1
|
Ishii K, Idesako M, Asahara R, Liang N, Matsukawa K. Central modulation of cardiac baroreflex moment-to-moment sensitivity during treadmill exercise in conscious cats. Physiol Rep 2022; 10:e15371. [PMID: 35757967 PMCID: PMC9234745 DOI: 10.14814/phy2.15371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 06/06/2022] [Accepted: 06/11/2022] [Indexed: 11/24/2022] Open
Abstract
It remains undetermined whether the cardiac component of the entire arterial baroreflex is blunted even at the onset of low-intensity exercise. We sought to examine the moment-to-moment sensitivity of the cardiac baroreflex during walking at different speeds and the presumed mechanisms responsible for baroreflex modulation in conscious cats. Arterial baroreflex sensitivity for heart rate was estimated from the baroreflex ratio between changes in systolic arterial blood pressure and heart rate and from the slope of the baroreflex curve between the cardiovascular responses to brief occlusion of the abdominal aorta. Treadmill walking was performed for 1 min at three levels of speed (low: 20-30 m/min, moderate: 40 m/min, and high: 50-60 m/min) or for 3 min at the stepwise change of speed (low to high to low transition). Cardiac baroreflex sensitivity was blunted at the onset of walking, irrespective of speed. Thereafter, the blunted cardiac baroreflex sensitivity was restored around 15 s of walking at any speed, while the blunting occurred again at 45 s of high-speed walking. The inhibition of cardiac baroreflex sensitivity also occurred (1) during the speed transition from low to high and (2) at 45 s of high-speed exercise of the stepwise exercise. The blunted cardiac baroreflex sensitivity was restored immediately to the resting level during the speed transition from high to low, despite sustained pressor and tachycardiac responses. Therefore, moment-to-moment modulation of the cardiac baroreflex during exercise would occur in association with motor intention (i.e., exercise onset) and effort (i.e., treadmill speed).
Collapse
Affiliation(s)
- Kei Ishii
- Human Informatics and Interaction Research InstituteNational Institute of Advanced Industrial Science and TechnologyIbarakiJapan
- Department of Integrative Physiology, Graduate School of Biomedical and Health SciencesHiroshima UniversityHiroshimaJapan
| | - Mitsuhiro Idesako
- Department of Integrative Physiology, Graduate School of Biomedical and Health SciencesHiroshima UniversityHiroshimaJapan
| | - Ryota Asahara
- Human Informatics and Interaction Research InstituteNational Institute of Advanced Industrial Science and TechnologyIbarakiJapan
- Department of Integrative Physiology, Graduate School of Biomedical and Health SciencesHiroshima UniversityHiroshimaJapan
| | - Nan Liang
- Department of Integrative Physiology, Graduate School of Biomedical and Health SciencesHiroshima UniversityHiroshimaJapan
- Cognitive Motor Neuroscience, Human Health SciencesGraduate School of Medicine, Kyoto UniversityKyotoJapan
| | - Kanji Matsukawa
- Department of Integrative Physiology, Graduate School of Biomedical and Health SciencesHiroshima UniversityHiroshimaJapan
| |
Collapse
|
2
|
Kiang L, Woodington B, Carnicer-Lombarte A, Malliaras G, Barone DG. Spinal cord bioelectronic interfaces: opportunities in neural recording and clinical challenges. J Neural Eng 2022; 19. [PMID: 35320780 DOI: 10.1088/1741-2552/ac605f] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 03/23/2022] [Indexed: 11/11/2022]
Abstract
Bioelectronic stimulation of the spinal cord has demonstrated significant progress in restoration of motor function in spinal cord injury (SCI). The proximal, uninjured spinal cord presents a viable target for the recording and generation of control signals to drive targeted stimulation. Signals have been directly recorded from the spinal cord in behaving animals and correlated with limb kinematics. Advances in flexible materials, electrode impedance and signal analysis will allow SCR to be used in next-generation neuroprosthetics. In this review, we summarize the technological advances enabling progress in SCR and describe systematically the clinical challenges facing spinal cord bioelectronic interfaces and potential solutions, from device manufacture, surgical implantation to chronic effects of foreign body reaction and stress-strain mismatches between electrodes and neural tissue. Finally, we establish our vision of bi-directional closed-loop spinal cord bioelectronic bypass interfaces that enable the communication of disrupted sensory signals and restoration of motor function in SCI.
Collapse
Affiliation(s)
- Lei Kiang
- Orthopaedic Surgery, Singapore General Hospital, Outram Road, Singapore, Singapore, 169608, SINGAPORE
| | - Ben Woodington
- Department of Engineering, University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, Cambridge, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Alejandro Carnicer-Lombarte
- Clinical Neurosciences, University of Cambridge, Bioelectronics Laboratory, Cambridge, CB2 0PY, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - George Malliaras
- University of Cambridge, University of Cambridge, Cambridge, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Damiano G Barone
- Department of Engineering, University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, Cambridge, Cambridgeshire, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| |
Collapse
|
3
|
Sabetian P, Yoo PB. Feasibility of differentially measuring afferent and efferent neural activity with a single nerve cuff electrode. J Neural Eng 2020; 17:016040. [PMID: 31698350 DOI: 10.1088/1741-2552/ab5551] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Advances in electrode technology have facilitated the development of neuroprostheses for restoring motor/sensory function in disabled individuals. Information extracted from a whole nerve, recorded using cuffs, can provide signals that control the operation of neuroprostheses. However, the amount of information that can be extracted from a tripolar cuff-which provides the highest signal-to-noise ratio (SNR)-is limited. The physical symmetry of the tripolar cuff results in neural recordings that cannot differentiate afferent versus efferent signals. In this study, we introduced a tetrapolar cuff to achieve low-noise and directionally sensitive recording. APPROACH The tetrapolar cuff was initially designed using a computational approach. A finite element model was used to solve the electric potential generated at the electrode contacts by active electrical sources, such as the nodes of Ranvier and an artifact noise source. The resulting single fiber action potentials (SFAPs) and artifact noise signals (ANS) were used to characterize the performance of the tetrapolar configuration of the electrode length (EL) and electrode edge length (EEL) on simulated SFAP and ANS. The feasibility of using a tetrapolar cuff to differentiate afferent/efferent action potentials by applying potassium chloride in anesthetized rats was also investigated. MAIN RESULTS Both the computational and experimental results of this study indicated that directional recording can be achieved using a tetrapolar cuff. Testing different design criteria (e.g. EL and EEL) showed that at EL values above 15 mm and EEL ⩾ 2 mm, the tetrapolar cuffs can yield larger SNRs than equally-sized tripolar cuffs. SIGNIFICANCE This study indicated that low-noise directionally sensitive measurement of neural activity can be achieved with a tetrapolar cuff. The experimental results confirmed the feasibility of using a tetrapolar cuff to differentiate afferent/efferent signals by applying potassium chloride. Further work is needed to determine whether the tetrapolar cuff can differentiate afferent/efferent physiologically elicited neural activities.
Collapse
Affiliation(s)
- P Sabetian
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada
| | | |
Collapse
|
4
|
Song KI, Park SE, Lee S, Kim H, Lee SH, Youn I. Compact Optical Nerve Cuff Electrode for Simultaneous Neural Activity Monitoring and Optogenetic Stimulation of Peripheral Nerves. Sci Rep 2018; 8:15630. [PMID: 30353118 PMCID: PMC6199280 DOI: 10.1038/s41598-018-33695-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 10/03/2018] [Indexed: 01/05/2023] Open
Abstract
Optogenetic stimulation of the peripheral nervous system is a novel approach to motor control, somatosensory transduction, and pain processing. Various optical stimulation tools have been developed for optogenetic stimulation using optical fibers and light-emitting diodes positioned on the peripheral nerve. However, these tools require additional sensors to monitor the limb or muscle status. We present herein a novel optical nerve cuff electrode that uses a single cuff electrode to conduct to simultaneously monitor neural activity and optogenetic stimulation of the peripheral nerve. The proposed optical nerve cuff electrode is designed with a polydimethylsiloxane substrate, on which electrodes can be positioned to record neural activity. We confirm that the illumination intensity and the electrical properties of the optical nerve cuff electrode are suitable for optical stimulation with simultaneous neural activity monitoring in Thy1::ChR2 transgenic mice. With the proposed electrode, the limb status is monitored with continuous streaming signals during the optical stimulation of anesthetized and moving animals. In conclusion, this optical nerve cuff electrode provides a new optical modulation tool for peripheral nervous system studies.
