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Abstract
Many investigators who make extracellular recordings from populations of cortical neurons are now using spike shape parameters, and particularly spike duration, as a means of classifying different neuronal sub-types. Because of the nature of the experimental approach, particularly that involving nonhuman primates, it is very difficult to validate directly which spike characteristics belong to particular types of pyramidal neurons and interneurons, as defined by modern histological approaches. This commentary looks at the way antidromic identification of pyramidal cells projecting to different targets, and in particular, pyramidal tract neurons (PTN), can inform the utility of spike width classification. Spike duration may provide clues to a diversity of function across the pyramidal cell population, and also highlights important differences that exist across species. Our studies suggest that further electrophysiological and optogenetic approaches are needed to validate spike duration as a means of cell classification and to relate this to well-established histological differences in neocortical cell types.
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Affiliation(s)
- Roger N Lemon
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Stuart N Baker
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Alexander Kraskov
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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Kraskov A, Baker S, Soteropoulos D, Kirkwood P, Lemon R. The Corticospinal Discrepancy: Where are all the Slow Pyramidal Tract Neurons? Cereb Cortex 2020; 29:3977-3981. [PMID: 30365013 DOI: 10.1093/cercor/bhy278] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 09/17/2018] [Accepted: 10/10/2018] [Indexed: 11/13/2022] Open
Abstract
This feature article focuses on the discrepancy between the distribution of axon diameters within the primate corticospinal tract, determined neuroanatomically, and the distribution of axonal conduction velocities within the same tract, determined electrophysiologically. We point out the importance of resolving this discrepancy for a complete understanding of corticospinal functions, and discuss the various explanations for the mismatch between anatomy and physiology.
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Affiliation(s)
- Alexander Kraskov
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | - Stuart Baker
- Institute of Neuroscience, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Demetris Soteropoulos
- Institute of Neuroscience, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Peter Kirkwood
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | - Roger Lemon
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
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Sandhu A, Tzou WS, Borne RT, Zipse MM, Nguyen DT, Sauer WH. Uncovering a unique path: Antidromic AVRT utilizing a left anteroseptal Mahaim-like accessory pathway. Pacing Clin Electrophysiol 2020; 44:185-188. [PMID: 32794265 DOI: 10.1111/pace.14024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 07/17/2020] [Accepted: 07/26/2020] [Indexed: 11/27/2022]
Abstract
A 40-year-old man presented to our emergency department 2 hours after onset of shortness of breath, palpitations, and presyncope secondary to an adenosine-responsive wide complex tachycardia. Electrophysiology study was diagnostic for antidromic atrioventricular (AV) reentrant tachycardia utilizing a muscular connection from the anterior interventricular vein to the left ventricle with Mahaim-like properties, successfully treated with ablation in the distal coronary sinus (CS) system. This case highlights accessory pathways (a) with unique features (i.e., Mahaim-like characteristics) and (b) involving musculature from the distal CS system, thereby limiting the value of endocardial ablation for durable treatment. Importantly, the coronary venous system is an accessible vascular network for evaluation and catheter ablation of such arrhythmias.
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Affiliation(s)
- Amneet Sandhu
- Section of Electrophysiology, The University of Colorado, Aurora, Colorado.,Section of Electrophysiology, Rocky Mountain Regional VA Medical Center, Aurora, Colorado
| | - Wendy S Tzou
- Section of Electrophysiology, The University of Colorado, Aurora, Colorado
| | - Ryan T Borne
- Section of Electrophysiology, The University of Colorado, Aurora, Colorado
| | - Matthew M Zipse
- Section of Electrophysiology, The University of Colorado, Aurora, Colorado
| | - Duy T Nguyen
- Section of Electrophysiology, Stanford University, Palo Alto, California
| | - William H Sauer
- Section of Electrophysiology, Brigham and Women's Hospital, Boston, Massachusetts
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Abstract
Analog signaling describes the use of graded voltage changes as signals in the axonal compartment. Analog signaling has been described originally in invertebrates but more recent work has established its presence in the mammalian brain (Alle and Geiger, 2006; Shu et al., 2006). In recent years, many different groups have contributed to the understanding of the physiological significance of analog signaling from a cellular perspective (for a recent review the reader may take a look at the work by Zbili and Debanne, 2019 in this Frontiers in Neuroscience Special Issue). The great majority of the experimental work related to analog signaling, however, concerns the propagation of subthreshold voltage changes from the soma to the axon. Much less attention has been paid to the propagation of subthreshold voltage changes in the opposite direction, from the axon to the soma, or to the propagation of local signals within the axon. In this mini review we will describe these other variants of analog signaling that we call here “antidromic” coupling and “local” coupling.
