Among tested paradigms, low-frequency, low-intensity, long-duration stimulation of the medial amygdala is the most effective breathing enhancement stimulation strategy. Such approaches may pave the way for the future development of neuromodulatory techniques that aid rescue from seizure-related apnea, potentially as a targeted sudden unexpected death in epilepsy prevention method.
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Affiliation(s)
- Blanca Talavera
- Texas Institute of Restorative Neurotechnologies, University of Texas Health Science Center, Houston, Texas, USA
| | - Ganne Chaitanya
- Texas Institute of Restorative Neurotechnologies, University of Texas Health Science Center, Houston, Texas, USA
| | - Norma Hupp
- Texas Institute of Restorative Neurotechnologies, University of Texas Health Science Center, Houston, Texas, USA
| | - Sandipan Pati
- Texas Institute of Restorative Neurotechnologies, University of Texas Health Science Center, Houston, Texas, USA
| | - Johnson P Hampson
- Texas Institute of Restorative Neurotechnologies, University of Texas Health Science Center, Houston, Texas, USA
| | - Xi Luo
- Texas Institute of Restorative Neurotechnologies, University of Texas Health Science Center, Houston, Texas, USA
- Department of Biostatistics and Data Science, University of Texas Health Science Center, School of Public Health, Houston, Texas, USA
| | - Jaison Hampson
- Texas Institute of Restorative Neurotechnologies, University of Texas Health Science Center, Houston, Texas, USA
| | - Yash S Vakilna
- Texas Institute of Restorative Neurotechnologies, University of Texas Health Science Center, Houston, Texas, USA
| | - M R Sandhya Rani
- Texas Institute of Restorative Neurotechnologies, University of Texas Health Science Center, Houston, Texas, USA
| | - Rabeha Noor
- Epilepsy Monitoring Unit, Memorial Hermann Houston Medical Center, Houston, Texas, USA
| | - John C Mosher
- Texas Institute of Restorative Neurotechnologies, University of Texas Health Science Center, Houston, Texas, USA
| | - Nitin Tandon
- Texas Institute of Restorative Neurotechnologies, University of Texas Health Science Center, Houston, Texas, USA
- Department of Neurosurgery, University of Texas Health Science Center, School of Public Health, Houston, Texas, USA
| | - Samden D Lhatoo
- Texas Institute of Restorative Neurotechnologies, University of Texas Health Science Center, Houston, Texas, USA
| | - Nuria Lacuey
- Texas Institute of Restorative Neurotechnologies, University of Texas Health Science Center, Houston, Texas, USA
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10
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Luettich A, Sievers C, Alfaro Almagro F, Allen M, Jbabdi S, Smith SM, Pattinson KTS. Functional connectivity between interoceptive brain regions is associated with distinct health-related domains: A population-based neuroimaging study. Hum Brain Mapp 2023; 44:3210-3221. [PMID: 36939141 PMCID: PMC10171512 DOI: 10.1002/hbm.26275] [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] [Received: 09/02/2022] [Revised: 02/08/2023] [Accepted: 02/27/2023] [Indexed: 03/21/2023] Open
Abstract
Interoception is the sensation, perception, and integration of signals from within the body. It has been associated with a broad range of physiological and psychological processes. Further, interoceptive variables are related to specific regions and networks in the human brain. However, it is not clear whether or how these networks relate empirically to different domains of physiological and psychological health at the population level. We analysed a data set of 19,020 individuals (10,055 females, 8965 males; mean age: 63 years, age range: 45-81 years), who have participated in the UK Biobank Study, a very large-scale prospective epidemiological health study. Using canonical correlation analysis (CCA), allowing for the examination of associations between two sets of variables, we related the functional connectome of brain regions implicated in interoception to a selection of nonimaging health and lifestyle related phenotypes, exploring their relationship within modes of population co-variation. In one integrated and data driven analysis, we obtained four statistically significant modes. Modes could be categorised into domains of arousal and affect and cardiovascular health, respiratory health, body mass, and subjective health (all p < .0001) and were meaningfully associated with distinct neural circuits. Circuits represent specific neural "fingerprints" of functional domains and set the scope for future studies on the neurobiology of interoceptive involvement in different lifestyle and health-related phenotypes. Therefore, our research contributes to the conceptualisation of interoception and may lead to a better understanding of co-morbid conditions in the light of shared interoceptive structures.
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Affiliation(s)
- Alexander Luettich
- Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
- Wellcome Centre for Integrative NeuroimagingUniversity of OxfordOxfordUK
| | - Carolin Sievers
- Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
- Wellcome Centre for Integrative NeuroimagingUniversity of OxfordOxfordUK
| | - Fidel Alfaro Almagro
- Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
- Wellcome Centre for Integrative NeuroimagingUniversity of OxfordOxfordUK
| | - Micah Allen
- Center of Functionally Integrative NeuroscienceAarhus UniversityAarhusDenmark
- Aarhus Institute of Advanced StudiesAarhus UniversityAarhusDenmark
- Cambridge PsychiatryUniversity of CambridgeCambridgeUK
| | - Saad Jbabdi
- Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
- Wellcome Centre for Integrative NeuroimagingUniversity of OxfordOxfordUK
| | - Stephen M. Smith
- Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
- Wellcome Centre for Integrative NeuroimagingUniversity of OxfordOxfordUK
| | - Kyle T. S. Pattinson
- Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
- Wellcome Centre for Integrative NeuroimagingUniversity of OxfordOxfordUK
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11
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Kinkead R, Ambrozio-Marques D, Fournier S, Gagnon M, Guay LM. Estrogens, age, and, neonatal stress: panic disorders and novel views on the contribution of non-medullary structures to respiratory control and CO 2 responses. Front Physiol 2023; 14:1183933. [PMID: 37265841 PMCID: PMC10229816 DOI: 10.3389/fphys.2023.1183933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 04/21/2023] [Indexed: 06/03/2023] Open
Abstract
CO2 is a fundamental component of living matter. This chemical signal requires close monitoring to ensure proper match between metabolic production and elimination by lung ventilation. Besides ventilatory adjustments, CO2 can also trigger innate behavioral and physiological responses associated with fear and escape but the changes in brain CO2/pH required to induce ventilatory adjustments are generally lower than those evoking fear and escape. However, for patients suffering from panic disorder (PD), the thresholds for CO2-evoked hyperventilation, fear and escape are reduced and the magnitude of those reactions are excessive. To explain these clinical observations, Klein proposed the false suffocation alarm hypothesis which states that many spontaneous panics occur when the brain's suffocation monitor erroneously signals a lack of useful air, thereby maladaptively triggering an evolved suffocation alarm system. After 30 years of basic and clinical research, it is now well established that anomalies in respiratory control (including the CO2 sensing system) are key to PD. Here, we explore how a stress-related affective disorder such as PD can disrupt respiratory control. We discuss rodent models of PD as the concepts emerging from this research has influenced our comprehension of the CO2 chemosensitivity network, especially structure that are not located in the medulla, and how factors such as stress and biological sex modulate its functionality. Thus, elucidating why hormonal fluctuations can lead to excessive responsiveness to CO2 offers a unique opportunity to gain insights into the neuroendocrine mechanisms regulating this key aspect of respiratory control and the pathophysiology of respiratory manifestations of PD.
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12
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Legouhy A, Allen LA, Vos SB, Oliveira JFA, Kassinopoulos M, Winston GP, Duncan JS, Ogren JA, Scott C, Kumar R, Lhatoo SD, Thom M, Lemieux L, Harper RM, Zhang H, Diehl B. Volumetric and microstructural abnormalities of the amygdala in focal epilepsy with varied levels of SUDEP risk. Epilepsy Res 2023; 192:107139. [PMID: 37068421 DOI: 10.1016/j.eplepsyres.2023.107139] [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] [Received: 10/24/2022] [Revised: 02/24/2023] [Accepted: 04/06/2023] [Indexed: 04/19/2023]
Abstract
Although the mechanisms of sudden unexpected death in epilepsy (SUDEP) are not yet well understood, generalised- or focal-to-bilateral tonic-clonic seizures (TCS) are a major risk factor. Previous studies highlighted alterations in structures linked to cardio-respiratory regulation; one structure, the amygdala, was enlarged in people at high risk of SUDEP and those who subsequently died. We investigated volume changes and the microstructure of the amygdala in people with epilepsy at varied risk for SUDEP since that structure can play a key role in triggering apnea and mediating blood pressure. The study included 53 healthy subjects and 143 patients with epilepsy, the latter separated into two groups according to whether TCS occur in years before scan. We used amygdala volumetry, derived from structural MRI, and tissue microstructure, derived from diffusion MRI, to identify differences between the groups. The diffusion metrics were obtained by fitting diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) models. The analyses were performed at the whole amygdala level and at the scale of amygdaloid nuclei. Patients with epilepsy showed larger amygdala volumes and lower neurite density indices (NDI) than healthy subjects; the left amygdala volumes were especially enhanced. Microstructural changes, reflected by NDI differences, were more prominent on the left side and localized in the lateral, basal, central, accessory basal and paralaminar amygdala nuclei; basolateral NDI lowering appeared bilaterally. No significant microstructural differences appeared between epilepsy patients with and without current TCS. The central amygdala nuclei, with prominent interactions from surrounding nuclei of that structure, project to cardiovascular regions and respiratory phase switching areas of the parabrachial pons, as well as to the periaqueductal gray. Consequently, they have the potential to modify blood pressure and heart rate, and induce sustained apnea or apneusis. The findings here suggest that lowered NDI, indicative of reduced dendritic density, could reflect an impaired structural organization influencing descending inputs that modulate vital respiratory timing and drive sites and areas critical for blood pressure control.
