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Karimov T, Ostrovskii V, Rybin V, Druzhina O, Kolev G, Butusov D. Magnetic Flux Sensor Based on Spiking Neurons with Josephson Junctions. SENSORS (BASEL, SWITZERLAND) 2024; 24:2367. [PMID: 38610577 PMCID: PMC11014145 DOI: 10.3390/s24072367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/05/2024] [Accepted: 04/06/2024] [Indexed: 04/14/2024]
Abstract
Josephson junctions (JJs) are superconductor-based devices used to build highly sensitive magnetic flux sensors called superconducting quantum interference devices (SQUIDs). These sensors may vary in design, being the radio frequency (RF) SQUID, direct current (DC) SQUID, and hybrid, such as D-SQUID. In addition, recently many of JJ's applications were found in spiking models of neurons exhibiting nearly biological behavior. In this study, we propose and investigate a new circuit model of a sensory neuron based on DC SQUID as part of the circuit. The dependence of the dynamics of the designed model on the external magnetic flux is demonstrated. The design of the circuit and derivation of the corresponding differential equations that describe the dynamics of the system are given. Numerical simulation is used for experimental evaluation. The experimental results confirm the applicability and good performance of the proposed magnetic-flux-sensitive neuron concept: the considered device can encode the magnetic flux in the form of neuronal dynamics with the linear section. Furthermore, some complex behavior was discovered in the model, namely the intermittent chaotic spiking and plateau bursting. The proposed design can be efficiently applied to developing the interfaces between circuitry and spiking neural networks. However, it should be noted that the proposed neuron design shares the main limitation of all the superconductor-based technologies, i.e., the need for a cryogenic and shielding system.
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Affiliation(s)
- Timur Karimov
- Youth Research Institute, Saint Petersburg Electrotechnical University “LETI”, 197022 Saint Petersburg, Russia; (T.K.); (V.O.)
| | - Valerii Ostrovskii
- Youth Research Institute, Saint Petersburg Electrotechnical University “LETI”, 197022 Saint Petersburg, Russia; (T.K.); (V.O.)
| | - Vyacheslav Rybin
- Computer-Aided Design Department, Saint Petersburg Electrotechnical University “LETI”, 5 Professora Popova St., 197022 Saint Petersburg, Russia; (V.R.); (O.D.); (G.K.)
| | - Olga Druzhina
- Computer-Aided Design Department, Saint Petersburg Electrotechnical University “LETI”, 5 Professora Popova St., 197022 Saint Petersburg, Russia; (V.R.); (O.D.); (G.K.)
| | - Georgii Kolev
- Computer-Aided Design Department, Saint Petersburg Electrotechnical University “LETI”, 5 Professora Popova St., 197022 Saint Petersburg, Russia; (V.R.); (O.D.); (G.K.)
| | - Denis Butusov
- Computer-Aided Design Department, Saint Petersburg Electrotechnical University “LETI”, 5 Professora Popova St., 197022 Saint Petersburg, Russia; (V.R.); (O.D.); (G.K.)
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2
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Cortical waste clearance in normal and restricted sleep with potential runaway tau buildup in Alzheimer's disease. Sci Rep 2022; 12:13740. [PMID: 35961995 PMCID: PMC9374764 DOI: 10.1038/s41598-022-15109-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 06/17/2022] [Indexed: 01/10/2023] Open
Abstract
Accumulation of waste in cortical tissue and glymphatic waste clearance via extracellular voids partly drives the sleep-wake cycle and modeling has reproduced much of its dynamics. Here, new modeling incorporates higher void volume and clearance in sleep, multiple waste compounds, and clearance obstruction by waste. This model reproduces normal sleep-wake cycles, sleep deprivation effects, and performance decreases under chronic sleep restriction (CSR). Once fitted to calibration data, it successfully predicts dynamics in further experiments on sleep deprivation, intermittent CSR, and recovery after restricted sleep. The results imply a central role for waste products with lifetimes similar to tau protein. Strong tau buildup is predicted if pathologically enhanced production or impaired clearance occur, with runaway buildup above a critical threshold. Predicted tau accumulation has timescales consistent with the development of Alzheimer’s disease. The model unifies a wide sweep of phenomena, clarifying the role of glymphatic clearance and targets for interventions against waste buildup.
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3
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TRPC4 and GIRK channels underlie neuronal coding of firing patterns that reflect G q/11-G i/o coincidence signals of variable strengths. Proc Natl Acad Sci U S A 2022; 119:e2120870119. [PMID: 35544691 DOI: 10.1073/pnas.2120870119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
SignificanceNeurons communicate by releasing neurotransmitters, many of which act at G protein-coupled receptors. Although it is well known that Gq/11 accelerates action potential firing while Gi/o inhibits firing, how firing patterns change in response to simultaneous activation of Gq/11 and Gi/o remains elusive, especially because the relative strength of Gq/11 versus Gi/o activation varies greatly from event to event. This study reveals that neurons encode distinct messages that reflect coincident Gq/11 and Gi/o stimulation by activating two ion channels, TRPC4 and GIRK. The resulting firing patterns, composed of burst, pause, and firing recovery phases, reflect both the occurrence of coincident Gq/11 and Gi/o activation and their relative strengths. With these, we may begin to interpret the language of neurons.
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4
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Jeon H, Lee H, Kwon DH, Kim J, Tanaka-Yamamoto K, Yook JS, Feng L, Park HR, Lim YH, Cho ZH, Paek SH, Kim J. Topographic connectivity and cellular profiling reveal detailed input pathways and functionally distinct cell types in the subthalamic nucleus. Cell Rep 2022; 38:110439. [PMID: 35235786 DOI: 10.1016/j.celrep.2022.110439] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 12/02/2021] [Accepted: 02/03/2022] [Indexed: 11/27/2022] Open
Abstract
The subthalamic nucleus (STN) controls psychomotor activity and is an efficient therapeutic deep brain stimulation target in individuals with Parkinson's disease. Despite evidence indicating position-dependent therapeutic effects and distinct functions within the STN, the input circuit and cellular profile in the STN remain largely unclear. Using neuroanatomical techniques, we construct a comprehensive connectivity map of the indirect and hyperdirect pathways in the mouse STN. Our circuit- and cellular-level connectivities reveal a topographically graded organization with three types of indirect and hyperdirect pathways (external globus pallidus only, STN only, and collateral). We confirm consistent pathways into the human STN by 7 T MRI-based tractography. We identify two functional types of topographically distinct glutamatergic STN neurons (parvalbumin [PV+/-]) with synaptic connectivity from indirect and hyperdirect pathways. Glutamatergic PV+ STN neurons contribute to burst firing. These data suggest a complex interplay of information integration within the basal ganglia underlying coordinated movement control and therapeutic effects.
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Affiliation(s)
- Hyungju Jeon
- Brain Science Institute, Korea Institute of Science and Technology (KIST), 39-1 Hawolgokdong, Seongbukgu, Seoul 02792 Korea
| | - Hojin Lee
- Brain Science Institute, Korea Institute of Science and Technology (KIST), 39-1 Hawolgokdong, Seongbukgu, Seoul 02792 Korea; Division of Bio-Medical Science & Technology, KIST School, University of Science and Technology, Seoul 02792, Korea
| | - Dae-Hyuk Kwon
- Neuroscience Convergence Center, Korea University, Seoul 02841, Korea
| | - Jiwon Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), 39-1 Hawolgokdong, Seongbukgu, Seoul 02792 Korea; Division of Bio-Medical Science & Technology, KIST School, University of Science and Technology, Seoul 02792, Korea
| | - Keiko Tanaka-Yamamoto
- Brain Science Institute, Korea Institute of Science and Technology (KIST), 39-1 Hawolgokdong, Seongbukgu, Seoul 02792 Korea; Division of Bio-Medical Science & Technology, KIST School, University of Science and Technology, Seoul 02792, Korea
| | - Jang Soo Yook
- Brain Science Institute, Korea Institute of Science and Technology (KIST), 39-1 Hawolgokdong, Seongbukgu, Seoul 02792 Korea
| | - Linqing Feng
- Brain Science Institute, Korea Institute of Science and Technology (KIST), 39-1 Hawolgokdong, Seongbukgu, Seoul 02792 Korea
| | - Hye Ran Park
- Soonchunhyang University Seoul Hospital, Seoul 04401, Korea
| | - Yong Hoon Lim
- Neurosurgery, Movement Disorder Center, Seoul National University College of Medicine, Advanced Institute of Convergence Technology (AICT), Seoul National University, Seoul 03080, Korea
| | - Zang-Hee Cho
- Neuroscience Convergence Center, Korea University, Seoul 02841, Korea
| | - Sun Ha Paek
- Neurosurgery, Movement Disorder Center, Seoul National University College of Medicine, Advanced Institute of Convergence Technology (AICT), Seoul National University, Seoul 03080, Korea
| | - Jinhyun Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), 39-1 Hawolgokdong, Seongbukgu, Seoul 02792 Korea; Division of Bio-Medical Science & Technology, KIST School, University of Science and Technology, Seoul 02792, Korea.
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5
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Peng Y, Schöneberg N, Esposito MS, Geiger JRP, Sharott A, Tovote P. Current approaches to characterize micro- and macroscale circuit mechanisms of Parkinson's disease in rodent models. Exp Neurol 2022; 351:114008. [PMID: 35149118 PMCID: PMC7612860 DOI: 10.1016/j.expneurol.2022.114008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 01/17/2022] [Accepted: 02/04/2022] [Indexed: 11/24/2022]
Abstract
Accelerating technological progress in experimental neuroscience is increasing the scale as well as specificity of both observational and perturbational approaches to study circuit physiology. While these techniques have also been used to study disease mechanisms, a wider adoption of these approaches in the field of experimental neurology would greatly facilitate our understanding of neurological dysfunctions and their potential treatments at cellular and circuit level. In this review, we will introduce classic and novel methods ranging from single-cell electrophysiological recordings to state-of-the-art calcium imaging and cell-type specific optogenetic or chemogenetic stimulation. We will focus on their application in rodent models of Parkinson’s disease while also presenting their use in the context of motor control and basal ganglia function. By highlighting the scope and limitations of each method, we will discuss how they can be used to study pathophysiological mechanisms at local and global circuit levels and how novel frameworks can help to bridge these scales.
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Affiliation(s)
- Yangfan Peng
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany; Department of Neurology, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany; MRC Brain Network Dynamics Unit, University of Oxford, Mansfield Road, Oxford OX1 3TH, United Kingdom.
| | - Nina Schöneberg
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Versbacher Str. 5, 97078 Wuerzburg, Germany
| | - Maria Soledad Esposito
- Medical Physics Department, Centro Atomico Bariloche, Comision Nacional de Energia Atomica (CNEA), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Av. E. Bustillo 9500, R8402AGP San Carlos de Bariloche, Rio Negro, Argentina
| | - Jörg R P Geiger
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Andrew Sharott
- MRC Brain Network Dynamics Unit, University of Oxford, Mansfield Road, Oxford OX1 3TH, United Kingdom
| | - Philip Tovote
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Versbacher Str. 5, 97078 Wuerzburg, Germany; Center for Mental Health, University of Wuerzburg, Margarete-Höppel-Platz 1, 97080 Wuerzburg, Germany.