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Affiliation(s)
- Federico F Trigo
- CNRS UMR8003, SPPIN Laboratory, Cerebellar Neurophysiology Group, Faculté des Sciences Fondamentales et Biomédicales, Université de Paris, Paris, France.,Departamento de Neurofisiología Celular y Molecular, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
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Cohen JA, Edwards TN, Liu AW, Hirai T, Jones MR, Wu J, Li Y, Zhang S, Ho J, Davis BM, Albers KM, Kaplan DH. Cutaneous TRPV1 + Neurons Trigger Protective Innate Type 17 Anticipatory Immunity. Cell 2019; 178:919-932.e14. [PMID: 31353219 DOI: 10.1016/j.cell.2019.06.022] [Citation(s) in RCA: 179] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 05/03/2019] [Accepted: 06/12/2019] [Indexed: 12/31/2022]
Abstract
Cutaneous TRPV1+ neurons directly sense noxious stimuli, inflammatory cytokines, and pathogen-associated molecules and are required for innate immunity against some skin pathogens. Important unanswered questions are whether TRPV1+ neuron activation in isolation is sufficient to initiate innate immune responses and what is the biological function for TRPV1+ neuron-initiated immune responses. We used TRPV1-Ai32 optogenetic mice and cutaneous light stimulation to activate cutaneous neurons in the absence of tissue damage or pathogen-associated products. We found that TRPV1+ neuron activation was sufficient to elicit a local type 17 immune response that augmented host defense to C. albicans and S. aureus. Moreover, local neuron activation elicited type 17 responses and augmented host defense at adjacent, unstimulated skin through a nerve reflex arc. These data show the sufficiency of TRPV1+ neuron activation for host defense and demonstrate the existence of functional anticipatory innate immunity at sites adjacent to infection that depends on antidromic neuron activation.
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Affiliation(s)
- Jonathan A Cohen
- Department of Dermatology, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Tara N Edwards
- Department of Dermatology, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Andrew W Liu
- Department of Dermatology, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Toshiro Hirai
- Department of Dermatology, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Marsha Ritter Jones
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Jianing Wu
- Department of Dermatology, University of Pittsburgh, Pittsburgh, PA 15261, USA; School of Medicine, Tsinghua University, No. 1 Tsinghua Yuan, Haidian District, Beijing 100084, China; Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Yao Li
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Shiqun Zhang
- Department of Dermatology, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Jonhan Ho
- Department of Dermatology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Brian M Davis
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15261, USA; Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Kathryn M Albers
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15261, USA; Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Daniel H Kaplan
- Department of Dermatology, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA; Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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Summerson SR, Aazhang B, Kemere C. Investigating irregularly patterned deep brain stimulation signal design using biophysical models. Front Comput Neurosci 2015; 9:78. [PMID: 26167150 PMCID: PMC4481153 DOI: 10.3389/fncom.2015.00078] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 06/10/2015] [Indexed: 11/13/2022] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder which follows from cell loss of dopaminergic neurons in the substantia nigra pars compacta (SNc), a nucleus in the basal ganglia (BG). Deep brain stimulation (DBS) is an electrical therapy that modulates the pathological activity to treat the motor symptoms of PD. Although this therapy is currently used in clinical practice, the sufficient conditions for therapeutic efficacy are unknown. In this work we develop a model of critical motor circuit structures in the brain using biophysical cell models as the base components and then evaluate performance of different DBS signals in this model to perform comparative studies of their efficacy. Biological models are an important tool for gaining insights into neural function and, in this case, serve as effective tools for investigating innovative new DBS paradigms. Experiments were performed using the hemi-parkinsonian rodent model to test the same set of signals, verifying the obedience of the model to physiological trends. We show that antidromic spiking from DBS of the subthalamic nucleus (STN) has a significant impact on cortical neural activity, which is frequency dependent and additionally modulated by the regularity of the stimulus pulse train used. Irregular spacing between stimulus pulses, where the amount of variability added is bounded, is shown to increase diversification of response of basal ganglia neurons and reduce entropic noise in cortical neurons, which may be fundamentally important to restoration of information flow in the motor circuit.
