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Xu M, Hu B, Wang Z, Zhu L, Lin J, Wang D. Mathematical derivation and mechanism analysis of beta oscillations in a cortex-pallidum model. Cogn Neurodyn 2024; 18:1359-1378. [PMID: 38826645 PMCID: PMC11143146 DOI: 10.1007/s11571-023-09951-1] [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: 05/31/2022] [Revised: 01/07/2023] [Accepted: 03/09/2023] [Indexed: 06/04/2024] Open
Abstract
In this paper, we develop a new cortex-pallidum model to study the origin mechanism of Parkinson's oscillations in the cortex. In contrast to many previous models, the globus pallidus internal (GPi) and externa (GPe) both exert direct inhibitory feedback to the cortex. Using Hopf bifurcation analysis, two new critical conditions for oscillations, which can include the self-feedback projection of GPe, are obtained. In this paper, we find that the average discharge rate (ADR) is an important marker of oscillations, which can divide Hopf bifurcations into two types that can uniformly be used to explain the oscillation mechanism. Interestingly, the ADR of the cortex first increases and then decreases with increasing coupling weights that are projected to the GPe. Regarding the Hopf bifurcation critical conditions, the quantitative relationship between the inhibitory projection and excitatory projection to the GPe is monotonically increasing; in contrast, the relationship between different coupling weights in the cortex is monotonically decreasing. In general, the oscillation amplitude is the lowest near the bifurcation points and reaches the maximum value with the evolution of oscillations. The GPe is an effective target for deep brain stimulation to alleviate oscillations in the cortex.
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Affiliation(s)
- Minbo Xu
- Department of Applied Mathematics, Zhejiang University of Technology, Hangzhou, 310023 China
| | - Bing Hu
- Department of Applied Mathematics, Zhejiang University of Technology, Hangzhou, 310023 China
| | - Zhizhi Wang
- Department of Applied Mathematics, Zhejiang University of Technology, Hangzhou, 310023 China
| | - Luyao Zhu
- Department of Applied Mathematics, Zhejiang University of Technology, Hangzhou, 310023 China
| | - Jiahui Lin
- Department of Applied Mathematics, Zhejiang University of Technology, Hangzhou, 310023 China
| | - Dingjiang Wang
- Department of Applied Mathematics, Zhejiang University of Technology, Hangzhou, 310023 China
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2
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Cherian S, Simms G, Chen L, Chu HY. Loss of Midbrain Dopamine Neurons Does Not Alter GABAergic Inhibition Mediated by Parvalbumin-Expressing Interneurons in Mouse Primary Motor Cortex. eNeuro 2024; 11:ENEURO.0010-24.2024. [PMID: 38658137 PMCID: PMC11082919 DOI: 10.1523/eneuro.0010-24.2024] [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: 01/08/2024] [Revised: 03/29/2024] [Accepted: 04/17/2024] [Indexed: 04/26/2024] Open
Abstract
The primary motor cortex (M1) integrates sensory and cognitive inputs to generate voluntary movement. Its functional impairments have been implicated in the pathophysiology of motor symptoms in Parkinson's disease (PD). Specifically, dopaminergic degeneration and basal ganglia dysfunction entrain M1 neurons into the abnormally synchronized bursting pattern of activity throughout the cortico-basal ganglia-thalamocortical network. However, how degeneration of the midbrain dopaminergic neurons affects the anatomy, microcircuit connectivity, and function of the M1 network remains poorly understood. The present study examined whether and how the loss of dopamine (DA) affects the morphology, cellular excitability, and synaptic physiology of Layer 5 parvalbumin-expressing (PV+) cells in the M1 of mice of both sexes. Here, we reported that loss of midbrain dopaminergic neurons does not alter the number, morphology, and physiology of Layer 5 PV+ cells in M1. Moreover, we demonstrated that the number of perisomatic PV+ puncta of M1 pyramidal neurons as well as their functional innervation of cortical pyramidal neurons were not altered following the loss of DA. Together, the present study documents an intact GABAergic inhibitory network formed by PV+ cells following the loss of midbrain dopaminergic neurons.
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Affiliation(s)
- Suraj Cherian
- Department of Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - Gabriel Simms
- Department of Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - Liqiang Chen
- Department of Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - Hong-Yuan Chu
- Department of Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, Michigan 49503
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3
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Xu M, Hu B, Zhou W, Wang Z, Zhu L, Lin J, Wang D. The mechanism of Parkinson oscillation in the cortex: Possible evidence in a feedback model projecting from the globus pallidus to the cortex. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2023; 20:6517-6550. [PMID: 37161117 DOI: 10.3934/mbe.2023281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The origin, location and cause of Parkinson's oscillation are not clear at present. In this paper, we establish a new cortex-basal ganglia model to study the origin mechanism of Parkinson beta oscillation. Unlike many previous models, this model includes two direct inhibitory projections from the globus pallidus external (GPe) segment to the cortex. We first obtain the critical calculation formula of Parkinson's oscillation by using the method of Quasilinear analysis. Different from previous studies, the formula obtained in this paper can include the self-feedback connection of GPe. Then, we use the bifurcation analysis method to systematically explain the influence of some key parameters on the oscillation. We find that the bifurcation principle of different cortical nuclei is different. In general, the increase of the discharge capacity of the nuclei will cause oscillation. In some special cases, the sharp reduction of the discharge rate of the nuclei will also cause oscillation. The direction of bifurcation simulation is consistent with the critical condition curve. Finally, we discuss the characteristics of oscillation amplitude. At the beginning of the oscillation, the amplitude is relatively small; with the evolution of oscillation, the amplitude will gradually strengthen. This is consistent with the experimental phenomenon. In most cases, the amplitude of cortical inhibitory nuclei (CIN) is greater than that of cortical excitatory nuclei (CEX), and the two direct inhibitory projections feedback from GPe can significantly reduce the amplitude gap between them. We calculate the main frequency of the oscillation generated in this model, which basically falls between 13 and 30 Hz, belonging to the typical beta frequency band oscillation. Some new results obtained in this paper can help to better understand the origin mechanism of Parkinson's disease and have guiding significance for the development of experiments.
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Affiliation(s)
- Minbo Xu
- Department of Applied Mathematics, Zhejiang University of Technology, Hangzhou 310023, China
| | - Bing Hu
- Department of Applied Mathematics, Zhejiang University of Technology, Hangzhou 310023, China
| | - Weiting Zhou
- Department of Applied Mathematics, Zhejiang University of Technology, Hangzhou 310023, China
| | - Zhizhi Wang
- Department of Applied Mathematics, Zhejiang University of Technology, Hangzhou 310023, China
| | - Luyao Zhu
- Department of Applied Mathematics, Zhejiang University of Technology, Hangzhou 310023, China
| | - Jiahui Lin
- Department of Applied Mathematics, Zhejiang University of Technology, Hangzhou 310023, China
| | - Dingjiang Wang
- Department of Applied Mathematics, Zhejiang University of Technology, Hangzhou 310023, China
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4
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Macías M, Lopez-Virgen V, Olivares-Moreno R, Rojas-Piloni G. Corticospinal neurons from motor and somatosensory cortices exhibit different temporal activity dynamics during motor learning. Front Hum Neurosci 2022; 16:1043501. [PMID: 36504625 PMCID: PMC9732016 DOI: 10.3389/fnhum.2022.1043501] [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: 09/13/2022] [Accepted: 11/10/2022] [Indexed: 11/27/2022] Open
Abstract
The ability to learn motor skills implicates an improvement in accuracy, speed and consistency of movements. Motor control is related to movement execution and involves corticospinal neurons (CSp), which are broadly distributed in layer 5B of the motor and somatosensory cortices. CSp neurons innervate the spinal cord and are functionally diverse. However, whether CSp activity differs between different cortical areas throughout motor learning has been poorly explored. Given the importance and interaction between primary motor (M1) and somatosensory (S1) cortices related to movement, we examined the functional roles of CSp neurons in both areas. We induced the expression of GCaMP7s calcium indicator to perform photometric calcium recordings from layer 5B CSp neurons simultaneously in M1 and S1 cortices and track their activity while adult mice learned and performed a cued lever-press task. We found that during early learning sessions, the population calcium activity of CSp neurons in both cortices during movement did not change significantly. In late learning sessions the peak amplitude and duration of calcium activity CSp neurons increased in both, M1 and S1 cortices. However, S1 and M1 CSp neurons display a different temporal dynamic during movements that occurred when animals learned the task; both M1 and S1 CSp neurons activate before movement initiation, however, M1 CSp neurons continue active during movement performance, reinforcing the idea of the diversity of the CSp system and suggesting that CSp neuron activity in M1 and S1 cortices throughout motor learning have different functional roles for sensorimotor integration.
