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Southwell DG. Interneuron Transplantation for Drug-Resistant Epilepsy. Neurosurg Clin N Am 2024; 35:151-160. [PMID: 38000838 DOI: 10.1016/j.nec.2023.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2023]
Abstract
Current epilepsy surgical techniques, such as brain resection, laser ablation, and neurostimulation, target seizure networks macroscopically, and they may yield an unfavorable balance between seizure reduction, procedural invasiveness, and neurologic morbidity. The transplantation of GABAergic interneurons is a regenerative technique for altering neural inhibition in cortical circuits, with potential as an alternative and minimally invasive approach to epilepsy treatment. This article (1) reviews some of the preclinical evidence supporting interneuron transplantation as an epilepsy therapy, (2) describes a first-in-human study of interneuron transplantation for epilepsy, and (3) considers knowledge gaps that stand before the effective clinical application of this novel treatment.
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Affiliation(s)
- Derek G Southwell
- Department of Neurosurgery, Graduate Program in Neurobiology, Duke University, DUMC 3807, 200 Trent Drive, Durham, NC 27710, USA.
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Frankowski JC, Tierno A, Pavani S, Cao Q, Lyon DC, Hunt RF. Brain-wide reconstruction of inhibitory circuits after traumatic brain injury. Nat Commun 2022; 13:3417. [PMID: 35701434 PMCID: PMC9197933 DOI: 10.1038/s41467-022-31072-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 05/31/2022] [Indexed: 11/09/2022] Open
Abstract
Despite the fundamental importance of understanding the brain's wiring diagram, our knowledge of how neuronal connectivity is rewired by traumatic brain injury remains remarkably incomplete. Here we use cellular resolution whole-brain imaging to generate brain-wide maps of the input to inhibitory neurons in a mouse model of traumatic brain injury. We find that somatostatin interneurons are converted into hyperconnected hubs in multiple brain regions, with rich local network connections but diminished long-range inputs, even at areas not directly damaged. The loss of long-range input does not correlate with cell loss in distant brain regions. Interneurons transplanted into the injury site receive orthotopic local and long-range input, suggesting the machinery for establishing distant connections remains intact even after a severe injury. Our results uncover a potential strategy to sustain and optimize inhibition after traumatic brain injury that involves spatial reorganization of the direct inputs to inhibitory neurons across the brain.
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Affiliation(s)
- Jan C Frankowski
- Department of Anatomy & Neurobiology, University of California, Irvine, CA, 92697, USA
| | - Alexa Tierno
- Department of Anatomy & Neurobiology, University of California, Irvine, CA, 92697, USA.
| | - Shreya Pavani
- Department of Anatomy & Neurobiology, University of California, Irvine, CA, 92697, USA
| | - Quincy Cao
- Department of Anatomy & Neurobiology, University of California, Irvine, CA, 92697, USA
| | - David C Lyon
- Department of Anatomy & Neurobiology, University of California, Irvine, CA, 92697, USA
| | - Robert F Hunt
- Department of Anatomy & Neurobiology, University of California, Irvine, CA, 92697, USA. .,Epilepsy Research Center, University of California, Irvine, CA, 92697, USA. .,Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, CA, 92697, USA. .,Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, 92697, USA. .,Center for Neural Circuit Mapping, University of California, Irvine, Irvine, CA, 92697, USA.
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Ferrer C, De Marco García NV. The Role of Inhibitory Interneurons in Circuit Assembly and Refinement Across Sensory Cortices. Front Neural Circuits 2022; 16:866999. [PMID: 35463203 PMCID: PMC9021723 DOI: 10.3389/fncir.2022.866999] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/16/2022] [Indexed: 12/15/2022] Open
Abstract
Sensory information is transduced into electrical signals in the periphery by specialized sensory organs, which relay this information to the thalamus and subsequently to cortical primary sensory areas. In the cortex, microcircuits constituted by interconnected pyramidal cells and inhibitory interneurons, distributed throughout the cortical column, form the basic processing units of sensory information underlying sensation. In the mouse, these circuits mature shortly after birth. In the first postnatal week cortical activity is characterized by highly synchronized spontaneous activity. While by the second postnatal week, spontaneous activity desynchronizes and sensory influx increases drastically upon eye opening, as well as with the onset of hearing and active whisking. This influx of sensory stimuli is fundamental for the maturation of functional properties and connectivity in neurons allocated to sensory cortices. In the subsequent developmental period, spanning the first five postnatal weeks, sensory circuits are malleable in response to sensory stimulation in the so-called critical periods. During these critical periods, which vary in timing and duration across sensory areas, perturbations in sensory experience can alter cortical connectivity, leading to long-lasting modifications in sensory processing. The recent advent of intersectional genetics, in vivo calcium imaging and single cell transcriptomics has aided the identification of circuit components in emergent networks. Multiple studies in recent years have sought a better understanding of how genetically-defined neuronal subtypes regulate circuit plasticity and maturation during development. In this review, we discuss the current literature focused on postnatal development and critical periods in the primary auditory (A1), visual (V1), and somatosensory (S1) cortices. We compare the developmental trajectory among the three sensory areas with a particular emphasis on interneuron function and the role of inhibitory circuits in cortical development and function.
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Ceto S, Courtine G. Optogenetic Interrogation of Circuits Following Neurotrauma. Front Mol Neurosci 2022; 14:803856. [PMID: 34975403 PMCID: PMC8716760 DOI: 10.3389/fnmol.2021.803856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 11/18/2021] [Indexed: 11/13/2022] Open
Abstract
Biological and engineering strategies for neural repair and recovery from neurotrauma continue to emerge at a rapid pace. Until recently, studies of the impact of neurotrauma and repair strategies on the reorganization of the central nervous system have focused on broadly defined circuits and pathways. Optogenetic modulation and recording methods now enable the interrogation of precisely defined neuronal populations in the brain and spinal cord, allowing unprecedented precision in electrophysiological and behavioral experiments. This mini-review summarizes the spectrum of light-based tools that are currently available to probe the properties and functions of well-defined neuronal subpopulations in the context of neurotrauma. In particular, we highlight the challenges to implement these tools in damaged and reorganizing tissues, and we discuss best practices to overcome these obstacles.
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Affiliation(s)
- Steven Ceto
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Department of Clinical Neuroscience, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), EPFL/CHUV/UNIL, Lausanne, Switzerland
| | - Grégoire Courtine
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Department of Clinical Neuroscience, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), EPFL/CHUV/UNIL, Lausanne, Switzerland.,Department of Neurosurgery, Lausanne University Hospital (CHUV), Lausanne, Switzerland
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