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Affiliation(s)
- Antoine Legouhy
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK; Centre for Medical Image Computing, Department of Computer Science, University College London, London, UK.
| | - Luke A Allen
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK; Epilepsy Society MRI Unit, Chalfont St Peter, Buckinghamshire, UK; The Center for SUDEP Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Sjoerd B Vos
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK; Centre for Medical Image Computing, Department of Computer Science, University College London, London, UK; Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, UCL, London, UK; Centre for Microscopy, Characterisation, and Analysis, The University of Western Australia, Nedlands, Australia
| | - Joana F A Oliveira
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Michalis Kassinopoulos
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK; Epilepsy Society MRI Unit, Chalfont St Peter, Buckinghamshire, UK
| | - Gavin P Winston
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK; Epilepsy Society MRI Unit, Chalfont St Peter, Buckinghamshire, UK; Division of Neurology, Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - John S Duncan
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK; Epilepsy Society MRI Unit, Chalfont St Peter, Buckinghamshire, UK
| | - Jennifer A Ogren
- The Center for SUDEP Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA; Brain Research Institute, UCLA, Los Angeles, CA, USA
| | - Catherine Scott
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK; The Center for SUDEP Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Rajesh Kumar
- Brain Research Institute, UCLA, Los Angeles, CA, USA; Department of Anesthesiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Department of Radiological Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Department of Bioengineering, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Samden D Lhatoo
- Department of Neurology, University of Texas Health Sciences Center at Houston, Houston, TX, USA
| | - Maria Thom
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Louis Lemieux
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK; Epilepsy Society MRI Unit, Chalfont St Peter, Buckinghamshire, UK
| | - Ronald M Harper
- The Center for SUDEP Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA; Brain Research Institute, UCLA, Los Angeles, CA, USA; Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Hui Zhang
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, UK
| | - Beate Diehl
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK; Epilepsy Society MRI Unit, Chalfont St Peter, Buckinghamshire, UK; The Center for SUDEP Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
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13
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Legouhy A, Allen LA, Vos SB, Oliveira JFA, Kassinopoulos M, Winston GP, Duncan JS, Ogren JA, Scott C, Kumar R, Lhatoo SD, Thom M, Lemieux L, Harper RM, Zhang H, Diehl B. Volumetric and microstructural abnormalities of the amygdala in focal epilepsy with varied levels of SUDEP risk. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.03.13.23287045. [PMID: 36993394 PMCID: PMC10055456 DOI: 10.1101/2023.03.13.23287045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Although the mechanisms of sudden unexpected death in epilepsy (SUDEP) are not yet well understood, generalised- or focal-to-bilateral tonic-clonic seizures (TCS) are a major risk factor. Previous studies highlighted alterations in structures linked to cardio-respiratory regulation; one structure, the amygdala, was enlarged in people at high risk of SUDEP and those who subsequently died. We investigated volume changes and the microstructure of the amygdala in people with epilepsy at varied risk for SUDEP since that structure can play a key role in triggering apnea and mediating blood pressure. The study included 53 healthy subjects and 143 patients with epilepsy, the latter separated into two groups according to whether TCS occur in years before scan. We used amygdala volumetry, derived from structural MRI, and tissue microstructure, derived from diffusion MRI, to identify differences between the groups. The diffusion metrics were obtained by fitting diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) models. The analyses were performed at the whole amygdala level and at the scale of amygdaloid nuclei. Patients with epilepsy showed larger amygdala volumes and lower neurite density indices (NDI) than healthy subjects; the left amygdala volumes were especially enhanced. Microstructural changes, reflected by NDI differences, were more prominent on the left side and localized in the lateral, basal, central, accessory basal and paralaminar amygdala nuclei; basolateral NDI lowering appeared bilaterally. No significant microstructural differences appeared between epilepsy patients with and without current TCS. The central amygdala nuclei, with prominent interactions from surrounding nuclei of that structure, project to cardiovascular regions and respiratory phase switching areas of the parabrachial pons, as well as to the periaqueductal gray. Consequently, they have the potential to modify blood pressure and heart rate, and induce sustained apnea or apneusis. The findings here suggest that lowered NDI, indicative of reduced dendritic density, could reflect an impaired structural organization influencing descending inputs that modulate vital respiratory timing and drive sites and areas critical for blood pressure control.
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Affiliation(s)
- Antoine Legouhy
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, UK
| | - Luke A Allen
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
- Epilepsy Society MRI Unit, Chalfont St Peter, Buckinghamshire, UK
- The Center for SUDEP Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Sjoerd B Vos
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, UK
- Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, UCL, London, UK
- Centre for Microscopy, Characterisation, and Analysis, The University of Western Australia, Nedlands, Australia
| | - Joana F A Oliveira
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Michalis Kassinopoulos
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
- Epilepsy Society MRI Unit, Chalfont St Peter, Buckinghamshire, UK
| | - Gavin P Winston
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
- Epilepsy Society MRI Unit, Chalfont St Peter, Buckinghamshire, UK
- Division of Neurology, Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - John S Duncan
- Epilepsy Society MRI Unit, Chalfont St Peter, Buckinghamshire, UK
| | - Jennifer A Ogren
- The Center for SUDEP Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
- Brain Research Institute, UCLA, Los Angeles, CA, USA
| | - Catherine Scott
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
- The Center for SUDEP Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Rajesh Kumar
- The Center for SUDEP Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
- Department of Anesthesiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
- Department of Radiological Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
- Department of Bioengineering, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Samden D Lhatoo
- Department of Neurology, University of Texas Health Sciences Center at Houston, Houston, TX, USA
| | - Maria Thom
- Department of Neuropathology, Institute of Neurology, University College London, London, UK
| | - Louis Lemieux
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
- Epilepsy Society MRI Unit, Chalfont St Peter, Buckinghamshire, UK
| | - Ronald M Harper
- The Center for SUDEP Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
- Brain Research Institute, UCLA, Los Angeles, CA, USA
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Hui Zhang
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, UK
| | - Beate Diehl
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
- Epilepsy Society MRI Unit, Chalfont St Peter, Buckinghamshire, UK
- The Center for SUDEP Research, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
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14
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Faingold CL, Feng HJ. A unified hypothesis of SUDEP: Seizure-induced respiratory depression induced by adenosine may lead to SUDEP but can be prevented by autoresuscitation and other restorative respiratory response mechanisms mediated by the action of serotonin on the periaqueductal gray. Epilepsia 2023; 64:779-796. [PMID: 36715572 PMCID: PMC10673689 DOI: 10.1111/epi.17521] [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] [Received: 10/07/2022] [Revised: 01/20/2023] [Accepted: 01/27/2023] [Indexed: 01/31/2023]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is a major cause of death in people with epilepsy (PWE). Postictal apnea leading to cardiac arrest is the most common sequence of terminal events in witnessed cases of SUDEP, and postconvulsive central apnea has been proposed as a potential biomarker of SUDEP susceptibility. Research in SUDEP animal models has led to the serotonin and adenosine hypotheses of SUDEP. These neurotransmitters influence respiration, seizures, and lethality in animal models of SUDEP, and are implicated in human SUDEP cases. Adenosine released during seizures is proposed to be an important seizure termination mechanism. However, adenosine also depresses respiration, and this effect is mediated, in part, by inhibition of neuronal activity in subcortical structures that modulate respiration, including the periaqueductal gray (PAG). Drugs that enhance the action of adenosine increase postictal death in SUDEP models. Serotonin is also released during seizures, but enhances respiration in response to an elevated carbon dioxide level, which often occurs postictally. This effect of serotonin can potentially compensate, in part, for the adenosine-mediated respiratory depression, acting to facilitate autoresuscitation and other restorative respiratory response mechanisms. A number of drugs that enhance the action of serotonin prevent postictal death in several SUDEP models and reduce postictal respiratory depression in PWE. This effect of serotonergic drugs may be mediated, in part, by actions on brainstem sites that modulate respiration, including the PAG. Enhanced activity in the PAG increases respiration in response to hypoxia and other exigent conditions and can be activated by electrical stimulation. Thus, we propose the unifying hypothesis that seizure-induced adenosine release leads to respiratory depression. This can be reversed by serotonergic action on autoresuscitation and other restorative respiratory responses acting, in part, via the PAG. Therefore, we hypothesize that serotonergic or direct activation of this brainstem site may be a useful approach for SUDEP prevention.
