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Gala AS, Wilkins KB, Petrucci MN, Kehnemouyi YM, Velisar A, Trager MH, Bronte-Stewart HM. The digital signature of emergent tremor in Parkinson's disease. NPJ Parkinsons Dis 2024; 10:147. [PMID: 39112485 PMCID: PMC11306561 DOI: 10.1038/s41531-024-00754-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 07/22/2024] [Indexed: 08/10/2024] Open
Abstract
Emergent tremor in Parkinson's disease (PD) can occur during sustained postures or movements that are different from action tremor. Tremor can contaminate the clinical rating of bradykinesia during finger tapping. Currently, there is no reliable way of isolating emergent tremor and measuring the cardinal motor symptoms based on voluntary movements only. In this study, we investigated whether emergent tremor during repetitive alternating finger tapping (RAFT) on a quantitative digitography (QDG) device could be reliably identified and distinguished from voluntary tapping. Ninety-six individuals with PD and forty-two healthy controls performed a thirty-second QDG-RAFT task and the Movement Disorders Society - Unified Parkinson's Disease Rating Scale Part III (MDS-UPDRS III). Visual identification of tremor during QDG-RAFT was labeled by an experienced movement disorders specialist. Two methods of identifying tremor were investigated: 1) physiologically informed temporal thresholds 2) XGBoost model using temporal and amplitude features of tapping. The XGBoost model showed high accuracy for identifying tremor (area under the precision-recall curve of 0.981) and outperformed temporal-based thresholds. Percent time duration of classifier-identified tremor showed significant correlations with MDS-UPDRS III tremor subscores (r = 0.50, p < 0.0001). There was a significant change in QDG metrics for bradykinesia, rigidity, and arrhythmicity after tremor strikes were excluded (p < 0.01). The results demonstrate that emergent tremor during QDG-RAFT has a unique digital signature and the duration of tremor correlated with the MDS-UPDRS III tremor items. When involuntary tremor strikes were excluded, the QDG metrics of bradykinesia and rigidity were significantly worse, demonstrating the importance of distinguishing tremor from voluntary movement when rating bradykinesia.
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Affiliation(s)
- Aryaman S Gala
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Kevin B Wilkins
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | | | | | - Anca Velisar
- The Smith-Kettlewell Eye Research Institute, San Francisco, CA, USA
| | - Megan H Trager
- Columbia University College of Physicians and Surgeons, New York City, NY, USA
| | - Helen M Bronte-Stewart
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA.
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, US.
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Bronte-Stewart H, Gala A, Wilkins K, Pettruci M, Kehnemouyi Y, Velisar A, Trager M. The digital signature of emergent tremor in Parkinson's disease. RESEARCH SQUARE 2023:rs.3.rs-3467667. [PMID: 37961117 PMCID: PMC10635351 DOI: 10.21203/rs.3.rs-3467667/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Background Emergent tremor in Parkinson's disease (PD) can occur during sustained postures or movement that is different from action tremor. Tremor can contaminate the clinical rating of bradykinesia during finger tapping. Currently, there is no reliable way of isolating emergent tremor and measuring the cardinal motor symptoms based on voluntary movements only. Objective Investigate whether emergent tremor during repetitive alternating finger tapping (RAFT) on a quantitative digitography (QDG) device can be reliably identified and distinguished from voluntary tapping. Methods Ninety-six individuals with PD and forty-two healthy controls performed a thirty-second QDG-RAFT task and the Movement Disorders Society - Unified Parkinson's Disease Rating Scale Part III (MDS-UPDRS III). Visual identification of tremor during QDG-RAFT was labelled by an experienced movement disorders specialist. Two methods of identifying tremor were investigated: 1) physiologically-informed temporal thresholds 2) XGBoost model using temporal and amplitude features of tapping. Results The XGBoost model showed high accuracy for identifying tremor (area under the precision-recall curve of 0.981) and outperformed temporal-based thresholds. Percent time duration of classifier-identified tremor showed significant correlations with MDS-UPDRS III tremor subscores (r = 0.50, P < 0.0001). There was a significant change in QDG metrics for bradykinesia, rigidity and arrhythmicity after tremor strikes were excluded (p < 0.01). Conclusions Emergent tremor during QDG-RAFT has a unique digital signature and the duration of tremor correlated with the MDS-UPDRS III tremor items. When involuntary tremor strikes were excluded, the QDG metrics of bradykinesia and rigidity were significantly worse, demonstrating the importance of distinguishing tremor from voluntary movement when rating bradykinesia.