Collapse
Affiliation(s)
- Kang-Il Song
- Biomedical Research Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Sunghee Estelle Park
- Biomedical Research Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea.,Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Seul Lee
- Department of Dentistry, Graduate School, Kyunghee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| | - Hyungmin Kim
- Biomedical Research Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Soo Hyun Lee
- Brain Science Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Inchan Youn
- Biomedical Research Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea. .,KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul, 02447, Republic of Korea.
| |
Collapse
|
5
|
Daneshi Kohan E, Lashkari BS, Sparrey CJ. The effects of paranodal myelin damage on action potential depend on axonal structure. Med Biol Eng Comput 2017; 56:395-411. [PMID: 28770425 DOI: 10.1007/s11517-017-1691-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 07/17/2017] [Indexed: 12/31/2022]
Abstract
Biophysical computational models of axons provide an important tool for quantifying the effects of injury and disease on signal conduction characteristics. Several studies have used generic models to study the average behavior of healthy and injured axons; however, few studies have included the effects of normal structural variation on the simulated axon's response to injury. The effects of variations in physiological characteristics on axonal function were mapped by altering the structure of the nodal, paranodal, and juxtaparanodal regions across reported values in three different caliber axons (1, 2, and 5.7 μm). Myelin detachment and retraction were simulated to quantify the effects of each injury mechanism on signal conduction. Conduction velocity was most affected by axonal fiber diameter (89%), while membrane potential amplitude was most affected by nodal length (86%) in healthy axons. Postinjury axonal functionality was most affected by myelin detachment in the paranodal and juxtaparanodal regions when retraction and detachment were modeled simultaneously. The efficacy of simulated potassium channel blockers on restoring membrane potential and velocity varied with axonal caliber and injury type. The structural characteristics of axons affect their functional response to myelin retraction and detachment and their subsequent response to potassium channel blocker treatment.
Collapse
Affiliation(s)
- Ehsan Daneshi Kohan
- Mechatronic Systems Engineering, Simon Fraser University, 250-13450 102 Avenue, Surrey, BC, V3T 0A3, Canada.,International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia, 5th floor, 5200, 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada
| | - Behnia Shadab Lashkari
- International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia, 5th floor, 5200, 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada
| | - Carolyn Jennifer Sparrey
- Mechatronic Systems Engineering, Simon Fraser University, 250-13450 102 Avenue, Surrey, BC, V3T 0A3, Canada. .,International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia, 5th floor, 5200, 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada.
| |
Collapse
|
6
|
López Ruiz JR, Castillo Hernández L, De la Torre Valdovinos B, Franco Rodríguez NE, Dueñas Jiménez JM, Dueñas Jiménez A, Rivas-Carrillo JD, Dueñas Jiménez SH. Locomotion in intact and in brain cortex-ablated cats. Neuroscience 2017; 358:37-48. [PMID: 28663091 DOI: 10.1016/j.neuroscience.2017.06.026] [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: 10/03/2016] [Revised: 06/18/2017] [Accepted: 06/19/2017] [Indexed: 01/31/2023]
Abstract
The current decerebration procedures discard the role of the thalamus in the motor control and decortication only rules out the brain cortex part, leaving a gap between the brain cortex and the subthalamic motor regions. In here we define a new preparation denominated Brain Cortex-Ablated Cat (BCAC), in which the frontal and parietal brain cortices as well as the central white matter beneath them were removed, this decerebration process may be considered as suprathalamic, since the thalamus remained intact. To characterize this preparation cat hindlimb electromyograms (EMG), kinematics and cutaneous reflexes (CR) produced by electrical stimulation of sural (SU) or saphenous (SAPH) nerves were analyzed during locomotion in intact and in BCAC. In cortex-ablated cats compared to intact cats, the hindlimb EMG amplitude was increased in the flexors, whereas in most extensors the amplitude was decreased. Bifunctional muscle EMGs presented complex and speed-dependent amplitude changes. In intact cats CR produced an inhibition of extensors, as well as excitation and inhibition of flexors, and a complex pattern of withdrawal responses in bifunctional muscles. The same stimuli applied to BCAC produced no detectable responses, but in some cats cutaneous reflexes produced by electrical stimulation of saphenous nerve reappeared when the locomotion speed increased. In BCAC, EMG and kinematic changes, as well as the absence of CR, imply that for this cat preparation there is a partial compensation due to the subcortical locomotor apparatus generating close to normal locomotion.
Collapse
Affiliation(s)
- José Roberto López Ruiz
- Departmento de Neurociencias, Universidad de Guadalajara, CUCS, Sierra Mojada #950, Edificio P, Tercer Piso, Guadalajara, Jalisco 44340, Mexico.
| | - Luis Castillo Hernández
- Departmento de Fisiología y Farmacología, Centro Básico, Universidad Autónoma de Aguascalientes, Avenida Universidad 940, Aguascalientes, Aguascalientes 20131, Mexico.
| | - Braniff De la Torre Valdovinos
- Departmento de Ciencias Computacionales, CUCEI, Universidad de Guadalajara, Blvd. Marcelino García Barragán #1421, Edificio M-212, Guadalajara, Jalisco 44430, Mexico.
| | - Nancy Elizabeth Franco Rodríguez
- Departmento de Ciencias Computacionales, CUCEI, Universidad de Guadalajara, Blvd. Marcelino García Barragán #1421, Edificio M-212, Guadalajara, Jalisco 44430, Mexico.
| | - Judith Marcela Dueñas Jiménez
- Departmento de Fisiología, Universidad de Guadalajara, CUCS, Sierra Mojada #950 Edificio P, Tercer Piso, Guadalajara, Jalisco 44340, Mexico.
| | - Alejandro Dueñas Jiménez
- Departmento de Electrónica, CUCEI, Universidad de Guadalajara, Blvd. Marcelino García Barragán #1421, Edificio M-212, Guadalajara, Jalisco 44430, Mexico.
| | - Jorge David Rivas-Carrillo
- Departmento de Fisiología y Farmacología, Centro Básico, Universidad Autónoma de Aguascalientes, Avenida Universidad 940, Aguascalientes, Aguascalientes 20131, Mexico; Departmento de Fisiología, Universidad de Guadalajara, CUCS, Sierra Mojada #950 Edificio P, Tercer Piso, Guadalajara, Jalisco 44340, Mexico.
| | - Sergio Horacio Dueñas Jiménez
- Departmento de Neurociencias, Universidad de Guadalajara, CUCS, Sierra Mojada #950, Edificio P, Tercer Piso, Guadalajara, Jalisco 44340, Mexico.