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5
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Siebner HR, Funke K, Aberra AS, Antal A, Bestmann S, Chen R, Classen J, Davare M, Di Lazzaro V, Fox PT, Hallett M, Karabanov AN, Kesselheim J, Beck MM, Koch G, Liebetanz D, Meunier S, Miniussi C, Paulus W, Peterchev AV, Popa T, Ridding MC, Thielscher A, Ziemann U, Rothwell JC, Ugawa Y. Transcranial magnetic stimulation of the brain: What is stimulated? - A consensus and critical position paper. Clin Neurophysiol 2022; 140:59-97. [PMID: 35738037 PMCID: PMC9753778 DOI: 10.1016/j.clinph.2022.04.022] [Citation(s) in RCA: 116] [Impact Index Per Article: 58.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 03/14/2022] [Accepted: 04/15/2022] [Indexed: 12/11/2022]
Abstract
Transcranial (electro)magnetic stimulation (TMS) is currently the method of choice to non-invasively induce neural activity in the human brain. A single transcranial stimulus induces a time-varying electric field in the brain that may evoke action potentials in cortical neurons. The spatial relationship between the locally induced electric field and the stimulated neurons determines axonal depolarization. The induced electric field is influenced by the conductive properties of the tissue compartments and is strongest in the superficial parts of the targeted cortical gyri and underlying white matter. TMS likely targets axons of both excitatory and inhibitory neurons. The propensity of individual axons to fire an action potential in response to TMS depends on their geometry, myelination and spatial relation to the imposed electric field and the physiological state of the neuron. The latter is determined by its transsynaptic dendritic and somatic inputs, intrinsic membrane potential and firing rate. Modeling work suggests that the primary target of TMS is axonal terminals in the crown top and lip regions of cortical gyri. The induced electric field may additionally excite bends of myelinated axons in the juxtacortical white matter below the gyral crown. Neuronal excitation spreads ortho- and antidromically along the stimulated axons and causes secondary excitation of connected neuronal populations within local intracortical microcircuits in the target area. Axonal and transsynaptic spread of excitation also occurs along cortico-cortical and cortico-subcortical connections, impacting on neuronal activity in the targeted network. Both local and remote neural excitation depend critically on the functional state of the stimulated target area and network. TMS also causes substantial direct co-stimulation of the peripheral nervous system. Peripheral co-excitation propagates centrally in auditory and somatosensory networks, but also produces brain responses in other networks subserving multisensory integration, orienting or arousal. The complexity of the response to TMS warrants cautious interpretation of its physiological and behavioural consequences, and a deeper understanding of the mechanistic underpinnings of TMS will be critical for advancing it as a scientific and therapeutic tool.
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Affiliation(s)
- Hartwig R Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark; Department of Neurology, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark; Institute for Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.
| | - Klaus Funke
- Department of Neurophysiology, Medical Faculty, Ruhr-University Bochum, Bochum, Germany
| | - Aman S Aberra
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Andrea Antal
- Department of Clinical Neurophysiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Sven Bestmann
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom; Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Robert Chen
- Krembil Brain Institute, University Health Network and Division of Neurology, University of Toronto, Toronto, Ontario, Canada
| | - Joseph Classen
- Department of Neurology, University of Leipzig, Leipzig, Germany
| | - Marco Davare
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom; Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Vincenzo Di Lazzaro
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Università Campus Bio-Medico di Roma, via Álvaro del Portillo 21, 00128 Rome, Italy
| | - Peter T Fox
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Mark Hallett
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Anke N Karabanov
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark; Department of Nutrition and Exercise, University of Copenhagen, Copenhagen, Denmark
| | - Janine Kesselheim
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
| | - Mikkel M Beck
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
| | - Giacomo Koch
- Department of Neuroscience and Rehabilitation, University of Ferrara, Ferrara, Italy; Non-invasive Brain Stimulation Unit, Laboratorio di NeurologiaClinica e Comportamentale, Fondazione Santa Lucia IRCCS, Rome, Italy
| | - David Liebetanz
- Department of Clinical Neurophysiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Sabine Meunier
- Sorbonne Université, Faculté de Médecine, INSERM U 1127, CNRS 4 UMR 7225, Institut du Cerveau, F-75013, Paris, France
| | - Carlo Miniussi
- Center for Mind/Brain Sciences (CIMeC), University of Trento, Italy; Cognitive Neuroscience Section, IRCCS Centro San Giovanni di DioFatebenefratelli, Brescia, Italy
| | - Walter Paulus
- Department of Clinical Neurophysiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Angel V Peterchev
- Department of Biomedical Engineering, Duke University, Durham, NC, USA; Department of Psychiatry & Behavioral Sciences, School of Medicine, Duke University, Durham, NC, USA; Department of Electrical & Computer Engineering, Duke University, Durham, NC, USA; Department of Neurosurgery, School of Medicine, Duke University, Durham, NC, USA
| | - Traian Popa
- Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Swiss Federal Institute of Technology (EPFL), Geneva, Switzerland; Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Swiss Federal Institute of Technology (EPFL Valais), Clinique Romande de Réadaptation, Sion, Switzerland
| | - Michael C Ridding
- University of South Australia, IIMPACT in Health, Adelaide, Australia
| | - Axel Thielscher
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark; Department of Health Technology, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Ulf Ziemann
- Department of Neurology & Stroke, University Tübingen, Tübingen, Germany; Hertie Institute for Clinical Brain Research, University Tübingen, Tübingen, Germany
| | - John C Rothwell
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Yoshikazu Ugawa
- Department of Neurology, Fukushima Medical University, Fukushima, Japan; Fukushima Global Medical Science Centre, Advanced Clinical Research Centre, Fukushima Medical University, Fukushima, Japan
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6
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Tsuda S, Golam M, Hou J, Nelson R, Bernavil P, Richardson K, Wang KKW, Thompson F, Bose P. Altered monoaminergic levels, spasticity, and balance disability following repetitive blast-induced traumatic brain injury in rats. Brain Res 2020; 1747:147060. [PMID: 32828734 PMCID: PMC10424094 DOI: 10.1016/j.brainres.2020.147060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/28/2020] [Accepted: 08/13/2020] [Indexed: 12/14/2022]
Abstract
Spasticity and balance disability are major complications following traumatic brain injury (TBI). Although monoaminergic inputs provide critical adaptive neuromodulations to the motor system, data are not available regarding the levels of monoamines in the brain regions related to motor functions following repetitive blast TBI (bTBI). The objective of this study was to determine if mild, repetitive bTBI results in spasticity/balance deficits and if these are correlated with altered levels of norepinephrine, dopamine, and serotonin in the brain regions related to the motor system. Repetitive bTBI was induced by a blast overpressure wave in male rats on days 1, 4, and 7. Following bTBI, physiological/behavioral tests were conducted and tissues in the central motor system (i.e., motor cortex, locus coeruleus, vestibular nuclei, and lumbar spinal cord) were collected for electrochemical detection of norepinephrine, dopamine, and serotonin by high-performance liquid chromatography. The results showed that norepinephrine was significantly increased in the locus coeruleus and decreased in the vestibular nuclei, while dopamine was significantly decreased in the vestibular nuclei. On the other hand, serotonin was significantly increased in the motor cortex and the lumbar spinal cord. Because these monoamines play important roles in regulating the excitability of neurons, these results suggest that mild, repetitive bTBI-induced dysregulation of monoaminergic inputs in the central motor system could contribute to spasticity and balance disability. This is the first study to report altered levels of multiple monoamines in the central motor system following acute mild, repetitive bTBI.