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Affiliation(s)
| | | | | | | | | | | | - Megan Trager
- Columbia University College of Physicians and Surgeons
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3
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Enteric neuroimmune interactions coordinate intestinal responses in health and disease. Mucosal Immunol 2022; 15:27-39. [PMID: 34471248 PMCID: PMC8732275 DOI: 10.1038/s41385-021-00443-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 08/02/2021] [Accepted: 08/05/2021] [Indexed: 02/04/2023]
Abstract
The enteric nervous system (ENS) of the gastrointestinal (GI) tract interacts with the local immune system bidirectionally. Recent publications have demonstrated that such interactions can maintain normal GI functions during homeostasis and contribute to pathological symptoms during infection and inflammation. Infection can also induce long-term changes of the ENS resulting in the development of post-infectious GI disturbances. In this review, we discuss how the ENS can regulate and be regulated by immune responses and how such interactions control whole tissue physiology. We also address the requirements for the proper regeneration of the ENS and restoration of GI function following the resolution of infection.
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Schaeffer EL, Liu DY, Guerin J, Ahn M, Lee S, Asaad WF. A low-cost solution for quantification of movement during DBS surgery. J Neurosci Methods 2018; 303:136-145. [PMID: 29605668 DOI: 10.1016/j.jneumeth.2018.03.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 03/23/2018] [Accepted: 03/24/2018] [Indexed: 11/17/2022]
Abstract
BACKGROUND During the deep brain stimulation (DBS) electrode implantation operation with microelectrode recordings (MER) in awake patients, somatotopic testing and test stimulation are performed to improve electrode placement and provide the most beneficial symptom reduction possible, while minimizing side effects. As this procedure is commonly used to alleviate abnormal movements associated with Parkinson's disease (PD) and Essential Tremor (ET), intraoperative assessment of a patient's movements is critical to optimizing surgical benefit. However, despite its importance, movement assessment is typically subjective and qualitative. NEW METHOD Here, we present a detailed description of a low-cost, open-source system as a solution. RESULTS The described system measures movements intraoperatively and in synchrony with neurophysiological recordings for both online visualization and offline analysis. COMPARISON WITH EXISTING METHOD(S) Few movement quantification systems are designed to interface with intraoperative neurophysiological recordings; the widespread application of such systems may be limited by their cost and proprietary, closed-source nature. The system presented provides a low-cost, open-source alternative. CONCLUSIONS The system outlined in this work may improve the DBS procedure by adding valuable objectivity in movement quantification.
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Affiliation(s)
- Erin L Schaeffer
- Department of Neuroscience, Brown University, Providence, RI, 02903, United States
| | - Daniel Y Liu
- Department of Neuroscience, Brown University, Providence, RI, 02903, United States
| | - Julie Guerin
- Department of Neuroscience, Brown University, Providence, RI, 02903, United States
| | - Minkyu Ahn
- School of Computer Science and Electrical Engineering, Handong Global University, Pohang, 37554, South Korea
| | - Shane Lee
- Department of Neuroscience, Brown University, Providence, RI, 02903, United States; Brown Institute for Brain Science (BIBS), Brown University, Providence, RI, 02903, United States
| | - Wael F Asaad
- Department of Neuroscience, Brown University, Providence, RI, 02903, United States; Brown Institute for Brain Science (BIBS), Brown University, Providence, RI, 02903, United States; Department of Neurosurgery, The Warren Alpert Medical School, Providence, RI, 02903, United States; Department of Neuosurgry, Rhode Island Hospital, Providence, RI, 02903, United States; Norman Prince Neurosciences Institute, Lifespan, Providence, RI, 02903, United States.