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6
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Challenges for future theories of Parkinson pathophysiology. Neurosci Res 2021; 177:1-7. [PMID: 34861293 DOI: 10.1016/j.neures.2021.11.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 11/23/2021] [Accepted: 11/29/2021] [Indexed: 11/24/2022]
Abstract
Current theories on the basal ganglia-thalamic-cortical circuitry address the phenomena of hypokinesia and hyperkinesia. In this Perspective, we question whether the current models can address the orchestration of the motor units which is the common final pathway of the motor system. We conclude that the current theories do not to address this orchestration in health and disease. One alternative approach worthy of consideration is nonmonotonic nonlinear dynamics that contrast with a fundamentally linear or monotonic nonlinear approach that are presumed by current theories of basal ganglia-thalamic-cortical system. The purpose here is to make the case that current theories do presuppose a linear or monotonic nonlinear perspective which will be demonstrated as failing to adequately explicate the complex orchestration of motor unit activities in normal movement and in movement disorders. The notion of nonlinear dynamics is not new to neurophysiology; however, it is argued that it is new to the concepts of the physiology and pathophysiology of the basal ganglia-thalamic-cortical system. Providing a wholesale reconceptualization of the basal ganglia-thalamic-cortical system is beyond the scope of this effort. Rather, the contribution of the essay is convincing that there is a need to reconceptualize theories as nonlinear dynamical systems and there are metaphors and analogies from nonlinear science that can be productive in the reconsideration.
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7
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Tai CH. Subthalamic burst firing: A pathophysiological target in Parkinson's disease. Neurosci Biobehav Rev 2021; 132:410-419. [PMID: 34856222 DOI: 10.1016/j.neubiorev.2021.11.044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 11/16/2021] [Accepted: 11/28/2021] [Indexed: 11/27/2022]
Abstract
Understanding the pathophysiological mechanism of Parkinson's disease (PD) in the subthalamic nucleus (STN) has become a critical issue since deep brain stimulation (DBS) in this region has been proven as an effective treatment for this disease. The STN possesses a special ability to switch from the spike to the burst firing mode in response to dopamine deficiency in parkinsonism, and this STN burst is considered an electrophysiological signature of the cortico-basal ganglia circuit in the brains of PD patients. This review focuses on the role of STN burst firing in the pathophysiology of PD and during DBS. Here, we review existing literature on how STN bursts originate and the specific factors affecting their formation; how STN burst firing causes motor symptoms in PD and how interventions can rescue these symptoms. Finally, the similarities and differences between the two electrophysiological hallmarks of PD, STN burst firing and beta-oscillation, are discussed. STN burst firing should be considered as a pathophysiological target in PD during treatment with DBS.
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Affiliation(s)
- Chun-Hwei Tai
- Department of Neurology, National Taiwan University Hospital, No. 7, Jhongshan South Road, 100225, Taipei, Taiwan.
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8
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Gordleeva SY, Tsybina YA, Krivonosov MI, Ivanchenko MV, Zaikin AA, Kazantsev VB, Gorban AN. Modeling Working Memory in a Spiking Neuron Network Accompanied by Astrocytes. Front Cell Neurosci 2021; 15:631485. [PMID: 33867939 PMCID: PMC8044545 DOI: 10.3389/fncel.2021.631485] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 03/04/2021] [Indexed: 01/07/2023] Open
Abstract
We propose a novel biologically plausible computational model of working memory (WM) implemented by a spiking neuron network (SNN) interacting with a network of astrocytes. The SNN is modeled by synaptically coupled Izhikevich neurons with a non-specific architecture connection topology. Astrocytes generating calcium signals are connected by local gap junction diffusive couplings and interact with neurons via chemicals diffused in the extracellular space. Calcium elevations occur in response to the increased concentration of the neurotransmitter released by spiking neurons when a group of them fire coherently. In turn, gliotransmitters are released by activated astrocytes modulating the strength of the synaptic connections in the corresponding neuronal group. Input information is encoded as two-dimensional patterns of short applied current pulses stimulating neurons. The output is taken from frequencies of transient discharges of corresponding neurons. We show how a set of information patterns with quite significant overlapping areas can be uploaded into the neuron-astrocyte network and stored for several seconds. Information retrieval is organized by the application of a cue pattern representing one from the memory set distorted by noise. We found that successful retrieval with the level of the correlation between the recalled pattern and ideal pattern exceeding 90% is possible for the multi-item WM task. Having analyzed the dynamical mechanism of WM formation, we discovered that astrocytes operating at a time scale of a dozen of seconds can successfully store traces of neuronal activations corresponding to information patterns. In the retrieval stage, the astrocytic network selectively modulates synaptic connections in the SNN leading to successful recall. Information and dynamical characteristics of the proposed WM model agrees with classical concepts and other WM models.
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Affiliation(s)
- Susanna Yu Gordleeva
- Scientific and Educational Mathematical Center "Mathematics of Future Technology," Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.,Neuroscience and Cognitive Technology Laboratory, Center for Technologies in Robotics and Mechatronics Components, Innopolis University, Innopolis, Russia
| | - Yuliya A Tsybina
- Scientific and Educational Mathematical Center "Mathematics of Future Technology," Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Mikhail I Krivonosov
- Scientific and Educational Mathematical Center "Mathematics of Future Technology," Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Mikhail V Ivanchenko
- Scientific and Educational Mathematical Center "Mathematics of Future Technology," Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Alexey A Zaikin
- Scientific and Educational Mathematical Center "Mathematics of Future Technology," Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.,Center for Analysis of Complex Systems, Sechenov First Moscow State Medical University, Sechenov University, Moscow, Russia.,Institute for Women's Health and Department of Mathematics, University College London, London, United Kingdom
| | - Victor B Kazantsev
- Scientific and Educational Mathematical Center "Mathematics of Future Technology," Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.,Neuroscience and Cognitive Technology Laboratory, Center for Technologies in Robotics and Mechatronics Components, Innopolis University, Innopolis, Russia.,Neuroscience Research Institute, Samara State Medical University, Samara, Russia
| | - Alexander N Gorban
- Scientific and Educational Mathematical Center "Mathematics of Future Technology," Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.,Department of Mathematics, University of Leicester, Leicester, United Kingdom
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9
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Alexander RPD, Bowie D. Intrinsic plasticity of cerebellar stellate cells is mediated by NMDA receptor regulation of voltage-gated Na + channels. J Physiol 2020; 599:647-665. [PMID: 33146903 DOI: 10.1113/jp280627] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 10/28/2020] [Indexed: 12/12/2022] Open
Abstract
KEY POINTS We show that NMDA receptors (NMDARs) elicit a long-term increase in the firing rates of inhibitory stellate cells of the cerebellum NMDARs induce intrinsic plasticity through a Ca2+ - and CaMKII-dependent pathway that drives shifts in the activation and inactivation properties of voltage-gated Na+ (Nav ) channels An identical Ca2+ - and CaMKII-dependent signalling pathway is triggered during whole-cell recording which lowers the action potential threshold by causing a hyperpolarizing shift in the gating properties of Nav channels. Our findings open the more general possibility that NMDAR-mediated intrinsic plasticity found in other cerebellar neurons may involve similar shifts in Nav channel gating. ABSTRACT Memory storage in the mammalian brain is mediated not only by long-lasting changes in the efficacy of neurotransmitter receptors but also by long-term modifications to the activity of voltage-gated ion channels. Activity-dependent plasticity of voltage-gated ion channels, or intrinsic plasticity, is found throughout the brain in virtually all neuronal types, including principal cells and interneurons. Although intrinsic plasticity has been identified in neurons of the cerebellum, it has yet to be studied in inhibitory cerebellar stellate cells of the molecular layer which regulate activity outflow from the cerebellar cortex by feedforward inhibition onto Purkinje cells. The study of intrinsic plasticity in stellate cells has been particularly challenging as membrane patch breakthrough in electrophysiology experiments unintentionally triggers changes in spontaneous firing rates. Using cell-attached patch recordings to avoid disruption, we show that activation of extrasynaptic N-methyl-d-aspartate receptors (NMDARs) elicits a long-term increase in the firing properties of stellate cells by stimulating a rise in cytosolic Ca2+ and activation of Ca²⁺/calmodulin-dependent protein kinase II (CaMKII). An identical signalling pathway is triggered during whole-cell recording which lowers the action potential threshold by causing a hyperpolarizing shift in the gating properties of voltage-gated sodium (Nav ) channels. Together, our findings identify an unappreciated role of Nav channel-dependent intrinsic plasticity in cerebellar stellate cells which, in concert with non-canonical NMDAR signalling, provides the cerebellum with an unconventional mechanism to fine-tune motor behaviour.
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Affiliation(s)
- Ryan P D Alexander
- Integrated Program in Neuroscience, McGill University, Montréal, Québec, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada
| | - Derek Bowie
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada
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10
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Traub RD, Moeller F, Rosch R, Baldeweg T, Whittington MA, Hall SP. Seizure initiation in infantile spasms vs. focal seizures: proposed common cellular mechanisms. Rev Neurosci 2020; 31:181-200. [PMID: 31525161 DOI: 10.1515/revneuro-2019-0030] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/01/2019] [Indexed: 11/15/2022]
Abstract
Infantile spasms (IS) and seizures with focal onset have different clinical expressions, even when electroencephalography (EEG) associated with IS has some degree of focality. Oddly, identical pathology (with, however, age-dependent expression) can lead to IS in one patient vs. focal seizures in another or even in the same, albeit older, patient. We therefore investigated whether the cellular mechanisms underlying seizure initiation are similar in the two instances: spasms vs. focal. We noted that in-common EEG features can include (i) a background of waves at alpha to delta frequencies; (ii) a period of flattening, lasting about a second or more - the electrodecrement (ED); and (iii) often an interval of very fast oscillations (VFO; ~70 Hz or faster) preceding, or at the beginning of, the ED. With IS, VFO temporally coincides with the motor spasm. What is different between the two conditions is this: with IS, the ED reverts to recurring slow waves, as occurring before the ED, whereas with focal seizures the ED instead evolves into an electrographic seizure, containing high-amplitude synchronized bursts, having superimposed VFO. We used in vitro data to help understand these patterns, as such data suggest cellular mechanisms for delta waves, for VFO, for seizure-related burst complexes containing VFO, and, more recently, for the ED. We propose a unifying mechanistic hypothesis - emphasizing the importance of brain pH - to explain the commonalities and differences of EEG signals in IS versus focal seizures.
