The Cellular Basis for the Generation of Firing Patterns in Human Motor Units.
Motoneuron
Motor control
Motor unit
Neuromodulation
Persistent inward currents
Journal
Advances in neurobiology
ISSN: 2190-5215
Titre abrégé: Adv Neurobiol
Pays: United States
ID NLM: 101571545
Informations de publication
Date de publication:
2022
2022
Historique:
entrez:
6
9
2022
pubmed:
7
9
2022
medline:
9
9
2022
Statut:
ppublish
Résumé
Motor units, which comprise a motoneuron and the set of muscle fibers it innervates, are the fundamental neuromuscular transducers for all motor commands. The one to one relationship between a motoneuron and its innervated muscle fibers allow motoneuron firing patterns to be readily measured in humans. In this chapter, we summarize the current understanding of the cellular basis for the generation of firing patterns in human motor units. We provide a brief review of landmark insights from classic studies and then proceed to consider the features of motor unit firing patterns that are most likely to be sensitive estimators of motoneuron inputs and properties. In addition, we discuss recent advances in technology for recording human motor unit firing patterns and highly realistic computer simulations of motoneurons. The final section presents our recent efforts to use the power of supercomputers for implementation of the motoneuron models, with a goal of achieving a true "reverse engineering" approach that maximizes the insights from motor unit firing patterns into the synaptic structure of motor commands.
Identifiants
pubmed: 36066828
doi: 10.1007/978-3-031-07167-6_10
doi:
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
233-258Informations de copyright
© 2022. Springer Nature Switzerland AG.
Références
Adrian ED, Bronk DW (1929) The discharge of impulses in motor nerve fibres: part II. The frequency of discharge in reflex and voluntary contractions. J Physiol 67(2):i3–i151
doi: 10.1113/jphysiol.1929.sp002557
Afsharipour B, Manzur N, Duchcherer J, Fenrich KF, Thompson CK, Negro F, Quinlan KA, Bennett DJ, Gorassini MA (2020) Estimation of self-sustained activity produced by persistent inward currents using firing rate profiles of multiple motor units in humans. J Neurophysiol 124(1):63–85. https://doi.org/10.1152/jn.00194.2020
doi: 10.1152/jn.00194.2020
pubmed: 32459555
pmcid: 7474459
Bennett DJ, Hultborn H, Fedirchuk B, Gorassini MA (1998) Synaptic activation of plateaus in hindlimb motoneurons of decerebrate cats. J Neurophysiol 80(4):2023–2037. https://doi.org/10.1152/jn.1998.80.4.2023
doi: 10.1152/jn.1998.80.4.2023
pubmed: 9772258
Bennett DJ, Li Y, Harvey PJ, Gorassini MA (2001a) Evidence for plateau potentials in tail motoneurons of awake chronic spinal rats with spasticity. J Neurophysiol 86(4):1972–1982. https://doi.org/10.1152/jn.2001.86.4.1972
doi: 10.1152/jn.2001.86.4.1972
pubmed: 11600654
Bennett DJ, Li Y, Siu M (2001b) Plateau potentials in sacrocaudal motoneurons of chronic spinal rats, recorded in vitro. J Neurophysiol 86(4):1955–1971. https://doi.org/10.1152/jn.2001.86.4.1955
doi: 10.1152/jn.2001.86.4.1955
pubmed: 11600653
Binder MD, Powers RK, Heckman CJ (2020) Nonlinear input-output functions of motoneurons. Physiology (Bethesda) 35(1):31–39. https://doi.org/10.1152/physiol.00026.2019
doi: 10.1152/physiol.00026.2019
Bui TV, Grande G, Rose PK (2008) Multiple modes of amplification of synaptic inhibition to motoneurons by persistent inward currents. J Neurophysiol 99(2):571–582. https://doi.org/10.1152/jn.00717.2007
doi: 10.1152/jn.00717.2007
pubmed: 18046007
Burke RE (1981) Motor units: anatomy, physiology, and functional organization. In: Brooks VB (ed) Handbook of physiology, the nervous system, motor control. American Physiological Society, pp 345–422
Burke RE, Levine DN, Tsairis P, Zajac FE 3rd. (1973) Physiological types and histochemical profiles in motor units of the cat gastrocnemius. J Physiol 234(3):723–748. https://doi.org/10.1113/jphysiol.1973.sp010369
doi: 10.1113/jphysiol.1973.sp010369
pubmed: 4148752
pmcid: 1350696