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Chan PY, Ripin ZM, Halim SA, Tharakan J, Muzaimi M, Ng KS, Kamarudin MI, Eow GB, Hor JY, Tan K, Cheah CF, Soong N, Then L, Yahya AS. An In-Laboratory Validity and Reliability Tested System for Quantifying Hand-Arm Tremor in Motions. IEEE Trans Neural Syst Rehabil Eng 2018; 26:460-467. [PMID: 29432113 DOI: 10.1109/tnsre.2017.2782361] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Despite the advancement of the tremor assessment systems, the current technology still lacks a method that can objectively characterize tremors in relative segmental movements. This paper presents a measurement system, which quantifies multi-degrees-of-freedom coupled relative motions of hand-arm tremor, in terms of joint angular displacement. In-laboratory validity and reliability tests of the system algorithm to provide joint angular displacement was carried out by using the two-degrees-of-freedom tremor simulator with incremental rotary encoder systems installed. The statistical analyses show that the developed system has high validity results and comparable reliability performances using the rotary encoder system as the reference. In the clinical trials, the system was tested on 38 Parkinson's disease patients. The system readings were correlated with the observational tremor ratings of six trained medical doctors. The moderate to very high clinical correlations of the system readings in measuring rest, postural and task-specific tremors add merits to the degree of readiness of the developed tremor measurement system in a routine clinical setting and/or intervention trial for tremor amelioration.
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Hasan H, Athauda DS, Foltynie T, Noyce AJ. Technologies Assessing Limb Bradykinesia in Parkinson's Disease. JOURNAL OF PARKINSONS DISEASE 2017; 7:65-77. [PMID: 28222539 PMCID: PMC5302048 DOI: 10.3233/jpd-160878] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Background: The MDS-UPDRS (Movement Disorders Society – Unified Parkinson’s Disease Rating Scale) is the most widely used scale for rating impairment in PD. Subscores measuring bradykinesia have low reliability that can be subject to rater variability. Novel technological tools can be used to overcome such issues. Objective: To systematically explore and describe the available technologies for measuring limb bradykinesia in PD that were published between 2006 and 2016. Methods: A systematic literature search using PubMed (MEDLINE), IEEE Xplore, Web of Science, Scopus and Engineering Village (Compendex and Inspec) databases was performed to identify relevant technologies published until 18 October 2016. Results: 47 technologies assessing bradykinesia in PD were identified, 17 of which offered home and clinic-based assessment whilst 30 provided clinic-based assessment only. Of the eligible studies, 7 were validated in a PD patient population only, whilst 40 were tested in both PD and healthy control groups. 19 of the 47 technologies assessed bradykinesia only, whereas 28 assessed other parkinsonian features as well. 33 technologies have been described in additional PD-related studies, whereas 14 are not known to have been tested beyond the pilot phase. Conclusion: Technology based tools offer advantages including objective motor assessment and home monitoring of symptoms, and can be used to assess response to intervention in clinical trials or routine care. This review provides an up-to-date repository and synthesis of the current literature regarding technology used for assessing limb bradykinesia in PD. The review also discusses the current trends with regards to technology and discusses future directions in development.
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Affiliation(s)
- Hasan Hasan
- UCL Institute of Neurology, Queen Square, London, UK
| | - Dilan S Athauda
- UCL Institute of Neurology, Queen Square, London, UK.,Sobell Department of Motor Neuroscience and Movement Disorders, The National Hospital for Neurology and Neurosurgery, London, UK
| | - Thomas Foltynie
- UCL Institute of Neurology, Queen Square, London, UK.,Sobell Department of Motor Neuroscience and Movement Disorders, The National Hospital for Neurology and Neurosurgery, London, UK
| | - Alastair J Noyce
- UCL Institute of Neurology, Queen Square, London, UK.,Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University London, London, UK.,Reta Lila Weston Institute of Neurological studies, UCL Institute of Neurology, London, UK
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Chakraborty S, Kopecká J, Šprdlík O, Hoskovcová M, Ulmanová O, Růžička E, Zapotocky M. Intermittent bilateral coherence in physiological and essential hand tremor. Clin Neurophysiol 2017; 128:622-634. [PMID: 28231479 DOI: 10.1016/j.clinph.2016.12.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 11/30/2016] [Accepted: 12/23/2016] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To investigate the prevalence and the temporal structure of bilateral coherence in physiological (PT) and essential (ET) hand tremor. METHODS Triaxial accelerometric recordings from both hands in 30 healthy subjects and 34 ET patients were analyzed using spectral coherence and wavelet coherence methods. In 12 additional healthy subjects, the relation between the hand tremor and the chest wall acceleration was evaluated using partial coherence analysis. RESULTS The majority of both PT and ET subjects displayed significant bilateral coherence. While in PT, bilateral coherence was most frequently found in resting hand position (97% of subjects), in ET the prevalence was comparable for resting (54%) and postural (49%-57%) positions. In both PT and ET, epochs of strong coherence lasting several to a dozen seconds were separated by intervals of insignificant coherence. In PT, bilateral coherence at the main tremor frequency (8-12Hz) was coupled with the ballistocardiac rhythm. CONCLUSION The oscillations of the two hands are intermittently synchronized in both PT and ET. We propose that in postural PT, bilateral coherence at the main tremor frequency arises from transient simultaneous entrainment of the left and right hand oscillations to ballistocardiac forcing. SIGNIFICANCE Bilateral coherence of hand kinematics provides a sensitive measure of synchronizing influences on the left and right tremor oscillators.