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Affiliation(s)
- Roger D Traub
- IBM Thomas J. Watson Research Center, Yorktown Heights, NY 10598, USA
- Department of Neurology, Columbia University, New York, NY 10032, USA
| | - Friederike Moeller
- Department of Clinical Neurophysiology, Great Ormond Street Hospital, London WC1N 3JH, UK
| | - Richard Rosch
- MRC Centre for Neurodevelopmental Disorders, King's College London, New Hunt's House, London SE1 1UL, UK
| | - Torsten Baldeweg
- Institute of Child Health, University College London, 30 Guildford Street, London WC1N 1EH, UK
| | | | - Stephen P Hall
- Hull York Medical School, University of York, Heslington YO10 5DD, UK
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11
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Multistable properties of human subthalamic nucleus neurons in Parkinson's disease. Proc Natl Acad Sci U S A 2019; 116:24326-24333. [PMID: 31712414 PMCID: PMC6883794 DOI: 10.1073/pnas.1912128116] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Behaviors are realized through concerted activity in neural circuits. This activity results from a combination of neural connectivity and the properties of the involved neurons. By studying the activity of neurons in the human subthalamic nucleus during surgery for Parkinson’s disease, we report that these neurons have multiple stable states, and that brief electrical stimuli can lead to transitions between states. We thus suggest that these neurons function as finite state machines. The different states could influence the function of key motor circuits of the basal ganglia, and thus knowledge of these states in disease or in response to treatment could help to define new treatment strategies for people with movement disorders. To understand the function and dysfunction of neural circuits, it is necessary to understand the properties of the neurons participating in the behavior, the connectivity between these neurons, and the neuromodulatory status of the circuits at the time they are producing the behavior. Such knowledge of human neural circuits is difficult, at best, to obtain. Here, we study firing properties of human subthalamic neurons, using microelectrode recordings and microstimulation during awake surgery for Parkinson’s disease. We demonstrate that low-amplitude, brief trains of microstimulation can lead to persistent changes in neuronal firing behavior including switching between firing rates, entering silent periods, or firing several bursts then entering a silent period. We suggest that these multistable states reflect properties of finite state machines and could have implications for the function of circuits involving the subthalamic nucleus. Furthermore, understanding these states could lead to therapeutic strategies aimed at regulating the transitions between states.
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12
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Zhuang QX, Li GY, Li B, Zhang CZ, Zhang XY, Xi K, Li HZ, Wang JJ, Zhu JN. Regularizing firing patterns of rat subthalamic neurons ameliorates parkinsonian motor deficits. J Clin Invest 2018; 128:5413-5427. [PMID: 30226827 DOI: 10.1172/jci99986] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 09/11/2018] [Indexed: 12/18/2022] Open
Abstract
The subthalamic nucleus (STN) is an effective therapeutic target for deep brain stimulation (DBS) for Parkinson's disease (PD), and histamine levels are elevated in the basal ganglia in PD patients. However, the effect of endogenous histaminergic modulation on STN neuronal activities and the neuronal mechanism underlying STN-DBS are unknown. Here, we report that STN neuronal firing patterns are more crucial than firing rates for motor control. Histamine excited STN neurons, but paradoxically ameliorated parkinsonian motor deficits, which we attributed to regularizing firing patterns of STN neurons via the hyperpolarization-activated cyclic nucleotide-gated channel 2 (HCN2) channel coupled to the H2 receptor. Intriguingly, DBS increased histamine release in the STN and regularized STN neuronal firing patterns under parkinsonian conditions. HCN2 contributed to the DBS-induced regularization of neuronal firing patterns, suppression of excessive β oscillations, and alleviation of motor deficits in PD. The results reveal an indispensable role for regularizing STN neuronal firing patterns in amelioration of parkinsonian motor dysfunction and a functional compensation for histamine in parkinsonian basal ganglia circuitry. The findings provide insights into mechanisms of STN-DBS as well as potential therapeutic targets and STN-DBS strategies for PD.
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Affiliation(s)
- Qian-Xing Zhuang
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Physiology, School of Life Sciences, and
| | - Guang-Ying Li
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Physiology, School of Life Sciences, and
| | - Bin Li
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Physiology, School of Life Sciences, and
| | - Chang-Zheng Zhang
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Physiology, School of Life Sciences, and
| | - Xiao-Yang Zhang
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Physiology, School of Life Sciences, and
| | - Kang Xi
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Physiology, School of Life Sciences, and
| | - Hong-Zhao Li
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Physiology, School of Life Sciences, and
| | - Jian-Jun Wang
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Physiology, School of Life Sciences, and.,Institute for Brain Sciences, Nanjing University, Nanjing, China
| | - Jing-Ning Zhu
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Physiology, School of Life Sciences, and.,Institute for Brain Sciences, Nanjing University, Nanjing, China
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Bonnevie T, Zaghloul KA. The Subthalamic Nucleus: Unravelling New Roles and Mechanisms in the Control of Action. Neuroscientist 2018; 25:48-64. [PMID: 29557710 DOI: 10.1177/1073858418763594] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
How do we decide what we do? This is the essence of action control, the process of selecting the most appropriate response among multiple possible choices. Suboptimal action control can involve a failure to initiate or adapt actions, or conversely it can involve making actions impulsively. There has been an increasing focus on the specific role of the subthalamic nucleus (STN) in action control. This has been fueled by the clinical relevance of this basal ganglia nucleus as a target for deep brain stimulation (DBS), primarily in Parkinson's disease but also in obsessive-compulsive disorder. The context of DBS has opened windows to study STN function in ways that link neuroscientific and clinical fields closely together, contributing to an exceptionally high level of two-way translation. In this review, we first outline the role of the STN in both motor and nonmotor action control, and then discuss how these functions might be implemented by neuronal activity in the STN. Gaining a better understanding of these topics will not only provide important insights into the neurophysiology of action control but also the pathophysiological mechanisms relevant for several brain disorders and their therapies.
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Affiliation(s)
- Tora Bonnevie
- 1 Department of Neuromedicine and Movement Science, NTNU, Trondheim, Norway.,2 Neuroclinic, Trondheim University Hospital, Trondheim, Norway.,3 Kavli Institute for Systems Neuroscience, NTNU, Trondheim, Norway
| | - Kareem A Zaghloul
- 4 Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD, USA
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14
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Gouty-Colomer LA, Michel FJ, Baude A, Lopez-Pauchet C, Dufour A, Cossart R, Hammond C. Mouse subthalamic nucleus neurons with local axon collaterals. J Comp Neurol 2017; 526:275-284. [DOI: 10.1002/cne.24334] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 09/08/2017] [Accepted: 09/10/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Laurie-Anne Gouty-Colomer
- INSERM U901; Marseille France
- Aix-Marseille University, UMR 901; Marseille France
- INMED; Marseille France
| | - François J Michel
- INSERM U901; Marseille France
- Aix-Marseille University, UMR 901; Marseille France
- INMED; Marseille France
| | - Agnès Baude
- INSERM U901; Marseille France
- Aix-Marseille University, UMR 901; Marseille France
- INMED; Marseille France
| | - Catherine Lopez-Pauchet
- INSERM U901; Marseille France
- Aix-Marseille University, UMR 901; Marseille France
- INMED; Marseille France
| | | | - Rosa Cossart
- INSERM U901; Marseille France
- Aix-Marseille University, UMR 901; Marseille France
- INMED; Marseille France
| | - Constance Hammond
- INSERM U901; Marseille France
- Aix-Marseille University, UMR 901; Marseille France
- INMED; Marseille France
- B&A Therapeutics, INMED; Marseille France
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15
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Hamani C, Florence G, Heinsen H, Plantinga BR, Temel Y, Uludag K, Alho E, Teixeira MJ, Amaro E, Fonoff ET. Subthalamic Nucleus Deep Brain Stimulation: Basic Concepts and Novel Perspectives. eNeuro 2017; 4:ENEURO.0140-17.2017. [PMID: 28966978 PMCID: PMC5617209 DOI: 10.1523/eneuro.0140-17.2017] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 07/07/2017] [Accepted: 08/06/2017] [Indexed: 12/21/2022] Open
Abstract
Over the last decades, extensive basic and clinical knowledge has been acquired on the use of subthalamic nucleus (STN) deep brain stimulation (DBS) for Parkinson's disease (PD). It is now clear that mechanisms involved in the effects of this therapy are far more complex than previously anticipated. At frequencies commonly used in clinical practice, neural elements may be excited or inhibited and novel dynamic states of equilibrium are reached. Electrode contacts used for chronic DBS in PD are placed near the dorsal border of the nucleus, a highly cellular region. DBS may thus exert its effects by modulating these cells, hyperdirect projections from motor cortical areas, afferent and efferent fibers to the motor STN. Advancements in neuroimaging techniques may allow us to identify these structures optimizing surgical targeting. In this review, we provide an update on mechanisms and the neural elements modulated by STN DBS.
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Affiliation(s)
- Clement Hamani
- Division of Neurosurgery Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
- Division of Neuroimaging, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Division of Neurosurgery, Department of Neurology, University of São Paulo Medical School, São Paulo, Brazil
| | - Gerson Florence
- Division of Neurosurgery, Department of Neurology, University of São Paulo Medical School, São Paulo, Brazil
| | - Helmut Heinsen
- Department of Radiology, University of São Paulo Medical School, São Paulo, Brazil
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University Clinic of Würzburg, Würzburg, Germany
| | - Birgit R. Plantinga
- Department of Biomedical Image Analysis, Eindhoven University of Technology, Eindhoven, The Netherlands
- Department of Neurosurgery, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Yasin Temel
- Department of Neurosurgery, Maastricht University Medical Center, Maastricht, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Kamil Uludag
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Eduardo Alho
- Division of Neurosurgery, Department of Neurology, University of São Paulo Medical School, São Paulo, Brazil
| | - Manoel J. Teixeira
- Division of Neurosurgery, Department of Neurology, University of São Paulo Medical School, São Paulo, Brazil
| | - Edson Amaro
- Department of Radiology, University of São Paulo Medical School, São Paulo, Brazil
| | - Erich T. Fonoff
- Division of Neurosurgery, Department of Neurology, University of São Paulo Medical School, São Paulo, Brazil
- Instituto de Ensino e Pesquisa Hospital Sírio-Libanês, São Paulo, Brazil
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16
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Zylberberg J, Strowbridge BW. Mechanisms of Persistent Activity in Cortical Circuits: Possible Neural Substrates for Working Memory. Annu Rev Neurosci 2017; 40:603-627. [PMID: 28772102 PMCID: PMC5995341 DOI: 10.1146/annurev-neuro-070815-014006] [Citation(s) in RCA: 113] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A commonly observed neural correlate of working memory is firing that persists after the triggering stimulus disappears. Substantial effort has been devoted to understanding the many potential mechanisms that may underlie memory-associated persistent activity. These rely either on the intrinsic properties of individual neurons or on the connectivity within neural circuits to maintain the persistent activity. Nevertheless, it remains unclear which mechanisms are at play in the many brain areas involved in working memory. Herein, we first summarize the palette of different mechanisms that can generate persistent activity. We then discuss recent work that asks which mechanisms underlie persistent activity in different brain areas. Finally, we discuss future studies that might tackle this question further. Our goal is to bridge between the communities of researchers who study either single-neuron biophysical, or neural circuit, mechanisms that can generate the persistent activity that underlies working memory.