Cope TC, Clark BD (1991) Motor-unit recruitment in the decerebrate cat: several unit properties are equally good predictors of order. J Neurophysiol 66(4):1127–1138. https://doi.org/10.1152/jn.1991.66.4.1127
doi: 10.1152/jn.1991.66.4.1127
pubmed: 1761976
De Luca CJ, Contessa P (2012) Hierarchical control of motor units in voluntary contractions. J Neurophysiol 107(1):178–195. https://doi.org/10.1152/jn.00961.2010
doi: 10.1152/jn.00961.2010
pubmed: 21975447
De Luca CJ, LeFever RS, McCue MP, Xenakis AP (1982) Behaviour of human motor units in different muscles during linearly varying contractions. J Physiol 329:113–128. https://doi.org/10.1113/jphysiol.1982.sp014293
doi: 10.1113/jphysiol.1982.sp014293
pubmed: 7143246
pmcid: 1224770
Denny-Brown D, Pennybacker J (1938) Fibrillation and fasciculation in voluntary muscle. Brain 61(3):311–312
doi: 10.1093/brain/61.3.311
Duchateau J, Enoka RM (2011) Human motor unit recordings: origins and insight into the integrated motor system. Brain Res 1409:42–61. https://doi.org/10.1016/j.brainres.2011.06.011
doi: 10.1016/j.brainres.2011.06.011
pubmed: 21762884
Eccles JC (1952) The electrophysiological properties of the motoneurone. Cold Spring Harb Symp Quant Biol 17:175–183. https://doi.org/10.1101/sqb.1952.017.01.017
doi: 10.1101/sqb.1952.017.01.017
pubmed: 13049164
Elbasiouny SM, Bennett DJ, Mushahwar VK (2006) Simulation of Ca
doi: 10.1113/jphysiol.2005.099119
pubmed: 16308349
Farina D, Holobar A (2016) Characterization of human motor units from surface EMG decomposition. Proc IEEE 104(2):353–373
doi: 10.1109/JPROC.2015.2498665
Farina D, Negro F, Muceli S, Enoka RM (2016) Principles of motor unit physiology evolve with advances in technology. Physiology (Bethesda) 31(2):83–94. https://doi.org/10.1152/physiol.00040.2015
doi: 10.1152/physiol.00040.2015
Foley RCA, Kalmar JM (2019) Estimates of persistent inward current in human motor neurons during postural sway. J Neurophysiol 122(5):2095–2110. https://doi.org/10.1152/jn.00254.2019
doi: 10.1152/jn.00254.2019
pubmed: 31533012
pmcid: 6879958
Fuglevand AJ, Winter DA, Patla AE (1993) Models of recruitment and rate coding organization in motor-unit pools. J Neurophysiol 70(6):2470–2488. https://doi.org/10.1152/jn.1993.70.6.2470
doi: 10.1152/jn.1993.70.6.2470
pubmed: 8120594
Fuglevand AJ, Lester RA, Johns RK (2015) Distinguishing intrinsic from extrinsic factors underlying firing rate saturation in human motor units. J Neurophysiol 113(5):1310–1322. https://doi.org/10.1152/jn.00777.2014
doi: 10.1152/jn.00777.2014
pubmed: 25475356
Garnett R, Stephens JA (1981) Changes in the recruitment threshold of motor units produced by cutaneous stimulation in man. J Physiol 311:463–473. https://doi.org/10.1113/jphysiol.1981.sp013598
doi: 10.1113/jphysiol.1981.sp013598
pubmed: 7264979
pmcid: 1275423
Gerstein GL, Kiang NY (1960) An approach to the quantitative analysis of electrophysiological data from single neurons. Biophys J 1:15–28. https://doi.org/10.1016/s0006-3495(60)86872-5
doi: 10.1016/s0006-3495(60)86872-5
pubmed: 13704760
pmcid: 1366309
Gorassini MA, Yang JF, Siu M, Bennett DJ (2002) Intrinsic activation of human motoneurons: possible contribution to motor unit excitation. J Neurophysiol 87(4):1850–1858. https://doi.org/10.1152/jn.00024.2001
doi: 10.1152/jn.00024.2001
pubmed: 11929906
Gorassini MA, Knash ME, Harvey PJ, Bennett DJ, Yang JF (2004) Role of motoneurons in the generation of muscle spasms after spinal cord injury. Brain 127(Pt 10):2247–2258. https://doi.org/10.1093/brain/awh243
doi: 10.1093/brain/awh243
pubmed: 15342360
Gustafsson B, Pinter MJ (1984) An investigation of threshold properties among cat spinal alpha-motoneurones. J Physiol 357:453–483. https://doi.org/10.1113/jphysiol.1984.sp015511
doi: 10.1113/jphysiol.1984.sp015511
pubmed: 6512700
pmcid: 1193269
Gydikov A, Kosarov D (1973) Physiological characteristics of the tonic and phasic motor units in human muscles. In: Motor control. Springer, pp 75–94
doi: 10.1007/978-1-4613-4502-2_6
Gydikov A, Kosarov D (1974) Some features of different motor units in human biceps brachii. Pflugers Arch 347(1):75–88. https://doi.org/10.1007/BF00587056