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Affiliation(s)
- Carl L Faingold
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois, USA
- Department of Neurology, Southern Illinois University School of Medicine, Springfield, Illinois, USA
| | - Hua-Jun Feng
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Anesthesia, Harvard Medical School, Boston, Massachusetts, USA
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15
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Sun X, Lv Y, Lin J. The mechanism of sudden unexpected death in epilepsy: A mini review. Front Neurol 2023; 14:1137182. [PMID: 36815002 PMCID: PMC9939452 DOI: 10.3389/fneur.2023.1137182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 01/20/2023] [Indexed: 02/08/2023] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is defined as a sudden, unexpected, non-traumatic, non-drowning death in a person with epilepsy. SUDEP is generally considered to result from seizure-related cardiac dysfunction, respiratory depression, autonomic nervous dysfunction, or brain dysfunction. Frequency of generalized tonic clonic seizures (GTCS), prone posture, and refractory epilepsy are considered risk factors. SUDEP has also been associated with inherited cardiac ion channel disease and severe obstructive sleep apnea. Most previous studies of SUDEP mechanisms have focused on cardiac and respiratory dysfunction and imbalance of the neural regulatory system. Cardiac-related mechanisms include reduction in heart rate variability and prolongation of QT interval, which can lead to arrhythmias. Laryngospasm and amygdala activation may cause obstructive and central apnea, respectively. Neural mechanisms include impairment of 5-HT and adenosine neuromodulation. The research to date regarding molecular mechanisms of SUDEP is relatively limited. Most studies have focused on p-glycoprotein, catecholamines, potassium channels, and the renin-angiotensin system, all of which affect cardiac and respiratory function.
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Affiliation(s)
- Xinyi Sun
- School of Basic Medical Sciences, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Yehui Lv
- School of Basic Medical Sciences, Shanghai University of Medicine and Health Sciences, Shanghai, China,Institute of Wound Prevention and Treatment, Shanghai University of Medicine and Health Sciences, Shanghai, China,*Correspondence: Yehui Lv ✉
| | - Jian Lin
- Institute of Wound Prevention and Treatment, Shanghai University of Medicine and Health Sciences, Shanghai, China,Chongming Hospital Affiliated to Shanghai University of Medicine and Health Sciences, Shanghai, China
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16
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Corli G, Tirri M, Arfè R, Marchetti B, Bernardi T, Borsari M, Odoardi S, Mestria S, Strano-Rossi S, Neri M, Gaudio RM, Bilel S, Marti M. Pharmaco-Toxicological Effects of Atypical Synthetic Cathinone Mephtetramine (MTTA) in Mice: Possible Reasons for Its Brief Appearance over NPSs Scene. Brain Sci 2023; 13:brainsci13020161. [PMID: 36831704 PMCID: PMC9954072 DOI: 10.3390/brainsci13020161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/11/2023] [Accepted: 01/16/2023] [Indexed: 01/20/2023] Open
Abstract
Over the last year, NPSs have been steadily on the rise in the illicit drug market. Among these, synthetic cathinones seem to become increasingly popular among young adults, mainly because of their ability to replicate the effects of traditional psychostimulant drugs, such as cocaine, MDMA and amphetamines. However, scarce data are available about the in vivo pharmaco-toxicology of these new substances. To this end, this study focused on evaluation of effects induced by repeated administration of mephtetramine (MTTA 0.1-30 mg/kg i.p.) in mice. This atypical cathinone highlighted a sensorial (inhibition of visual and acoustic reflexes) and transient physiological parameter (decrease in breath rate and temperature) change in mice. Regarding motor activity, both a dose-dependent increase (accelerod test) and biphasic effect (drag and mobility time test) have been shown. In addition, blood and urine samples have been analysed to enrich the experimental featuring of the present study with reference to evaluation of potential toxicity related to consumption of MTTA. The latter analysis has particularly revealed important changes in blood cells count and blood and urine physicochemical profile after repeated treatment with this atypical cathinone. Moreover, MTTA induced histological changes in heart, kidney and liver samples, emphasizing its potential toxicity.
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Affiliation(s)
- Giorgia Corli
- Department of Translational Medicine, Section of Legal Medicine, LTTA Center and University Center of Gender Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Micaela Tirri
- Department of Translational Medicine, Section of Legal Medicine, LTTA Center and University Center of Gender Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Raffaella Arfè
- Department of Translational Medicine, Section of Legal Medicine, LTTA Center and University Center of Gender Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Beatrice Marchetti
- Department of Translational Medicine, Section of Legal Medicine, LTTA Center and University Center of Gender Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Tatiana Bernardi
- Department of Environmental Sciences and Prevention, University of Ferrara, 44121 Ferrara, Italy
| | - Martina Borsari
- Department of Translational Medicine, Section of Legal Medicine, LTTA Center and University Center of Gender Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Sara Odoardi
- Forensic Toxicology Laboratory, Department of Health Surveillance and Bioethics, Università Cattolica del Sacro Cuore F. Policlinico Gemelli IRCCS, 00169 Rome, Italy
| | - Serena Mestria
- Forensic Toxicology Laboratory, Department of Health Surveillance and Bioethics, Università Cattolica del Sacro Cuore F. Policlinico Gemelli IRCCS, 00169 Rome, Italy
| | - Sabina Strano-Rossi
- Forensic Toxicology Laboratory, Department of Health Surveillance and Bioethics, Università Cattolica del Sacro Cuore F. Policlinico Gemelli IRCCS, 00169 Rome, Italy
| | - Margherita Neri
- Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Rosa Maria Gaudio
- Department of Translational Medicine, Section of Legal Medicine, LTTA Center and University Center of Gender Medicine, University of Ferrara, 44121 Ferrara, Italy
- University Center for Studies on Gender Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Sabrine Bilel
- Department of Translational Medicine, Section of Legal Medicine, LTTA Center and University Center of Gender Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Matteo Marti
- Department of Translational Medicine, Section of Legal Medicine, LTTA Center and University Center of Gender Medicine, University of Ferrara, 44121 Ferrara, Italy
- University Center for Studies on Gender Medicine, University of Ferrara, 44121 Ferrara, Italy
- Collaborative Center for the Italian National Early Warning System, Department of Anti-Drug Policies, Presidency of the Council of Ministers, 00186 Rome, Italy
- Correspondence:
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17
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Bauer J, Devinsky O, Rothermel M, Koch H. Autonomic dysfunction in epilepsy mouse models with implications for SUDEP research. Front Neurol 2023; 13:1040648. [PMID: 36686527 PMCID: PMC9853197 DOI: 10.3389/fneur.2022.1040648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 12/12/2022] [Indexed: 01/09/2023] Open
Abstract
Epilepsy has a high prevalence and can severely impair quality of life and increase the risk of premature death. Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in drug-resistant epilepsy and most often results from respiratory and cardiac impairments due to brainstem dysfunction. Epileptic activity can spread widely, influencing neuronal activity in regions outside the epileptic network. The brainstem controls cardiorespiratory activity and arousal and reciprocally connects to cortical, diencephalic, and spinal cord areas. Epileptic activity can propagate trans-synaptically or via spreading depression (SD) to alter brainstem functions and cause cardiorespiratory dysfunction. The mechanisms by which seizures propagate to or otherwise impair brainstem function and trigger the cascading effects that cause SUDEP are poorly understood. We review insights from mouse models combined with new techniques to understand the pathophysiology of epilepsy and SUDEP. These techniques include in vivo, ex vivo, invasive and non-invasive methods in anesthetized and awake mice. Optogenetics combined with electrophysiological and optical manipulation and recording methods offer unique opportunities to study neuronal mechanisms under normal conditions, during and after non-fatal seizures, and in SUDEP. These combined approaches can advance our understanding of brainstem pathophysiology associated with seizures and SUDEP and may suggest strategies to prevent SUDEP.
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Affiliation(s)
- Jennifer Bauer
- Department of Epileptology and Neurology, RWTH Aachen University, Aachen, Germany,Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Orrin Devinsky
- Departments of Neurology, Neurosurgery and Psychiatry, NYU Langone School of Medicine, New York, NY, United States
| | - Markus Rothermel
- Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Henner Koch
- Department of Epileptology and Neurology, RWTH Aachen University, Aachen, Germany,*Correspondence: Henner Koch ✉
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18
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Buchanan GF. ABCDEF…SUDEP: Action Potential Barrage in (Superior) Colliculus Causes (Spreading) Depolarization Leading to Epilepsy Fatality. Epilepsy Curr 2023; 23:53-55. [PMID: 36923334 PMCID: PMC10009128 DOI: 10.1177/15357597221136962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Hyperexcitable Superior Colliculus and Fatal Brainstem Spreading Depolarization in a Model of Sudden Unexpected Death in Epilepsy Cain SM, Bernier LP, Zhang Y, Yung AC, Kass J, Bohnet B, Yang Y, Gopaul R, Kozlowski P, MacVicar BA, Snutch TP. Brain Commun. 2022;4(2):fcac006. doi:10.1093/braincomms/fcac006 Cardiorespiratory arrest and death in mouse models of sudden unexpected death in epilepsy occur when spreading depolarization (SD) is triggered by cortical seizures and then propagates to the brainstem. However, the critical brain regions and the specific changes required to allow SD to propagate to the brainstem under the relatively rare circumstances leading to a fatal seizure are unknown. We previously found that following cortical seizure-inducing electrical stimulation, SD could occur in both the superior and inferior colliculi in Cacna1aS218L mice, but was never observed in wild-type animals or following non-seizure-inducing stimuli in Cacna1aS218L mice. Here, we show that optogenetic stimulation of the superior/inferior colliculi in Cacna1aS218L mice induces severe seizures, and resulting SD in the superior/inferior colliculi that propagates to the brainstem and correlates with the respiratory arrest followed by cardiac arrest. Further, we show that neurons of the superior colliculus in Cacna1aS218L mice exhibit hyperexcitable properties that we propose underlie a distinct susceptibility to SD. Our data suggest that the susceptibility of the superior colliculus to elicit fatal SD is a result of either genetic or seizure-related alterations within the superior colliculus that may involve changes to structure, connectivity and/or excitability.