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Affiliation(s)
- Joel Zylberberg
- Department of Physiology and Biophysics, Center for Neuroscience, and Computational Bioscience Program, University of Colorado School of Medicine, Aurora, Colorado 80045
- Department of Applied Mathematics, University of Colorado, Boulder, Colorado 80309
- Learning in Machines and Brains Program, Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada
| | - Ben W Strowbridge
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106;
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
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17
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Phillips AJK, Robinson PA. A Quantitative Model of Sleep-Wake Dynamics Based on the Physiology of the Brainstem Ascending Arousal System. J Biol Rhythms 2016; 22:167-79. [PMID: 17440218 DOI: 10.1177/0748730406297512] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A quantitative, physiology-based model of the ascending arousal system is developed, using continuum neuronal population modeling, which involves averaging properties such as firing rates across neurons in each population. The model includes the ventrolateral preoptic area (VLPO), where circadian and homeostatic drives enter the system, the monoaminergic and cholinergic nuclei of the ascending arousal system, and their interconnections. The human sleep-wake cycle is governed by the activities of these nuclei, which modulate the behavioral state of the brain via diffuse neuromodulatory projections. The model parameters are not free since they correspond to physiological observables. Approximate parameter bounds are obtained by requiring consistency with physiological and behavioral measures, and the model replicates the human sleep-wake cycle, with physiologically reasonable voltages and firing rates. Mutual inhibition between the wake-promoting monoaminergic group and sleep-promoting VLPO causes ``flip-flop'' behavior, with most time spent in 2 stable steady states corresponding to wake and sleep, with transitions between them on a timescale of a few minutes. The model predicts hysteresis in the sleep-wake cycle, with a region of bistability of the wake and sleep states. Reducing the monoaminergic-VLPO mutual inhibition results in a smaller hysteresis loop. This makes the model more prone to wake-sleep transitions in both directions and makes the states less distinguishable, as in narcolepsy. The model behavior is robust across the constrained parameter ranges, but with sufficient flexibility to describe a wide range of observed phenomena.
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Affiliation(s)
- A J K Phillips
- School of Physics, University of Sydney, New South Wales 2006, Australia.
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18
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Wenger Combremont AL, Bayer L, Dupré A, Mühlethaler M, Serafin M. Slow Bursting Neurons of Mouse Cortical Layer 6b Are Depolarized by Hypocretin/Orexin and Major Transmitters of Arousal. Front Neurol 2016; 7:88. [PMID: 27379007 PMCID: PMC4908144 DOI: 10.3389/fneur.2016.00088] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/30/2016] [Indexed: 11/17/2022] Open
Abstract
Neurons firing spontaneously in bursts in the absence of synaptic transmission have been previously recorded in different layers of cortical brain slices. It has been suggested that such neurons could contribute to the generation of alternating UP and DOWN states, a pattern of activity seen during slow-wave sleep. Here, we show that in layer 6b (L6b), known from our previous studies to contain neurons highly responsive to the wake-promoting transmitter hypocretin/orexin (hcrt/orx), there is a set of neurons, endowed with distinct intrinsic properties, which displayed a strong propensity to fire spontaneously in rhythmic bursts. In response to small depolarizing steps, they responded with a delayed firing of action potentials which, upon higher depolarizing steps, invariably inactivated and were followed by a depolarized plateau potential and a depolarizing afterpotential. These cells also displayed a strong hyperpolarization-activated rectification compatible with the presence of an Ih current. Most L6b neurons with such properties were able to fire spontaneously in bursts. Their bursting activity was of intrinsic origin as it persisted not only in presence of blockers of ionotropic glutamatergic and GABAergic receptors but also in a condition of complete synaptic blockade. However, a small number of these neurons displayed a mix of intrinsic bursting and synaptically driven recurrent UP and DOWN states. Most of the bursting L6b neurons were depolarized and excited by hcrt/orx through a direct postsynaptic mechanism that led to tonic firing and eventually inactivation. Similarly, they were directly excited by noradrenaline, histamine, dopamine, and neurotensin. Finally, the intracellular injection of these cells with dye and their subsequent Neurolucida reconstruction indicated that they were spiny non-pyramidal neurons. These results lead us to suggest that the propensity for slow rhythmic bursting of this set of L6b neurons could be directly impeded by hcrt/orx and other wake-promoting transmitters.
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Affiliation(s)
| | - Laurence Bayer
- Département des neurosciences fondamentales, Centre Médical Universitaire, Geneva, Switzerland; Centre de médecine du sommeil, Hôpitaux Universitaires de Genève, Geneva, Switzerland
| | - Anouk Dupré
- Département des neurosciences fondamentales, Centre Médical Universitaire , Geneva , Switzerland
| | - Michel Mühlethaler
- Département des neurosciences fondamentales, Centre Médical Universitaire , Geneva , Switzerland
| | - Mauro Serafin
- Département des neurosciences fondamentales, Centre Médical Universitaire , Geneva , Switzerland
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19
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Krishna V, Elias G, Sammartino F, Basha D, King NKK, Fasano A, Munhoz R, Kalia SK, Hodaie M, Venkatraghavan L, Lozano AM, Hutchison WD. The effect of dexmedetomidine on the firing properties of STN neurons in Parkinson's disease. Eur J Neurosci 2015; 42:2070-7. [DOI: 10.1111/ejn.13004] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 06/10/2015] [Accepted: 06/18/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Vibhor Krishna
- Division of Neurosurgery; Toronto Western Hospital; University of Toronto; 399 Bathurst Street Toronto ON M5T2S8 Canada
| | - Gavin Elias
- Division of Neurosurgery; Toronto Western Hospital; University of Toronto; 399 Bathurst Street Toronto ON M5T2S8 Canada
| | - Francesco Sammartino
- Division of Neurosurgery; Toronto Western Hospital; University of Toronto; 399 Bathurst Street Toronto ON M5T2S8 Canada
| | - Diellor Basha
- Department of Physiology; Toronto Western Hospital; University of Toronto; Toronto ON Canada
| | - Nicolas K. K. King
- Division of Neurosurgery; Toronto Western Hospital; University of Toronto; 399 Bathurst Street Toronto ON M5T2S8 Canada
| | - Alfonso Fasano
- Morton and Gloria Shulman Movement Disorders Centre and the Edmond J. Safra Program in Parkinson's Disease; Toronto Western Hospital; Toronto ON Canada
| | - Renato Munhoz
- Morton and Gloria Shulman Movement Disorders Centre and the Edmond J. Safra Program in Parkinson's Disease; Toronto Western Hospital; Toronto ON Canada
| | - Suneil K. Kalia
- Division of Neurosurgery; Toronto Western Hospital; University of Toronto; 399 Bathurst Street Toronto ON M5T2S8 Canada
| | - Mojgan Hodaie
- Division of Neurosurgery; Toronto Western Hospital; University of Toronto; 399 Bathurst Street Toronto ON M5T2S8 Canada
| | - Lashmi Venkatraghavan
- Department of Anesthesiology; Toronto Western Hospital; University of Toronto; Toronto ON Canada
| | - Andres M. Lozano
- Division of Neurosurgery; Toronto Western Hospital; University of Toronto; 399 Bathurst Street Toronto ON M5T2S8 Canada
| | - William D. Hutchison
- Department of Physiology; Toronto Western Hospital; University of Toronto; Toronto ON Canada
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20
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AMP kinase regulates K-ATP currents evoked by NMDA receptor stimulation in rat subthalamic nucleus neurons. Neuroscience 2014; 274:138-52. [PMID: 24875176 DOI: 10.1016/j.neuroscience.2014.05.031] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 05/10/2014] [Accepted: 05/18/2014] [Indexed: 11/21/2022]
Abstract
Our lab recently showed that N-methyl-D-aspartate (NMDA) evokes ATP-sensitive K(+) (K-ATP) currents in subthalamic nucleus (STN) neurons in slices of the rat brain. Both K-ATP channels and 5'-adenosine monophosphate-activated protein kinase (AMPK) are considered cellular energy sensors because their activities are influenced by the phosphorylation state of adenosine nucleotides. Moreover, AMPK has been shown to regulate K-ATP function in a variety of tissues including pancreas, cardiac myocytes, and hypothalamus. We used whole-cell patch clamp recordings to study the effect of AMPK activation on K-ATP channel function in STN neurons in slices of the rat brain. We found that bath or intracellular application of the AMPK activators A769662 and PT1 augmented tolbutamide-sensitive K-ATP currents evoked by NMDA receptor stimulation. The effect of AMPK activators was blocked by the AMPK inhibitor dorsomorphin (compound C), and by STO609, an inhibitor of the upstream AMPK activator CaMKKβ. AMPK augmentation of NMDA-induced K-ATP current was also blocked by intracellular BAPTA and by inhibitors of nitric oxide synthase and guanylyl cyclase. However, A769662 did not augment currents evoked by the K-ATP channel opener diazoxide. In the presence of NMDA, A769662 inhibited depolarizing plateau potentials and burst firing, both of which could be antagonized by tolbutamide or dorsomorphin. These studies show that AMPK augments NMDA-induced K-ATP currents by a Ca(2+)-dependent process that involves nitric oxide and cGMP. By augmenting K-ATP currents, AMPK activation would be expected to dampen the excitatory effect of glutamate-mediated transmission in the STN.
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21
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Predicting the responses of repetitively firing neurons to current noise. PLoS Comput Biol 2014; 10:e1003612. [PMID: 24809636 PMCID: PMC4014400 DOI: 10.1371/journal.pcbi.1003612] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 03/26/2014] [Indexed: 11/22/2022] Open
Abstract
We used phase resetting methods to predict firing patterns of rat subthalamic nucleus (STN) neurons when their rhythmic firing was densely perturbed by noise. We applied sequences of contiguous brief (0.5–2 ms) current pulses with amplitudes drawn from a Gaussian distribution (10–100 pA standard deviation) to autonomously firing STN neurons in slices. Current noise sequences increased the variability of spike times with little or no effect on the average firing rate. We measured the infinitesimal phase resetting curve (PRC) for each neuron using a noise-based method. A phase model consisting of only a firing rate and PRC was very accurate at predicting spike timing, accounting for more than 80% of spike time variance and reliably reproducing the spike-to-spike pattern of irregular firing. An approximation for the evolution of phase was used to predict the effect of firing rate and noise parameters on spike timing variability. It quantitatively predicted changes in variability of interspike intervals with variation in noise amplitude, pulse duration and firing rate over the normal range of STN spontaneous rates. When constant current was used to drive the cells to higher rates, the PRC was altered in size and shape and accurate predictions of the effects of noise relied on incorporating these changes into the prediction. Application of rate-neutral changes in conductance showed that changes in PRC shape arise from conductance changes known to accompany rate increases in STN neurons, rather than the rate increases themselves. Our results show that firing patterns of densely perturbed oscillators cannot readily be distinguished from those of neurons randomly excited to fire from the rest state. The spike timing of repetitively firing neurons may be quantitatively predicted from the input and their PRCs, even when they are so densely perturbed that they no longer fire rhythmically. Most neurons receive thousands of synaptic inputs per second. Each of these may be individually weak but collectively they shape the temporal pattern of firing by the postsynaptic neuron. If the postsynaptic neuron fires repetitively, its synaptic inputs need not directly trigger action potentials, but may instead control the timing of action potentials that would occur anyway. The phase resetting curve encapsulates the influence of an input on the timing of the next action potential, depending on its time of arrival. We measured the phase resetting curves of neurons in the subthalamic nucleus and used them to accurately predict the timing of action potentials in a phase model subjected to complex input patterns. A simple approximation to the phase model accurately predicted the changes in firing pattern evoked by dense patterns of noise pulses varying in amplitude and pulse duration, and by changes in firing rate. We also showed that the phase resetting curve changes systematically with changes in total neuron conductance, and doing so predicts corresponding changes in firing pattern. Our results indicate that the phase model may accurately represent the temporal integration of complex patterns of input to repetitively firing neurons.