doi: 10.1007/BF00587056
pubmed: 4407539
Harvey PJ, Li Y, Li X, Bennett DJ (2006) Persistent sodium currents and repetitive firing in motoneurons of the sacrocaudal spinal cord of adult rats. J Neurophysiol 96(3):1141–1157. https://doi.org/10.1152/jn.00335.2005
doi: 10.1152/jn.00335.2005
pubmed: 16282206
Hassan AS, Kim EH, Khurram OU, Cummings M, Thompson CK, Miller McPherson L, Heckman CJ, Dewald JPA, Negro F (2019) Properties of motor units of elbow and ankle muscles decomposed using high-density surface EMG. Conf Proc IEEE Eng Med Biol Soc 2019:3874–3878. https://doi.org/10.1109/EMBC.2019.8857475
doi: 10.1109/EMBC.2019.8857475
pmcid: 6986378
Hassan AS, Thompson CK, Negro F, Cummings M, Powers RK, Heckman CJ, Dewald JPA, McPherson LM (2020) Impact of parameter selection on estimates of motoneuron excitability using paired motor unit analysis. J Neural Eng 17(1):016063. https://doi.org/10.1088/1741-2552/ab5eda
doi: 10.1088/1741-2552/ab5eda
pubmed: 31801123
pmcid: 7295184
Heckman CJ (1994) Computer simulations of the effects of different synaptic input systems on the steady-state input-output structure of the motoneuron pool. J Neurophysiol 71(5):1727–1739. https://doi.org/10.1152/jn.1994.71.5.1727
doi: 10.1152/jn.1994.71.5.1727
pubmed: 7914915
Heckman CJ, Binder MD (1988) Analysis of effective synaptic currents generated by homonymous Ia afferent fibers in motoneurons of the cat. J Neurophysiol 60(6):1946–1966. https://doi.org/10.1152/jn.1988.60.6.1946
doi: 10.1152/jn.1988.60.6.1946
pubmed: 3236057
Heckman CJ, Binder MD (1991a) Analysis of Ia-inhibitory synaptic input to cat spinal motoneurons evoked by vibration of antagonist muscles. J Neurophysiol 66(6):1888–1893. https://doi.org/10.1152/jn.1991.66.6.1888
doi: 10.1152/jn.1991.66.6.1888
pubmed: 1812223
Heckman CJ, Binder MD (1991b) Computer simulation of the steady-state input-output function of the cat medial gastrocnemius motoneuron pool. J Neurophysiol 65(4):952–967. https://doi.org/10.1152/jn.1991.65.4.952
doi: 10.1152/jn.1991.65.4.952
pubmed: 2051212
Heckman CJ, Binder MD (1993a) Computer simulations of motoneuron firing rate modulation. J Neurophysiol 69(4):1005–1008. https://doi.org/10.1152/jn.1993.69.4.1005
doi: 10.1152/jn.1993.69.4.1005
pubmed: 8492143
Heckman CJ, Binder MD (1993b) Computer simulations of the effects of different synaptic input systems on motor unit recruitment. J Neurophysiol 70(5):1827–1840. https://doi.org/10.1152/jn.1993.70.5.1827
doi: 10.1152/jn.1993.70.5.1827
pubmed: 8294958
Heckman CJ, Enoka RM (2012) Motor unit. Compr Physiol 2(4):2629–2682. https://doi.org/10.1002/cphy.c100087
doi: 10.1002/cphy.c100087
pubmed: 23720261
Henneman E (1957) Relation between size of neurons and their susceptibility to discharge. Science 126(3287):1345–1347. https://doi.org/10.1126/science.126.3287.1345
doi: 10.1126/science.126.3287.1345
pubmed: 13495469
Henneman E, Mendell LM (1981) Functional organization of motoneuron pool and its inputs. In: Brooks VB (ed) Handbook of physiology, the nervous system, motor control. American Physiological Society, pp 423–507
Henneman E, Olson CB (1965) Relations between structure and function in the design of skeletal muscles. J Neurophysiol 28:581–598. https://doi.org/10.1152/jn.1965.28.3.581
doi: 10.1152/jn.1965.28.3.581
pubmed: 14328455
Henneman E, Somjen G, Carpenter DO (1965a) Excitability and inhibitability of motoneurons of different sizes. J Neurophysiol 28(3):599–620. https://doi.org/10.1152/jn.1965.28.3.599
doi: 10.1152/jn.1965.28.3.599
pubmed: 5835487
Henneman E, Somjen G, Carpenter DO (1965b) Functional significance of cell size in spinal motoneurons. J Neurophysiol 28:560–580. https://doi.org/10.1152/jn.1965.28.3.560
doi: 10.1152/jn.1965.28.3.560
pubmed: 14328454
Holobar A, Zazula D (2008) On the selection of the cost function for gradient-based decomposition of surface electromyograms. Conf Proc IEEE Eng Med Biol Soc 2008:4668–4671. https://doi.org/10.1109/IEMBS.2008.4650254
doi: 10.1109/IEMBS.2008.4650254