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Affiliation(s)
- Gordon F Buchanan
- Department of Neurology, University of Iowa Roy J and Lucille A Carver College of Medicine
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19
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Respiratory influence on brain dynamics: the preponderant role of the nasal pathway and deep slow regime. Pflugers Arch 2023; 475:23-35. [PMID: 35768698 DOI: 10.1007/s00424-022-02722-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 06/17/2022] [Accepted: 06/21/2022] [Indexed: 01/31/2023]
Abstract
As a possible body signal influencing brain dynamics, respiration is fundamental for perception, cognition, and emotion. The olfactory system has recently acquired its credentials by proving to be crucial in the transmission of respiratory influence on the brain via the sensitivity to nasal airflow of its receptor cells. Here, we present recent findings evidencing respiration-related activities in the brain. Then, we review the data explaining the fact that breathing is (i) nasal and (ii) being slow and deep is crucial in its ability to stimulate the olfactory system and consequently influence the brain. In conclusion, we propose a possible scenario explaining how this optimal respiratory regime can promote changes in brain dynamics of an olfacto-limbic-respiratory circuit, providing a possibility to induce calm and relaxation by coordinating breathing regime and brain state.
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20
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Mulkey DK, Milla BM. Perspectives on the basis of seizure-induced respiratory dysfunction. Front Neural Circuits 2022; 16:1033756. [PMID: 36605420 PMCID: PMC9807672 DOI: 10.3389/fncir.2022.1033756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 11/28/2022] [Indexed: 12/24/2022] Open
Abstract
Epilepsy is an umbrella term used to define a wide variety of seizure disorders and sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in epilepsy. Although some SUDEP risk factors have been identified, it remains largely unpredictable, and underlying mechanisms remain poorly understood. Most seizures start in the cortex, but the high mortality rate associated with certain types of epilepsy indicates brainstem involvement. Therefore, to help understand SUDEP we discuss mechanisms by which seizure activity propagates to the brainstem. Specifically, we highlight clinical and pre-clinical evidence suggesting how seizure activation of: (i) descending inhibitory drive or (ii) spreading depolarization might contribute to brainstem dysfunction. Furthermore, since epilepsy is a highly heterogenous disorder, we also considered factors expected to favor or oppose mechanisms of seizure propagation. We also consider whether epilepsy-associated genetic variants directly impact brainstem function. Because respiratory failure is a leading cause of SUDEP, our discussion of brainstem dysfunction focuses on respiratory control.
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Affiliation(s)
- Daniel K. Mulkey
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
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21
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Gu B, Adeli H. Toward automated prediction of sudden unexpected death in epilepsy. Rev Neurosci 2022; 33:877-887. [PMID: 35619127 DOI: 10.1515/revneuro-2022-0024] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 04/19/2022] [Indexed: 12/14/2022]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is a devastating yet overlooked complication of epilepsy. The rare and complex nature of SUDEP makes it challenging to study. No prediction or prevention of SUDEP is currently available in a clinical setting. In the past decade, significant advances have been made in our knowledge of the pathophysiologic cascades that lead to SUDEP. In particular, studies of brain, heart, and respiratory functions in both human patients at the epilepsy monitoring unit and animal models during fatal seizures provide critical information to integrate computational tools for SUDEP prediction. The rapid advances in automated seizure detection and prediction algorithms provide a fundamental framework for their adaption in predicting SUDEP. If a SUDEP can be predicted, then there will be a potential for medical intervention to be administered, either by their caregivers or via an implanted device automatically delivering electrical stimulation or medication, and finally save lives from fatal seizures. This article presents recent developments of SUDEP studies focusing on the pathophysiologic basis of SUDEP and computational implications of machine learning techniques that can be adapted and extended for SUDEP prediction. This article also discusses some novel ideas for SUDEP prediction and rescue including principal component analysis and closed-loop intervention.
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Affiliation(s)
- Bin Gu
- Department of Neuroscience, Ohio State University, Columbus, OH 43210, USA
| | - Hojjat Adeli
- Department of Neuroscience, Ohio State University, Columbus, OH 43210, USA.,Department of Biomedical Informatics, Ohio State University, Columbus, OH 43210, USA
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22
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Schottelkotte KM, Crone SA. Forebrain control of breathing: Anatomy and potential functions. Front Neurol 2022; 13:1041887. [PMID: 36388186 PMCID: PMC9663927 DOI: 10.3389/fneur.2022.1041887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 10/11/2022] [Indexed: 01/25/2023] Open
Abstract
The forebrain plays important roles in many critical functions, including the control of breathing. We propose that the forebrain is important for ensuring that breathing matches current and anticipated behavioral, emotional, and physiological needs. This review will summarize anatomical and functional evidence implicating forebrain regions in the control of breathing. These regions include the cerebral cortex, extended amygdala, hippocampus, hypothalamus, and thalamus. We will also point out areas where additional research is needed to better understand the specific roles of forebrain regions in the control of breathing.
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Affiliation(s)
- Karl M. Schottelkotte
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Steven A. Crone
- Division of Pediatric Neurosurgery, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, OH, United States
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23
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Ogren JA, Allen LA, Roy B, Diehl B, Stern JM, Eliashiv DS, Lhatoo SD, Harper RM, Kumar R. Regional variation in brain tissue texture in patients with tonic-clonic seizures. PLoS One 2022; 17:e0274514. [PMID: 36137154 PMCID: PMC9499268 DOI: 10.1371/journal.pone.0274514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 08/28/2022] [Indexed: 11/19/2022] Open
Abstract
Patients with epilepsy, who later succumb to sudden unexpected death, show altered brain tissue volumes in selected regions. It is unclear whether the alterations in brain tissue volume represent changes in neurons or glial properties, since volumetric procedures have limited sensitivity to assess the source of volume changes (e.g., neuronal loss or glial cell swelling). We assessed a measure, entropy, which can determine tissue homogeneity by evaluating tissue randomness, and thus, shows tissue integrity; the measure is easily calculated from T1-weighted images. T1-weighted images were collected with a 3.0-Tesla MRI from 53 patients with tonic-clonic (TC) seizures and 53 healthy controls; images were bias-corrected, entropy maps calculated, normalized to a common space, smoothed, and compared between groups (TC patients and controls using ANCOVA; covariates, age and sex; SPM12, family-wise error correction for multiple comparisons, p<0.01). Decreased entropy, indicative of increased tissue homogeneity, appeared in major autonomic (ventromedial prefrontal cortex, hippocampus, dorsal and ventral medulla, deep cerebellar nuclei), motor (sensory and motor cortex), or both motor and autonomic regulatory sites (basal-ganglia, ventral-basal cerebellum), and external surfaces of the pons. The anterior and posterior thalamus and midbrain also showed entropy declines. Only a few isolated regions showed increased entropy. Among the spared autonomic regions was the anterior cingulate and anterior insula; the posterior insula and cingulate were, however, affected. The entropy alterations overlapped areas of tissue changes found earlier with volumetric measures, but were more extensive, and indicate widespread injury to tissue within critical autonomic and breathing regulatory areas, as well as prominent damage to more-rostral sites that exert influences on both breathing and cardiovascular regulation. The entropy measures provide easily-collected supplementary information using only T1-weighted images, showing aspects of tissue integrity other than volume change that are important for assessing function.