| |
Collapse
|
7
|
Huh S, Siripuram R, Lee RH, Turkin VV, O'Neill D, Hamm TM, Heckman CJ, Manuel M. PICs in motoneurons do not scale with the size of the animal: a possible mechanism for faster speed of muscle contraction in smaller species. J Neurophysiol 2017; 118:93-102. [PMID: 28356469 DOI: 10.1152/jn.00045.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/27/2017] [Accepted: 03/28/2017] [Indexed: 11/22/2022] Open
Abstract
The majority of studies on the electrical properties of neurons are carried out in rodents, and in particular in mice. However, the minute size of this animal compared with humans potentially limits the relevance of the resulting insights. To be able to extrapolate results obtained in a small animal such as a rodent, one needs to have proper knowledge of the rules governing how electrical properties of neurons scale with the size of the animal. Generally speaking, electrical resistances of neurons increase as cell size decreases, and thus maintenance of equal depolarization across cells of different sizes requires the underlying currents to decrease in proportion to the size decrease. Thus it would generally be expected that voltage-sensitive currents are smaller in smaller animals. In this study, we used in vivo preparations to record electrical properties of spinal motoneurons in deeply anesthetized adult mice and cats. We found that PICs do not scale with size, but instead are constant in their amplitudes across these species. This constancy, coupled with the threefold differences in electrical resistances, means that PICs contribute a threefold larger depolarization in the mouse than in the cat. As a consequence, motoneuronal firing rate sharply increases as animal size decreases. These differences in firing rates are likely essential in allowing different species to control muscles with widely different contraction speeds (smaller animals have faster muscle fibers). Thus from our results we have identified a possible new mechanism for how electrical properties are tuned to match mechanical properties within the motor output system.NEW & NOTEWORTHY The small size of the mouse warrants concern over whether the properties of their neurons are a scaled version of those in larger animals or instead have unique features. Comparison of spinal motoneurons in mice to cats showed unique features. Firing rates in the mouse were much higher, in large part due to relatively larger persistent inward currents. These differences likely reflect adaptations for controlling much faster muscle fibers in mouse than cat.
Collapse
Affiliation(s)
- Seoan Huh
- Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - Ramamurthy Siripuram
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Robert H Lee
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Vladimir V Turkin
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
| | - Derek O'Neill
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
| | - Thomas M Hamm
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
| | - Charles J Heckman
- Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois.,Department of Physical Medicine and Rehabilitation, Northwestern University, Feinberg School of Medicine, Chicago, Illinois.,Department of Physical Therapy and Human Movement Science, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - Marin Manuel
- Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois; .,Centre de Neurophysique, Physiologie et Pathologie, UMR 8119, CNRS/Université Paris Descartes, Paris, France
| |
Collapse
|
8
|
Korfage JAM, Koolstra JH, Langenbach GEJ, van Eijden TMGJ. Fiber-type Composition of the Human Jaw Muscles—(Part 1) Origin and Functional Significance of Fiber-type Diversity. J Dent Res 2016; 84:774-83. [PMID: 16109984 DOI: 10.1177/154405910508400901] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
This is the first of two articles on the fiber-type composition of the human jaw muscles. The present article discusses the origin of fiber-type composition and its consequences. This discussion is presented in the context of the requirements for functional performance and adaptation that are imposed upon the jaw muscles. The human masticatory system must perform a much larger variety of motor tasks than the average limb or trunk motor system. An important advantage of fiber-type diversity, as observed in the jaw muscles, is that it optimizes the required function while minimizing energy use. The capacity for adaptation is reflected by the large variability in fiber-type composition among muscle groups, individual muscles, and muscle regions. Adaptive changes are related, for example, to the amount of daily activation and/or stretch of fibers. Generally, the number of slow, fatigue-resistant fibers is relatively large in muscles and muscle regions that are subjected to considerable activity and/or stretch.
Collapse
Affiliation(s)
- J A M Korfage
- Department of Functional Anatomy, Academic Center for Dentistry Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
| | | | | | | |
Collapse
|
9
|
Debnath S, Bauman MJ, Fisher LE, Weber DJ, Gaunt RA. Microelectrode array recordings from the ventral roots in chronically implanted cats. Front Neurol 2014; 5:104. [PMID: 25071697 PMCID: PMC4083189 DOI: 10.3389/fneur.2014.00104] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 06/07/2014] [Indexed: 11/13/2022] Open
Abstract
The ventral spinal roots contain the axons of spinal motoneurons and provide the only location in the peripheral nervous system where recorded neural activity can be assured to be motor rather than sensory. This study demonstrates recordings of single unit activity from these ventral root axons using floating microelectrode arrays (FMAs). Ventral root recordings were characterized by examining single unit yield and signal-to-noise ratios (SNR) with 32-channel FMAs implanted chronically in the L6 and L7 spinal roots of nine cats. Single unit recordings were performed for implant periods of up to 12 weeks. Motor units were identified based on active discharge during locomotion and inactivity under anesthesia. Motor unit yield and SNR were calculated for each electrode, and results were grouped by electrode site size, which were varied systematically between 25 and 160 μm to determine effects on signal quality. The unit yields and SNR did not differ significantly across this wide range of electrode sizes. Both SNR and yield decayed over time, but electrodes were able to record spikes with SNR >2 up to 12 weeks post-implant. These results demonstrate that it is feasible to record single unit activity from multiple isolated motor units with penetrating microelectrode arrays implanted chronically in the ventral spinal roots. This approach could be useful for creating a spinal nerve interface for advanced neural prostheses, and results of this study will be used to improve design of microelectrodes for chronic neural recording in the ventral spinal roots.
Collapse
Affiliation(s)
- Shubham Debnath
- Department of Bioengineering, University of Pittsburgh , Pittsburgh, PA , USA
| | - Matthew J Bauman
- Department of Bioengineering, University of Pittsburgh , Pittsburgh, PA , USA
| | - Lee E Fisher
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh , Pittsburgh, PA , USA
| | - Douglas J Weber
- Department of Bioengineering, University of Pittsburgh , Pittsburgh, PA , USA ; Department of Physical Medicine and Rehabilitation, University of Pittsburgh , Pittsburgh, PA , USA
| | - Robert A Gaunt
- Department of Bioengineering, University of Pittsburgh , Pittsburgh, PA , USA ; Department of Physical Medicine and Rehabilitation, University of Pittsburgh , Pittsburgh, PA , USA
| |
Collapse
|
10
|
Holt NC, Wakeling JM, Biewener AA. The effect of fast and slow motor unit activation on whole-muscle mechanical performance: the size principle may not pose a mechanical paradox. Proc Biol Sci 2014; 281:20140002. [PMID: 24695429 DOI: 10.1098/rspb.2014.0002] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The output of skeletal muscle can be varied by selectively recruiting different motor units. However, our knowledge of muscle function is largely derived from muscle in which all motor units are activated. This discrepancy may limit our understanding of in vivo muscle function. Hence, this study aimed to characterize the mechanical properties of muscle with different motor unit activation. We determined the isometric properties and isotonic force-velocity relationship of rat plantaris muscles in situ with all of the muscle active, 30% of the muscle containing predominately slower motor units active or 20% of the muscle containing predominately faster motor units active. There was a significant effect of active motor unit type on isometric force rise time (p < 0.001) and the force-velocity relationship (p < 0.001). Surprisingly, force rise time was longer and maximum shortening velocity higher when all motor units were active than when either fast or slow motor units were selectively activated. We propose this is due to the greater relative effects of factors such as series compliance and muscle resistance to shortening during sub-maximal contractions. The findings presented here suggest that recruitment according to the size principle, where slow motor units are activated first and faster ones recruited as demand increases, may not pose a mechanical paradox, as has been previously suggested.