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Affiliation(s)
- Samantha R Summerson
- Department of Electrical Engineering and Computer Science, University of California, Berkeley Berkeley, CA, USA
| | - Behnaam Aazhang
- Department of Electrical and Computer Engineering, Rice University Houston, TX, USA
| | - Caleb Kemere
- Department of Electrical and Computer Engineering, Rice University Houston, TX, USA ; Department of Neuroscience, Baylor College of Medicine Houston, TX, USA
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Kang G, Lowery MM. Effects of antidromic and orthodromic activation of STN afferent axons during DBS in Parkinson's disease: a simulation study. Front Comput Neurosci 2014; 8:32. [PMID: 24678296 PMCID: PMC3958751 DOI: 10.3389/fncom.2014.00032] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 02/25/2014] [Indexed: 11/28/2022] Open
Abstract
Recent studies suggest that subthalamic nucleus (STN)-Deep Brain Stimulation (DBS) may exert at least part of its therapeutic effect through the antidromic suppression of pathological oscillations in the cortex in 6-OHDA treated rats and in parkinsonian patients. STN-DBS may also activate STN neurons by initiating action potential propagation in the orthodromic direction, similarly resulting in suppression of pathological oscillations in the STN. While experimental studies have provided strong evidence in support of antidromic stimulation of cortical neurons, it is difficult to separate relative contributions of antidromic and orthodromic effects of STN-DBS. The aim of this computational study was to examine the effects of antidromic and orthodromic activation on neural firing patterns and beta-band (13-30 Hz) oscillations in the STN and cortex during DBS of STN afferent axons projecting from the cortex. High frequency antidromic stimulation alone effectively suppressed simulated beta activity in both the cortex and STN-globus pallidus externa (GPe) network. High frequency orthodromic stimulation similarly suppressed beta activity within the STN and GPe through the direct stimulation of STN neurons driven by DBS at the same frequency as the stimulus. The combined effect of both antidromic and orthodromic stimulation modulated cortical activity antidromically while simultaneously orthodromically driving STN neurons. While high frequency DBS reduced STN beta-band power, low frequency stimulation resulted in resonant effects, increasing beta-band activity, consistent with previous experimental observations. The simulation results indicate effective suppression of simulated oscillatory activity through both antidromic stimulation of cortical neurons and direct orthodromic stimulation of STN neurons. The results of the study agree with experimental recordings of STN and cortical neurons in rats and support the therapeutic potential of stimulation of cortical neurons.
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Affiliation(s)
- Guiyeom Kang
- UCD School of Electrical, Electronic and Communications Engineering, University College Dublin Dublin, Ireland
| | - Madeleine M Lowery
- UCD School of Electrical, Electronic and Communications Engineering, University College Dublin Dublin, Ireland
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Carron R, Chaillet A, Filipchuk A, Pasillas-Lépine W, Hammond C. Closing the loop of deep brain stimulation. Front Syst Neurosci 2013; 7:112. [PMID: 24391555 PMCID: PMC3868949 DOI: 10.3389/fnsys.2013.00112] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 11/28/2013] [Indexed: 01/20/2023] Open
Abstract
High-frequency deep brain stimulation is used to treat a wide range of brain disorders, like Parkinson's disease. The stimulated networks usually share common electrophysiological signatures, including hyperactivity and/or dysrhythmia. From a clinical perspective, HFS is expected to alleviate clinical signs without generating adverse effects. Here, we consider whether the classical open-loop HFS fulfills these criteria and outline current experimental or theoretical research on the different types of closed-loop DBS that could provide better clinical outcomes. In the first part of the review, the two routes followed by HFS-evoked axonal spikes are explored. In one direction, orthodromic spikes functionally de-afferent the stimulated nucleus from its downstream target networks. In the opposite direction, antidromic spikes prevent this nucleus from being influenced by its afferent networks. As a result, the pathological synchronized activity no longer propagates from the cortical networks to the stimulated nucleus. The overall result can be described as a reversible functional de-afferentation of the stimulated nucleus from its upstream and downstream nuclei. In the second part of the review, the latest advances in closed-loop DBS are considered. Some of the proposed approaches are based on mathematical models, which emphasize different aspects of the parkinsonian basal ganglia: excessive synchronization, abnormal firing-rate rhythms, and a deficient thalamo-cortical relay. The stimulation strategies are classified depending on the control-theory techniques on which they are based: adaptive and on-demand stimulation schemes, delayed and multi-site approaches, stimulations based on proportional and/or derivative control actions, optimal control strategies. Some of these strategies have been validated experimentally, but there is still a large reservoir of theoretical work that may point to ways of improving practical treatment.