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Affiliation(s)
- Shigeharu Tsuda
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Rd, Gainesville 32608-1197, USA; Department of Anesthesiology, College of Medicine, University of Florida, 1600 SW Archer Rd m509, Gainesville, FL 32610-0254, USA
| | - Mustafa Golam
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Rd, Gainesville 32608-1197, USA; Department of Physiological Sciences, University of Florida, 1333 Center Dr, Gainesville, FL 32603, USA
| | - Jiamei Hou
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Rd, Gainesville 32608-1197, USA; Department of Anesthesiology, College of Medicine, University of Florida, 1600 SW Archer Rd m509, Gainesville, FL 32610-0254, USA
| | - Rachel Nelson
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Rd, Gainesville 32608-1197, USA
| | - Phillip Bernavil
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Rd, Gainesville 32608-1197, USA
| | - Kenneth Richardson
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Rd, Gainesville 32608-1197, USA
| | - Kevin K W Wang
- Department of Emergency Medicine, University of Florida, 1329 SW 16th Street, Suite 5270, Gainesville, FL 32610, USA
| | - Floyd Thompson
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Rd, Gainesville 32608-1197, USA; Department of Physiological Sciences, University of Florida, 1333 Center Dr, Gainesville, FL 32603, USA; Department of Neuroscience, University of Florida, 1149 Newell Dr, Gainesville, FL 32610, USA
| | - Prodip Bose
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Rd, Gainesville 32608-1197, USA; Department of Anesthesiology, College of Medicine, University of Florida, 1600 SW Archer Rd m509, Gainesville, FL 32610-0254, USA; Department of Neurology, University of Florida, 1149 Newell Dr, Gainesville, FL 32611, USA.
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7
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Frezel N, Platonova E, Voigt FF, Mateos JM, Kastli R, Ziegler U, Karayannis T, Helmchen F, Wildner H, Zeilhofer HU. In-Depth Characterization of Layer 5 Output Neurons of the Primary Somatosensory Cortex Innervating the Mouse Dorsal Spinal Cord. Cereb Cortex Commun 2020; 1:tgaa052. [PMID: 34296117 PMCID: PMC8152836 DOI: 10.1093/texcom/tgaa052] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 07/07/2020] [Accepted: 08/09/2020] [Indexed: 12/26/2022] Open
Abstract
Neuronal circuits of the spinal dorsal horn integrate sensory information from the periphery with inhibitory and facilitating input from higher central nervous system areas. Most previous work focused on projections descending from the hindbrain. Less is known about inputs descending from the cerebral cortex. Here, we identified cholecystokinin (CCK) positive layer 5 pyramidal neurons of the primary somatosensory cortex (CCK + S1-corticospinal tract [CST] neurons) as a major source of input to the spinal dorsal horn. We combined intersectional genetics and virus-mediated gene transfer to characterize CCK+ S1-CST neurons and to define their presynaptic input and postsynaptic target neurons. We found that S1-CST neurons constitute a heterogeneous population that can be subdivided into distinct molecular subgroups. Rabies-based retrograde tracing revealed monosynaptic input from layer 2/3 pyramidal neurons, from parvalbumin positive cortical interneurons, and from thalamic relay neurons in the ventral posterolateral nucleus. Wheat germ agglutinin-based anterograde tracing identified postsynaptic target neurons in dorsal horn laminae III and IV. About 60% of these neurons were inhibitory and about 60% of all spinal target neurons expressed the transcription factor c-Maf. The heterogeneous nature of both S1-CST neurons and their spinal targets suggest complex roles in the fine-tuning of sensory processing.
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Affiliation(s)
- N Frezel
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zürich, Switzerland
| | - E Platonova
- Center for Microscopy and Image Analysis, University of Zurich, CH-8057 Zürich CH-8057, Switzerland
| | - F F Voigt
- Brain Research Institute, University of Zurich, CHJ-8057 Zurich CH-8057 , Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH Zurich, CH-8057 Zurich CH-8057, Switzerland
| | - J M Mateos
- Center for Microscopy and Image Analysis, University of Zurich, CH-8057 Zürich CH-8057, Switzerland
| | - R Kastli
- Brain Research Institute, University of Zurich, CHJ-8057 Zurich CH-8057 , Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH Zurich, CH-8057 Zurich CH-8057, Switzerland
| | - U Ziegler
- Center for Microscopy and Image Analysis, University of Zurich, CH-8057 Zürich CH-8057, Switzerland
| | - T Karayannis
- Brain Research Institute, University of Zurich, CHJ-8057 Zurich CH-8057 , Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH Zurich, CH-8057 Zurich CH-8057, Switzerland
| | - F Helmchen
- Brain Research Institute, University of Zurich, CHJ-8057 Zurich CH-8057 , Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH Zurich, CH-8057 Zurich CH-8057, Switzerland
| | - H Wildner
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zürich, Switzerland
| | - H U Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zürich, Switzerland.,Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH Zürich), CH-8090 Zürich, Switzerland
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8
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Valverde S, Vandecasteele M, Piette C, Derousseaux W, Gangarossa G, Aristieta Arbelaiz A, Touboul J, Degos B, Venance L. Deep brain stimulation-guided optogenetic rescue of parkinsonian symptoms. Nat Commun 2020; 11:2388. [PMID: 32404907 PMCID: PMC7220902 DOI: 10.1038/s41467-020-16046-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 04/08/2020] [Indexed: 11/09/2022] Open
Abstract
Deep brain stimulation (DBS) of the subthalamic nucleus is a symptomatic treatment of Parkinson’s disease but benefits only to a minority of patients due to stringent eligibility criteria. To investigate new targets for less invasive therapies, we aimed at elucidating key mechanisms supporting deep brain stimulation efficiency. Here, using in vivo electrophysiology, optogenetics, behavioral tasks and mathematical modeling, we found that subthalamic stimulation normalizes pathological hyperactivity of motor cortex pyramidal cells, while concurrently activating somatostatin and inhibiting parvalbumin interneurons. In vivo opto-activation of cortical somatostatin interneurons alleviates motor symptoms in a parkinsonian mouse model. A computational model highlights that a decrease in pyramidal neuron activity induced by DBS or by a stimulation of cortical somatostatin interneurons can restore information processing capabilities. Overall, these results demonstrate that activation of cortical somatostatin interneurons may constitute a less invasive alternative than subthalamic stimulation. Deep brain stimulation (DBS) is a symptomatic treatment of Parkinson’s disease (PD) that benefits only a minority of patients. Here, the authors show that activation of cortical somatostatin interneurons alleviates motor symptoms in a mouse model of PD and may constitute a less invasive alternative than DBS.
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Affiliation(s)
- Sébastien Valverde
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR7241/INSERM U1050, MemoLife Labex, 75005, Paris, France
| | - Marie Vandecasteele
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR7241/INSERM U1050, MemoLife Labex, 75005, Paris, France
| | - Charlotte Piette
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR7241/INSERM U1050, MemoLife Labex, 75005, Paris, France.,Department of Mathematics and Volen National Center for Complex Systems, Brandeis University, Waltham, MA, USA
| | - Willy Derousseaux
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR7241/INSERM U1050, MemoLife Labex, 75005, Paris, France
| | - Giuseppe Gangarossa
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR7241/INSERM U1050, MemoLife Labex, 75005, Paris, France
| | - Asier Aristieta Arbelaiz
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR7241/INSERM U1050, MemoLife Labex, 75005, Paris, France
| | - Jonathan Touboul
- Department of Mathematics and Volen National Center for Complex Systems, Brandeis University, Waltham, MA, USA
| | - Bertrand Degos
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR7241/INSERM U1050, MemoLife Labex, 75005, Paris, France.,Department of Neurology, Avicenne University Hospital, Sorbonne Paris Nord University, 93009, Bobigny, France
| | - Laurent Venance
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR7241/INSERM U1050, MemoLife Labex, 75005, Paris, France.