Collapse
Affiliation(s)
- N C Holt
- UC Irvine, , McGaugh Hall, Irvine, CA 92697, USA, Concord Field Station, , 100 Old Causeway Road, Bedford, MA 01730, USA, Department of Biomedical Physiology and Kinesiology, Simon Fraser University, , 8888 University Drive, Burnaby, British Columbia, Canada , V5A 1S6
| | | | | |
Collapse
|
11
|
Harwood B, Rice CL. Short interspike intervals and double discharges of anconeus motor unit action potentials for the production of dynamic elbow extensions. J Neurophysiol 2014; 111:2039-46. [PMID: 24554783 DOI: 10.1152/jn.00412.2013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Incidence of double discharges (DDs; >100 Hz) and short interspike intervals (ISIs; >50 to <100 Hz) is reported to vary widely among different muscles and tasks, with a higher incidence in motor unit (MU) trains of fast muscles and for the production of fast contractions in humans. However, it is unclear whether human muscles with a large composition of slower motor units exhibit DDs or short ISIs when activated with maximal synaptic drive, such as those required for maximal velocity dynamic contractions. Thus the purpose of this study was to determine the effect of increasing peak contraction velocity on the incidence of DDs and short ISIs in the anconeus muscle. Seventeen anconeus MUs in 10 young males were recorded across dynamic elbow extensions ranging from low submaximal velocities (16% of maximal velocity) up to maximal velocities. A low incidence of DDs (4%) and short ISIs (29%) was observed among the 583 MU trains recorded. Despite the low incidence in individual MU trains, a majority (71% and 94%, respectively) of MUs exhibited at least one DD or short ISI. The number of short ISIs shared no variance with MU recruitment threshold (R(2) = 0.02), but their distribution was skewed toward higher peak velocities (G = -1.26) and a main effect of peak elbow extension velocity was observed (P < 0.05). Although a greater number of short ISIs was observed with increasing velocity, the low incidence of DDs and short ISIs in the anconeus muscle is likely related to the function of the anconeus as a stabilizer rather than voluntary elbow extensor torque and velocity production.
Collapse
Affiliation(s)
- B Harwood
- Canadian Centre for Activity and Aging, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada; and
| | - C L Rice
- Canadian Centre for Activity and Aging, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada; and Department of Anatomy and Cell Biology, The University of Western Ontario, London, Ontario, Canada
| |
Collapse
|
12
|
Schuettler M, Donaldson N, Seetohul V, Taylor J. Fibre-selective recording from the peripheral nerves of frogs using a multi-electrode cuff. J Neural Eng 2013; 10:036016. [DOI: 10.1088/1741-2560/10/3/036016] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
13
|
Chu JU, Song KI, Han S, Lee SH, Kim J, Kang JY, Hwang D, Suh JKF, Choi K, Youn I. Improvement of signal-to-interference ratio and signal-to-noise ratio in nerve cuff electrode systems. Physiol Meas 2012; 33:943-67. [PMID: 22551721 DOI: 10.1088/0967-3334/33/6/943] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
14
|
Kaufman MP, Forster HV. Reflexes Controlling Circulatory, Ventilatory and Airway Responses to Exercise. Compr Physiol 2011. [DOI: 10.1002/cphy.cp120110] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
|
15
|
|
16
|
Hudson HM, Griffin DM, Belhaj-Saïf A, Lee SP, Cheney PD. Methods for chronic recording of EMG activity from large numbers of hindlimb muscles in awake rhesus macaques. J Neurosci Methods 2010; 189:153-61. [PMID: 20346976 DOI: 10.1016/j.jneumeth.2010.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2009] [Revised: 03/11/2010] [Accepted: 03/15/2010] [Indexed: 11/24/2022]
Abstract
Studies of the neural control of movement often rely on the ability to record EMG activity during natural behavioral tasks over long periods of time. Increasing the number of recorded muscles and the time over which recordings are made allows more rigorous answers to many questions related to the descending control of motor output. Chronic recording of EMG activity from multiple hindlimb muscles has been reported in the cat but few studies have been done in non-human primates. This paper describes two chronic EMG implant methods that are minimally invasive, relatively non-traumatic and capable of recording from large numbers of hindlimb muscles simultaneously for periods of many months to years.
Collapse
Affiliation(s)
- Heather M Hudson
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, United States.
| | | | | | | | | |
Collapse
|
17
|
Hayes SG, McCord JL, Koba S, Kaufman MP. Gadolinium inhibits group III but not group IV muscle afferent responses to dynamic exercise. J Physiol 2008; 587:873-82. [PMID: 19103679 DOI: 10.1113/jphysiol.2008.164640] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Dynamic exercise has been shown to stimulate rapidly both group III and IV muscle afferents. The often rapid (i.e. 2 s) onset latencies of the group IV afferents is particularly surprising because these unmyelinated afferents are thought to respond to the gradual accumulation of metabolites signalling a mismatch between blood/oxygen demand and supply in exercising muscles. One explanation for the rapid onset to exercise by group IV afferents is that they are mechanosensitive, a concept that has been supported by the finding that these afferents were stimulated by vasodilatation induced by injection of vasoactive drugs. We therefore examined in decerebrated cats the effect of gadolinium, a blocker of mechanogated channels, on the responses of group III and IV muscle afferents to dynamic exercise induced by electrical stimulation of the mesencephalic locomotor region. We found that gadolinium (10 mm; 1 ml) injected into the abdominal aorta had no significant effect (P > 0.05) on the responses of 11 group IV afferents to dynamic exercise. In contrast, gadolinium markedly attenuated the responses of 11 group III afferents to exercise (P < 0.05). Our findings suggest that group IV afferents are not responding to a mechanical stimulus during exercise. Instead their rapid response to dynamic exercise might be caused by a chemical substance whose concentration is directly proportional to blood flow, which increases in the skeletal muscles when they are dynamically exercising.
Collapse
Affiliation(s)
- Shawn G Hayes
- Heart and Vascular Institute, Penn State College of Medicine, Hershey, PA 17033, USA
| | | | | | | |
Collapse
|
18
|
Hodson-Tole EF, Wakeling JM. Motor unit recruitment for dynamic tasks: current understanding and future directions. J Comp Physiol B 2008; 179:57-66. [DOI: 10.1007/s00360-008-0289-1] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Revised: 06/12/2008] [Accepted: 06/19/2008] [Indexed: 11/24/2022]
|
19
|
Chalmers GR. Can fast-twitch muscle fibres be selectively recruited during lengthening contractions? Review and applications to sport movements. Sports Biomech 2008; 7:137-57. [DOI: 10.1080/14763140701683023] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
20
|
Omori T, Kawashima H, Kizuka T, Ohiwa N, Tateoka M, Soya H. Increased c-fos gene expression in alpha motoneurons in rat loaded hindlimb muscles with inclined locomotion. Neurosci Lett 2005; 389:25-9. [PMID: 16055265 DOI: 10.1016/j.neulet.2005.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Revised: 06/17/2005] [Accepted: 07/01/2005] [Indexed: 11/22/2022]
Abstract
The potential usefulness of c-fos gene expression as an indicator of the activity level of spinal alpha motoneurons was examined in loaded locomotive rats. The motor pools of the plantaris (PL) and soleus muscles (SOL), mainly composed respectively of fast- and slow-twitch muscle fibers, were investigated in rats under locomotion at 25 m/min on a 20% incline. We first labeled motoneurons with a retrograde tracer, Nuclear Yellow (NY), and then quantified the c-fos mRNA expression level in the NY-labeled alpha motoneurons by means of in situ hybridization. Electromyographic (EMG) activities were also recorded. The c-fos expression level per alpha motoneuron showed a greater increase in the PL (75%) than in the SOL motor pool (38%). EMG activities also showed a greater increase in the PL (159%) than in the SOL (43%). Taken together, these results suggest that c-fos expression levels in alpha motoneurons are associated with the activity levels of their corresponding muscle. This cytochemical method for identifying the c-fos expression level has potential for use as a tool for estimating the activity level of large populations of alpha motoneurons in unrestricted animals.