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Affiliation(s)
- Jennifer A. Ogren
- Department of Neurobiology, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Luke A. Allen
- Department of Clinical and Experimental Epilepsy, University College London Institute of Neurology, London, United Kingdom
| | - Bhaswati Roy
- Department of Anesthesiology and Perioperative Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Beate Diehl
- Department of Clinical and Experimental Epilepsy, University College London Institute of Neurology, London, United Kingdom
| | - John M. Stern
- Department of Neurology, University of California Los Angeles, Los Angeles, California, United States of America
| | - Dawn S. Eliashiv
- Department of Neurology, University of California Los Angeles, Los Angeles, California, United States of America
| | - Samden D. Lhatoo
- Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Ronald M. Harper
- Department of Neurobiology, University of California at Los Angeles, Los Angeles, California, United States of America
- Brain Research Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Rajesh Kumar
- Department of Anesthesiology and Perioperative Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Brain Research Institute, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Radiological Sciences, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, United States of America
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24
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Wenker IC, Boscia AR, Lewis C, Tariq A, Miralles R, Hanflink JC, Saraf P, Patel MK. Forebrain epileptiform activity is not required for seizure-induced apnea in a mouse model of Scn8a epilepsy. Front Neural Circuits 2022; 16:1002013. [PMID: 36160949 PMCID: PMC9490431 DOI: 10.3389/fncir.2022.1002013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 08/19/2022] [Indexed: 11/24/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) accounts for the deaths of 8-17% of patients with epilepsy. Although the mechanisms of SUDEP are essentially unknown, one proposed mechanism is respiratory arrest initiated by a convulsive seizure. In mice, we have previously observed that extended apnea occurs during the tonic phase of seizures. Although often survived, tonic seizures became fatal when breathing did not immediately recover postictally. We also found that respiratory muscles were tonically contracted during the apnea, suggesting that muscle contraction could be the cause of apnea. In the present study, we tested the hypothesis that pyramidal neurons of the motor cortex drive motor units during the tonic phase, which produces apnea. Mice harboring the patient-derived N1768D point mutation of an Scn8a allele were crossed with transgenic mice such that inhibitory Designer Receptors Exclusively Activated by Designer Drugs (DREADD) receptors were selectively expressed in excitatory forebrain neurons. We then triggered audiogenic and hippocampal (HC) stimulated seizures under control conditions and when excitatory forebrain neurons were inhibited with the synthetic ligand Clozapine-N-Oxide (CNO). We found that inhibition with CNO was sufficient to increase seizure threshold of HC stimulated, but not audiogenic, seizures. In addition, regardless of seizure type, CNO nearly eliminated epileptiform activity that occurred proximal to the tonic phase; however, the seizure behaviors, notably the tonic phase and concomitant apnea, were unchanged. We interpret these results to indicate that while cortical neurons are likely critical for epileptogenesis and seizure initiation, the behavioral manifestations of tonic seizures are generated by neural circuitry in the mid- and/or hindbrain.
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25
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Patodia S, Lim YM, Chung F, Stylianou I, El Hachami H, Thom M. Cortical neuronal hypertrophy and mTOR pathway activation in CAN regions in SUDEP. Epilepsia 2022; 63:2427-2438. [PMID: 35716147 PMCID: PMC9795893 DOI: 10.1111/epi.17335] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 06/14/2022] [Accepted: 06/15/2022] [Indexed: 12/31/2022]
Abstract
OBJECTIVES Dysfunctional connectivity and preexisting structural abnormalities of central autonomic network (CAN) regions have been shown on magnetic resonance imaging (MRI) in sudden unexpected death in epilepsy (SUDEP) and may be mechanistically relevant. In a previous postmortem study we reported increased microglia in CAN regions, including the superior temporal gyrus (STG) in SUDEP. In this current study we investigated mammalian target of rapamycin (mTOR) pathway activation and neuronal c-Fos activation in CAN regions in SUDEP compared to control groups. METHODS In a series of 59 postmortem cases (SUDEP, n = 26; epilepsy controls [EPCs], n = 14; and nonepilepsy controls [NECs], n = 19), we quantified pS6-240/4, pS6-235/6 (markers of mTOR activation) and c-Fos neuronal densities and labeling index in the STG, anterior cingulate, insula, frontobasal, and pulvinar regions using immunohistochemistry with whole-slide automated image analysis. RESULTS Significantly more pS6-positive neurons were present in the STG in cases with a history of recent seizures prior to death and also in SUDEP compared to other cause of death groups. No differences were noted for c-Fos neuronal labeling in any region between cause of death groups. Cortical neuronal hypertrophy in the STG was observed in some SUDEP cases and associated with pS6-240/4 expression. pS6-235/6 highlighted neuronal intranuclear inclusions, mainly in SUDEP cases and in the STG region. SIGNIFICANCE Neuronal labeling for pS6 in the STG correlated with both seizure activity in the period prior to death and SUDEP. Further investigations are required to explore the significance of this region in terms of autonomic network dysfunction that may increase the vulnerability for SUDEP.
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Affiliation(s)
- Smriti Patodia
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
| | - Yau Mun Lim
- Department of NeurodegenerationUCL Queen Square Institute of NeurologyLondonUK
| | - Freda Chung
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
| | - Irene Stylianou
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
| | - Hanaa El Hachami
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
| | - Maria Thom
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
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26
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Joyal KG, Kreitlow BL, Buchanan GF. The role of sleep state and time of day in modulating breathing in epilepsy: implications for sudden unexpected death in epilepsy. Front Neural Circuits 2022; 16:983211. [PMID: 36082111 PMCID: PMC9445500 DOI: 10.3389/fncir.2022.983211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 07/25/2022] [Indexed: 11/13/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death among patients with refractory epilepsy. While the exact etiology of SUDEP is unknown, mounting evidence implicates respiratory dysfunction as a precipitating factor in cases of seizure-induced death. Dysregulation of breathing can occur in epilepsy patients during and after seizures as well as interictally, with many epilepsy patients exhibiting sleep-disordered breathing (SDB), such as obstructive sleep apnea (OSA). The majority of SUDEP cases occur during the night, with the victim found prone in or near a bed. As breathing is modulated in both a time-of-day and sleep state-dependent manner, it is relevant to examine the added burden of nocturnal seizures on respiratory function. This review explores the current state of understanding of the relationship between respiratory function, sleep state and time of day, and epilepsy. We highlight sleep as a particularly vulnerable period for individuals with epilepsy and press that this topic warrants further investigation in order to develop therapeutic interventions to mitigate the risk of SUDEP.
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Affiliation(s)
- Katelyn G. Joyal
- Interdisciplinary Graduate Program in Neuroscience, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Benjamin L. Kreitlow
- Interdisciplinary Graduate Program in Neuroscience, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Medical Scientist Training Program, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Gordon F. Buchanan
- Interdisciplinary Graduate Program in Neuroscience, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Medical Scientist Training Program, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- *Correspondence: Gordon F. Buchanan
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Sawada M, Adolphs R, Dlouhy BJ, Jenison RL, Rhone AE, Kovach CK, Greenlee JDW, Howard Iii MA, Oya H. Mapping effective connectivity of human amygdala subdivisions with intracranial stimulation. Nat Commun 2022; 13:4909. [PMID: 35987994 PMCID: PMC9392722 DOI: 10.1038/s41467-022-32644-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Accepted: 08/08/2022] [Indexed: 01/21/2023] Open
Abstract
The primate amygdala is a complex consisting of over a dozen nuclei that have been implicated in a host of cognitive functions, individual differences, and psychiatric illnesses. These functions are implemented through distinct connectivity profiles, which have been documented in animals but remain largely unknown in humans. Here we present results from 25 neurosurgical patients who had concurrent electrical stimulation of the amygdala with intracranial electroencephalography (electrical stimulation tract-tracing; es-TT), or fMRI (electrical stimulation fMRI; es-fMRI), methods providing strong inferences about effective connectivity of amygdala subdivisions with the rest of the brain. We quantified functional connectivity with medial and lateral amygdala, the temporal order of these connections on the timescale of milliseconds, and also detail second-order effective connectivity among the key nodes. These findings provide a uniquely detailed characterization of human amygdala functional connectivity that will inform functional neuroimaging studies in healthy and clinical populations.
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Affiliation(s)
- Masahiro Sawada
- Department of Neurosurgery, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Department of Neurosurgery, Tazuke Kofukai Medical Research Institute and Kitano Hospital, Osaka, Japan
| | - Ralph Adolphs
- Division of Humanities and Social Sciences, California Institute of Technology, Pasadena, CA, USA
| | - Brian J Dlouhy
- Department of Neurosurgery, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
| | - Rick L Jenison
- Department of Neuroscience, University of Wisconsin - Madison, Madison, WI, USA
| | - Ariane E Rhone
- Department of Neurosurgery, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Christopher K Kovach
- Department of Neurosurgery, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Jeremy D W Greenlee
- Department of Neurosurgery, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
| | - Matthew A Howard Iii
- Department of Neurosurgery, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
- Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA, USA
| | - Hiroyuki Oya
- Department of Neurosurgery, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA.
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28
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Collard R, Aziz MC, Rapp K, Cutshall C, Duyvesteyn E, Metcalf CS. Galanin analogs prevent mortality from seizure-induced respiratory arrest in mice. Front Neural Circuits 2022; 16:901334. [PMID: 36051473 PMCID: PMC9425456 DOI: 10.3389/fncir.2022.901334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 07/28/2022] [Indexed: 11/13/2022] Open
Abstract
ObjectiveSudden Unexpected Death in Epilepsy (SUDEP) accounts for 20% of mortality in those with recurrent seizures. While risk factors, monitoring systems, and standard practices are in place, the pathophysiology of SUDEP is still not well understood. Better knowledge of SUDEP and its potential mechanisms of action is crucial to reducing risk in this patient population and developing potential treatment options. Clinical studies and animal models of SUDEP suggest that diminished post-ictal respiratory control may be the dominant mechanism contributing to mortality. Recently, it was demonstrated that the depletion of the neuropeptide galanin in the amygdala occurs in human SUDEP. The amygdala plays a key role in the central integration of respiratory signaling; the depletion of galanin may represent a critical change that predisposes individuals to SUDEP.Materials and methodsTo evaluate the impact of enhancing galaninergic signaling to potentially protect against SUDEP, we studied seizure-induced respiratory arrest (S-IRA) following central (intracerebroventricular, intra-amygdala) and systemic (intraperitoneal, subcutaneous) administration of galanin analogs. Seizure naïve and seizure experienced (fully kindled) mice were tested.ResultsCentral and systemically administered galanin analogs protect against S-IRA in naïve C57Bl/6J mice. Differential efficacy between receptor subtype-selective analogs varied based on the route of administration. Sub-chronic systemic administration at doses that reduced 6 Hz seizures also protected against S-IRA. Acute treatment benefits also extended to fully kindled mice experiencing tonic extension.SignificanceThese data demonstrate that galanin analogs may be protective against post-ictal respiratory collapse.