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22
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Lavrova AI, Vanag VK. Two pulse-coupled non-identical, frequency-different BZ oscillators with time delay. Phys Chem Chem Phys 2014; 16:6764-72. [DOI: 10.1039/c3cp54373k] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Anastasia I Lavrova
- Immanuel Kant Baltic Federal University, A.Nevskogo str. 14A, Kaliningrad, 236041, Russia.
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23
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Ramirez JM, Doi A, Garcia AJ, Elsen FP, Koch H, Wei AD. The cellular building blocks of breathing. Compr Physiol 2013; 2:2683-731. [PMID: 23720262 DOI: 10.1002/cphy.c110033] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Respiratory brainstem neurons fulfill critical roles in controlling breathing: they generate the activity patterns for breathing and contribute to various sensory responses including changes in O2 and CO2. These complex sensorimotor tasks depend on the dynamic interplay between numerous cellular building blocks that consist of voltage-, calcium-, and ATP-dependent ionic conductances, various ionotropic and metabotropic synaptic mechanisms, as well as neuromodulators acting on G-protein coupled receptors and second messenger systems. As described in this review, the sensorimotor responses of the respiratory network emerge through the state-dependent integration of all these building blocks. There is no known respiratory function that involves only a small number of intrinsic, synaptic, or modulatory properties. Because of the complex integration of numerous intrinsic, synaptic, and modulatory mechanisms, the respiratory network is capable of continuously adapting to changes in the external and internal environment, which makes breathing one of the most integrated behaviors. Not surprisingly, inspiration is critical not only in the control of ventilation, but also in the context of "inspiring behaviors" such as arousal of the mind and even creativity. Far-reaching implications apply also to the underlying network mechanisms, as lessons learned from the respiratory network apply to network functions in general.
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Affiliation(s)
- J M Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institut, Seattle, Washington, USA.
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24
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Lindahl M, Kamali Sarvestani I, Ekeberg Ö, Kotaleski JH. Signal enhancement in the output stage of the basal ganglia by synaptic short-term plasticity in the direct, indirect, and hyperdirect pathways. Front Comput Neurosci 2013; 7:76. [PMID: 23801960 PMCID: PMC3685803 DOI: 10.3389/fncom.2013.00076] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 05/18/2013] [Indexed: 11/13/2022] Open
Abstract
Many of the synapses in the basal ganglia display short-term plasticity. Still, computational models have not yet been used to investigate how this affects signaling. Here we use a model of the basal ganglia network, constrained by available data, to quantitatively investigate how synaptic short-term plasticity affects the substantia nigra reticulata (SNr), the basal ganglia output nucleus. We find that SNr becomes particularly responsive to the characteristic burst-like activity seen in both direct and indirect pathway striatal medium spiny neurons (MSN). As expected by the standard model, direct pathway MSNs are responsible for decreasing the activity in SNr. In particular, our simulations indicate that bursting in only a few percent of the direct pathway MSNs is sufficient for completely inhibiting SNr neuron activity. The standard model also suggests that SNr activity in the indirect pathway is controlled by MSNs disinhibiting the subthalamic nucleus (STN) via the globus pallidus externa (GPe). Our model rather indicates that SNr activity is controlled by the direct GPe-SNr projections. This is partly because GPe strongly inhibits SNr but also due to depressing STN-SNr synapses. Furthermore, depressing GPe-SNr synapses allow the system to become sensitive to irregularly firing GPe subpopulations, as seen in dopamine depleted conditions, even when the GPe mean firing rate does not change. Similar to the direct pathway, simulations indicate that only a few percent of bursting indirect pathway MSNs can significantly increase the activity in SNr. Finally, the model predicts depressing STN-SNr synapses, since such an assumption explains experiments showing that a brief transient activation of the hyperdirect pathway generates a tri-phasic response in SNr, while a sustained STN activation has minor effects. This can be explained if STN-SNr synapses are depressing such that their effects are counteracted by the (known) depressing GPe-SNr inputs.
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Affiliation(s)
- Mikael Lindahl
- Department of Computational Biology, School of Computer Science and Communication, KTH Royal Institute of TechnologyStockholm, Sweden
| | - Iman Kamali Sarvestani
- Department of Computational Biology, School of Computer Science and Communication, KTH Royal Institute of TechnologyStockholm, Sweden
| | - Örjan Ekeberg
- Department of Computational Biology, School of Computer Science and Communication, KTH Royal Institute of TechnologyStockholm, Sweden
| | - Jeanette Hellgren Kotaleski
- Department of Computational Biology, School of Computer Science and Communication, KTH Royal Institute of TechnologyStockholm, Sweden
- Department of Neuroscience, Karolinska InstituteStockholm, Sweden
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25
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Shen KZ, Johnson SW. Group I mGluRs evoke K-ATP current by intracellular Ca2+ mobilization in rat subthalamus neurons. J Pharmacol Exp Ther 2013; 345:139-50. [PMID: 23335392 DOI: 10.1124/jpet.112.201566] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
We reported previously that Ca(2+) influx through N-methly-d-aspartate-gated channels evokes ATP-sensitive K(+) (K-ATP) currents in rat subthalamic nucleus (STN) neurons. By using whole-cell patch clamp recordings in brain slices, we investigated the ability of (RS)-3,5-dihydroxyphenylglycine (DHPG), a group I metabotropic glutamate receptor (mGluR) agonist, to evoke K-ATP currents. DHPG (20 µM) evoked outward current at -70 mV and was associated with a positive slope conductance of 2.7 nS. The sulfonylurea agent tolbutamide (100 µM) converted the positive slope to negative slope conductance, indicating mediation by K-ATP channels (ATP-sensitive K+ channels). Currents evoked by DHPG were significantly reduced by a combination of mGluR1 and mGluR5 negative allosteric modulators. DHPG-evoked outward current was blocked by cyclopiazonic acid and thapsigargin and mimicked by caffeine, suggesting mediation by release of intracellular Ca(2+). DHPG outward current was also blocked by ryanodine and 2-aminoethoxydiphenylborane, suggesting mediation by ryanodine- and inositol 1,4,5-triphosphate-sensitive Ca(2+) release. The nitric oxide synthase inhibitor N(G)-nitro-l-arginine methyl ester and inhibitors of protein kinase G activity also suppressed DHPG-induced outward current. Voltage recordings showed that tolbutamide prolonged depolarizing plateau potentials and increased the spontaneous firing rate of STN neurons recorded in the presence of DHPG. These results show that group I mGluR stimulation generates K-ATP current by a nitric oxide- and protein kinase G-dependent process that is mediated by release of Ca(2+) from intracellular stores. Because burst firing is linked to symptoms of Parkinson's disease, we suggest that K-ATP channels might provide a physiologically important inhibitory influence on STN neuronal activity.
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Affiliation(s)
- Ke-Zhong Shen
- Department of Neurology, Oregon Health & Science University, Portland, Oregon, USA
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26
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Michmizos KP, Sakas D, Nikita KS. Parameter identification for a local field potential driven model of the Parkinsonian subthalamic nucleus spike activity. Neural Netw 2012; 36:146-56. [PMID: 23131592 DOI: 10.1016/j.neunet.2012.10.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 10/09/2012] [Accepted: 10/10/2012] [Indexed: 11/15/2022]
Abstract
Several models, with various degrees of complexity have been proposed to model the neuronal activity from different parts of the human brain. We have shown before that various modeling approaches, including a Hammerstein-Wiener (H-W) model, can be used to predict the spike trains from a deep nucleus, the subthalamic nucleus, using the underlying local field potentials. In this article, we present, in depth, the various choices one has to make, and the limitations that they introduce, during the H-W model parameter identification process. From a segment of the recorded data, which contains information about the spike times of a single neuron, we identify and extract the model parameters. We then use those parameters to numerically simulate the spike timing, the rhythm and the inter-spike intervals for the rest of the recording. To assess how well the model fits to the measured data we combine measures of spike train synchrony, namely the Victor-Purpura distance and the Gaussian similarity measure, with time-scale independent train distances. We show that a wise combination of metrics results in models that predict the spikes with temporal accuracy ranging, on average, from 53% to more than 80%, depending on the number of the neurons' spikes recorded. The model's prediction is adequate for estimating accurately the spike rhythm. Quantitative results establish the model's validity as a simple yet biologically plausible model of the spike activity recorded from a deep nucleus inside the human brain.
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Lavrova AI, Zaks MA, Schimansky-Geier L. Modeling rhythmic patterns in the hippocampus. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:041922. [PMID: 22680513 DOI: 10.1103/physreve.85.041922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 02/10/2012] [Indexed: 06/01/2023]
Abstract
We investigate different dynamical regimes of the neuronal network in the CA3 area of the hippocampus. The proposed neuronal circuit includes two fast- and two slowly spiking cells which are interconnected by means of dynamical synapses. On the individual level, each neuron is modeled by FitzHugh-Nagumo equations. Three basic rhythmic patterns are observed: the gamma rhythm in which the fast neurons are uniformly spiking, the theta rhythm in which the individual spikes are separated by quiet epochs, and the theta-gamma rhythm with repeated patches of spikes. We analyze the influence of asymmetry of synaptic strengths on the synchronization in the network and demonstrate that strong asymmetry reduces the variety of available dynamical states. The model network exhibits multistability; this results in the occurrence of hysteresis in dependence on the conductances of individual connections. We show that switching between different rhythmic patterns in the network depends on the degree of synchronization between the slow cells.
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Affiliation(s)
- A I Lavrova
- Institute of Physics, Humboldt-University at Berlin, Newtonstrasse 15, 12489 Berlin, Germany.