Holobar A, Farina D, Gazzoni M, Merletti R, Zazula D (2009) Estimating motor unit discharge patterns from high-density surface electromyogram. Clin Neurophysiol 120(3):551–562. https://doi.org/10.1016/j.clinph.2008.10.160
doi: 10.1016/j.clinph.2008.10.160
pubmed: 19208498
Hounsgaard J, Kiehn O (1985) Ca++ dependent bistability induced by serotonin in spinal motoneurons. Exp Brain Res 57(2):422–425. https://doi.org/10.1007/BF00236551
doi: 10.1007/BF00236551
pubmed: 2578974
Hounsgaard J, Kiehn O (1993) Calcium spikes and calcium plateaux evoked by differential polarization in dendrites of turtle motoneurones in vitro. J Physiol 468:245–259. https://doi.org/10.1113/jphysiol.1993.sp019769
doi: 10.1113/jphysiol.1993.sp019769
pubmed: 8254508
pmcid: 1143824
Hounsgaard J, Hultborn H, Jespersen B, Kiehn O (1988) Bistability of alpha-motoneurones in the decerebrate cat and in the acute spinal cat after intravenous 5-hydroxytryptophan. J Physiol 405:345–367. https://doi.org/10.1113/jphysiol.1988.sp017336
doi: 10.1113/jphysiol.1988.sp017336
pubmed: 3267153
pmcid: 1190979
Hyngstrom AS, Johnson MD, Heckman CJ (2008) Summation of excitatory and inhibitory synaptic inputs by motoneurons with highly active dendrites. J Neurophysiol 99(4):1643–1652. https://doi.org/10.1152/jn.01253.2007
doi: 10.1152/jn.01253.2007
pubmed: 18234978
Jacobs BL, Martin-Cora FJ, Fornal CA (2002) Activity of medullary serotonergic neurons in freely moving animals. Brain Res Brain Res Rev 40(1–3):45–52. https://doi.org/10.1016/s0165-0173(02)00187-x
doi: 10.1016/s0165-0173(02)00187-x
pubmed: 12589905
Johnson MD, Thompson CK, Tysseling VM, Powers RK, Heckman CJ (2017) The potential for understanding the synaptic organization of human motor commands via the firing patterns of motoneurons. J Neurophysiol 118(1):520–531. https://doi.org/10.1152/jn.00018.2017
doi: 10.1152/jn.00018.2017
pubmed: 28356467
pmcid: 5511870
Kahya MC, Yavuz SU, Turker KS (2010) Cutaneous silent period in human FDI motor units. Exp Brain Res 205(4):455–463. https://doi.org/10.1007/s00221-010-2380-6
doi: 10.1007/s00221-010-2380-6
pubmed: 20694723
Kanda K, Burke RE, Walmsley B (1977) Differential control of fast and slow twitch motor units in the decerebrate cat. Exp Brain Res 29(1):57–74. https://doi.org/10.1007/BF00236875
doi: 10.1007/BF00236875
pubmed: 891681
Kernell D (1966) Input resistance, electrical excitability, and size of ventral horn cells in cat spinal cord. Science 152(3729):1637–1640. https://doi.org/10.1126/science.152.3729.1637
doi: 10.1126/science.152.3729.1637
pubmed: 5936887
Kernell D (1983) Functional properties of spinal motoneurons and gradation of muscle force. Adv Neurol 39:213–226
pubmed: 6318530
Kiehn O, Eken T (1997) Prolonged firing in motor units: evidence of plateau potentials in human motoneurons? J Neurophysiol 78(6):3061–3068. https://doi.org/10.1152/jn.1997.78.6.3061
doi: 10.1152/jn.1997.78.6.3061
pubmed: 9405525
Kim H, Jones KE (2011) Asymmetric electrotonic coupling between the soma and dendrites alters the bistable firing behaviour of reduced models. J Comput Neurosci 30(3):659–674. https://doi.org/10.1007/s10827-010-0284-x
doi: 10.1007/s10827-010-0284-x
pubmed: 20941536
Kim H, Jones KE (2012) The retrograde frequency response of passive dendritic trees constrains the nonlinear firing behaviour of a reduced neuron model. PLoS One 7(8):e43654. https://doi.org/10.1371/journal.pone.0043654
doi: 10.1371/journal.pone.0043654
pubmed: 22916290
pmcid: 3423382
Kim H, Major LA, Jones KE (2009) Derivation of cable parameters for a reduced model that retains asymmetric voltage attenuation of reconstructed spinal motor neuron dendrites. J Comput Neurosci 27(3):321–336. https://doi.org/10.1007/s10827-009-0145-7
doi: 10.1007/s10827-009-0145-7
pubmed: 19387812
Kim H, Jones KE, Heckman CJ (2014) Asymmetry in signal propagation between the soma and dendrites plays a key role in determining dendritic excitability in motoneurons. PLoS One 9(8):e95454. https://doi.org/10.1371/journal.pone.0095454
doi: 10.1371/journal.pone.0095454
pubmed: 25083794
pmcid: 4118843