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Affiliation(s)
- Ryley Collard
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, United States
| | - Miriam C. Aziz
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, United States
| | - Kevin Rapp
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, United States
| | - Connor Cutshall
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, United States
| | - Evalien Duyvesteyn
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, United States
| | - Cameron S. Metcalf
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, United States
- Epilepsy Therapy Screening Program Contract Site, Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, United States
- *Correspondence: Cameron S. Metcalf,
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29
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Abstract
Breathing is a vital rhythmic motor behavior with a surprisingly broad influence on the brain and body. The apparent simplicity of breathing belies a complex neural control system, the breathing central pattern generator (bCPG), that exhibits diverse operational modes to regulate gas exchange and coordinate breathing with an array of behaviors. In this review, we focus on selected advances in our understanding of the bCPG. At the core of the bCPG is the preBötzinger complex (preBötC), which drives inspiratory rhythm via an unexpectedly sophisticated emergent mechanism. Synchronization dynamics underlying preBötC rhythmogenesis imbue the system with robustness and lability. These dynamics are modulated by inputs from throughout the brain and generate rhythmic, patterned activity that is widely distributed. The connectivity and an emerging literature support a link between breathing, emotion, and cognition that is becoming experimentally tractable. These advances bring great potential for elucidating function and dysfunction in breathing and other mammalian neural circuits.
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Affiliation(s)
- Sufyan Ashhad
- Department of Neurobiology, University of California at Los Angeles, Los Angeles, California, USA;
| | - Kaiwen Kam
- Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA
| | | | - Jack L Feldman
- Department of Neurobiology, University of California at Los Angeles, Los Angeles, California, USA;
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30
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Xia M, Owen B, Chiang J, Levitt A, Preisinger K, Yan WW, Huffman R, Nobis WP. Disruption of Synaptic Transmission in the Bed Nucleus of the Stria Terminalis Reduces Seizure-Induced Death in DBA/1 Mice and Alters Brainstem E/I Balance. ASN Neuro 2022; 14:17590914221103188. [PMID: 35611439 PMCID: PMC9136462 DOI: 10.1177/17590914221103188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in refractory epilepsy patients. Accumulating evidence from recent human studies and animal models suggests that seizure-related respiratory arrest may be important for initiating cardiorespiratory arrest and death. Prior evidence suggests that apnea onset can coincide with seizure spread to the amygdala and that stimulation of the amygdala can reliably induce apneas in epilepsy patients, potentially implicating amygdalar regions in seizure-related respiratory arrest and subsequent postictal hypoventilation and cardiorespiratory death. This study aimed to determine if an extended amygdalar structure, the dorsal bed nucleus of the stria terminalis (dBNST), is involved in seizure-induced respiratory arrest (S-IRA) and death using DBA/1 mice, a mouse strain which has audiogenic seizures (AGS) and a high incidence of postictal respiratory arrest and death. The presence of S-IRA significantly increased c-Fos expression in the dBNST of DBA/1 mice. Furthermore, disruption of synaptic output from the dBNST via viral-induced tetanus neurotoxin (TeNT) significantly improved survival following S-IRA in DBA/1 mice without affecting baseline breathing or hypercapnic (HCVR) and hypoxic ventilatory response (HVR). This disruption in the dBNST resulted in changes to the balance of excitatory/inhibitory (E/I) synaptic events in the downstream brainstem regions of the lateral parabrachial nucleus (PBN) and the periaqueductal gray (PAG). These findings suggest that the dBNST is a potential subcortical forebrain site necessary for the mediation of S-IRA, potentially through its outputs to brainstem respiratory regions.
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Affiliation(s)
| | | | | | | | | | | | | | - William P. Nobis
- Department of Neurology, Vanderbilt University Medical Center, 6130A MRB 3/Bio Sci Building, 465 21st Ave S, Nashville, TN 37235, USA.
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31
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Patodia S, Somani A, Liu J, Cattaneo A, Paradiso B, Garcia M, Othman M, Diehl B, Devinsky O, Mills JD, Foong J, Thom M. Serotonin transporter in the temporal lobe, hippocampus and amygdala in SUDEP. Brain Pathol 2022; 32:e13074. [PMID: 35478467 PMCID: PMC9425018 DOI: 10.1111/bpa.13074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/17/2022] [Accepted: 03/31/2022] [Indexed: 11/30/2022] Open
Abstract
Several lines of evidence link deficient serotonin function and SUDEP. Chronic treatment with serotonin reuptake inhibitors (SRIs) reduces ictal central apnoea, a risk factor for SUDEP. Reduced medullary serotonergic neurones, modulators of respiration in response to hypercapnia, were reported in a SUDEP post‐mortem series. The amygdala and hippocampus have high serotonergic innervation and are functionally implicated in seizure‐related respiratory dysregulation. We explored serotonergic networks in mesial temporal lobe structures in a surgical and post‐mortem epilepsy series in relation to SUDEP risk. We stratified 75 temporal lobe epilepsy patients with hippocampal sclerosis (TLE/HS) into high (N = 16), medium (N = 11) and low risk (N = 48) groups for SUDEP based on generalised seizure frequency. We also included the amygdala in 35 post‐mortem cases, including SUDEP (N = 17), epilepsy controls (N = 10) and non‐epilepsy controls (N = 8). The immunohistochemistry labelling index (LI) and axonal length (AL) of serotonin transporter (SERT)‐positive axons were quantified in 13 regions of interest with image analysis. SERT LI was highest in amygdala and subiculum regions. In the surgical series, higher SERT LI was observed in high risk than low risk cases in the dentate gyrus, CA1 and subiculum (p < 0.05). In the post‐mortem cases higher SERT LI and AL was observed in the basal and accessory basal nuclei of the amygdala and peri‐amygdala cortex in SUDEP compared to epilepsy controls (p < 0.05). Patients on SRI showed higher SERT in the dentate gyrus (p < 0.005) and CA4 (p < 0.05) but there was no difference in patients with or without a psychiatric history. Higher SERT in hippocampal subfields in TLE/HS cases with SUDEP risk factors and higher amygdala SERT in post‐mortem SUDEP cases than epilepsy controls supports a role for altered serotonergic networks involving limbic regions in SUDEP. This may be of functional relevance through reduced 5‐HT availability.
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Affiliation(s)
- Smriti Patodia
- Department of clinical and experimental epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Alyma Somani
- Department of clinical and experimental epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Joan Liu
- Department of clinical and experimental epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Alice Cattaneo
- Department of clinical and experimental epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Beatrice Paradiso
- Department of clinical and experimental epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Maria Garcia
- Department of clinical and experimental epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Muhammad Othman
- Department of clinical and experimental epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Beate Diehl
- Department of clinical and experimental epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Departments of Neurology, National Hospital for Neurology and Neurosurgery, London, UK
| | - Orrin Devinsky
- NYU Langone Comprehensive Epilepsy Center, New York University, New York City, New York, USA
| | - James D Mills
- Department of clinical and experimental epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Chalfont St Peter, UK.,Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Jackie Foong
- Department of clinical and experimental epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Departments of Psychiatry, National Hospital for Neurology and Neurosurgery, London, UK
| | - Maria Thom
- Department of clinical and experimental epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Departments of Neuropathology, National Hospital for Neurology and Neurosurgery, London, UK
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32
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Betka S, Adler D, Similowski T, Blanke O. Breathing control, brain, and bodily self-consciousness: Toward immersive digiceuticals to alleviate respiratory suffering. Biol Psychol 2022; 171:108329. [PMID: 35452780 DOI: 10.1016/j.biopsycho.2022.108329] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 04/11/2022] [Accepted: 04/11/2022] [Indexed: 01/19/2023]
Abstract
Breathing is peculiar among autonomic functions through several characteristics. It generates a very rich afferent traffic from an array of structures belonging to the respiratory system to various areas of the brain. It is intimately associated with bodily movements. It bears particular relationships with consciousness as its efferent motor control can be automatic or voluntary. In this review within the scope of "respiratory neurophysiology" or "respiratory neuroscience", we describe the physiological organisation of breathing control. We then review findings linking breathing and bodily self-consciousness through respiratory manipulations using virtual reality (VR). After discussing the currently admitted neurophysiological model for dyspnea, as well as a new Bayesian model applied to breathing control, we propose that visuo-respiratory paradigms -as developed in cognitive neuroscience- will foster insights into some of the basic mechanisms of the human respiratory system and will also lead to the development of immersive VR-based digital health tools (i.e. digiceuticals).