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Affiliation(s)
- Soma Chakraborty
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic; Department of Neurology, First Faculty of Medicine, Charles University in Prague, Czech Republic
| | - Jana Kopecká
- Department of Neurology, First Faculty of Medicine, Charles University in Prague, Czech Republic
| | - Otakar Šprdlík
- Department of Neurology, First Faculty of Medicine, Charles University in Prague, Czech Republic; Institute of Information Theory and Automation, Czech Academy of Sciences, Prague, Czech Republic
| | - Martina Hoskovcová
- Department of Neurology, First Faculty of Medicine, Charles University in Prague, Czech Republic
| | - Olga Ulmanová
- Department of Neurology, First Faculty of Medicine, Charles University in Prague, Czech Republic
| | - Evžen Růžička
- Department of Neurology, First Faculty of Medicine, Charles University in Prague, Czech Republic.
| | - Martin Zapotocky
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic; Institute of Biophysics and Informatics, First Faculty of Medicine, Charles University in Prague, Czech Republic.
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Shah A, Coste J, Lemaire JJ, Taub E, Schüpbach WMM, Pollo C, Schkommodau E, Guzman R, Hemm-Ode S. Intraoperative acceleration measurements to quantify improvement in tremor during deep brain stimulation surgery. Med Biol Eng Comput 2016; 55:845-858. [PMID: 27631560 DOI: 10.1007/s11517-016-1559-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Accepted: 08/08/2016] [Indexed: 11/25/2022]
Abstract
Deep brain stimulation (DBS) surgery is extensively used in the treatment of movement disorders. Nevertheless, methods to evaluate the clinical response during intraoperative stimulation tests to identify the optimal position for the implantation of the chronic DBS lead remain subjective. In this paper, we describe a new, versatile method for quantitative intraoperative evaluation of improvement in tremor with an acceleration sensor that is mounted on the patient's wrist during surgery. At each anatomical test position, the improvement in tremor compared to the initial tremor is estimated on the basis of extracted outcome measures. This method was tested on 15 tremor patients undergoing DBS surgery in two centers. Data from 359 stimulation tests were acquired. Our results suggest that accelerometric evaluation detects tremor changes more sensitively than subjective visual ratings. The effective stimulation current amplitudes identified from the quantitative data (1.1 ± 0.8 mA) are lower than those identified by visual evaluation (1.7 ± 0.8 mA) for similar improvement in tremor. Additionally, if these data had been used to choose the chronic implant position of the DBS lead, 15 of the 26 choices would have been different. These results show that our method of accelerometric evaluation can potentially improve DBS targeting.
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Affiliation(s)
- Ashesh Shah
- Institute for Medical and Analytical Technologies, University of Applied Sciences and Arts Northwestern Switzerland, Gruendenstrasse 40, 4132, Muttenz, Switzerland
| | - Jérôme Coste
- Image-Guided Clinical Neuroscience and Connectomics (EA 7282), Université Clermont Auvergne, Clermont-Ferrand, France.,Service de Neurochirurgie, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Jean-Jacques Lemaire
- Image-Guided Clinical Neuroscience and Connectomics (EA 7282), Université Clermont Auvergne, Clermont-Ferrand, France.,Service de Neurochirurgie, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Ethan Taub
- Departments of Neurosurgery and Biomedicine, University of Basel, Basel, Switzerland
| | - W M Michael Schüpbach
- Department of Neurology, University Hospital Bern and University of Bern, Bern, Switzerland.,Assistance Publique Hôpitaux de Paris, Institut National de Santé et en Recherche Médicale, Institut du Cerveau et de la Moelle Epinière, Centre d'Investigation Clinique 1422, Département de Neurologie, Hôpital Pitié-Salpêtrière, 75013, Paris, France
| | - Claudio Pollo
- Department of Neurosurgery, University Hospital Bern, Bern, Switzerland
| | - Erik Schkommodau
- Institute for Medical and Analytical Technologies, University of Applied Sciences and Arts Northwestern Switzerland, Gruendenstrasse 40, 4132, Muttenz, Switzerland
| | - Raphael Guzman
- Departments of Neurosurgery and Biomedicine, University of Basel, Basel, Switzerland
| | - Simone Hemm-Ode
- Institute for Medical and Analytical Technologies, University of Applied Sciences and Arts Northwestern Switzerland, Gruendenstrasse 40, 4132, Muttenz, Switzerland.