Kim EH, Wilson JM, Thompson CK, Heckman CJ (2020) Differences in estimated persistent inward currents between ankle flexors and extensors in humans. J Neurophysiol 124(2):525–535. https://doi.org/10.1152/jn.00746.2019
doi: 10.1152/jn.00746.2019
pubmed: 32667263
pmcid: 7500370
Klass M, Baudry S, Duchateau J (2008) Age-related decline in rate of torque development is accompanied by lower maximal motor unit discharge frequency during fast contractions. J Appl Physiol (1985) 104(3):739–746. https://doi.org/10.1152/japplphysiol.00550.2007
doi: 10.1152/japplphysiol.00550.2007
Kukulka CG, Clamann HP (1981) Comparison of the recruitment and discharge properties of motor units in human brachial biceps and adductor pollicis during isometric contractions. Brain Res 219(1):45–55. https://doi.org/10.1016/0006-8993(81)90266-3
doi: 10.1016/0006-8993(81)90266-3
pubmed: 7260629
Kuo JJ, Lee RH, Johnson MD, Heckman HM, Heckman CJ (2003) Active dendritic integration of inhibitory synaptic inputs in vivo. J Neurophysiol 90(6):3617–3624. https://doi.org/10.1152/jn.00521.2003
doi: 10.1152/jn.00521.2003
pubmed: 12944534
Kuo JJ, Lee RH, Zhang L, Heckman CJ (2006) Essential role of the persistent sodium current in spike initiation during slowly rising inputs in mouse spinal neurones. J Physiol 574(Pt 3):819–834. https://doi.org/10.1113/jphysiol.2006.107094
doi: 10.1113/jphysiol.2006.107094
pubmed: 16728453
pmcid: 1817738
Lee RH, Heckman CJ (1996) Influence of voltage-sensitive dendritic conductances on bistable firing and effective synaptic current in cat spinal motoneurons in vivo. J Neurophysiol 76(3):2107–2110. https://doi.org/10.1152/jn.1996.76.3.2107
doi: 10.1152/jn.1996.76.3.2107
pubmed: 8890322
Lee RH, Heckman CJ (1998) Bistability in spinal motoneurons in vivo: systematic variations in rhythmic firing patterns. J Neurophysiol 80(2):572–582. https://doi.org/10.1152/jn.1998.80.2.572
doi: 10.1152/jn.1998.80.2.572
pubmed: 9705451
Lee RH, Heckman CJ (1999a) Enhancement of bistability in spinal motoneurons in vivo by the noradrenergic alpha1 agonist methoxamine. J Neurophysiol 81(5):2164–2174. https://doi.org/10.1152/jn.1999.81.5.2164
doi: 10.1152/jn.1999.81.5.2164
pubmed: 10322057
Lee RH, Heckman CJ (1999b) Paradoxical effect of QX-314 on persistent inward currents and bistable behavior in spinal motoneurons in vivo. J Neurophysiol 82(5):2518–2527. https://doi.org/10.1152/jn.1999.82.5.2518
doi: 10.1152/jn.1999.82.5.2518
pubmed: 10561423
Lee RH, Heckman CJ (2000) Adjustable amplification of synaptic input in the dendrites of spinal motoneurons in vivo. J Neurosci 20(17):6734–6740
doi: 10.1523/JNEUROSCI.20-17-06734.2000
Lee RH, Heckman CJ (2001) Essential role of a fast persistent inward current in action potential initiation and control of rhythmic firing. J Neurophysiol 85(1):472–475. https://doi.org/10.1152/jn.2001.85.1.472
doi: 10.1152/jn.2001.85.1.472
pubmed: 11152749
Lindsay AD, Binder MD (1991) Distribution of effective synaptic currents underlying recurrent inhibition in cat triceps surae motoneurons. J Neurophysiol 65(2):168–177. https://doi.org/10.1152/jn.1991.65.2.168
doi: 10.1152/jn.1991.65.2.168
pubmed: 2016635
MacDonell CW, Ivanova TD, Garland SJ (2007) Reliability of the interval death rate analysis for estimating the time course of the motoneurone afterhyperpolarization in humans. J Neurosci Methods 162(1–2):314–319. https://doi.org/10.1016/j.jneumeth.2007.01.020
doi: 10.1016/j.jneumeth.2007.01.020
pubmed: 17350691
MacDonell CW, Ivanova TD, Garland SJ (2008) Afterhyperpolarization time-course and minimal discharge rate in low threshold motor units in humans. Exp Brain Res 189(1):23–33. https://doi.org/10.1007/s00221-008-1400-2
doi: 10.1007/s00221-008-1400-2
pubmed: 18463855
MacDonell CW, Ivanova TD, Garland SJ (2010) Changes in the estimated time course of the motoneuron afterhyperpolarization induced by tendon vibration. J Neurophysiol 104(6):3240–3249. https://doi.org/10.1152/jn.00941.2009
doi: 10.1152/jn.00941.2009
pubmed: 20861437
Marder E (1996) Neural modulation: following your own rhythm. Curr Biol 6(2):119–121. https://doi.org/10.1016/s0960-9822(02)00438-4
doi: 10.1016/s0960-9822(02)00438-4
pubmed: 8673452