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Affiliation(s)
- Sophie Betka
- Laboratory of Cognitive Neuroscience, Brain Mind Institute and Center for Neuroprosthetics, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, (EPFL), Geneva 1202, Switzerland.
| | - Dan Adler
- Division of Lung Diseases, University Hospital and Geneva Medical School, University of Geneva, Switzerland
| | - Thomas Similowski
- Sorbonne Université, INSERM, UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, F-75005 Paris, France; AP-HP, Groupe Hospitalier Universitaire APHP-Sorbonne Université, site Pitié-Salpêtrière, Département R3S (Respiration, Réanimation, Réhabilitation respiratoire, Sommeil), F-75013 Paris, France
| | - Olaf Blanke
- Laboratory of Cognitive Neuroscience, Brain Mind Institute and Center for Neuroprosthetics, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, (EPFL), Geneva 1202, Switzerland; Department of Clinical Neurosciences, University Hospital and Geneva Medical School, University of Geneva, Switzerland
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33
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Feinstein JS, Gould D, Khalsa SS. Amygdala-driven apnea and the chemoreceptive origin of anxiety. Biol Psychol 2022; 170:108305. [PMID: 35271957 DOI: 10.1016/j.biopsycho.2022.108305] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 02/09/2022] [Accepted: 03/03/2022] [Indexed: 12/13/2022]
Abstract
Although the amygdala plays an important part in the pathogenesis of anxiety and generation of exteroceptive fear, recent discoveries have challenged the directionality of this brain-behavior relationship with respect to interoceptive fear. Here we highlight several paradoxical findings including: (1) amygdala lesion patients who experience excessive fear and panic following inhalation of carbon dioxide (CO2), (2) clinically anxious patients who have significantly smaller (rather than larger) amygdalae and a pronounced hypersensitivity toward CO2, and (3) epilepsy patients who exhibit apnea immediately following stimulation of their amygdala yet have no awareness that their breathing has stopped. The above findings elucidate an entirely novel role for the amygdala in the induction of apnea and inhibition of CO2-induced fear. Such a role is plausible given the strong inhibitory connections linking the central nucleus of the amygdala with respiratory and chemoreceptive centers in the brainstem. Based on this anatomical arrangement, we propose a model of Apnea-induced Anxiety (AiA) which predicts that recurring episodes of apnea are being unconsciously elicited by amygdala activation, resulting in transient spikes in CO2 that provoke fear and anxiety, and lead to characteristic patterns of escape and avoidance behavior in patients spanning the spectrum of anxiety. If this new conception of AiA proves to be true, and activation of the amygdala can repeatedly trigger states of apnea outside of one's awareness, then it remains possible that the chronicity of anxiety disorders is being interoceptively driven by a chemoreceptive system struggling to maintain homeostasis in the midst of these breathless states.
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Affiliation(s)
- Justin S Feinstein
- Laureate Institute for Brain Research, Tulsa, Oklahoma, USA, 74136; University of Tulsa, Oxley College of Health Sciences, Tulsa, Oklahoma, USA, 74104; University of Iowa, Department of Neurology, Iowa City, Iowa, USA, 52242.
| | - Dylan Gould
- Laureate Institute for Brain Research, Tulsa, Oklahoma, USA, 74136
| | - Sahib S Khalsa
- Laureate Institute for Brain Research, Tulsa, Oklahoma, USA, 74136; University of Tulsa, Oxley College of Health Sciences, Tulsa, Oklahoma, USA, 74104
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34
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Teran FA, Bravo E, Richerson GB. Sudden unexpected death in epilepsy: Respiratory mechanisms. HANDBOOK OF CLINICAL NEUROLOGY 2022; 189:153-176. [PMID: 36031303 PMCID: PMC10191258 DOI: 10.1016/b978-0-323-91532-8.00012-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Epilepsy is one of the most common chronic neurologic diseases, with a prevalence of 1% in the US population. Many people with epilepsy live normal lives, but are at risk of sudden unexpected death in epilepsy (SUDEP). This mysterious comorbidity of epilepsy causes premature death in 17%-50% of those with epilepsy. Most SUDEP occurs after a generalized seizure, and patients are typically found in bed in the prone position. Until recently, it was thought that SUDEP was due to cardiovascular failure, but patients who died while being monitored in hospital epilepsy units revealed that most SUDEP is due to postictal central apnea. Some cases may occur when seizures invade the amygdala and activate projections to the brainstem. Evidence suggests that the pathophysiology is linked to defects in the serotonin system and central CO2 chemoreception, and that there is considerable overlap with mechanisms thought to be involved in sudden infant death syndrome (SIDS). Future work is needed to identify biomarkers for patients at highest risk, improve ascertainment, develop methods to alert caregivers when SUDEP is imminent, and find effective approaches to prevent these fatal events.
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Affiliation(s)
- Frida A Teran
- Department of Neurology, University of Iowa, Iowa City, IA, United States; Medical Scientist Training Program, University of Iowa, Iowa City, IA, United States.
| | - Eduardo Bravo
- Department of Neurology, University of Iowa, Iowa City, IA, United States
| | - George B Richerson
- Department of Neurology, University of Iowa, Iowa City, IA, United States; Department of Molecular Physiology & Biophysics, University of Iowa, Iowa City, IA, United States
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35
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Noto T, Zhou G, Yang Q, Lane G, Zelano C. Human Primary Olfactory Amygdala Subregions Form Distinct Functional Networks, Suggesting Distinct Olfactory Functions. Front Syst Neurosci 2021; 15:752320. [PMID: 34955769 PMCID: PMC8695617 DOI: 10.3389/fnsys.2021.752320] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 11/08/2021] [Indexed: 12/02/2022] Open
Abstract
Three subregions of the amygdala receive monosynaptic projections from the olfactory bulb, making them part of the primary olfactory cortex. These primary olfactory areas are located at the anterior-medial aspect of the amygdala and include the medial amygdala (MeA), cortical amygdala (CoA), and the periamygdaloid complex (PAC). The vast majority of research on the amygdala has focused on the larger basolateral and basomedial subregions, which are known to be involved in implicit learning, threat responses, and emotion. Fewer studies have focused on the MeA, CoA, and PAC, with most conducted in rodents. Therefore, our understanding of the functions of these amygdala subregions is limited, particularly in humans. Here, we first conducted a review of existing literature on the MeA, CoA, and PAC. We then used resting-state fMRI and unbiased k-means clustering techniques to show that the anatomical boundaries of human MeA, CoA, and PAC accurately parcellate based on their whole-brain resting connectivity patterns alone, suggesting that their functional networks are distinct, relative both to each other and to the amygdala subregions that do not receive input from the olfactory bulb. Finally, considering that distinct functional networks are suggestive of distinct functions, we examined the whole-brain resting network of each subregion and speculated on potential roles that each region may play in olfactory processing. Based on these analyses, we speculate that the MeA could potentially be involved in the generation of rapid motor responses to olfactory stimuli (including fight/flight), particularly in approach/avoid contexts. The CoA could potentially be involved in olfactory-related reward processing, including learning and memory of approach/avoid responses. The PAC could potentially be involved in the multisensory integration of olfactory information with other sensory systems. These speculations can be used to form the basis of future studies aimed at clarifying the olfactory functions of these under-studied primary olfactory areas.
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Affiliation(s)
- Torben Noto
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Guangyu Zhou
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Qiaohan Yang
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Gregory Lane
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Christina Zelano
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
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36
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Patodia S, Somani A, Thom M. Review: Neuropathology findings in autonomic brain regions in SUDEP and future research directions. Auton Neurosci 2021; 235:102862. [PMID: 34411885 PMCID: PMC8455454 DOI: 10.1016/j.autneu.2021.102862] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 07/16/2021] [Accepted: 07/24/2021] [Indexed: 12/21/2022]
Abstract
Autonomic dysfunction is implicated from clinical, neuroimaging and experimental studies in sudden and unexpected death in epilepsy (SUDEP). Neuropathological analysis in SUDEP series enable exploration of acquired, seizure-related cellular adaptations in autonomic and brainstem autonomic centres of relevance to dysfunction in the peri-ictal period. Alterations in SUDEP compared to control groups have been identified in the ventrolateral medulla, amygdala, hippocampus and central autonomic regions. These involve neuropeptidergic, serotonergic and adenosine systems, as well as specific regional astroglial and microglial populations, as potential neuronal modulators, orchestrating autonomic dysfunction. Future research studies need to extend to clinically and genetically characterized epilepsies, to explore if common or distinct pathways of autonomic dysfunction mediate SUDEP. The ultimate objective of SUDEP research is the identification of disease biomarkers for at risk patients, to improve post-mortem recognition and disease categorisation, but ultimately, for exposing potential treatment targets of pharmacologically modifiable and reversible cellular alterations.
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Affiliation(s)
- Smriti Patodia
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Alyma Somani
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Maria Thom
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK.