Collapse
Affiliation(s)
- Takenori Omori
- Laboratory of Exercise Biochemistry, University of Tsukuba Graduate School of Comprehensive Human Sciences, 1-1-1 Tennôdai, Tsukuba, Ibaraki 305-8574, Japan
| | | | | | | | | | | |
Collapse
|
21
|
Kaufman MP, Hayes SG, Adreani CM, Pickar JG. Discharge properties of group III and IV muscle afferents. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 508:25-32. [PMID: 12171119 DOI: 10.1007/978-1-4615-0713-0_4] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
Stimulation of group III and IV muscle afferents has been shown to have important reflex effects on both the somatic and autonomic nervous systems. These include an inhibitory effect on alpha motoneurones, an excitatory effect on gamma motoneurones and an excitatory effect on the sympathetic nervous system. The purpose of this review is to describe the mechanical and metabolic stimuli that discharge group III and IV muscle afferents. Particular attention will be paid to the responses of these afferents to dynamic exercise induced by electrical stimulation of the mesencephalic locomotor region.
Collapse
Affiliation(s)
- Marc P Kaufman
- Department of Internal Medicine and Human Physiology, University of California, Davis, USA.
| | | | | | | |
Collapse
|
22
|
Abstract
For more than 50 years, it has been known that vertebrates engage in a wide range of motor activities and that they possess muscle types with a similarly large range of contractile properties. However, only during the past 15 years has it been shown experimentally that the contractile properties of muscle fibers are well adjusted to their in vivo function. Arriving at this conclusion has required an integrative approach, that is, comparing measurements of muscle fiber properties with measurements of fiber use during normal motor activity. Because the muscles of mammals (and humans) generally are heterogenous in fiber type, this makes it technically very difficult to measure either the contractile properties of different fiber types or their use during normal motor activity. Therefore, many of the advances in the understanding of the design and function of vertebrate muscular systems have come from work on lower vertebrates. Fish, because of the anatomic separation of different muscle fiber types, have provided a key experimental model on which much of what is known about muscle design has been determined. Frogs, because of the near homogeneity of their large extensor muscles used during jumping, also provide an important model which will, in the near future, serve as the first platform where molecular properties of muscle (calcium and cross-bridge kinetics) can be related to whole body movement in a meaningful and predictive manner.
Collapse
Affiliation(s)
- Lawrence C Rome
- Department of Biology, Leidy Labs, University of Pennsylvania, Philadelphia, PA 19104, USA
| |
Collapse
|
23
|
van Lunteren E, Dick TE. Heterogeneity within geniohyoid motor unit subpopulations in firing patterns during breathing. RESPIRATION PHYSIOLOGY 2001; 124:23-33. [PMID: 11084200 DOI: 10.1016/s0034-5687(00)00182-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Respiratory motor units (MU) segregate into subpopulations, which differ in firing patterns during resting and stimulated breathing. For phrenic/diaphragm MUs, diversity also exists within subpopulations, and is greater for late than early-onset MUs. The present study characterized the extent of diversity within upper airway respiratory MU subpopulations by recording geniohyoid MUs in anesthetized cats. Inspiratory MUs (I-MU, n=21) had a wide range of firing durations (coefficient of variation (CV)=42%). In contrast, inspiratory-expiratory MUs (I/E-MU, n=19) had a narrow range of firing durations during inspiration (CV=13%), but a wide range of firing durations during expiration (CV=36%). Mean firing frequency had similar degrees of diversity among units for I-MU and I/E-MU (CV=31-40%). For I-MU firing duration correlated with mean firing frequency, whereas no such relationship was apparent for I/E-MU. Single-breath end-expiratory airway occlusion decreased heterogeneity in firing duration during inspiration and increased it during expiration, whereas end-inspiratory airway occlusion decreased heterogeneity during expiration. In conclusion, (a) there is considerable diversity within geniohyoid MU subpopulations receiving respiratory drive; (b) the degree of diversity within subpopulations differs for I-MU and I/E-MU; and (c) diversity within subpopulations in timing of activity is modulated by single-breath airway occlusion.
Collapse
Affiliation(s)
- E van Lunteren
- Department of Medicine, Cleveland VA Medical Center, Pulmonary Section, Case Western Reserve University, 111J(W), 10701 East Boulevard, Cleveland, OH 44106, USA.
| | | |
Collapse
|
24
|
Cope TC, Sokoloff AJ. Orderly recruitment tested across muscle boundaries. PROGRESS IN BRAIN RESEARCH 2000; 123:177-90. [PMID: 10635715 DOI: 10.1016/s0079-6123(08)62855-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Affiliation(s)
- T C Cope
- Department of Physiology, Emory University, Atlanta, GA 30322, USA.
| | | |
Collapse
|
25
|
Callister RJ, Peterson EH, Brichta AM. Neuromuscular strategies underlying ballistic movements. PROGRESS IN BRAIN RESEARCH 2000; 123:233-43. [PMID: 10635720 DOI: 10.1016/s0079-6123(08)62860-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Affiliation(s)
- R J Callister
- Neuroscience Group and Discipline of Anatomy, School of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Newcastle, Callaghan, Australia.
| | | | | |
Collapse
|
26
|
Loeb GE. Asymmetry of hindlimb muscle activity and cutaneous reflexes after tendon transfers in kittens. J Neurophysiol 1999; 82:3392-405. [PMID: 10601470 DOI: 10.1152/jn.1999.82.6.3392] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mechanical actions of various ankle muscles were changed by surgically crossing or transferring the tendons in kittens. After the kittens grew to adults, both hindlimbs were implanted with multiple electromyogram (EMG) recording and cutaneous nerve stimulation electrodes to compare the activity of altered and normal muscles. The tendon transfers showed a remarkable tendency to regrow toward normal or only slightly altered mechanical action. In these animals and in the sham-operation controls, the patterns of muscle activity and reflexes were symmetrical in corresponding muscles of the two legs, although they could differ substantially between animals, particularly for the cutaneous reflexes. Eleven animals had at least some persistent alterations in muscle action. Their cutaneous reflex patterns tended to be asymmetric, in some cases quite markedly. EMG activity during unperturbed locomotion and paw-shaking was more symmetrical, but there were some changes in altered muscles and their synergists. The central pattern generators for locomotion and paw-shaking and particularly for cutaneous reflexes during locomotion appear to be at least partially malleable rather than entirely hardwired. This may provide a tool for studying their development and spinal plasticity in general.
Collapse
Affiliation(s)
- G E Loeb
- Medical Research Council Group in Sensory-Motor Neuroscience, Queen's University, Kingston, Ontario K7L 3E6, Canada
| |
Collapse
|
27
|
Struijk JJ, Thomsen M, Larsen JO, Sinkjaer T. Cuff electrodes for long-term recording of natural sensory information. IEEE ENGINEERING IN MEDICINE AND BIOLOGY MAGAZINE : THE QUARTERLY MAGAZINE OF THE ENGINEERING IN MEDICINE & BIOLOGY SOCIETY 1999; 18:91-8. [PMID: 10337568 DOI: 10.1109/51.765194] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- J J Struijk
- Center for Sensory-Motor Interaction, Aalborg University, Denmark.