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9
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Saiki A, Sakai Y, Fukabori R, Soma S, Yoshida J, Kawabata M, Yawo H, Kobayashi K, Kimura M, Isomura Y. In Vivo Spiking Dynamics of Intra- and Extratelencephalic Projection Neurons in Rat Motor Cortex. Cereb Cortex 2019; 28:1024-1038. [PMID: 28137723 DOI: 10.1093/cercor/bhx012] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 01/11/2017] [Indexed: 12/15/2022] Open
Abstract
In motor cortex, 2 types of deep layer pyramidal cells send their axons to other areas: intratelencephalic (IT)-type neurons specifically project bilaterally to the cerebral cortex and striatum, whereas neurons of the extratelencephalic (ET)-type, termed conventionally pyramidal tract-type, project ipsilaterally to the thalamus and other areas. Although they have totally different synaptic and membrane potential properties in vitro, little is known about the differences between them in ongoing spiking dynamics in vivo. We identified IT-type and ET-type neurons, as well as fast-spiking-type interneurons, using novel multineuronal analysis based on optogenetically evoked spike collision along their axons in behaving/resting rats expressing channelrhodopsin-2 (Multi-Linc method). We found "postspike suppression" (~100 ms) as a characteristic of ET-type neurons in spike auto-correlograms, and it remained constant independent of behavioral conditions in functionally different ET-type neurons. Postspike suppression followed even solitary spikes, and spike bursts significantly extended its duration. We also observed relatively strong spike synchrony in pairs containing IT-type neurons. Thus, spiking dynamics in IT-type and ET-type neurons may be optimized differently for precise and coordinated motor control.
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Affiliation(s)
- Akiko Saiki
- Brain Science Institute, Tamagawa University, Tokyo 194-8610, Japan.,JST CREST, Tokyo 102-0076, Japan.,Department of Neurobiology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Yutaka Sakai
- Brain Science Institute, Tamagawa University, Tokyo 194-8610, Japan.,JST CREST, Tokyo 102-0076, Japan.,Graduate School of Brain Sciences, Tamagawa University, Tokyo 194-8610, Japan
| | - Ryoji Fukabori
- JST CREST, Tokyo 102-0076, Japan.,Department of Molecular Genetics, Institute of Biomedical Sciences, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan
| | - Shogo Soma
- Brain Science Institute, Tamagawa University, Tokyo 194-8610, Japan.,Japan Society for the Promotion of Science, Tokyo 102-0083, Japan
| | - Junichi Yoshida
- Graduate School of Brain Sciences, Tamagawa University, Tokyo 194-8610, Japan.,Japan Society for the Promotion of Science, Tokyo 102-0083, Japan
| | - Masanori Kawabata
- Graduate School of Brain Sciences, Tamagawa University, Tokyo 194-8610, Japan
| | - Hiromu Yawo
- Department of Developmental Biology and Neuroscience, Tohoku University Graduate School of Life Sciences, Sendai 980-8577, Japan
| | - Kazuto Kobayashi
- JST CREST, Tokyo 102-0076, Japan.,Department of Molecular Genetics, Institute of Biomedical Sciences, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan
| | - Minoru Kimura
- Brain Science Institute, Tamagawa University, Tokyo 194-8610, Japan.,Graduate School of Brain Sciences, Tamagawa University, Tokyo 194-8610, Japan
| | - Yoshikazu Isomura
- Brain Science Institute, Tamagawa University, Tokyo 194-8610, Japan.,JST CREST, Tokyo 102-0076, Japan.,Graduate School of Brain Sciences, Tamagawa University, Tokyo 194-8610, Japan
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10
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Synaptic mechanisms underlying the intense firing of neocortical layer 5B pyramidal neurons in response to cortico-cortical inputs. Brain Struct Funct 2019; 224:1403-1416. [PMID: 30756190 PMCID: PMC6509071 DOI: 10.1007/s00429-019-01842-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 01/30/2019] [Indexed: 11/23/2022]
Abstract
In the neocortex, large layer 5B pyramidal neurons implement a high-density firing code. In contrast, other subtypes of pyramidal neurons, including those in layer 2/3, are functionally characterized by their sparse firing rate. Here, we investigate the synaptic basis of this behavior by comparing the properties of the postsynaptic responses evoked by cortical inputs in layer 5B and layer 2/3 pyramidal neurons in vitro. We demonstrate that a major determinant of the larger responsiveness of layer 5B with respect to layer 2/3 pyramidal neurons is the different properties in their inhibitory postsynaptic currents (IPSCs): layer 5B pyramidal neurons have IPSCs of lower amplitude and the temporal delay between the excitatory and inhibitory synaptic components is also larger in these cells. Our data also suggest that this difference depends on the lower gain of the cortical response of layer 5 parvalbumin-positive fast-spiking (PV-FS) interneurons with respect to PV-FS cells from layer 2/3. We propose that, while superficial PV-FS interneurons are well suited to provide a powerful feed-forward inhibitory control of pyramidal neuron responses, layer 5 PV-FS interneurons are mainly engaged in a feedback inhibitory loop and only after a substantial recruitment of surrounding pyramidal cells do they respond to an external input.
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11
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Steketee JD, Liu K. Effects of repeated cocaine administration on dopamine D1 receptor modulation of mesocorticolimbic GABA and glutamate transmission. Brain Res 2018; 1698:106-113. [PMID: 30075100 DOI: 10.1016/j.brainres.2018.07.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 06/27/2018] [Accepted: 07/30/2018] [Indexed: 11/30/2022]
Abstract
Repeated cocaine exposure alters medial prefrontal cortex (mPFC) function to allow for enhanced excitatory transmission to the nucleus accumbens and ventral tegmental area (VTA). Previous studies have demonstrated changes in receptor function in the mPFC in animals repeatedly exposed to cocaine that produced increased excitatory output. The present report tested the hypothesis that daily injections of cocaine would enhance D1 receptor responsiveness by infusing the D1 receptor agonist SKF 38393 into the mPFC and monitoring glutamate and/or GABA release in the mPFC, nucleus accumbens and VTA of saline- and cocaine-pretreated animals using in vivo microdialysis. The data demonstrated that intra-mPFC SKF 38393 reduced GABA and glutamate levels in the mPFC in control animals. Intra-mPFC SKF 38393 had no effect on glutamate levels in animals 1 day after daily cocaine treatments, increased mPFC glutamate at 7 days of withdrawal and reverted to decreasing glutamate at 30 days of withdrawal. SKF 38393 induced reduction in mPFC GABA is lost at 7 and 30 days of withdrawal. Intra-mPFC SKF 38393 did not alter glutamate levels in the nucleus accumbens or VTA of control animals. Infusion of SKF 38393 into the mPFC of animals previously exposed to cocaine increased and reduced glutamate release in the nucleus accumbens after 7 and 30 days of withdrawal, respectively and increased glutamate levels in the VTA 7 and 30 days after daily cocaine injections. The data suggest that repeated cocaine exposure alters D1 receptor function in the mPFC that could contribute to enhanced behavioral responses that occur following repeated cocaine.