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Affiliation(s)
- Romain Carron
- Aix Marseille Université UMR 901 Marseille, France ; Institut national de la Recherche Médicale et de la Santé Inserm, INMED UMR 901 Marseille, France ; APHM, Hopital de la Timone, Service de Neurochirurgie Fonctionnelle et Stereotaxique Marseille, France
| | - Antoine Chaillet
- Laboratoire des Signaux et Systèmes(L2S), CNRS UMR 8506 Gif-sur-Yvette, France ; Université Paris Sud 11, UMR 8506, Supélec Gif-sur-Yvette, France
| | - Anton Filipchuk
- Aix Marseille Université UMR 901 Marseille, France ; Institut national de la Recherche Médicale et de la Santé Inserm, INMED UMR 901 Marseille, France
| | - William Pasillas-Lépine
- Laboratoire des Signaux et Systèmes(L2S), CNRS UMR 8506 Gif-sur-Yvette, France ; Centre national de la recherche scientifique Paris, France
| | - Constance Hammond
- Aix Marseille Université UMR 901 Marseille, France ; Institut national de la Recherche Médicale et de la Santé Inserm, INMED UMR 901 Marseille, France
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Mathai A, Wichmann T, Smith Y. More than meets the eye-myelinated axons crowd the subthalamic nucleus. Mov Disord 2013; 28:1811-5. [PMID: 23852565 DOI: 10.1002/mds.25603] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 04/30/2013] [Accepted: 05/29/2013] [Indexed: 11/10/2022] Open
Abstract
High frequency deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a successful treatment for patients with advanced Parkinson's disease (PD). Although its exact mechanism of action is unknown, it is currently believed that the beneficial effects of the stimulation are mediated either by alleviating pathological basal ganglia output patterns of activity or by activation of the axons of passage that arise from the cerebral cortex and other sources. In this study, we show that the anatomical composition of the primate STN provides a substrate through which DBS may elicit widespread changes in brain activity via stimulation of fibers of passage. Using quantitative high-resolution electron microscopy, we found that the primate STN is traversed by numerous myelinated axons, which occupy as much as 45% of its sensorimotor territory and 36% of its associative region. In comparison, myelinated axons occupy only 27% of the surface areas of the sensorimotor and associative regions of the internal segment of the globus pallidus (GPi), another target for therapeutic DBS in PD. We also noted that myelinated axons in the STN, on average, have a larger diameter than those in GPi, which may render them more susceptible to electrical stimulation. Because axons are more excitable than other neuronal elements, our findings support the hypothesis that STN DBS, even when carried out entirely within the confines of the nucleus, mediates some of its effects by activating myelinated axons of passage.
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Affiliation(s)
- Abraham Mathai
- Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, USA; Morris K. Udall Center of Excellence for Parkinson's Disease Research, Emory University, Atlanta, Georgia, USA
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Veenhuyzen GD, Quinn FR. Principles of entrainment: diagnostic utility for supraventricular tachycardia. Indian Pacing Electrophysiol J 2008; 8:51-65. [PMID: 18270602 PMCID: PMC2231607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Entrainment is an important pacing maneuver that can be used to identify reentry as a tachycardia mechanism and define components of the circuit. This review examines how principles of entrainment can be used to arrive at a firm supraventricular tachycardia diagnosis using a simple algorithm and builds a foundation for the application of entrainment to more complex or unknown circuits.
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