| | | | | | | |
Collapse
|
28
|
Eldred E, Yung L, Eldred D, Roy RR. Distribution of muscle spindles in a simply structured muscle: integrated total sensory representation. Anat Rec (Hoboken) 1998; 251:161-72. [PMID: 9624445 DOI: 10.1002/(sici)1097-0185(199806)251:2<161::aid-ar3>3.0.co;2-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND The distribution of muscle spindles (Sps) in a small muscle of simple architecture, the capsularis at the cat's hip joint, was quantified to reveal the patterns of proprioceptive representation in the transverse and sagittal planes as well as to model the effect a local disturbance in muscle length would have on total Sp discharge. METHODS Locations in serial cross-sections of the 32 and 38 Sps in 2 muscles, 1 perfused with the hip joint flexed and the other extended, were plotted, and their patterns of integrated sensitivity calculated assuming that (1) the discharge rate of a Sp afferent varies linearly with change in length along the Sp's axis, and (2) that within a local disturbance produced by contraction of a motor unit (MU), lengths decrease either linearly or as the square of the distance from its center. RESULTS The isomeric pattern of "integrated, total Sp representation on cross-section" showed two peaks of sensitivity in the half of the muscle that had been next to the joint capsule, offset by low representation in a small, central area and along the extensive zone bordering the laterally facing "superficial surface." The equivalent radius of an idealized symmetrical MU territory was estimated from distributions of the few fast, oxidative-glycolytic fibers found in two muscles, and the effect of a MU's contraction on net Sp discharge predicted when the unit was positioned at distinctive sites within the pattern. As an index of Ia and II afferent representation in the sagittal plane, the distribution of the nucleated regions of Sps and the summed lengths of segments of Sp axial bundles and capsules, respectively, within successive 1-mm segments of the muscle were graphed. CONCLUSIONS The longitudinal representation and structure of the muscle are not suited for reflex adjustment of differences in length along the muscle. The isomeric pattern of high relief in the transverse plane suggests that in this approximately 0.2 g muscle, the localization of myotatic reflexes might be accommodated but the need for adjustment in activation of MUs seems minimal. This is because the muscle is not compartmentalized, its fibers extend between the muscle's origin and insertion, their angle of pinnation is low, and greater than 90% are of slow type. The distribution of Sps is consistent with gauging length of the entire muscle and hence angulation at the hip joint.
Collapse
Affiliation(s)
- E Eldred
- Department of Neurobiology, University of California at Los Angeles 91109, USA
| | | | | | | |
Collapse
|
29
|
Rome LC, Lindstedt SL. Mechanical and Metabolic Design of the Muscular System in Vertebrates. Compr Physiol 1997. [DOI: 10.1002/cphy.cp130223] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
30
|
Adreani CM, Hill JM, Kaufman MP. Responses of group III and IV muscle afferents to dynamic exercise. J Appl Physiol (1985) 1997; 82:1811-7. [PMID: 9173945 DOI: 10.1152/jappl.1997.82.6.1811] [Citation(s) in RCA: 172] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Tetanic contraction of hindlimb skeletal muscle, induced by electrical stimulation of either ventral roots or peripheral nerves, is well known to activate group III and IV afferents. Nevertheless, the effect of dynamic exercise on the discharge of these thin fiber afferents is unknown. To shed some light on this question, we recorded in decerebrate cats the discharge of 24 group III and 10 group IV afferents while the mesencephalic locomotor region (MLR) was stimulated electrically. Each of the 34 afferents had their receptive fields in the triceps surae muscles. Stimulation of the MLR for 1 min caused the triceps surae muscles to contract rhythmically, an effect induced by an alpha-motoneuron discharge pattern and recruitment order almost identical to that occurring during dynamic exercise. Eighteen of the 24 group III and 8 of the 10 group IV muscle afferents were stimulated by MLR stimulation. The oxygen consumption of the dynamically exercising triceps surae muscles was increased by 2.5-fold over their resting levels. We conclude that low levels of dynamic exercise stimulate group III and IV muscle afferents.
Collapse
Affiliation(s)
- C M Adreani
- Department of Internal Medicine, University of California, Davis 95616, USA
| | | | | |
Collapse
|
31
|
Koh TJ, Leonard TR. An implantable electrical interface for in vivo studies of the neuromuscular system. J Neurosci Methods 1996; 70:27-32. [PMID: 8982978 DOI: 10.1016/s0165-0270(96)00099-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The purposes of this study were to develop and test an implantable interface that could be used for repeated temporary electrical connections between implanted stimulating and recording devices and external equipment. The implantable multi-use interface (TIMI) consists of an implanted set of connectors and temporary percutaneous leads. The connector(s) and attached devices are implanted during a sterile surgery. For each experimental session, a percutaneous lead is introduced into each connector with a hypodermic needle. The external ends of the percutaneous leads are then connected to the desired equipment. After the session is finished, the percutaneous leads are removed. TIMIs have been used successfully with nerve cuff stimulating electrodes, a tendon force transducer and an electromyography electrode, and have been implanted with nerve cuffs for up to 14 weeks without failure. The advantages of the TIMI over the standard backpack connector include: (1) the internal location of the connector reduces the risk that the animal will damage the connector and (2) the temporary and relatively controlled nature of the percutaneous connection reduces the risk of infection associated with permanent percutaneous leads. The TIMI provides an inexpensive, simple and reliable electrical connection between implanted devices and external equipment.
Collapse
Affiliation(s)
- T J Koh
- Faculty of Kinesiology, University of Calgary, Alberta, Canada
| | | |
Collapse
|
32
|
Loeb GE, Peck RA. Cuff electrodes for chronic stimulation and recording of peripheral nerve activity. J Neurosci Methods 1996; 64:95-103. [PMID: 8869489 DOI: 10.1016/0165-0270(95)00123-9] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A comparative study of 5 different designs of nerve cuff electrodes was undertaken to determine their relative merits for stimulating and recording whole-nerve activity over extended periods of chronic implantation on large and small peripheral nerves in 8 cats. Four of the designs represent novel fabrication strategies, including 2 based on flexible, thin-film substrates and 2 based on dip-coating silicone elastomer on a cylindrical mandrel. Various advantages and shortcomings of these materials and designs are discussed in the context of the biophysical factors that influence these electrophysiological interfaces, particularly the problem of recording microvolt-level neurograms in the presence of millivolt-level electromyograms from adjacent muscles in freely behaving subjects. The most effective design was one in which a thin sheath of silicone rubber was wrapped around and intra-operatively sealed to a longitudinally slit, tripolar cuff made by dip-coating silicone over stranded stainless steel leads that were prepositioned on a mandrel using polyvinyl alcohol as a temporary adhesive. When properly installed, these electrodes had stable impedances, recruitment thresholds and relatively interference-free recording properties for the duration of this study (up to 9 weeks).
Collapse
Affiliation(s)
- G E Loeb
- Bio-Medical Engineering Unit, Queen's University, Kingston, Ontario, Canada.
| | | |
Collapse
|
33
|
An electromyographic analysis of functional differentiation in human pectoralis major muscle. J Electromyogr Kinesiol 1994; 4:161-9. [DOI: 10.1016/1050-6411(94)90017-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/1993] [Revised: 03/01/1994] [Accepted: 03/01/1994] [Indexed: 11/18/2022] Open
|
34
|
Loeb GE. The distal hindlimb musculature of the cat: interanimal variability of locomotor activity and cutaneous reflexes. Exp Brain Res 1993; 96:125-40. [PMID: 8243575 DOI: 10.1007/bf00230446] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
During stereotyped behaviors such as locomotion, patterns of muscle recruitment are usually quite consistent from animal to animal, even in the face of many surgical and pharmacological reductions. However, as studies of musculoskeletal structure, neuromuscular architecture, and sensorimotor circuitry become more detailed, it is important to ask whether there is some level of organization at which individual differences begin to dominate. This study concentrated on the small muscles of the foot and ankle, using standardized methods that consistently record stereotypical electromyographic activity from prime mover muscles and that permit well-calibrated stimulation of cutaneous nerves to elicit reflexes during treadmill locomotion. Some muscles (particularly the main ankle extensors, triceps surae, and plantaris) had stereotyped activity during both unperturbed locomotion and reflex responses. Others had stereotyped activity during locomotion but variable reflex patterns among animals (tibialis anterior, extensor digitorum longus, flexor hallucis longus, and peroneus brevis). Still others had variable locomotor activity but reflexes that were consistent (flexor digitorum longus) or variable for only peroneal nerve stimulation (peroneus longus), only plantar nerve stimulation (peroneus tertius), or the two (flexor digitorum brevis). Among muscles with interanimal variability, there seemed to be no particular correlation between locomotor and reflexive recruitment in a given animal. This functional heterogeneity is discussed in terms of the development of locomotor and reflex programs and in the context of structural heterogeneity of some of these muscles that is described in the companion paper.