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Affiliation(s)
- Jeffery D Steketee
- Department Pharmacology, University of Tennessee Health Science Center, Memphis, TN 38163, United States.
| | - Kun Liu
- Department Pharmacology, University of Tennessee Health Science Center, Memphis, TN 38163, United States
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12
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Preferential inputs from cholecystokinin-positive neurons to the somatic compartment of parvalbumin-expressing neurons in the mouse primary somatosensory cortex. Brain Res 2018; 1695:18-30. [DOI: 10.1016/j.brainres.2018.05.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 05/10/2018] [Accepted: 05/19/2018] [Indexed: 12/22/2022]
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13
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Tanaka YH, Tanaka YR, Kondo M, Terada SI, Kawaguchi Y, Matsuzaki M. Thalamocortical Axonal Activity in Motor Cortex Exhibits Layer-Specific Dynamics during Motor Learning. Neuron 2018; 100:244-258.e12. [PMID: 30174116 DOI: 10.1016/j.neuron.2018.08.016] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 05/17/2018] [Accepted: 08/10/2018] [Indexed: 01/09/2023]
Abstract
The thalamus is the hub through which neural signals are transmitted from the basal ganglia and cerebellum to the neocortex. However, thalamocortical axonal activity during motor learning remains largely undescribed. We conducted two-photon calcium imaging of thalamocortical axonal activity in the motor cortex of mice learning a self-initiated lever-pull task. Layer 1 (L1) axons came to exhibit activity at lever-pull initiation and termination, while layer 3 (L3) axons did so at lever-pull initiation. L1 population activity had a sequence structure related to both lever-pull duration and reproducibility. Stimulation of the substantia nigra pars reticulata activated more L1 than L3 axons, whereas deep cerebellar nuclei (DCN) stimulation did the opposite. Lesions to either the dorsal striatum or the DCN impaired motor learning and disrupted temporal dynamics in both layers. Thus, layer-specific thalamocortical signals evolve with the progression of learning, which requires both the basal ganglia and cerebellar activities.
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Affiliation(s)
- Yasuyo H Tanaka
- Division of Brain Circuits, National Institute for Basic Biology, Okazaki, Japan; CREST, Japan Science and Technology Agency, Saitama, Japan; Department of Physiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yasuhiro R Tanaka
- Division of Brain Circuits, National Institute for Basic Biology, Okazaki, Japan; CREST, Japan Science and Technology Agency, Saitama, Japan; Department of Physiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Masashi Kondo
- Division of Brain Circuits, National Institute for Basic Biology, Okazaki, Japan; Department of Physiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Shin-Ichiro Terada
- Division of Brain Circuits, National Institute for Basic Biology, Okazaki, Japan; Department of Physiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Yasuo Kawaguchi
- CREST, Japan Science and Technology Agency, Saitama, Japan; SOKENDAI (the Graduate University of Advanced Studies), Okazaki, Japan; Division of Cerebral Circuitry, National Institute for Physiological Sciences, Okazaki, Japan
| | - Masanori Matsuzaki
- Division of Brain Circuits, National Institute for Basic Biology, Okazaki, Japan; CREST, Japan Science and Technology Agency, Saitama, Japan; Department of Physiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; SOKENDAI (the Graduate University of Advanced Studies), Okazaki, Japan; International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo Institutes for Advanced Study, Tokyo, Japan.
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14
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Jiang X, Shen S, Sinz F, Reimer J, Cadwell CR, Berens P, Ecker AS, Patel S, Denfield GH, Froudarakis E, Li S, Walker E, Tolias AS. Response to Comment on “Principles of connectivity among morphologically defined cell types in adult neocortex”. Science 2016; 353:1108. [DOI: 10.1126/science.aaf6102] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 08/03/2016] [Indexed: 11/02/2022]
Affiliation(s)
- Xiaolong Jiang
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Shan Shen
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Fabian Sinz
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Jacob Reimer
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Cathryn R. Cadwell
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Philipp Berens
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Bernstein Centre for Computational Neuroscience, Tübingen, Germany
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Werner Reichardt Center for Integrative Neuroscience and Institute of Theoretical Physics, University of Tübingen, Tübingen, Germany
| | - Alexander S. Ecker
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Bernstein Centre for Computational Neuroscience, Tübingen, Germany
- Werner Reichardt Center for Integrative Neuroscience and Institute of Theoretical Physics, University of Tübingen, Tübingen, Germany
| | - Saumil Patel
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - George H. Denfield
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | | | - Shuang Li
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Edgar Walker
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Andreas S. Tolias
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Bernstein Centre for Computational Neuroscience, Tübingen, Germany
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15
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Fogarty MJ, Mu EWH, Noakes PG, Lavidis NA, Bellingham MC. Marked changes in dendritic structure and spine density precede significant neuronal death in vulnerable cortical pyramidal neuron populations in the SOD1(G93A) mouse model of amyotrophic lateral sclerosis. Acta Neuropathol Commun 2016; 4:77. [PMID: 27488828 PMCID: PMC4973034 DOI: 10.1186/s40478-016-0347-y] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 07/12/2016] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is characterised by the death of upper (corticospinal) and lower motor neurons (MNs) with progressive muscle weakness. This incurable disease is clinically heterogeneous and its aetiology remains unknown. Increased excitability of corticospinal MNs has been observed prior to symptoms in human and rodent studies. Increased excitability has been correlated with structural changes in neuronal dendritic arbors and spines for decades. Here, using a modified Golgi-Cox staining method, we have made the first longitudinal study examining the dendrites of pyramidal neurons from the motor cortex, medial pre-frontal cortex, somatosensory cortex and entorhinal cortex of hSOD1G93A (SOD1) mice compared to wild-type (WT) littermate controls at postnatal (P) days 8–15, 28–35, 65–75 and 120. Progressive decreases in dendritic length and spine density commencing at pre-symptomatic ages (P8-15 or P28-35) were observed in layer V pyramidal neurons within the motor cortex and medial pre-frontal cortex of SOD1 mice compared to WT mice. Spine loss without concurrent dendritic pathology was present in the pyramidal neurons of the somatosensory cortex from disease-onset (P65-75). Our results from the SOD1 model suggest that dendritic and dendritic spine changes foreshadow and underpin the neuromotor phenotypes present in ALS and may contribute to the varied cognitive, executive function and extra-motor symptoms commonly seen in ALS patients. Determining if these phenomena are compensatory or maladaptive may help explain differential susceptibility of neurons to degeneration in ALS.
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16
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Carron SF, Yan EB, Alwis DS, Rajan R. Differential susceptibility of cortical and subcortical inhibitory neurons and astrocytes in the long term following diffuse traumatic brain injury. J Comp Neurol 2016; 524:3530-3560. [PMID: 27072754 DOI: 10.1002/cne.24014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 04/01/2016] [Accepted: 04/04/2016] [Indexed: 02/02/2023]
Abstract
Long-term diffuse traumatic brain injury (dTBI) causes neuronal hyperexcitation in supragranular layers in sensory cortex, likely through reduced inhibition. Other forms of TBI affect inhibitory interneurons in subcortical areas but it is unknown if this occurs in cortex, or in any brain area in dTBI. We investigated dTBI effects on inhibitory neurons and astrocytes in somatosensory and motor cortex, and hippocampus, 8 weeks post-TBI. Brains were labeled with antibodies against calbindin (CB), parvalbumin (PV), calretinin (CR) and neuropeptide Y (NPY), and somatostatin (SOM) and glial fibrillary acidic protein (GFAP), a marker for astrogliosis during neurodegeneration. Despite persistent behavioral deficits in rotarod performance up to the time of brain extraction (TBI = 73.13 ± 5.23% mean ± SEM, Sham = 92.29 ± 5.56%, P < 0.01), motor cortex showed only a significant increase, in NPY neurons in supragranular layers (mean cells/mm2 ± SEM, Sham = 16 ± 0.971, TBI = 25 ± 1.51, P = 0.001). In somatosensory cortex, only CR+ neurons showed changes, being decreased in supragranular (TBI = 19 ± 1.18, Sham = 25 ± 1.10, P < 0.01) and increased in infragranular (TBI = 28 ± 1.35, Sham = 24 ± 1.07, P < 0.05) layers. Heterogeneous changes were seen in hippocampal staining: CB+ decreased in dentate gyrus (TBI = 2 ± 0.382, Sham = 4 ± 0.383, P < 0.01), PV+ increased in CA1 (TBI = 39 ± 1.26, Sham = 33 ± 1.69, P < 0.05) and CA2/3 (TBI = 26 ± 2.10, Sham = 20 ± 1.49, P < 0.05), and CR+ decreased in CA1 (TBI = 10 ± 1.02, Sham = 14 ± 1.14, P < 0.05). Astrogliosis significantly increased in corpus callosum (TBI = 6.7 ± 0.69, Sham = 2.5 ± 0.38; P = 0.007). While dTBI effects on inhibitory neurons appear region- and type-specific, a common feature in all cases of decrease was that changes occurred in dendrite targeting interneurons involved in neuronal integration. J. Comp. Neurol. 524:3530-3560, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Simone F Carron
- Department of Physiology, Monash University, Melbourne, VIC, Australia
| | - Edwin B Yan
- Department of Physiology, Monash University, Melbourne, VIC, Australia
| | - Dasuni S Alwis
- Department of Physiology, Monash University, Melbourne, VIC, Australia
| | - Ramesh Rajan
- Department of Physiology, Monash University, Melbourne, VIC, Australia.