Matthews PB (1996) Relationship of firing intervals of human motor units to the trajectory of post-spike after-hyperpolarization and synaptic noise. J Physiol 492(Pt 2):597–628. https://doi.org/10.1113/jphysiol.1996.sp021332
doi: 10.1113/jphysiol.1996.sp021332
pubmed: 9019553
pmcid: 1158851
Matthews PB (1999) Properties of human motoneurones and their synaptic noise deduced from motor unit recordings with the aid of computer modelling. J Physiol Paris 93(1–2):135–145. https://doi.org/10.1016/s0928-4257(99)80144-2
doi: 10.1016/s0928-4257(99)80144-2
pubmed: 10084717
Matthews PB (2002) Measurement of excitability of tonically firing neurones tested in a variable-threshold model motoneurone. J Physiol 544(Pt 1):315–332. https://doi.org/10.1113/jphysiol.2002.024984
doi: 10.1113/jphysiol.2002.024984
pubmed: 12356902
pmcid: 2290572
Mendell LM, Henneman E (1971) Terminals of single Ia fibers – location, density, and distribution within a pool of 300 homonymous motoneurons. J Neurophysiol 34(1):171
doi: 10.1152/jn.1971.34.1.171
Merletti R, Holobar A, Farina D (2008) Analysis of motor units with high-density surface electromyography. J Electromyogr Kinesiol 18(6):879–890. https://doi.org/10.1016/j.jelekin.2008.09.002
doi: 10.1016/j.jelekin.2008.09.002
pubmed: 19004645
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Monster AW, Chan H (1977) Isometric force production by motor units of extensor digitorum communis muscle in man. J Neurophysiol 40(6):1432–1443. https://doi.org/10.1152/jn.1977.40.6.1432
doi: 10.1152/jn.1977.40.6.1432
pubmed: 925737
Moore GE (1965) Cramming more components onto integrated circuits, Electronics, 38(8):114–117
Moore GP, Segundo JP, Perkel DH, Levitan H (1970) Statistical signs of synaptic interaction in neurons. Biophys J 10(9):876–900. https://doi.org/10.1016/S0006-3495(70)86341-X
doi: 10.1016/S0006-3495(70)86341-X
pubmed: 4322240
pmcid: 1367820
Moritz CT, Barry BK, Pascoe MA, Enoka RM (2005) Discharge rate variability influences the variation in force fluctuations across the working range of a hand muscle. J Neurophysiol 93(5):2449–2459. https://doi.org/10.1152/jn.01122.2004
doi: 10.1152/jn.01122.2004
pubmed: 15615827
Moritz AT, Newkirk G, Powers RK, Binder MD (2007) Facilitation of somatic calcium channels can evoke prolonged tail currents in rat hypoglossal motoneurons. J Neurophysiol 98(2):1042–1047. https://doi.org/10.1152/jn.01294.2006
doi: 10.1152/jn.01294.2006
pubmed: 17522175
Mottram CJ, Suresh NL, Heckman CJ, Gorassini MA, Rymer WZ (2009) Origins of abnormal excitability in biceps brachii motoneurons of spastic-paretic stroke survivors. J Neurophysiol 102(4):2026–2038. https://doi.org/10.1152/jn.00151.2009
doi: 10.1152/jn.00151.2009
pubmed: 19587321
pmcid: 2775372
Negro F, Muceli S, Castronovo AM, Holobar A, Farina D (2016) Multi-channel intramuscular and surface EMG decomposition by convolutive blind source separation. J Neural Eng 13(2):026027. https://doi.org/10.1088/1741-2560/13/2/026027
doi: 10.1088/1741-2560/13/2/026027
pubmed: 26924829
Norton JA, Bennett DJ, Knash ME, Murray KC, Gorassini MA (2008) Changes in sensory-evoked synaptic activation of motoneurons after spinal cord injury in man. Brain 131(Pt 6):1478–1491. https://doi.org/10.1093/brain/awn050
doi: 10.1093/brain/awn050
pubmed: 18344559
Oya T, Riek S, Cresswell AG (2009) Recruitment and rate coding organisation for soleus motor units across entire range of voluntary isometric plantar flexions. J Physiol 587(Pt 19):4737–4748. https://doi.org/10.1113/jphysiol.2009.175695
doi: 10.1113/jphysiol.2009.175695
pubmed: 19703968
pmcid: 2768026
Person RS, Kudina LP (1972) Discharge frequency and discharge pattern of human motor units during voluntary contraction of muscle. Electroencephalogr Clin Neurophysiol 32(5):471–483. https://doi.org/10.1016/0013-4694(72)90058-2
doi: 10.1016/0013-4694(72)90058-2
pubmed: 4112299
Piotrkiewicz M (1999) An influence of afterhyperpolarization on the pattern of motoneuronal rhythmic activity. J Physiol Paris 93(1–2):125–133. https://doi.org/10.1016/s0928-4257(99)80143-0
doi: 10.1016/s0928-4257(99)80143-0