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Michmizos KP, Sakas D, Nikita KS. Prediction of the Timing and the Rhythm of the Parkinsonian Subthalamic Nucleus Neural Spikes Using the Local Field Potentials. ACTA ACUST UNITED AC 2012; 16:190-7. [DOI: 10.1109/titb.2011.2158549] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Intrinsic dynamics and synaptic inputs control the activity patterns of subthalamic nucleus neurons in health and in Parkinson's disease. Neuroscience 2011; 198:54-68. [PMID: 21723918 DOI: 10.1016/j.neuroscience.2011.06.049] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 06/10/2011] [Accepted: 06/15/2011] [Indexed: 11/22/2022]
Abstract
Neurons in the subthalamic nucleus occupy a pivotal position in the circuitry of the basal ganglia. They receive direct excitatory input from the cerebral cortex and the intralaminar nuclei of the thalamus, and directly excite the inhibitory basal ganglia output neurons in the internal segment of the globus pallidus and the substantia nigra. They are also engaged in a reciprocal synaptic arrangement with inhibitory neurons in the external segment of the globus pallidus. Although once viewed as a simple relay of extrinsic input to the basal ganglia, physiological studies of subthalamic neurons have revealed that activity in these neurons does not directly reflect their pattern of extrinsic excitation. Subthalamic neurons are autonomously active at rates comparable to those observed in vivo, and they generate complex patterns of intrinsic activity arising from the interactions between voltage sensitive ion channels on the somatodendritic and axonal membranes. Extrinsic synaptic excitation does not create the firing pattern of the subthalamic neuron, but rather controls the timing of action potentials generated intrinsically. The dopaminergic innervation of the subthalamic nucleus, although moderate, can directly influence firing patterns by acting both on synaptic transmission and voltage-sensitive ion channels responsible for intrinsic properties. Furthermore, chronic dopamine depletion in Parkinson's disease may modify both synaptic transmission and integration in the subthalamic nucleus, in addition to its effects on other regions of the basal ganglia.
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Ammari R, Bioulac B, Garcia L, Hammond C. The Subthalamic Nucleus becomes a Generator of Bursts in the Dopamine-Depleted State. Its High Frequency Stimulation Dramatically Weakens Transmission to the Globus Pallidus. Front Syst Neurosci 2011; 5:43. [PMID: 21716635 PMCID: PMC3115486 DOI: 10.3389/fnsys.2011.00043] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 06/01/2011] [Indexed: 11/29/2022] Open
Abstract
Excessive burst firing in the dopamine-depleted basal ganglia correlates with severe motor symptoms of Parkinson's disease that are attenuated by high frequency electrical stimulation of the subthalamic nucleus (STN). Here we test the hypothesis that pathological bursts in dopamine-deprived basal ganglia are generated within the STN and transmitted to globus pallidus neurons. To answer this question we recorded excitatory synaptic currents and potentials from subthalamic and pallidal neurons in the basal ganglia slice (BGS) from dopamine-depleted mice while continuously blocking GABAA receptors. In control mice, a single electrical stimulus delivered to the internal capsule or the rostral pole of the STN evoked a short duration, small amplitude, monosynaptic EPSC in subthalamic neurons. In contrast, in the dopamine-depleted BGS, this monosynaptic EPSC was amplified and followed by a burst of polysynaptic EPSCs that eventually reverberated three to seven times, providing a long lasting response that gave rise to bursts of EPSCs and spikes in GP neurons. Repetitive (10–120 Hz) stimulation delivered to the STN in the dopamine-depleted BGS attenuated STN-evoked bursts of EPSCs in pallidal neurons after several minutes of stimulation but only high frequency (90–120 Hz) stimulation replaced them with small amplitude EPSCs at 20 Hz. We propose that the polysynaptic pathway within the STN amplifies subthalamic responses to incoming excitation in the dopamine-depleted basal ganglia, thereby transforming the STN into a burst generator and entraining pallidal neurons in pathogenic bursting activities. High frequency stimulation of the STN prevents the transmission of this pathological activity to globus pallidus and imposes a new glutamatergic synaptic noise on pallidal neurons.
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Selective participation of somatodendritic HCN channels in inhibitory but not excitatory synaptic integration in neurons of the subthalamic nucleus. J Neurosci 2010; 30:16025-40. [PMID: 21106841 DOI: 10.1523/jneurosci.3898-10.2010] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The activity patterns of subthalamic nucleus (STN) neurons are intimately linked to motor function and dysfunction and arise through the complex interaction of intrinsic properties and inhibitory and excitatory synaptic inputs. In many neurons, hyperpolarization-activated cyclic nucleotide-gated (HCN) channels play key roles in intrinsic excitability and synaptic integration both under normal conditions and in disease states. However, in STN neurons, which strongly express HCN channels, their roles remain relatively obscure. To address this deficit, complementary molecular and cellular electrophysiological, imaging, and computational approaches were applied to the rat STN. Molecular profiling demonstrated that individual STN neurons express mRNA encoding several HCN subunits, with HCN2 and 3 being the most abundant. Light and electron microscopic analysis showed that HCN2 subunits are strongly expressed and distributed throughout the somatodendritic plasma membrane. Voltage-, current-, and dynamic-clamp analysis, two-photon Ca(2+) imaging, and computational modeling revealed that HCN channels are activated by GABA(A) receptor-mediated inputs and thus limit synaptic hyperpolarization and deinactivation of low-voltage-activated Ca(2+) channels. Although HCN channels also limited the temporal summation of EPSPs, generated through two-photon uncaging of glutamate, this action was largely shunted by GABAergic inhibition that was necessary for HCN channel activation. Together the data demonstrate that HCN channels in STN neurons selectively counteract GABA(A) receptor-mediated inhibition arising from the globus pallidus and thus promote single-spike activity rather than rebound burst firing.
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Rommelfanger KS, Wichmann T. Extrastriatal dopaminergic circuits of the Basal Ganglia. Front Neuroanat 2010; 4:139. [PMID: 21103009 PMCID: PMC2987554 DOI: 10.3389/fnana.2010.00139] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Accepted: 09/23/2010] [Indexed: 11/20/2022] Open
Abstract
The basal ganglia are comprised of the striatum, the external and internal segment of the globus pallidus (GPe and GPi, respectively), the subthalamic nucleus (STN), and the substantia nigra pars compacta and reticulata (SNc and SNr, respectively). Dopamine has long been identified as an important modulator of basal ganglia function in the striatum, and disturbances of striatal dopaminergic transmission have been implicated in diseases such as Parkinson's disease (PD), addiction and attention deficit hyperactivity disorder. However, recent evidence suggests that dopamine may also modulate basal ganglia function at sites outside of the striatum, and that changes in dopaminergic transmission at these sites may contribute to the symptoms of PD and other neuropsychiatric disorders. This review summarizes the current knowledge of the anatomy, functional effects and behavioral consequences of the dopaminergic innervation to the GPe, GPi, STN, and SNr. Further insights into the dopaminergic modulation of basal ganglia function at extrastriatal sites may provide us with opportunities to develop new and more specific strategies for treating disorders of basal ganglia dysfunction.
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Network bistability mediates spontaneous transitions between normal and pathological brain states. J Neurosci 2010; 30:10734-43. [PMID: 20702704 DOI: 10.1523/jneurosci.1239-10.2010] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Little is known about how cortical networks support the emergence of remarkably different activity patterns. Physiological activity interspersed with epochs of pathological hyperactivity in the epileptic brain represents a clinically relevant yet poorly understood case of such rich dynamic repertoire. Using a realistic computational model, we demonstrate that physiological sparse and pathological tonic-clonic activity may coexist in the same cortical network for identical afferent input level. Transient perturbations in the afferent input were sufficient to switch the network between these two stable states. The effectiveness of the potassium regulatory apparatus determined the stability of the physiological state and the threshold for seizure initiation. Our findings contrast with the common notions of (1) pathological brain activity representing dynamic instabilities and (2) necessary adjustments of experimental conditions to elicit different network states. Rather, we propose that the rich dynamic repertoire of cortical networks may be based on multistabilities intrinsic to the network.
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Kliem MA, Pare JF, Khan ZU, Wichmann T, Smith Y. Ultrastructural localization and function of dopamine D1-like receptors in the substantia nigra pars reticulata and the internal segment of the globus pallidus of parkinsonian monkeys. Eur J Neurosci 2010; 31:836-51. [PMID: 20374284 DOI: 10.1111/j.1460-9568.2010.07109.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The motor symptoms of Parkinson's disease (PD) are commonly attributed to striatal dopamine loss, but reduced dopamine innervation of basal ganglia output nuclei, the internal globus pallidus (GPi) and the substantia nigra pars reticulata (SNr) may also contribute to symptoms and signs of PD. Both structures express dopamine D1 and D5 receptors under normal conditions, and we have recently demonstrated that their local activation reduces neuronal discharge rates and enhances bursts and oscillatory activity in both nuclei of normal monkeys [M.A. Kliem et al. (2007)J. Neurophysiol., 89, 1489-1500]. Here, we determined the ultrastructural localization and function of D1-like receptors in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated parkinsonian monkeys. In both normal and MPTP-treated monkeys, most of the D1 and D5 receptor immunoreactivity was associated with unmyelinated axons, but we also found significant postsynaptic D5 receptor immunostaining in dendrites of GPi and SNr neurons. A significant proportion of axonal D1 immunostaining was bound to the plasma membrane in both normal and MPTP-treated monkeys. Local microinjections of the D1/D5 receptor agonist SKF82958 significantly reduced discharge rates in GPi and SNr neurons, while they increased burst firing and oscillatory activity in the 3-15-Hz band in SNr, but not in GPi, of parkinsonian monkeys. Together with our recent findings from normal monkeys, these data provide evidence that functional D1/D5 receptors are expressed in GPi and SNr in both normal and parkinsonian states, and that their activation by endogenous dopamine (under normal conditions) or dopamine receptor agonists (in parkinsonism) may regulate basal ganglia outflow.
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Affiliation(s)
- Michele A Kliem
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
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Subthalamic nucleus evokes similar long lasting glutamatergic excitations in pallidal, entopeduncular and nigral neurons in the basal ganglia slice. Neuroscience 2010; 166:808-18. [PMID: 20074618 DOI: 10.1016/j.neuroscience.2010.01.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Accepted: 01/06/2010] [Indexed: 11/20/2022]
Abstract
The subthalamic nucleus (STN) modulates the activity of globus pallidus (GP), entopeduncular nucleus (EP) and substantia nigra pars reticulata (SNr) neurons via its direct glutamatergic projections. To investigate the mechanism by which STN affects activity in these structures and whether STN induced activity is comparable among STN target neurons, we performed patch clamp recordings in a tilted, parasagittal, basal ganglia slice (BGS) that preserves these functional connections. We report that single, brief stimulation of the STN generates a brief monosynaptic AMPA-mediated excitatory postsynaptic current (EPSC) in GP, EP and SNr neurons. A higher intensity, supra-threshold activation evokes a compound EPSC consisting of an early monosynaptic component followed by a slow inward NMDA-mediated current with an overlying barrage of AMPA-mediated EPSCs. These late EPSCs were polysynaptic and gave rise to bursts of spikes that lasted several hundreds of milliseconds. They were eliminated by surgical removal of the STN from the BGS slice, indicating that the STN is required for their generation. Reconstruction of biocytin-filled STN neurons revealed that a third of STN neurons project intra-STN axon collaterals that may underlie polysynaptic activity. We propose that activation of the STN yields comparable long lasting excitations in its target neurons by means of a polysynaptic network.