Collapse
Affiliation(s)
- G E Loeb
- MRC Group in Sensory-Motor Physiology, Queen's University, Kingston, Ontario, Canada
| |
Collapse
|
35
|
Richmond FJ, Thomson DB, Loeb GE. Electromyographic studies of neck muscles in the intact cat. I. Patterns of recruitment underlying posture and movement during natural behaviors. Exp Brain Res 1992; 88:41-58. [PMID: 1541361 DOI: 10.1007/bf02259127] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Natural head movements in alert, unrestrained cats were studied using video-filming, videofluoroscopy and electromyographic (EMG) recording methods. In each cat, up to sixteen neck muscles or neck-muscle compartments were implanted with recording electrodes. Patterns of muscle recruitment were examined during systematically-selected behavioral epochs in which the cat held a range of stationary postures, and when it performed volitional and exploratory behaviors such as flexion-extension or turning, grooming, eating, or headshaking. Patterns of muscular activity were interpreted with reference to simultaneous video images of head and neck movements. In separate, videofluoroscopic analysis, flexion-extension movements were examined to gain insight into the underlying movements of the skull and cervical vertebrae. These and other movements were found commonly to depend upon changes in joint angles between lower as well as upper cervical joints. Stationary postures in which the neck was held vertically were consistently associated with tonic EMG activity in only two long dorsal muscles, biventer cervicis and occipitoscapularis. Less consistent activity was also present in dorsal intervertebral muscles crossing lower cervical joints. When the neck was held horizontally, the long dorsal muscles increased their EMG activity and moderate activity was also recorded in deeper intervertebral and suboccipital muscles. When flexion-extension occurred around upper cervical joints, greatest activity was recorded in rectus capitis posterior and complexus, but when it involved the lower cervical joints, large changes in EMG activity could also be detected in biventer cervicis, occipitoscapularis, and the intervertebral muscles crossing lower cervical joints. During specialized, sagittal-plane movements such as grooming, well-defined patterns of synergy could be recognized that varied according to the degree of involvement of upper and lower cervical joint-sets. Movements in the horizontal plane were associated with EMG activity in a largely different subset of neck muscles including splenius, longissimus capitis and obliquus capitis inferior. The levels of EMG activity during flexion-extension or turning movements were much lower than those observed during other more vigorous behaviors, such as head shaking. Some neck muscles, such as clavotrapezius and sternomastoideus, could only be recruited during forceful or ballistic head movements. Results showed that the patterns of muscular activation were linked not only to the speed and trajectory of the movements of the skull, but also to the kinematics of the motion occurring across different parts of the cervical column.
Collapse
Affiliation(s)
- F J Richmond
- Department of Physiology, Queen's University, Kingston, Canada
| | | | | |
Collapse
|
36
|
Pratt CA, Loeb GE. Functionally complex muscles of the cat hindlimb. I. Patterns of activation across sartorius. Exp Brain Res 1991; 85:243-56. [PMID: 1893978 DOI: 10.1007/bf00229404] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The cat sartorius (SA) can be divided functionally into an anterior (SAa), knee extensor portion and a medial (SAm), knee flexor portion; it can be further subdivided anatomically by multiple nerve branches into parallel longitudinal columns that terminate in a distributed insertion at the knee with a continuous range of moment arms. Thus, SA may be controlled by a discrete number of motoneuron task groups reflecting a small number of central command signals or by a continuum of activation patterns associated with a continuum of moment arms. To resolve this question, the activation patterns across the width of the SA were recorded with an electrode array during three kinematically different movements--treadmill locomotion, scratching and paw shaking, in awake, unrestrained cats. Uniformity of activation along the longitudinal axis was also examined because individual muscle fibers do not extend the length of the SA. In addition, the cutaneous reflex responses were recorded throughout all regions of the SA during locomotion. Two fascial surface-patch arrays, each carrying 4-8 pairs of bipolar EMG electrodes, were sutured to the inner surface of the SA, one placed proximally and the other more distally. Each array sampled separate sites across the anterior to medial axis of SA. During locomotion, two basic EMG patterns were observed: the two burst-per-step-cycle pattern typical of SAa and the single burst pattern typical of SAm. There was an abrupt transition in the pattern of activation recorded in the two parts of SA during locomotion, and no continuum in the activation pattern was observed. Stimulation of both sural and saphenous cutaneous nerves during locomotion produced reflex responses that were uniformly distributed throughout SA, in contrast to the regional differences noted during unperturbed walking. Similarly, during scratching and paw shaking all parts of the SA were active simultaneously but with regional differences in EMG amplitude. The abrupt functional border between SAa and SAm coincided with the division of the SA into a knee flexor vs. a knee extensor. In all cases, the quantitative and qualitative differences in SAa and SAm EMGs were uniformly recorded throughout the entire extent of SAa or SAm; i.e., there was no segregation of activity within either SAa or SAm. Furthermore, the time course of EMG from each proximal recording site was nearly identical to the corresponding distal site, indicating no segregation of function along the longitudinal axis of SA. These results indicate that SAa and SAm constitute the smallest functional modules that can be recruited in SA.(ABSTRACT TRUNCATED AT 400 WORDS)
Collapse
Affiliation(s)
- C A Pratt
- Laboratory of Neural Control, National Institute of Neurological and Communicative Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | | |
Collapse
|
37
|
Chanaud CM, Pratt CA, Loeb GE. Functionally complex muscles of the cat hindlimb. V. The roles of histochemical fiber-type regionalization and mechanical heterogeneity in differential muscle activation. Exp Brain Res 1991; 85:300-13. [PMID: 1832646 DOI: 10.1007/bf00229408] [Citation(s) in RCA: 93] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Several cat hindlimb muscles that exhibit differential activation (activity that is restricted to a specific region of muscle) during natural movements were studied to determine the possible roles of 1) non-uniform distribution of histochemically-identified muscle fiber-types (semitendinosus, ST; tibialis anterior, TA) or 2) mechanical heterogeneity (biceps femoris, BF; tensor fasciae latae, TFL). Using chronic recording techniques, electromyographic (EMG) activity was recorded from multiple sites of each muscle during treadmill locomotion, ear scratch, and paw shake. Standard histochemical analysis was performed on each muscle to determine fiber-type distribution. The histochemically regionalized muscles (ST and TA) were differentially active during slow locomotion; the deep regions (high in type I [SO] fibers) were active, but the superficial regions (high in type IIB [FG] fibers) were inactive. Vigorous movements (fast locomotion, ear scratch, paw shake) produced additional, synchronous activation of the superficial regions. In all movements, ST and TA activation patterns were consistent with the existence of identically timed synaptic inputs to all motoneurons within each motoneuron pool, resulting in an orderly recruitment of each whole pool. The differential activation recorded from ST and TA during slow locomotion was presumably a consequence of the non-uniform distribution of the different muscle fiber types. In contrast, differential activation of the histochemically nonregionalized, mechanically heterogeneous muscles (BF and TFL) resulted from non-synchronous activation of different muscle regions. The selective activation of BF or TFL compartments was indicative of differential synaptic inputs to, and selective recruitment of, subpopulations of the motoneuron pool, with each motoneuron subpopulation exclusively innervating physically separate regions of the muscle consistent with the regions defined by the neuromuscular territories of the major nerve branches supplying each muscle. Individual neuromuscular compartments of BF and TFL differ in their mechanical arrangements to the skeleton and in their contribution to mechanical action(s) at the hip and knee joints. Selective neural activation of mechanically distinct compartments within a mechanically heterogeneous muscle can provide highly advantageous mechanical "options" for animals that perform kinematically diverse movements. With regard to EMG recording techniques, the results of this study emphasize the need for carefully chosen EMG sampling sites and the value of knowing the muscle histochemistry, neuromuscular and musculoskeletal anatomy and possible mechanical functions prior to recording EMG.