pubmed: 10084716
Powers RK, Binder MD (2000) Relationship between the time course of the afterhyperpolarization and discharge variability in cat spinal motoneurones. J Physiol 528(Pt 1):131–150. https://doi.org/10.1111/j.1469-7793.2000.t01-1-00131.x
doi: 10.1111/j.1469-7793.2000.t01-1-00131.x
pubmed: 11018112
pmcid: 2270116
Powers RK, Binder MD (2001) Input-output functions of mammalian motoneurons. Rev Physiol Biochem Pharmacol 143:137–263. https://doi.org/10.1007/BFb0115594
doi: 10.1007/BFb0115594
pubmed: 11428264
Powers RK, Heckman CJ (2015) Contribution of intrinsic motoneuron properties to discharge hysteresis and its estimation based on paired motor unit recordings: a simulation study. J Neurophysiol 114(1):184–198. https://doi.org/10.1152/jn.00019.2015
doi: 10.1152/jn.00019.2015
pubmed: 25904704
pmcid: 4507952
Powers RK, Heckman CJ (2017) Synaptic control of the shape of the motoneuron pool input-output function. J Neurophysiol 117(3):1171–1184. https://doi.org/10.1152/jn.00850.2016
doi: 10.1152/jn.00850.2016
pubmed: 28053245
pmcid: 5340877
Powers RK, Turker KS (2010) Estimates of EPSP amplitude based on changes in motoneuron discharge rate and probability. Exp Brain Res 206(4):427–440. https://doi.org/10.1007/s00221-010-2423-z
doi: 10.1007/s00221-010-2423-z
pubmed: 20862458
Powers RK, Dai Y, Bell BM, Percival DB, Binder MD (2005) Contributions of the input signal and prior activation history to the discharge behaviour of rat motoneurones. J Physiol 562(Pt 3):707–724. https://doi.org/10.1113/jphysiol.2004.069039
doi: 10.1113/jphysiol.2004.069039
pubmed: 15611038
Powers RK, Nardelli P, Cope TC (2008) Estimation of the contribution of intrinsic currents to motoneuron firing based on paired motoneuron discharge records in the decerebrate cat. J Neurophysiol 100(1):292–303. https://doi.org/10.1152/jn.90296.2008
doi: 10.1152/jn.90296.2008
pubmed: 18463182
pmcid: 2493492
Powers RK, Elbasiouny SM, Rymer WZ, Heckman CJ (2012) Contribution of intrinsic properties and synaptic inputs to motoneuron discharge patterns: a simulation study. J Neurophysiol 107(3):808–823. https://doi.org/10.1152/jn.00510.2011
doi: 10.1152/jn.00510.2011
pubmed: 22031773
Revill AL, Fuglevand AJ (2011) Effects of persistent inward currents, accommodation, and adaptation on motor unit behavior: a simulation study. J Neurophysiol 106(3):1467–1479. https://doi.org/10.1152/jn.00419.2011
doi: 10.1152/jn.00419.2011
pubmed: 21697447
pmcid: 3174816
Revill AL, Fuglevand AJ (2017) Inhibition linearizes firing rate responses in human motor units: implications for the role of persistent inward currents. J Physiol 595(1):179–191. https://doi.org/10.1113/JP272823
doi: 10.1113/JP272823
pubmed: 27470946
Schwindt PC, Crill WE (1980) Properties of a persistent inward current in normal and TEA-injected motoneurons. J Neurophysiol 43(6):1700–1724. https://doi.org/10.1152/jn.1980.43.6.1700
doi: 10.1152/jn.1980.43.6.1700
pubmed: 6251180
Selverston A, Elson R, Rabinovich M, Huerta R, Abarbanel H (1998) Basic principles for generating motor output in the stomatogastric ganglion. Ann N Y Acad Sci 860:35–50. https://doi.org/10.1111/j.1749-6632.1998.tb09037.x
doi: 10.1111/j.1749-6632.1998.tb09037.x
pubmed: 9928300
Stephenson JL, Maluf KS (2010) Discharge behaviors of trapezius motor units during exposure to low and high levels of acute psychosocial stress. J Clin Neurophysiol 27(1):52–61. https://doi.org/10.1097/WNP.0b013e3181cb81d3
doi: 10.1097/WNP.0b013e3181cb81d3
pubmed: 20087201
pmcid: 2856657
Stevens R, Taylor V, Nichols J, Maccabe AB, Yelick K, Brown D (2020) AI for Science (ANL-20/17). https://anl.app.box.com/s/f7m53y8beml6hs270h4yzh9l6cnmukph
Stuart DG, Brownstone RM (2011) The beginning of intracellular recording in spinal neurons: facts, reflections, and speculations. Brain Res 1409:62–92. https://doi.org/10.1016/j.brainres.2011.06.007
doi: 10.1016/j.brainres.2011.06.007
pubmed: 21782158
pmcid: 5061568
Taylor C, Kmiec T, Thompson C (2020) Differences in human motoneuron excitability between functionally diverse muscles. CommonHealth 1(1):12–23
doi: 10.15367/ch.v1i1.300