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Quantitative Assessment of Parkinsonian Tremor Based on an Inertial Measurement Unit. SENSORS 2015; 15:25055-71. [PMID: 26426020 PMCID: PMC4634500 DOI: 10.3390/s151025055] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 09/13/2015] [Accepted: 09/14/2015] [Indexed: 11/17/2022]
Abstract
Quantitative assessment of parkinsonian tremor based on inertial sensors can provide reliable feedback on the effect of medication. In this regard, the features of parkinsonian tremor and its unique properties such as motor fluctuations and dyskinesia are taken into account. Least-square-estimation models are used to assess the severities of rest, postural, and action tremors. In addition, a time-frequency signal analysis algorithm for tremor state detection was also included in the tremor assessment method. This inertial sensor-based method was verified through comparison with an electromagnetic motion tracking system. Seven Parkinson’s disease (PD) patients were tested using this tremor assessment system. The measured tremor amplitudes correlated well with the judgments of a neurologist (r = 0.98). The systematic analysis of sensor-based tremor quantification and the corresponding experiments could be of great help in monitoring the severity of parkinsonian tremor.
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10
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Hess CW, Pullman SL. Tremor: clinical phenomenology and assessment techniques. Tremor Other Hyperkinet Mov (N Y) 2012; 2:tre-02-65-365-1. [PMID: 23439931 PMCID: PMC3517187 DOI: 10.7916/d8wm1c41] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2011] [Accepted: 11/23/2011] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Tremors are among the most common movement disorders. As there can be considerable variability in the manner in which clinicians assess tremor, objective quantitative tools such as electromyography, accelerometry, and computerized, spiral analysis can be very useful in establishing a clinical diagnosis and in research settings. METHODS In this review, we discuss the various methods of quantitative tremor analysis and the classification and pathogenesis of tremor. The most common pathologic tremors and an approach to the diagnosis of tremor etiology are described. CONCLUSIONS Pathologic tremors are common, and the diagnosis of underlying etiology is not always straightforward. Computerized quantitative tremor analysis is a valuable adjunct to careful clinical evaluation in distinguishing tremulous diseases from physiologic tremors, and can also help shed light on their pathogenesis.
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Affiliation(s)
- Christopher W. Hess
- Clinical Motor Physiology Laboratory, Department of Neurology, Columbia University Medical Center, New York, New York, United States of America
| | - Seth L. Pullman
- Clinical Motor Physiology Laboratory, Department of Neurology, Columbia University Medical Center, New York, New York, United States of America
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11
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Monro RL, Bornstein JC, Bertrand PP. Synaptic transmission from the submucosal plexus to the myenteric plexus in Guinea-pig ileum. Neurogastroenterol Motil 2008; 20:1165-73. [PMID: 18643893 DOI: 10.1111/j.1365-2982.2008.01157.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Stimulation of the myenteric plexus results in activation of submucosal neurons and dilation of arterioles, one way that motility and secretion can be coupled together. The present study aimed to examine the converse, whether myenteric neurons receive synaptic input from the submucosal plexus (SMP). Intracellular recordings were made from guinea-pig ileal myenteric neurons while the SMP was electrically stimulated. Of the 29 neurons studied (13 S and 16 AH neurons), stimulation of the SMP evoked a synaptic potential in only seven cells, or 24% of neurons. When the SMP was situated oral to the myenteric plexus, 4 of 13 (31%) myenteric neurons had synaptic input. When it was situated circumferential, 2 of 8 (25%) had input, and when the SMP was situated anal 1 of 8 (13%) had input. Overall, 5 of the 13 (38%) S neurons responded with fast excitatory post-synaptic potentials (EPSPs), one of which also showed a slow EPSP, while 2 of the 16 (13%) AH neurons responded with a slow EPSP. This study indicates that the synaptic input from the SMP to myenteric neurons is relatively sparse. Whether this input is less important than the myenteric to submucosal input or simply represents a more selective form of control is unknown.