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17
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Clark R, Blizzard C, Dickson T. Inhibitory dysfunction in amyotrophic lateral sclerosis: future therapeutic opportunities. Neurodegener Dis Manag 2015; 5:511-25. [DOI: 10.2217/nmt.15.49] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In amyotrophic lateral sclerosis, motor neuron hyperexcitability and inhibitory dysfunction is emerging as a potential causative link in the dysfunction and degeneration of the motoneuronal circuitry that characterizes the disease. Interneurons, as key regulators of excitability, may mediate much of this imbalance, yet we know little about the way in which inhibitory deficits perturb excitability. In this review, we explore inhibitory control of excitability and the potential contribution of altered inhibition to amyotrophic lateral sclerosis disease processes and vulnerabilities, identifying important windows of therapeutic opportunity and potential interventions, specifically targeting inhibitory control at key disease stages.
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Affiliation(s)
- Rosemary Clark
- Menzies Institute for Medical Research, University of Tasmania, Hobart TAS 7000, Australia
| | - Catherine Blizzard
- Menzies Institute for Medical Research, University of Tasmania, Hobart TAS 7000, Australia
| | - Tracey Dickson
- Menzies Institute for Medical Research, University of Tasmania, Hobart TAS 7000, Australia
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18
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Pavlides A, Hogan SJ, Bogacz R. Computational Models Describing Possible Mechanisms for Generation of Excessive Beta Oscillations in Parkinson's Disease. PLoS Comput Biol 2015; 11:e1004609. [PMID: 26683341 PMCID: PMC4684204 DOI: 10.1371/journal.pcbi.1004609] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 10/07/2015] [Indexed: 01/20/2023] Open
Abstract
In Parkinson's disease, an increase in beta oscillations within the basal ganglia nuclei has been shown to be associated with difficulty in movement initiation. An important role in the generation of these oscillations is thought to be played by the motor cortex and by a network composed of the subthalamic nucleus (STN) and the external segment of globus pallidus (GPe). Several alternative models have been proposed to describe the mechanisms for generation of the Parkinsonian beta oscillations. However, a recent experimental study of Tachibana and colleagues yielded results which are challenging for all published computational models of beta generation. That study investigated how the presence of beta oscillations in a primate model of Parkinson's disease is affected by blocking different connections of the STN-GPe circuit. Due to a large number of experimental conditions, the study provides strong constraints that any mechanistic model of beta generation should satisfy. In this paper we present two models consistent with the data of Tachibana et al. The first model assumes that Parkinsonian beta oscillation are generated in the cortex and the STN-GPe circuits resonates at this frequency. The second model additionally assumes that the feedback from STN-GPe circuit to cortex is important for maintaining the oscillations in the network. Predictions are made about experimental evidence that is required to differentiate between the two models, both of which are able to reproduce firing rates, oscillation frequency and effects of lesions carried out by Tachibana and colleagues. Furthermore, an analysis of the models reveals how the amplitude and frequency of the generated oscillations depend on parameters.
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Affiliation(s)
- Alex Pavlides
- MRC Unit for Brain Network Dynamics, University of Oxford, Oxford, United Kingdom
- Nuffield Department of Clinical Neuroscience, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
- Faculty of Engineering, University of Bristol, Bristol, United Kingdom
| | - S. John Hogan
- Faculty of Engineering, University of Bristol, Bristol, United Kingdom
| | - Rafal Bogacz
- MRC Unit for Brain Network Dynamics, University of Oxford, Oxford, United Kingdom
- Nuffield Department of Clinical Neuroscience, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
- Faculty of Engineering, University of Bristol, Bristol, United Kingdom
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19
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Yekhlef L, Breschi GL, Lagostena L, Russo G, Taverna S. Selective activation of parvalbumin- or somatostatin-expressing interneurons triggers epileptic seizurelike activity in mouse medial entorhinal cortex. J Neurophysiol 2014; 113:1616-30. [PMID: 25505119 DOI: 10.1152/jn.00841.2014] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
GABAergic interneurons are thought to play a critical role in eliciting interictal spikes (IICs) and triggering ictal discharges in temporal lobe epilepsy, yet the contribution of different interneuronal subtypes to seizure initiation is still largely unknown. Here we took advantage of optogenetic techniques combined with patch-clamp and field recordings to selectively stimulate parvalbumin (PV)- or somatostatin (SOM)-positive interneurons expressing channelrhodopsin-2 (CHR-2) in layers II-III of adult mouse medial entorhinal cortical slices during extracellular perfusion with the proconvulsive compound 4-aminopyridine (4-AP, 100-200 μM). In control conditions, blue laser photostimulation selectively activated action potential firing in either PV or SOM interneurons and, in both cases, caused a robust GABAA-receptor-mediated inhibition in pyramidal cells (PCs). During perfusion with 4-AP, brief photostimuli (300 ms) activating either PV or SOM interneurons induced patterns of epileptiform activity that closely replicated spontaneously occurring IICs and tonic-clonic ictal discharges. Laser-induced synchronous firing in both interneuronal types elicited large compound GABAergic inhibitory postsynaptic currents (IPSCs) correlating with IICs and preictal spikes. In addition, spontaneous and laser-induced epileptic events were similarly initiated in concurrence with a large increase in extracellular potassium concentration. Finally, interneuron activation was unable to stop or significantly shorten the progression of seizurelike episodes. These results suggest that entorhinal PV and SOM interneurons are nearly equally effective in triggering interictal and ictal discharges that closely resemble human temporal lobe epileptic activity.
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Affiliation(s)
- Latefa Yekhlef
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Gian Luca Breschi
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Laura Lagostena
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Giovanni Russo
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Stefano Taverna
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa, Italy
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20
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Hioki H. Compartmental organization of synaptic inputs to parvalbumin-expressing GABAergic neurons in mouse primary somatosensory cortex. Anat Sci Int 2014; 90:7-21. [PMID: 25467527 DOI: 10.1007/s12565-014-0264-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 11/17/2014] [Indexed: 12/19/2022]
Abstract
Parvalbumin (PV)-positive fast-spiking cells in the neocortex are known to generate gamma oscillations by mutual chemical and electrical connections. Recent findings suggest that this rhythm might be responsible for higher-order brain functions, and related to psychiatric disorders. To elucidate the precise structural rules of the connections of PV neurons, we first produced genetic tools. Using a lentiviral expression system, we developed neuron-specific promoters and a new reporter protein that labels the somatodendritic membrane of neurons. We applied the reporter protein to the generation of transgenic mice, and succeeded in visualizing the dendrites and cell bodies of PV neurons efficiently. Then we analyzed excitatory and inhibitory inputs to PV neurons in the primary somatosensory cortex using the mice. Corticocortical glutamatergic inputs were more frequently found on the distal dendrites than on the soma, whereas thalamocortical inputs did not differ between the proximal and distal portions. Corticocortical inhibitory inputs were more densely distributed on the soma than on the dendrites. We further investigated which types of neocortical GABAergic neurons preferred the PV soma over their dendrites. We revealed that the somatic and dendritic compartments principally received GABAergic inputs from vasoactive intestinal polypeptide (VIP)-positive and PV neurons, respectively. This compartmental organization suggests that PV neurons communicate with each other mainly via the dendrites, and that their activity is effectively controlled by the somatic inputs of VIP neurons. These findings provide new insights into the neuronal circuits involving PV neurons, and contribute to a better understanding of brain functions and mental disorders.