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Barraza D, Kita H, Wilson CJ. Slow spike frequency adaptation in neurons of the rat subthalamic nucleus. J Neurophysiol 2009; 102:3689-97. [PMID: 19846619 DOI: 10.1152/jn.00759.2009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neurons of the subthalamic nucleus (STN) are very sensitive to applied currents, firing at 10-20/s during spontaneous activity, but increasing to peak firing rates of 200/s with applied currents <0.5 nA. They receive a powerful tonic excitatory input from neurons in the cerebral cortex, yet in vivo maintain an irregular firing rate only slightly higher than the autonomous firing rate seen in slices. Spike frequency adaptation acts to normalize background firing rate by removing slow trends in firing due to changes in average input. Subthalamic neurons have been previously described as showing little spike frequency adaptation, but this was based on tests using brief stimuli. We applied long-duration depolarizing current steps to STN neurons in slices and observed a very strong spike frequency adaptation with a time constant of 20 s and that recovered at a similar rate. This adaptation could return firing to near-baseline levels during prolonged current pulses that transiently drove the cells at high rates. The current responsible for adaptation was studied in voltage clamp during and after high-frequency driving of the cell and was determined to be a slowly accumulating K(+) current. This current was independent of calcium or sodium entry and could be induced with long-duration voltage steps after blockade of action potentials. In addition to the adaptation current, driven firing produced slow inactivation of the persistent Na(+) current, which also contributed to the reduced excitability of STN cells during and after driven firing.
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Affiliation(s)
- David Barraza
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX 78249, USA
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37
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Modolo J, Beuter A. Linking brain dynamics, neural mechanisms, and deep brain stimulation in Parkinson's disease: An integrated perspective. Med Eng Phys 2009; 31:615-23. [DOI: 10.1016/j.medengphy.2009.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Revised: 12/01/2008] [Accepted: 01/25/2009] [Indexed: 10/21/2022]
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Inhibitory contribution to suprathreshold corticostriatal responses: an experimental and modeling study. Cell Mol Neurobiol 2009; 29:719-31. [PMID: 19350384 DOI: 10.1007/s10571-009-9394-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Accepted: 03/12/2009] [Indexed: 10/20/2022]
Abstract
Neostriatal neurons may undergo events of spontaneous synchronization as those observed in recurrent networks of excitatory neurons, even when cortical afferents are transected. It is necessary to explain these events because the neostriatum is a recurrent network of inhibitory neurons. Synchronization of neuronal activity may be caused by plateau-like depolarizations. Plateau-like orthodromic depolarizations that resemble up-states in medium spiny neostriatal neurons (MSNs) may be induced by a single corticostriatal suprathreshold stimulus. Slow synaptic depolarizations may last hundreds of milliseconds, decay slower than the monosynaptic glutamatergic synaptic potentials that induce them, and sustain repetitive firing. Because inhibitory inputs impinging onto MSNs have a reversal potential above the resting membrane potential but below the threshold for firing, they conform a type of "shunting inhibition". This work asks if shunting GABAergic inputs onto MSNs arrive asynchronously enough as to help in sustaining the plateau-like corticostriatal response after a single cortical stimulus. This may help to begin explaining autonomous processing in the striatal micro-circuitry in the presence of a tonic excitatory drive and independently of spatio-temporally organized inputs. It is shown here that besides synaptic currents from AMPA/KA- and NMDA-receptors, as well as L-type intrinsic Ca(2+)- currents, inhibitory synapses help in maintaining the slow depolarization, although they accomplish the role of depressing firing at the beginning of the response. We then used a NEURON model of spiny cells to show that inhibitory synapses arriving asynchronously on the dendrites can help to simulate a plateau potential similar to that observed experimentally.
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Abstract
The ability of distinct anatomical circuits to generate multiple behavioral patterns is widespread among vertebrate and invertebrate species. These multifunctional neuronal circuits are the result of multistable neural dynamics and modular organization. The evidence suggests multifunctional circuits can be classified by distinct architectures, yet the activity patterns of individual neurons involved in more than one behavior can vary dramatically. Several mechanisms, including sensory input, the parallel activity of projection neurons, neuromodulation, and biomechanics, are responsible for the switching between patterns. Recent advances in both analytical and experimental tools have aided the study of these complex circuits.
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Affiliation(s)
- K L Briggman
- Department of Biomedical Optics, Max Planck Institute for Medical Research, Heidelberg, 69120 Germany.
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Santaniello S, Fiengo G, Glielmo L, Catapano G. A biophysically inspired microelectrode recording-based model for the subthalamic nucleus activity in Parkinson's disease. Biomed Signal Process Control 2008. [DOI: 10.1016/j.bspc.2008.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Ramanathan S, Tkatch T, Atherton JF, Wilson CJ, Bevan MD. D2-like dopamine receptors modulate SKCa channel function in subthalamic nucleus neurons through inhibition of Cav2.2 channels. J Neurophysiol 2007; 99:442-59. [PMID: 18094105 DOI: 10.1152/jn.00998.2007] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The activity patterns of subthalamic nucleus (STN) neurons are intimately related to motor function/dysfunction and modulated directly by dopaminergic neurons that degenerate in Parkinson's disease (PD). To understand how dopamine and dopamine depletion influence the activity of the STN, the functions/signaling pathways/substrates of D2-like dopamine receptors were studied using patch-clamp recording. In rat brain slices, D2-like dopamine receptor activation depolarized STN neurons, increased the frequency/irregularity of their autonomous activity, and linearized/enhanced their firing in response to current injection. Activation of D2-like receptors in acutely isolated neurons reduced transient outward currents evoked by suprathreshold voltage steps. Modulation was inhibited by a D2-like receptor antagonist and occluded by voltage-dependent Ca2+ (Cav) channel or small-conductance Ca2+-dependent K+ (SKCa) channel blockers or Ca2+-free media. Because Cav channels are targets of G(i/o)-linked receptors, actions on step- and action potential waveform-evoked Cav channel currents were studied. D2-like receptor activation reduced the conductance of Cav2.2 but not Cav1 channels. Modulation was mediated, in part, by direct binding of Gbetagamma subunits because it was attenuated by brief depolarization. D2 and/or D3 dopamine receptors may mediate modulation because a D4-selective agonist was ineffective and mRNA encoding D2 and D3 but not D4 dopamine receptors was detectable. Brain slice recordings confirmed that SKCa channel-mediated action potential afterhyperpolarization was attenuated by D2-like dopamine receptor activation. Together, these data suggest that D2-like dopamine receptors potently modulate the negative feedback control of firing that is mediated by the functional coupling of Cav2.2 and SKCa channels in STN neurons.
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Affiliation(s)
- Sankari Ramanathan
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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Abstract
Antipsychotic drugs are thought to exert their therapeutic action by antagonizing dopamine receptors but are also known to produce side effects in the heart by inhibiting cardiac ether-a-go-go-related gene (ERG) K(+) channels. Recently, it has been discovered that the same channels are present in the brain, including midbrain dopamine neurons. ERG channels are most active after the cessation of intense electrical activity, and blockade of these channels prolongs plateau potentials in bursting dopamine neurons. This change in excitability would be expected to alter dopamine release. Therefore, the therapeutic action of antipsychotic drugs may depend on inhibition of both postsynaptic dopamine receptors and presynaptic ERG K(+) channels.
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Affiliation(s)
- Paul D Shepard
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD 21228, USA.
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Inhibition of 5-HT neuron activity and induction of depressive-like behavior by high-frequency stimulation of the subthalamic nucleus. Proc Natl Acad Sci U S A 2007; 104:17087-92. [PMID: 17942692 DOI: 10.1073/pnas.0704144104] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Bilateral, high-frequency stimulation (HFS) of the subthalamic nucleus (STN) is the surgical therapy of choice for movement disability in advanced Parkinson's disease (PD), but this procedure evokes debilitating psychiatric effects, including depressed mood, of unknown neural origin. Here, we report the unexpected finding that HFS of the STN inhibits midbrain 5-hydroxytryptamine (5-HT) neurons to evoke depression-related behavioral changes. We found that bilateral HFS of the STN consistently inhibited (40-50%) the firing rate of 5-HT neurons in the dorsal raphe nucleus of the rat, but not neighboring non-5-HT neurons. This effect was apparent at clinically relevant stimulation parameters (> or =100 Hz, > or =30 microA), was not elicited by HFS of either neighboring or remote structures to the STN, and was still present in rat models of PD. We also found that bilateral HFS of the STN evoked clear-cut, depressive-like behavior in a widely used experimental paradigm of depression (forced swim test), and this effect was also observed in a PD model. Importantly, the depressive-like behavior elicited by HFS of the STN was reversed by a selective 5-HT-enhancing antidepressant, thereby linking the behavioral change to decreased 5-HT neuronal activity. Overall, these findings link reduced 5-HT function to the psychiatric effects of HFS of the STN observed in PD patients and provide a rational basis for their clinical management. More generally, the powerful interaction between the STN and 5-HT system uncovered here offers insights into the high level of comorbidity of basal ganglia disease and mood disorder.
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Belujon P, Bezard E, Taupignon A, Bioulac B, Benazzouz A. Noradrenergic modulation of subthalamic nucleus activity: behavioral and electrophysiological evidence in intact and 6-hydroxydopamine-lesioned rats. J Neurosci 2007; 27:9595-606. [PMID: 17804620 PMCID: PMC6672980 DOI: 10.1523/jneurosci.2583-07.2007] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The subthalamic nucleus (STN) plays a key role in the pathophysiology of Parkinson's disease. The modulation of the STN by norepinephrine, however, is unknown. The present study aims at characterizing the effects of systemic administration of noradrenergic agents on locomotor activity and on in vivo extracellularly recorded STN neuronal activity in intact and 6-hydroxydopamine (6-OHDA)-lesioned rats. Using selective agonists and antagonists of alpha1 and alpha2 adrenergic receptors (ARs), we show that STN neurons have functional alpha1- and alpha2-AR controlling STN firing with an impact on locomotor activity. We further demonstrate that those systemic effects are supported, at least in part, by a direct modulation of STN neuronal activity, using patch-clamp recordings of STN neurons in brain slices. These findings support the premise that hypokinesia is associated with an increased STN neuronal activity, and that improvements of parkinsonian motor abnormalities are associated with a decrease in STN activity. Our data challenge assumptions about the role of alpha1-AR and alpha2-AR in the regulation of STN neurons in both intact and 6-OHDA-lesioned rats and further ground the rationale for using alpha2-AR noradrenergic antagonists in Parkinson's disease, albeit via an unexpected mechanism.