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Affiliation(s)
- R L Monro
- Department of Physiology, University of Melbourne, Parkville, Australia
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12
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Wang S, Aziz TZ, Stein JF, Bain PG, Liu X. Physiological and harmonic components in neural and muscular coherence in Parkinsonian tremor. Clin Neurophysiol 2006; 117:1487-98. [PMID: 16737846 DOI: 10.1016/j.clinph.2006.03.027] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2005] [Revised: 03/21/2006] [Accepted: 03/29/2006] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To differentiate physiological from harmonic components in coherence analysis of the tremor-related neural and muscular signals by comparing power, cross-power and coherence spectra. METHODS Influences of waveform, burst-width and additional noise on generating harmonic peaks in the power, cross-power and coherence spectra were studied using simulated signals. The local field potentials (LFPs) of the subthalamic nucleus (STN) and the EMGs of the contralateral forearm muscles in PD patients with rest tremor were analysed. RESULTS (1) Waveform had significant effect on generating harmonics; (2) noise significantly decreased the coherence values in a frequency-dependent fashion; and (3) cross-spectrum showed high resistance to harmonics. Among six examples of paired LFP-EMG signals, significant coherence appeared at the tremor frequency only, both the tremor and double tremor frequencies and the double-tremor frequency only. CONCLUSIONS In coherence analysis of neural and muscular signals, distortion in waveform generates significant harmonic peaks in the coherence spectra and the coherence values of both physiological and harmonic components are modulated by extra noise or non-tremor related activity. SIGNIFICANCE The physiological or harmonic nature of a coherence peak at the double tremor frequency may be differentiated when the coherence spectra are compared with the power and in particular the cross-power spectra.
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Affiliation(s)
- Shouyan Wang
- Department of Physiology, Anatomy, and Genetics, University of Oxford, and Department of Neurosurgery, Radcliffe Infirmary, Woodstock Road, Oxford OX2 6HE, UK
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Furness JB, Jones C, Nurgali K, Clerc N. Intrinsic primary afferent neurons and nerve circuits within the intestine. Prog Neurobiol 2004; 72:143-64. [PMID: 15063530 DOI: 10.1016/j.pneurobio.2003.12.004] [Citation(s) in RCA: 253] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2003] [Accepted: 12/03/2003] [Indexed: 02/08/2023]
Abstract
Intrinsic primary afferent neurons (IPANs) of the enteric nervous system are quite different from all other peripheral neurons. The IPANs are transducers of physiological stimuli, including movement of the villi or distortion of the mucosa, contraction of intestinal muscle and changes in the chemistry of the contents of the gut lumen. They are the first neurons in intrinsic reflexes that influence the patterns of motility, secretion of fluid across the mucosal epithelium and local blood flow in the small and large intestines. In the guinea pig small intestine, where they have been characterized in detail, IPANs have Dogiel type II morphology, that is they are large round or oval neurons with multiple processes, some of which end close to the luminal surface of the intestine, and some of which form synapses with enteric interneurons, motor neurons and with other IPANs. The IPANs have well-defined ionic currents through which their excitability, and their functions in enteric nerve circuits, is determined. These include voltage-gated Na(+) and Ca(2+) currents, a long lasting calcium-activated K(+) current, and a hyperpolarization-activated cationic current. The IPANs exhibit long-term changes in their states of excitation that can be induced by extended periods of low frequency activity in synaptic inputs and by inflammatory mediators, either applied directly or released during an inflammatory challenge. The IPANs may be involved in pathological changes in enteric function following inflammation.
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Affiliation(s)
- John B Furness
- Department of Anatomy & Cell Biology and Centre for Neuroscience, University of Melbourne, Parkville, Vic. 3010, Australia.