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Affiliation(s)
- Hiroyuki Hioki
- Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan,
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21
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Molecular and functional diversity of GABA-A receptors in the enteric nervous system of the mouse colon. J Neurosci 2014; 34:10361-78. [PMID: 25080596 DOI: 10.1523/jneurosci.0441-14.2014] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The enteric nervous system (ENS) provides the intrinsic neural control of the gastrointestinal tract (GIT) and regulates virtually all GI functions. Altered neuronal activity within the ENS underlies various GI disorders with stress being a key contributing factor. Thus, elucidating the expression and function of the neurotransmitter systems, which determine neuronal excitability within the ENS, such as the GABA-GABAA receptor (GABAAR) system, could reveal novel therapeutic targets for such GI disorders. Molecular and functionally diverse GABAARs modulate rapid GABAergic-mediated regulation of neuronal excitability throughout the nervous system. However, the cellular and subcellular GABAAR subunit expression patterns within neurochemically defined cellular circuits of the mouse ENS, together with the functional contribution of GABAAR subtypes to GI contractility remains to be determined. Immunohistochemical analyses revealed that immunoreactivity for the GABAAR gamma (γ) 2 and alphas (α) 1, 2, 3 subunits was located on somatodendritic surfaces of neurochemically distinct myenteric plexus neurons, while being on axonal compartments of submucosal plexus neurons. In contrast, immunoreactivity for the α4-5 subunits was only detected in myenteric plexus neurons. Furthermore, α-γ2 subunit immunoreactivity was located on non-neuronal interstitial cells of Cajal. In organ bath studies, GABAAR subtype-specific ligands had contrasting effects on the force and frequency of spontaneous colonic longitudinal smooth muscle contractions. Finally, enhancement of γ2-GABAAR function with alprazolam reversed the stress-induced increase in the force of spontaneous colonic contractions. The study demonstrates the molecular and functional diversity of the GABAAR system within the mouse colon providing a framework for developing GABAAR-based therapeutics in GI disorders.
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22
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Jara JH, Genç B, Klessner JL, Ozdinler PH. Retrograde labeling, transduction, and genetic targeting allow cellular analysis of corticospinal motor neurons: implications in health and disease. Front Neuroanat 2014; 8:16. [PMID: 24723858 PMCID: PMC3972458 DOI: 10.3389/fnana.2014.00016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 03/10/2014] [Indexed: 12/11/2022] Open
Abstract
Corticospinal motor neurons (CSMN) have a unique ability to receive, integrate, translate, and transmit the cerebral cortex's input toward spinal cord targets and therefore act as a “spokesperson” for the initiation and modulation of voluntary movements that require cortical input. CSMN degeneration has an immense impact on motor neuron circuitry and is one of the underlying causes of numerous neurodegenerative diseases, such as primary lateral sclerosis (PLS), hereditary spastic paraplegia (HSP), and amyotrophic lateral sclerosis (ALS). In addition, CSMN death results in long-term paralysis in spinal cord injury patients. Detailed cellular analyses are crucial to gain a better understanding of the pathologies underlying CSMN degeneration. However, visualizing and identifying these vulnerable neuron populations in the complex and heterogeneous environment of the cerebral cortex have proved challenging. Here, we will review recent developments and current applications of novel strategies that reveal the cellular and molecular basis of CSMN health and vulnerability. Such studies hold promise for building long-term effective treatment solutions in the near future.
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Affiliation(s)
- Javier H Jara
- Davee Department of Neurology and Clinical Neurological Sciences, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
| | - Barış Genç
- Davee Department of Neurology and Clinical Neurological Sciences, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
| | - Jodi L Klessner
- Davee Department of Neurology and Clinical Neurological Sciences, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
| | - P Hande Ozdinler
- Davee Department of Neurology and Clinical Neurological Sciences, Feinberg School of Medicine, Northwestern University Chicago, IL, USA ; Robert H. Lurie Cancer Center, Feinberg School of Medicine, Northwestern University Chicago, IL, USA ; Cognitive Neurology and Alzheimer's Disease Center, Feinberg School of Medicine, Northwestern University Chicago IL, USA
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23
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Brecht M, Hatsopoulos NG, Kaneko T, Shepherd GMG. Motor cortex microcircuits. Front Neural Circuits 2013; 7:196. [PMID: 24376400 PMCID: PMC3859911 DOI: 10.3389/fncir.2013.00196] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Accepted: 11/26/2013] [Indexed: 12/04/2022] Open
Affiliation(s)
- Michael Brecht
- Bernstein Center for Computational Neuroscience, Humboldt University, and Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Germany
| | - Nicholas G Hatsopoulos
- Department of Organismal Biology and Anatomy, Committees on Computational Neuroscience and Neurobiology, University of Chicago Chicago, IL, USA
| | - Takeshi Kaneko
- Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University Kyoto, Japan
| | - Gordon M G Shepherd
- Department of Physiology, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
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24
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Packer AM, McConnell DJ, Fino E, Yuste R. Axo-dendritic overlap and laminar projection can explain interneuron connectivity to pyramidal cells. Cereb Cortex 2013; 23:2790-802. [PMID: 22941716 PMCID: PMC3968298 DOI: 10.1093/cercor/bhs210] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Neocortical GABAergic interneurons have important roles in the normal and pathological states of the circuit. Recent work has revealed that somatostatin-positive (SOM) and parvalbumin-positive (PV) interneurons connect promiscuously to pyramidal cells (PCs). We investigated whether Peters' rule, that is, the spatial overlap of axons and dendrites, could explain this unspecific connectivity. We reconstructed the morphologies of P11-17 mouse SOM and PV interneurons and their PC targets, and performed Monte Carlo simulations to build maps of predicted connectivity based on Peters' rule. We then compared the predicted with the real connectivity maps, measured with 2-photon uncaging experiments, and found no statistical differences between them in the probability of connection as a function of distance and in the spatial structure of the maps. Finally, using reconstructions of connected SOM-PCs and PV-PCs, we investigated the subcellular targeting specificity, by analyzing the postsynaptic position of the contacts, and found that their spatial distributions match the distribution of postsynaptic PC surface area, in agreement with Peters' rule. Thus, the spatial profile of the connectivity maps and even the postsynaptic position of interneuron contacts could result from the mere overlap of axonal and dendritic arborizations and their laminar projections patterns.
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Affiliation(s)
- Adam M Packer
- HHMI, Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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25
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Kaneko T. Local connections of excitatory neurons in motor-associated cortical areas of the rat. Front Neural Circuits 2013; 7:75. [PMID: 23754982 PMCID: PMC3664775 DOI: 10.3389/fncir.2013.00075] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 04/03/2013] [Indexed: 11/30/2022] Open
Abstract
In spite of recent progress in brain sciences, the local circuit of the cerebral neocortex, including motor areas, still remains elusive. Morphological works on excitatory cortical circuitry from thalamocortical (TC) afferents to corticospinal neurons (CSNs) in motor-associated areas are reviewed here. First, TC axons of motor thalamic nuclei have been re-examined by the single-neuron labeling method. There are middle layer (ML)-targeting and layer (L) 1-preferring TC axon types in motor-associated areas, being analogous to core and matrix types, respectively, of Jones (1998) in sensory areas. However, the arborization of core-like motor TC axons spreads widely and disregards the columnar structure that is the basis of information processing in sensory areas, suggesting that motor areas adopt a different information-processing framework such as area-wide laminar organization. Second, L5 CSNs receive local excitatory inputs not only from L2/3 pyramidal neurons but also from ML spiny neurons, the latter directly processing cerebellar information of core-like TC neurons (TCNs). In contrast, basal ganglia information is targeted to apical dendrites of L2/3 and L5 pyramidal neurons through matrix TCNs. Third, L6 corticothalamic neurons (CTNs) are most densely innervated by ML spiny neurons located just above CTNs. Since CTNs receive only weak connections from L2/3 and L5 pyramidal neurons, the TC recurrent circuit composed of TCNs, ML spiny neurons and CTNs appears relatively independent of the results of processing in L2/3 and L5. It is proposed that two circuits sharing the same TC projection and ML neurons are embedded in the neocortex: one includes L2/3 and L5 neurons, processes afferent information in a feedforward way and sends the processed information to other cortical areas and subcortical regions; and the other circuit participates in a dynamical system of the TC recurrent circuit and may serve as the basis of autonomous activity of the neocortex.