Thomas CK, Ross BH, Stein RB (1986) Motor-unit recruitment in human first dorsal interosseous muscle for static contractions in three different directions. J Neurophysiol 55(5):1017–1029. https://doi.org/10.1152/jn.1986.55.5.1017
doi: 10.1152/jn.1986.55.5.1017
pubmed: 3711964
Turker KS, Powers RK (1999) Effects of large excitatory and inhibitory inputs on motoneuron discharge rate and probability. J Neurophysiol 82(2):829–840. https://doi.org/10.1152/jn.1999.82.2.829
doi: 10.1152/jn.1999.82.2.829
pubmed: 10444680
Turker KS, Powers RK (2005) Black box revisited: a technique for estimating postsynaptic potentials in neurons. Trends Neurosci 28(7):379–386. https://doi.org/10.1016/j.tins.2005.05.007
doi: 10.1016/j.tins.2005.05.007
pubmed: 15927277
Udina E, D’Amico J, Bergquist AJ, Gorassini MA (2010) Amphetamine increases persistent inward currents in human motoneurons estimated from paired motor-unit activity. J Neurophysiol 103(3):1295–1303. https://doi.org/10.1152/jn.00734.2009
doi: 10.1152/jn.00734.2009
pubmed: 20053846
pmcid: 2887628
Vandenberk MS, Kalmar JM (2014) An evaluation of paired motor unit estimates of persistent inward current in human motoneurons. J Neurophysiol 111(9):1877–1884. https://doi.org/10.1152/jn.00469.2013
doi: 10.1152/jn.00469.2013
pubmed: 24523524
VanderMaelen CP, Aghajanian GK (1980) Intracellular studies showing modulation of facial motoneurone excitability by serotonin. Nature 287(5780):346–347. https://doi.org/10.1038/287346a0
doi: 10.1038/287346a0
pubmed: 7421993
Vandermaelen CP, Aghajanian GK (1982) Intracellular studies on the effects of systemic administration of serotonin agonists on rat facial motoneurons. Eur J Pharmacol 78(2):233–236. https://doi.org/10.1016/0014-2999(82)90242-4
doi: 10.1016/0014-2999(82)90242-4
pubmed: 7075673
Walton C, Kalmar JM, Cafarelli E (2002) Effect of caffeine on self-sustained firing in human motor units. J Physiol 545(2):671–679. https://doi.org/10.1113/jphysiol.2002.025064
doi: 10.1113/jphysiol.2002.025064
pubmed: 12456842
pmcid: 2290683
Wei K, Glaser JI, Deng L, Thompson CK, Stevenson IH, Wang Q, Hornby TG, Heckman CJ, Kording KP (2014) Serotonin affects movement gain control in the spinal cord. J Neurosci 34(38):12690–12700. https://doi.org/10.1523/JNEUROSCI.1855-14.2014
doi: 10.1523/JNEUROSCI.1855-14.2014
pubmed: 25232107
pmcid: 4166156
White SR, Fung SJ, Barnes CD (1991) Norepinephrine effects on spinal motoneurons. Prog Brain Res 88:343–350. https://doi.org/10.1016/s0079-6123(08)63821-2
doi: 10.1016/s0079-6123(08)63821-2
pubmed: 1813925
Wilson JM, Thompson CK, Miller LC, Heckman CJ (2015) Intrinsic excitability of human motoneurons in biceps brachii versus triceps brachii. J Neurophysiol 113(10):3692–3699. https://doi.org/10.1152/jn.00960.2014
doi: 10.1152/jn.00960.2014
pubmed: 25787957
pmcid: 4468975
Woodbury JW, Patton HD (1952) Electrical activity of single spinal cord elements. Cold Spring Harb Symp Quant Biol 17:185–188. https://doi.org/10.1101/sqb.1952.017.01.018
doi: 10.1101/sqb.1952.017.01.018
pubmed: 13049165
Yavuz SU, Mrachacz-Kersting N, Sebik O, Berna Unver M, Farina D, Turker KS (2014) Human stretch reflex pathways reexamined. J Neurophysiol 111(3):602–612. https://doi.org/10.1152/jn.00295.2013
doi: 10.1152/jn.00295.2013
pubmed: 24225537
Yavuz US, Negro F, Sebik O, Holobar A, Frommel C, Turker KS, Farina D (2015) Estimating reflex responses in large populations of motor units by decomposition of the high-density surface electromyogram. J Physiol 593(19):4305–4318. https://doi.org/10.1113/JP270635
doi: 10.1113/JP270635
pubmed: 26115007
pmcid: 4594244
Yavuz US, Negro F, Diedrichs R, Farina D (2018) Reciprocal inhibition between motor neurons of the tibialis anterior and triceps surae in humans. J Neurophysiol 119(5):1699–1706. https://doi.org/10.1152/jn.00424.2017
doi: 10.1152/jn.00424.2017
pubmed: 29384455
Zengel JE, Reid SA, Sypert GW, Munson JB (1985) Membrane electrical-properties and prediction of motor-unit type of medial gastrocnemius motoneurons in the cat. J Neurophysiol 53(5):1323–1344
doi: 10.1152/jn.1985.53.5.1323