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MESH Headings
- Adrenergic alpha-Agonists/pharmacology
- Adrenergic alpha-Antagonists/pharmacology
- Animals
- Behavior, Animal/drug effects
- Electrophysiology
- Hypokinesia/chemically induced
- Hypokinesia/physiopathology
- Immunohistochemistry
- Male
- Medial Forebrain Bundle/drug effects
- Motor Activity/drug effects
- Neurons/drug effects
- Neurons/metabolism
- Norepinephrine/metabolism
- Organ Culture Techniques
- Oxidopamine
- Parkinsonian Disorders/chemically induced
- Parkinsonian Disorders/physiopathology
- Patch-Clamp Techniques
- Rats
- Rats, Wistar
- Receptors, Adrenergic, alpha-1/drug effects
- Receptors, Adrenergic, alpha-1/metabolism
- Receptors, Adrenergic, alpha-2/drug effects
- Receptors, Adrenergic, alpha-2/metabolism
- Subthalamic Nucleus/drug effects
- Subthalamic Nucleus/metabolism
- Synaptic Transmission/drug effects
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Affiliation(s)
- Pauline Belujon
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5227, Université Victor Segalen, 33076 Bordeaux Cedex, France
| | - Erwan Bezard
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5227, Université Victor Segalen, 33076 Bordeaux Cedex, France
| | - Anne Taupignon
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5227, Université Victor Segalen, 33076 Bordeaux Cedex, France
| | - Bernard Bioulac
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5227, Université Victor Segalen, 33076 Bordeaux Cedex, France
| | - Abdelhamid Benazzouz
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5227, Université Victor Segalen, 33076 Bordeaux Cedex, France
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45
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Parr-Brownlie LC, Poloskey SL, Flanagan KK, Eisenhofer G, Bergstrom DA, Walters JR. Dopamine lesion-induced changes in subthalamic nucleus activity are not associated with alterations in firing rate or pattern in layer V neurons of the anterior cingulate cortex in anesthetized rats. Eur J Neurosci 2007; 26:1925-39. [PMID: 17897398 DOI: 10.1111/j.1460-9568.2007.05814.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Dysfunctional activity in the subthalamic nucleus (STN) is thought to underlie movement deficits of patients with Parkinson's disease. Alterations in STN firing patterns are also evident in the anesthetized rat model of Parkinson's disease, where studies show that loss of striatal dopamine and concomitant changes in the indirect pathway are associated with bursty and oscillatory firing patterns in STN output. However, the extent to which alterations in cortical activity contribute to changes in STN activity is unclear. As pyramidal neurons in the cingulate cortex project directly to the STN, cingulate output was assessed after dopamine lesion by simultaneously recording single-unit and local field potential (LFP) activities in STN and anterior cingulate cortex in control, dopamine-lesioned and non-lesioned hemispheres of urethane-anesthetized rats. Correlated oscillations were observed in cross-correlograms of spike trains from STN and cingulate layer V neurons with broad waveforms indicative of pyramidal neurons. One-2 weeks after dopamine cell lesion, firing rate, incidence of bursty and 0.3-2.5 Hz oscillatory activity of neurons and LFP power in the STN all increased significantly. In contrast, firing rate, incidence of bursty and 0.3-2.5 Hz oscillatory activity of cingulate layer V putative pyramidal neurons and power in cingulate LFPs did not differ significantly between dopamine-lesioned, non-lesioned or control hemispheres, despite significant loss of dopamine in the lesioned cingulate cortex. Data show that alterations in STN activity in the dopamine-lesioned hemisphere are not associated with alterations in neuronal activity in layer V of the anterior cingulate cortex in anesthetized rats.
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Affiliation(s)
- Louise C Parr-Brownlie
- Neurophysiological Pharmacology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 35 Convent Drive, Building 35 Room 1C 905, Bethesda, MD 20892-3702, USA.
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46
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Chiang E, Strowbridge BW. Diversity of neural signals mediated by multiple, burst-firing mechanisms in rat olfactory tubercle neurons. J Neurophysiol 2007; 98:2716-28. [PMID: 17855583 DOI: 10.1152/jn.00807.2007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Olfactory information is processed by a diverse group of interconnected forebrain regions. Most efforts to define the cellular mechanisms involved in processing olfactory information have been focused on understanding the function of the olfactory bulb, the primary second-order olfactory region, and its principal target, the piriform cortex. However, the olfactory bulb also projects to other targets, including the rarely studied olfactory tubercle, a ventral brain region recently implicated in regulating cocaine-related reward behavior. We used whole cell patch-clamp recordings from rat tubercle slices to define the intrinsic properties of neurons in the dense and multiform cell layers. We find three common firing modes of tubercle neurons: regular-spiking, intermittent-discharging, and bursting. Regular-spiking neurons are typically spiny-dense-cell-layer cells with pyramidal-shaped, dendritic arborizations. Intermittently discharging and bursting neurons comprise the majority of the deeper multiform layer and share a common morphology: multipolar, sparsely spiny cells. Rather than generating all-or-none stereotyped discharges, as observed in many brain areas, bursting cells in the tubercle generate depolarizing plateau potentials that trigger graded but time-limited discharges. We find two distinct subclasses of bursting cells that respond similarly to step stimuli but differ in the role transmembrane Ca currents play in their intrinsic behavior. Calcium currents amplify depolarizing inputs and enhance excitability in regenerative bursting cells, whereas the primary action of Ca in nonregenerative bursting tubercle neurons appears to be to decrease excitability by triggering Ca-activated K currents. Nonregenerative bursting cells exhibit a prolonged refractory period after even short discharges suggesting that they may function to detect transient events.
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Affiliation(s)
- Elizabeth Chiang
- Department of Neurosciences, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106, USA
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47
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Zold CL, Larramendy C, Riquelme LA, Murer MG. Distinct changes in evoked and resting globus pallidus activity in early and late Parkinson's disease experimental models. Eur J Neurosci 2007; 26:1267-79. [PMID: 17767504 DOI: 10.1111/j.1460-9568.2007.05754.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The main clinical manifestations of Parkinson's disease are caused by alterations of basal ganglia activity that are tied in with the progressive loss of mesencephalic dopaminergic neurons. Recent theoretical and modeling studies have suggested that changes in resting neuronal activity occurred later in the course of the disease than those evoked by phasic cortical input. However, there is no empirical support for this proposal. Here we report a marked increase in the responsiveness of globus pallidus neurons to electrical motor cortex stimulation, in the absence of noticeable changes in resting activity, in anesthetized rats that had consistently shown a deficit in forelimb use during behavioral testing before the experiments, and had approximately 45% dopamine neurons spared in the substantia nigra. Pallidal neurons were also over-responsive to motor cortex stimulation and lost spatial selectivity for cortical inputs in rats with extensive nigrostriatal damage. After partial lesions, over-responsiveness was mainly due to an increased proportion of neurons showing excitatory responses, while extensive lesions led to an increased likelihood of inhibitory responding neurons. Changes in resting neuronal activity, comprising pauses disrupting tonic discharge, occurred across different global brain states, including an activated condition which shares similarities with natural patterns of cortical activity seen in awake states and rapid eye-movement sleep, but only after massive nigrostriatal degeneration. These results suggest that a loss of functional segregation and an abnormal temporal encoding of phasic cortical inputs by globus pallidus neurons may contribute to inducing early motor impairment in Parkinson's disease.
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Affiliation(s)
- Camila L Zold
- Laboratorio de Fisiología de Circuitos Neuronales, Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Ciudad de Buenos Aires (CP1121), Argentina.
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48
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Lee CR, Tepper JM. A calcium-activated nonselective cation conductance underlies the plateau potential in rat substantia nigra GABAergic neurons. J Neurosci 2007; 27:6531-41. [PMID: 17567814 PMCID: PMC6672447 DOI: 10.1523/jneurosci.1678-07.2007] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Plateau potentials can be elicited in nigral GABAergic neurons by injection of 500 ms depolarizing current pulses from hyperpolarized holding potentials in whole-cell recordings in vitro. In approximately one-third of these neurons, plateau potentials were observed under control conditions and could be elicited in the remaining neurons after blocking potassium conductances. Application of the L-type calcium channel agonist Bay K 8644 or activation of NMDA receptors enhanced plateau potentials observed under control conditions and caused a plateau to be elicited in neurons not exhibiting it previously. The plateau potential was abolished in calcium-free buffer, as well as by nickel or cadmium. The L-type calcium channel blockers nimodipine and nifedipine abolished the plateau potential observed under control conditions but did not affect plateaus unmasked by tetraethylammonium. Plateau potentials observed under control conditions as well as those observed in the presence of Bay K 8644, NMDA, or tetraethylammonium were abolished in low-sodium buffer and by the calcium-activated nonselective cation conductance blocker flufenamic acid. These data suggest that nigral plateau potentials are mediated by a calcium-activated nonselective cation conductance (I(CAN)) that is activated by calcium entry predominantly through L-type calcium channels. In many nigral neurons, I(CAN) is masked by tetraethylammonium-sensitive potassium conductances, but plateaus can be evoked after increasing calcium conductances. The I(CAN)-mediated plateau potential in nigral GABAergic neurons likely affects the way these neurons integrate input and may represent a mechanism contributing to the rhythmic firing of these neurons seen in pathological conditions such as Parkinson's disease.
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Affiliation(s)
- Christian R. Lee
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, Newark, New Jersey 07102
| | - James M. Tepper
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, Newark, New Jersey 07102
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49
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Kliem MA, Maidment NT, Ackerson LC, Chen S, Smith Y, Wichmann T. Activation of nigral and pallidal dopamine D1-like receptors modulates basal ganglia outflow in monkeys. J Neurophysiol 2007; 98:1489-500. [PMID: 17634344 DOI: 10.1152/jn.00171.2007] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Studies of the effects of dopamine in the basal ganglia have focused on the striatum, whereas the functions of dopamine released in the internal pallidal segment (GPi) or in the substantia nigra pars reticulata (SNr) have received less attention. Anatomic and biochemical investigations have demonstrated the presence of dopamine D1-like receptors (D1LRs) in GPi and SNr, which are primarily located on axons and axon terminals of the GABAergic striatopallidal and striatonigral afferents. Our experiments assessed the effects of D1LR ligands in GPi and SNr on local gamma-aminobutyric acid (GABA) levels and neuronal activity in these nuclei in rhesus monkeys. Microinjections of the D1LR receptor agonist SKF82958 into GPi and SNr significantly reduced discharge rates in GPi and SNr, whereas injections of the D1LR antagonist SCH23390 increased firing in the majority of GPi neurons. D1LR activation also increased bursting and oscillations in neuronal discharge in the 3- to 15-Hz band in both structures, whereas D1LR blockade had the opposite effects in GPi. Microdialysis measurements of GABA concentrations in GPi and SNr showed that the D1LR agonist increased the level of the transmitter. Both findings are compatible with the hypothesis that D1LR activation leads to GABA release from striatopallidal or striatonigral afferents, which may secondarily reduce firing of basal ganglia output neurons. The antagonist experiments suggest that a dopaminergic "tone" exists in GPi. Our results support the finding that D1LR activation may have powerful effects on GPi and SNr neurons and may mediate some of the effects of dopamine replacement therapies in Parkinson's disease.
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Affiliation(s)
- Michele A Kliem
- Yerkes National Primate Center, Emory University, School of Medicine, 954 Gatewood Road, Atlanta, GA 30322, USA
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50
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Santaniello S, Fiengo G, Glielmo L, Grill WM. Basal Ganglia Modeling in Healthy and Parkinson's Disease State. I. Isolated Neurons Activity. ACTA ACUST UNITED AC 2007. [DOI: 10.1109/acc.2007.4282741] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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