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Affiliation(s)
- Takeshi Kaneko
- Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University Kyoto, Japan
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26
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Abstract
Corticostriatal projections are essential components of forebrain circuits and are widely involved in motivated behaviour. These axonal projections are formed by two distinct classes of cortical neurons, intratelencephalic (IT) and pyramidal tract (PT) neurons. Convergent evidence points to IT versus PT differentiation of the corticostriatal system at all levels of functional organization, from cellular signalling mechanisms to circuit topology. There is also growing evidence for IT/PT imbalance as an aetiological factor in neurodevelopmental, neuropsychiatric and movement disorders - autism, amyotrophic lateral sclerosis, obsessive-compulsive disorder, schizophrenia, Huntington's and Parkinson's diseases and major depression are highlighted here.
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Affiliation(s)
- Gordon M. G. Shepherd
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA;
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27
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Cell type-specific inhibitory inputs to dendritic and somatic compartments of parvalbumin-expressing neocortical interneuron. J Neurosci 2013; 33:544-55. [PMID: 23303934 DOI: 10.1523/jneurosci.2255-12.2013] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Parvalbumin (PV)-producing fast-spiking neurons are well known to generate gamma oscillation by mutual chemical and electrical connections in the neocortex. Although it was clearly demonstrated that PV neurons form a dense gap junction network with each other not only at the proximal sites but also at the distal dendrites, comprehensive quantitative data on the chemical connections are still lacking. To elucidate the connectivity, we investigated inhibitory inputs to PV neurons in the somatosensory cortex, using the transgenic mice in which the dendrites and cell bodies of PV neurons were clearly visualized. We first examined GABAergic inputs to PV neurons by labeling postsynaptic and presynaptic sites with the immunoreactivities for gephyrin and vesicular GABA transporter. The density of GABAergic inputs was highest on the cell bodies, and almost linearly decreased to the distal dendrites. We then investigated inhibitory inputs from three distinct subgroups of GABAergic interneurons by visualizing the axon terminals immunopositive for PV, somatostatin (SOM), or vasoactive intestinal polypeptide (VIP). PV and SOM inputs were frequently located on the dendrites with the ratio of 2.5:1, but much less on the cell bodies. By contrast, VIP inputs clearly preferred the cell bodies to the dendrites. Consequently, the dendritic and somatic compartments of PV neurons received ∼60 and 62% of inhibitory inputs from PV and VIP neurons, respectively. This compartmental organization of inhibitory inputs suggests that PV neurons, together with gap junctions, constitute mutual connections at the dendrites, and that their activities are negatively controlled by the somatic inputs of VIP neurons.
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Gabbott P, Warner TA, Brown J, Salway P, Gabbott T, Busby S. Amygdala afferents monosynaptically innervate corticospinal neurons in rat medial prefrontal cortex. J Comp Neurol 2012; 520:2440-58. [PMID: 22247040 DOI: 10.1002/cne.23047] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The amygdala provides the medial prefrontal cortex (mPFC; areas 25, 32, and 24b) with salient emotional information. This study investigated the synaptic connectivity of identified amygdalocortical boutons (ACBs; labeled anterogradely following injections of Phaseolus vulgaris leucoagglutinin into the basolateral nucleus of the amygdala), with the dendritic processes of identified layer 5 corticospinal neurons in the rat mPFC. The corticospinal (CS) neurons in the mPFC had been retrogradely labeled with rhodamine fluorescent latex microspheres and subsequently intracellularly filled with biotinylated lucifer yellow to visualize their basal and apical dendrites. Two main classes of mPFC CS neurons were identified. Type 1 cells had apical dendrites bearing numerous dendritic spines with radiate basal dendritic arbors. Type 2 cells possessed apical dendrites with greatly reduced spine densities and a broad range of basal dendritic tree morphologies. Identified ACBs made asymmetric synaptic junctions with labeled dendritic spines and the labeled apical and basal dendritic shafts of identified CS neurons. On average, eight ACBs were closely associated with the labeled basal dendritic arbors of type 1 CS neurons and five ACBs with type 2 CS basal dendrites. The mean Scholl distance of ACBs from CS somata (for both types 1 and 2 cells) was 66 μm-coinciding with a region containing the highest length density of CS neuron basal dendrites. These results indicate that neurons in the BLA can monosynaptically influence CS neurons in the mPFC that project to autonomic regions of the thoracic spinal cord and probably to other additional subcortical target regions, such as the lateral hypothalamus.
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Affiliation(s)
- Paul Gabbott
- Department of Pharmacology, Oxford University, Oxford OX1 3QT, United Kingdom.
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29
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Suter BA, Migliore M, Shepherd GMG. Intrinsic electrophysiology of mouse corticospinal neurons: a class-specific triad of spike-related properties. Cereb Cortex 2012; 23:1965-77. [PMID: 22761308 DOI: 10.1093/cercor/bhs184] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Corticospinal pyramidal neurons mediate diverse aspects of motor behavior. We measured spike-related electrophysiological properties of identified corticospinal neurons in primary motor cortex slices from young adult mice. Several consistent features were observed in the suprathreshold responses to current steps: 1) Corticospinal neurons fired relatively fast action potentials (APs; width at half-maximum 0.65 ± 0.13 ms, mean ± standard deviation [SD]) compared with neighboring callosally projecting corticostriatal neurons. Corticospinal AP width was intermediate between 2 classes of inhibitory interneuron in layer 5B. Spike-to-spike variability in AP width and other spike waveform parameters was low, even during repetitive firing up to 20 Hz, that is, the relative narrowness of corticospinal APs was essentially frequency independent. 2) Frequency-current (f-I) relationships were nearly linear. 3) Trains of APs displayed regular firing, with rates typically staying constant or accelerating over time. Corticospinal neurons recorded from older mice (up to 4 months) or from a separate lateral cortical area (Region B; corresponding to secondary somatosensory cortex) showed generally similar intrinsic properties. Our findings have implications for interpreting spike waveforms of in vivo recorded neurons in the motor cortex. This analysis provides a framework for further biophysical and computational investigations of corticospinal neurons and their roles in motor cortical function.
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Affiliation(s)
- Benjamin A Suter
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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Apicella AJ, Wickersham IR, Seung HS, Shepherd GMG. Laminarly orthogonal excitation of fast-spiking and low-threshold-spiking interneurons in mouse motor cortex. J Neurosci 2012; 32:7021-33. [PMID: 22593070 PMCID: PMC3377057 DOI: 10.1523/jneurosci.0011-12.2012] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 03/27/2012] [Accepted: 04/04/2012] [Indexed: 11/21/2022] Open
Abstract
In motor cortex, long-range output to subcortical motor circuits depends on excitatory and inhibitory inputs converging on projection neurons in layers 5A/B. How interneurons interconnect with these projection neurons, and whether these microcircuits are interneuron and/or projection specific, is unclear. We found that fast-spiking interneurons received strong intralaminar (horizontal) excitation from pyramidal neurons in layers 5A/B including corticostriatal and corticospinal neurons, implicating them in mediating disynaptic recurrent, feedforward, and feedback inhibition within and across the two projection classes. Low-threshold-spiking (LTS) interneurons were instead strongly excited by descending interlaminar (vertical) input from layer 2/3 pyramidal neurons, implicating them in mediating disynaptic feedforward inhibition to both projection classes. Furthermore, in a novel pattern, lower layer 2/3 preferentially excited interneurons in one layer (5A/LTS) and excitatory neurons in another (5B/corticospinal). Thus, these inhibitory microcircuits in mouse motor cortex follow an orderly arrangement that is laminarly orthogonalized by interneuron-specific, projection-nonspecific connectivity.
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Affiliation(s)
- Alfonso J. Apicella
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, and
| | - Ian R. Wickersham
- Howard Hughes Medical Institute and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - H. Sebastian Seung
- Howard Hughes Medical Institute and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Gordon M. G. Shepherd
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, and
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