Collapse
Affiliation(s)
- C M Chanaud
- Laboratory of Neural Control, National Institute of Neurological and Communicative Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | | | | |
Collapse
|
38
|
Abstract
1. Experiments were conducted to test the extent to which the electromyographic (EMG) activity generated by the activation of single motor units is conducted from one neuromuscular compartment of the cat lateral gastrocnemius (LG) muscle into adjacent compartments. 2. Potentials produced by stimulation of forty-five single motor units were monitored from bipolar fine-wire EMG electrodes which had been implanted either into the centres of each of the four neuromuscular compartments of LG or into regions of the muscle known to lie on the border of contiguous compartments. 3. In all cases single unit potentials could be recorded from the electrodes in the centre of the compartments which clearly identified the compartment of residence of the muscle unit. Regardless of unit type, the amplitude of the potential recorded from electrodes in one compartment was always greater than that recorded from any other compartment. 4. Smaller potentials could be recorded from electrodes in the centre of compartments adjacent to the compartment of residence of the muscle unit. For those motor units where the amplitude of the EMG potentials recorded from the compartment of residence was large, the amplitude of such 'cross-talk' could be greater than the amplitude of potentials recorded from the compartment of residence of smaller motor units. 5. In the case of electrodes placed at compartment boundaries, no clear compartment selectivity of recording of motor unit potentials was evident. 6. These results indicate that great care must be taken in choosing sites of EMG electrode placement when performing kinesiological studies, especially when the amplitude of the EMG activity recorded is of consideration.
Collapse
Affiliation(s)
- A W English
- Department of Anatomy and Cell Biology, Emory University, Atlanta, GA
| | | |
Collapse
|
39
|
Hoffer JA, Caputi AA, Pose IE, Griffiths RI. Roles of muscle activity and load on the relationship between muscle spindle length and whole muscle length in the freely walking cat. PROGRESS IN BRAIN RESEARCH 1989; 80:75-85; discussion 57-60. [PMID: 2634287 DOI: 10.1016/s0079-6123(08)62201-3] [Citation(s) in RCA: 110] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The objective of this research was to compare the length of muscle spindles to the length of the whole muscle, during normal movements. Pairs of piezoelectric crystals were implanted near the origin and insertion of muscle fibres in the medial gastrocnemius (MG) muscle of cats. The distance between crystals was measured with pulsed ultrasound, the origin-to-insertion length of the MG muscle was measured with a transducer made of saline-filled silicone tubing, MG force was measured with a tendon force transducer and EMG activity was selectively recorded in the vicinity of implanted crystals. These signals were simultaneously recorded during posture or locomotion on a motorized treadmill. Three periods were identified in the step cycle, during which the relation between muscle length and spindle length changed dramatically. In period I (roughly corresponding to the late F and E1 phases of swing), the MG muscle and spindles followed similar length changes: both were stretched and then shortened by about 6 mm. In period II (corresponding to the stance phase, E2-E3) the MG muscle yielded under the weight of the body and was stretched by 1-3 mm, whereas the MG spindles typically continued shortening. In period III, the MG muscle shortened rapidly by 6-8 mm after the foot left the ground and then stretched again by about the same amount, whereas the spindles could remain nearly isometric. We attribute these large discrepancies in muscle and spindle length to the architecture of the MG muscle and the compliance of long tendinous elements in series with the spindles. We conclude that the length changes imposed on muscle spindles during voluntary movements are not simply related to the parent muscle length changes and cannot be estimated without taking into account the muscle architecture, the location of the spindle within the muscle, the level of muscle activation and the external load.
Collapse
|
40
|
Gabella G, Trigg P, McPhail H. Quantitative cytology of ganglion neurons and satellite glial cells in the superior cervical ganglion of the sheep. Relationship with ganglion neuron size. JOURNAL OF NEUROCYTOLOGY 1988; 17:753-69. [PMID: 3230395 DOI: 10.1007/bf01216704] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Neurons and glial cells of the superior cervical ganglion of sheep were investigated with morphometric methods in the light and electron microscope. The nerve cell sectional area (measured on nucleated cell profiles) ranged from 165 to 2500 microns2, which corresponds to range in cell diameter from 14 to 56 microns and a range in cell volume from 1600 to 93,000 microns3, i.e. a 60-fold volume difference between smallest and largest neurons. The distribution of cell sizes appeared unimodal, with a predominance of small neurons; there were no variations in different parts of the ganglion. This wide range in nerve cell sizes is discussed in the light of the suggestion that large neurons innervate a greater amount of target tissue (e.g. smooth muscle) and are less readily excitable than smaller neurons: it is thus possible that there is differential recruitment of ganglion neurons in autonomic reflexes. The ultrastructural features of ganglion neurons in the sheep were similar to those observed in small laboratory animals. The relative volumes of perikaryal cytoplasm occupied by mitochondria and Golgi apparatus were 8.5% and 4.8%, respectively, but the average values were the same in small and large neurons. Subsurface cisternae of endoplasmic reticulum were common in the perikaryon, while in the dendrites clusters of synaptic vesicles were found beneath the plasma membrane; the absence of a glial wrapping at the latter sites suggests that they are points of (non-synaptic) release of transmitters. The extent of the capsule that satellite cells form around each neurons was compared in size-based classes of neurons. There was no difference in the size of glial nuclei, and this suggests that glial cells are probably of uniform size. However, glial cells were more densely packed over the surface of large neurons than over the surface of small neurons--in fact the packing density was proportional to the ganglion neuron volume, rather than to its surface. The average thickness of the glial capsule was significantly greater around large than around small neurons. It is suggested that the matching of glial cell number and nerve cell volume is achieved during development by glial cell mitosis taking place long after the nerve cells have ceased dividing.
Collapse
Affiliation(s)
- G Gabella
- Department of Anatomy, University College London, UK
| | | | | |
Collapse
|
41
|
Sinkjaer T, Hoffer JA. A computer-controlled system to perturb the ankle joint of freely standing cats trained to maintain a given force. J Neurosci Methods 1987; 21:311-20. [PMID: 3682881 DOI: 10.1016/0165-0270(87)90125-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A computer-based system was developed to (1) train freely standing cats to match various target forces with the left hindlimb, (2) perturb the left ankle joint when the cat was maintaining a desired force and (3) compare reflex responses before and after decerebration. Cats quickly learned to stand unaided on 4 pedestals. During a training session, a range of target force windows was presented to the cat. A successful trial consisted of maintaining the force applied on the left rear pedestal within the target window for a preset time period. To assist the cat, a light was turned on whenever the force was within the target window. A food pellet reward was delivered by the computer after each successful trial. To test reflex responses, the position of the left hindlimb could be briefly perturbed by activating a servo-controlled printed motor configured to rotate the pedestal about the axis of the ankle joint. Perturbations that either flexed or extended the ankle joint were presented pseudo-randomly by the computer. This approach has been used to quantify the magnitude of muscle afferent volleys and the reflex EMG in ankle extensor muscles of normal and decerebrated cats, in response to similar mechanical perturbations. It has also been used to study dynamic features in the electroneurogram recorded from a cutaneous nerve by implanted nerve cuff electrodes, and the correlations among the electroneurogram, the vertical contact force applied on the pedestal and the force recorded from muscle tendons by implanted transducers. This approach may have general applications in the study of postural control, including the study of the discharge patterns of individual motor, sensory or spinal cord neurons in freely standing cats.
Collapse
Affiliation(s)
- T Sinkjaer
- Department of Clinical Neurosciences, University of Calgary, Faculty of Medicine, Alta., Canada
| | | |
Collapse
|