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Abstract
The presence of neuronal reflexes within the intestine that modulate mucosal ion secretion and blood flow have been recognized for many years, but the organization of these reflexes was unclear. This review highlights important findings from recent in vitro guinea-pig studies which have shown that both intrinsic primary afferent neurones (IPANs) and extrinsic primary afferent neurones (EPANs) can respond to chemical and/or mechanical stimuli to activate pathways, the afferent and efferent elements of which are confined to the walls of the intestine. Enteric neuronal pathways involve both myenteric and submucosal plexus neurones whereas capsaicin-sensitive afferent nerves evoke secretion by stimulating submucosal secretomotor neurones and vasodilation by direct actions on the submucosal arterioles. In this review, the cellular mechanisms involved in these pathways are described and the implications of these findings are discussed.
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Affiliation(s)
- S Vanner
- GIDRU, Queen's University, Kingston, ON, Canada.
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Galligan JJ, North RA. Pharmacology and function of nicotinic acetylcholine and P2X receptors in the enteric nervous system. Neurogastroenterol Motil 2004; 16 Suppl 1:64-70. [PMID: 15066008 DOI: 10.1111/j.1743-3150.2004.00478.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
There are many cell surface receptors expressed by neurones in the enteric nervous system (ENS). Ligand-gated ion channels are an important class of receptors expressed by enteric neurones. This review will focus on nicotinic acetylcholine receptors (nAChRs) and P2X receptors for ATP, as these receptors contribute to fast synaptic transmission in identified pathways in the ENS. There are multiple subunit proteins that compose nAChRs and P2X receptors in the nervous system. Functional and pharmacological studies indicate that the predominant class of nAChR mediating fast synaptic transmission in enteric neurones is composed of alpha3 and beta4 subunits. P2X receptors mediating fast synaptic excitation are predominately P2X2 homomeric receptors.
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Affiliation(s)
- J J Galligan
- Department of Pharmacology and Toxicology and the Neuroscience Program, Michigan State University, East Lansing, MI, USA.
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Reed DE, Vanner SJ. Converging and diverging cholinergic inputs from submucosal neurons amplify activity of secretomotor neurons in guinea-pig ileal submucosa. Neuroscience 2002; 107:685-96. [PMID: 11720791 DOI: 10.1016/s0306-4522(01)00392-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The organization of synaptic connections between guinea-pig ileal submucosal neurons was examined using intracellular recordings from single or pairs of submucosal neurons. Synaptic inputs were elicited by stimulating cholinergic neurons using pressure-pulse application of 5-hydroxytryptamine (5-HT) in ganglia adjacent to those where intracellular recordings were obtained. In addition, when pairs of intracellular recordings were obtained, one neuron was activated by intracellular stimulation and synaptic responses were recorded in the other neuron. Neurobiotin-filled microelectrodes were employed to characterize cells electrophysiologically and immunohistochemically. Recordings were obtained from 176 (173 S-type and three AH-type) neurons; 81% of cells were classified as vasoactive intestinal peptide (VIP) neurons. No fast excitatory postsynaptic potentials and only rare slow excitatory postsynaptic potentials were recorded following intracellular stimulation of paired S-type neurons. However, when paired intracellular recordings were obtained from neurons within the same ganglion and 5-HT was applied to an adjacent ganglion, this stimulation evoked synchronized fast excitatory postsynaptic potentials in 94% of pairs. In contrast, when cell bodies of VIP-VIP pairs were located in different ganglia, fast synaptic activation evoked by 5-HT stimulation was not synchronized in 87% of pairs. When intracellular recordings were obtained from a single neuron and two separate ganglia were stimulated by 5-HT pressure-pulse activation, fast excitatory postsynaptic potentials originating from both sources were recorded in the same VIP neuron. Morphological study of 34 S-type and three AH-type horseradish peroxidase-labeled neurons was conducted. AH-type neurons had multiple axonal branches with dense arborization of collaterals containing numerous varicosities in three to nine ganglia, whereas axons of S-type neurons exhibited relatively rare collaterals and varicosities within adjacent ganglia. These results demonstrate that cholinergic neurons provide both diverging and converging inputs to VIP neurons, providing a mechanism to enhance activation of VIP secretomotor neurons. The axonal projections of AH-type neurons suggest they are likely candidates to provide diverging inputs to multiple VIP neurons.
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Affiliation(s)
- D E Reed
- GI Diseases Research Unit, Department of Biology, Queen's University, Kingston, ON, Canada
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