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37
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K v1.1 channels mediate network excitability and feed-forward inhibition in local amygdala circuits. Sci Rep 2021; 11:15180. [PMID: 34312446 PMCID: PMC8313690 DOI: 10.1038/s41598-021-94633-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 07/14/2021] [Indexed: 01/15/2023] Open
Abstract
Kv1.1 containing potassium channels play crucial roles towards dampening neuronal excitability. Mice lacking Kv1.1 subunits (Kcna1−/−) display recurrent spontaneous seizures and often exhibit sudden unexpected death. Seizures in Kcna1−/− mice resemble those in well-characterized models of temporal lobe epilepsy known to involve limbic brain regions and spontaneous seizures result in enhanced cFos expression and neuronal death in the amygdala. Yet, the functional alterations leading to amygdala hyperexcitability have not been identified. In this study, we used Kcna1−/− mice to examine the contributions of Kv1.1 subunits to excitability in neuronal subtypes from basolateral (BLA) and central lateral (CeL) amygdala known to exhibit distinct firing patterns. We also analyzed synaptic transmission properties in an amygdala local circuit predicted to be involved in epilepsy-related comorbidities. Our data implicate Kv1.1 subunits in controlling spontaneous excitatory synaptic activity in BLA pyramidal neurons. In the CeL, Kv1.1 loss enhances intrinsic excitability and impairs inhibitory synaptic transmission, notably resulting in dysfunction of feed-forward inhibition, a critical mechanism for controlling spike timing. Overall, we find inhibitory control of CeL interneurons is reduced in Kcna1−/− mice suggesting that basal inhibitory network functioning is less able to prevent recurrent hyperexcitation related to seizures.
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38
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Akyüz E, Üner AK, Köklü B, Arulsamy A, Shaikh MF. Cardiorespiratory findings in epilepsy: A recent review on outcomes and pathophysiology. J Neurosci Res 2021; 99:2059-2073. [PMID: 34109651 DOI: 10.1002/jnr.24861] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/16/2021] [Accepted: 05/06/2021] [Indexed: 12/17/2022]
Abstract
Epilepsy is a debilitating disorder of uncontrollable recurrent seizures that occurs as a result of imbalances in the brain excitatory and inhibitory neuronal signals, that could stem from a range of functional and structural neuronal impairments. Globally, nearly 70 million people are negatively impacted by epilepsy and its comorbidities. One such comorbidity is the effect epilepsy has on the autonomic nervous system (ANS), which plays a role in the control of blood circulation, respiration and gastrointestinal function. These epilepsy-induced impairments in the circulatory and respiratory systems may contribute toward sudden unexpected death in epilepsy (SUDEP). Although, various hypotheses have been proposed regarding the role of epilepsy on ANS, the linking pathological mechanism still remains unclear. Channelopathies and seizure-induced damages in ANS-control brain structures were some of the causal/pathological candidates of cardiorespiratory comorbidities in epilepsy patients, especially in those who were drug resistant. However, emerging preclinical research suggest that neurotransmitter/receptor dysfunction and synaptic changes in the ANS may also contribute to the epilepsy-related autonomic disorders. Thus, pathological mechanisms of cardiorespiratory dysfunction should be elucidated by considering the modifications in anatomy and physiology of the autonomic system caused by seizures. In this regard, we present a comprehensive review of the current literature, both clinical and preclinical animal studies, on the cardiorespiratory findings in epilepsy and elucidate the possible pathological mechanisms of these findings, in hopes to prevent SUDEP especially in patients who are drug resistant.
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Affiliation(s)
- Enes Akyüz
- Department of Biophysics, Faculty of Medicine, Yozgat Bozok University, Yozgat, Turkey
| | - Arda Kaan Üner
- Faculty of Medicine, Yozgat Bozok University, Yozgat, Turkey
| | - Betül Köklü
- Faculty of Medicine, Namık Kemal University, Tekirdağ, Turkey
| | - Alina Arulsamy
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Mohd Farooq Shaikh
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
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Yan WW, Xia M, Chiang J, Levitt A, Hawkins N, Kearney J, Swanson GT, Chetkovich D, Nobis WP. Enhanced Synaptic Transmission in the Extended Amygdala and Altered Excitability in an Extended Amygdala to Brainstem Circuit in a Dravet Syndrome Mouse Model. eNeuro 2021; 8:ENEURO.0306-20.2021. [PMID: 34045209 PMCID: PMC8213443 DOI: 10.1523/eneuro.0306-20.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 04/29/2021] [Accepted: 05/11/2021] [Indexed: 12/13/2022] Open
Abstract
Dravet syndrome (DS) is a developmental and epileptic encephalopathy with an increased incidence of sudden death. Evidence of interictal breathing deficits in DS suggests that alterations in subcortical projections to brainstem nuclei may exist, which might be driving comorbidities in DS. The aim of this study was to determine whether a subcortical structure, the bed nucleus of the stria terminalis (BNST) in the extended amygdala, is activated by seizures, exhibits changes in excitability, and expresses any alterations in neurons projecting to a brainstem nucleus associated with respiration, stress response, and homeostasis. Experiments were conducted using F1 mice generated by breeding 129.Scn1a+/- mice with wild-type C57BL/6J mice. Immunohistochemistry was performed to quantify neuronal c-fos activation in DS mice after observed spontaneous seizures. Whole-cell patch-clamp and current-clamp electrophysiology recordings were conducted to evaluate changes in intrinsic and synaptic excitability in the BNST. Spontaneous seizures in DS mice significantly enhanced neuronal c-fos expression in the BNST. Further, the BNST had altered AMPA/NMDA postsynaptic receptor composition and showed changes in spontaneous neurotransmission, with greater excitation and decreased inhibition. BNST to parabrachial nucleus (PBN) projection neurons exhibited intrinsic excitability in wild-type mice, while these projection neurons were hypoexcitable in DS mice. The findings suggest that there is altered excitability in neurons of the BNST, including BNST-to-PBN projection neurons, in DS mice. These alterations could potentially be driving comorbid aspects of DS outside of seizures, including respiratory dysfunction and sudden death.
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Affiliation(s)
- Wen Wei Yan
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Maya Xia
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Jeremy Chiang
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Alyssa Levitt
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Nicole Hawkins
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Jennifer Kearney
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Geoffrey T Swanson
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Dane Chetkovich
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - William P Nobis
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee 37232
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40
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Ochoa-Urrea M, Dayyani M, Sadeghirad B, Tandon N, Lacuey N, Lhatoo SD. Electrical Stimulation-Induced Seizures and Breathing Dysfunction: A Systematic Review of New Insights Into the Epileptogenic and Symptomatogenic Zones. Front Hum Neurosci 2021; 14:617061. [PMID: 33551780 PMCID: PMC7862564 DOI: 10.3389/fnhum.2020.617061] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/18/2020] [Indexed: 12/29/2022] Open
Abstract
Objective: Electrical stimulation (ES) potentially delineates epileptogenic cortex through induction of typical seizures. Although frequently employed, its value for epilepsy surgery remains controversial. Similarly, ES is used to identify symptomatogenic zones, but with greater success and a long-standing evidence base. Recent work points to new seizure symptoms such as ictal central apnea (ICA) that may enhance presurgical hypotheses. The aims of this review are 2-fold: to determine the value of ES-induced seizures (ESIS) in epilepsy surgery and to analyze current evidence on ICA as a new surrogate of symptomatogenic cortex. Methods: Three databases were searched for ESIS. Investigators independently selected studies according to pre-specified criteria. Studies reporting postoperative outcome in patients with ESIS were included in a meta-analysis. For ES-induced apnea, a thorough search was performed and reference list searching was employed. Results: Of 6,314 articles identified for ESIS, 25 were considered eligible to be reviewed in full text. Fourteen studies were included in the qualitative synthesis (1,069 patients); six studies were included in the meta-analysis (530 patients). The meta-analysis showed that favorable outcome is associated with ESIS prior to surgery (OR: 2.02; 95% CI: 1.332–3.08). In addition, the overall estimation of the occurrence of favorable outcome among cases with ESIS is 68.13% (95% CI: 56.62–78.7). On the other hand, recent studies have shown that stimulation of exclusively mesial temporal lobe structures elicits central apnea and represents symptomatogenic anatomic substrates of ICA. This is in variance with traditional teaching that mesial temporal ES is non-symptomatogenic. Conclusions: ES is a tool highly likely to aid in the delineation of the epileptogenic zone, since ESIS is associated with favorable postoperative outcomes (Engel I). There is an urgent need for prospective evaluation of this technique, including effective stimulation parameters and surgical outcomes, that will provide knowledge base for practice. In addition, ES-induced apnea studies suggest that ICA, especially when it is the first or only clinical sign, is an important semiological feature in localizing the symptomatogenic zone to mesial temporal lobe structures, which must be considered in SEEG explorations where this is planned, and in surgical resection strategies.
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Affiliation(s)
- Manuela Ochoa-Urrea
- Department of Neurology, University of Texas Health Sciences Center at Houston, Houston, TX, United States
| | - Mojtaba Dayyani
- Department of Neurology, University of Texas Health Sciences Center at Houston, Houston, TX, United States
| | - Behnam Sadeghirad
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada
| | - Nitin Tandon
- Department of Neurology, University of Texas Health Sciences Center at Houston, Houston, TX, United States
| | - Nuria Lacuey
- Department of Neurology, University of Texas Health Sciences Center at Houston, Houston, TX, United States
| | - Samden D Lhatoo
- Department of Neurology, University of Texas Health Sciences Center at Houston, Houston, TX, United States
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