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classification as "motor neurons." Essentially, motor neurons, also known as motoneurons, are made up of a variety of intricate, finely tuned circuits found throughout the body that innervate effector muscles and glands to enable both voluntary and involuntary motions. Two motor neurons come together to form a two-neuron circuit. While lower motor neurons start in the spinal cord and go to innervate muscles and glands all throughout the body, upper motor neurons originate in the cerebral cortex and travel to the brain stem or spinal cord. It is essential to comprehend the distinctions between upper and lower motor neurons as well as the routes they follow in order to effectively detect these neuronal injuries and localise the lesions.
29:
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1031:. Fly motor neurons vary by over 100X in the total number of input synapses. However, each motor neuron gets similar fractions of its synapses from each premotor source: ~70% from neurons within the VNC, ~10% from descending neurons, ~3% from sensory neurons, and ~6% from VNC neurons that also send a process up to the brain. The remaining 10% of synapses come from neuronal fragments that are unidentified by current image segmentation algorithms and require additional manual segmentation to measure.
375:
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Fast fatiguing (FF) motor units stimulate larger muscle groups, which apply large amounts of force but fatigue very quickly. They are used for tasks that require large brief bursts of energy, such as jumping or running. They gain their energy via glycolytic means and hence do not require oxygen. They
202:
Although the word "motor neuron" suggests that there is a single kind of neuron that controls movement, this is not the case. Indeed, upper and lower motor neurons—which differ greatly in their origins, synapse locations, routes, neurotransmitters, and lesion characteristics—are included in the same
920:
arrive before the end of the twitch. The twitches thus superimpose on one another, leading to a force greater than that of a single twitch. A tetanic contraction is caused by constant, very high frequency stimulation - the action potentials come at such a rapid rate that individual twitches are
640:
innervate intrafusal muscle fibers found within the muscle spindle. They regulate the sensitivity of the spindle to muscle stretching. With activation of gamma neurons, intrafusal muscle fibers contract so that only a small stretch is required to activate spindle sensory neurons and the stretch
587:
Slow (S) motor units stimulate small muscle fibers, which contract very slowly and provide small amounts of energy but are very resistant to fatigue, so they are used to sustain muscular contraction, such as keeping the body upright. They gain their energy via oxidative means and hence require
494:
are those that originate in the spinal cord and directly or indirectly innervate effector targets. The target of these neurons varies, but in the somatic nervous system the target will be some sort of muscle fiber. There are three primary categories of lower motor neurons, which can be further
943:
found within the motor end plate. Once two acetylcholine receptors have been bound, an ion channel is opened and sodium ions are allowed to flow into the cell. The influx of sodium into the cell causes depolarization and triggers a muscle action potential. T tubules of the sarcolemma are then
656:– recent animal study research has shown that constant flow of ions such as calcium and sodium through channels in the soma and dendrites influence the synaptic input. An alternate way to think of this is that the post-synaptic neuron is being primed before receiving an impulse.
595:
Fast fatigue-resistant motor units stimulate moderate-sized muscles groups that do not react as fast as the FF motor units, but can be sustained much longer (as implied by the name) and provide more force than S motor units. These use both oxidative and glycolytic means to gain
650:– this relates to the soma of the motor neuron. This restricts larger neurons to receive a larger excitatory signal in order to stimulate the muscle fibers it innervates. By reducing unnecessary muscle fiber recruitment, the body is able to optimize energy consumption.
1835:
Azevedo, Anthony; Lesser, Ellen; Mark, Brandon; Phelps, Jasper; Elabbady, Leila; Kuroda, Sumiya; Sustar, Anne; Moussa, Anthony; Kandelwal, Avinash; Dallmann, Chris J.; Agrawal, Sweta; Lee, Su-Yee J.; Pratt, Brandon; Cook, Andrew; Skutt-Kakaria, Kyobi (2022-12-15).
666:– A trend has been identified that shows slow motor neurons to have more intense AHPs for a longer duration. One way to remember this is that slow muscle fibers can contract for longer, so it makes sense that their corresponding motor neurons fire at a slower rate.
955:, however, the response of a muscle fiber to a neurotransmitter can only be excitatory, in other words, contractile. Muscle relaxation and inhibition of muscle contraction in vertebrates is obtained only by inhibition of the motor neuron itself. This is how
278:
transcription factors. There are 13 Hox transcription factors and along with the signals, determine whether a motor neuron will be more rostral or caudal in character. In the spinal column, Hox 4-11 sort motor neurons to one of the five motor columns.
445:
to their effectors. In the spinal cord these descending tracts carry impulses from different regions. These tracts also serve as the place of origin for lower motor neurons. There are seven major descending motor tracts to be found in the spinal cord:
614:
detect the degree of stretch and send a signal to the CNS. The CNS activates alpha motor neurons in the spinal cord, which cause extrafusal muscle fibers to contract and thereby resist further stretching. This process is also called the
1336:
Edgar R, Mazor Y, Rinon A, Blumenthal J, Golan Y, Buzhor E, Livnat I, Ben-Ari S, Lieder I, Shitrit A, Gilboa Y, Ben-Yehudah A, Edri O, Shraga N, Bogoch Y, Leshansky L, Aharoni S, West MD, Warshawsky D, Shtrichman R (2013).
1460:
Fitzpatrick, D. (2001) The
Primary Motor Cortex: Upper Motor Neurons That Initiate Complex Voluntary Movements. In D. Purves, G.J. Augustine, D. Fitzpatrick, et al. (Ed.), Neuroscience. Retrieved from
634:, with collaterals to extrafusal fibres. There are two types of beta motor neurons: Slow Contracting- These innervate extrafusal fibers. Fast Contracting- These innervate intrafusal fibers.
641:
reflex. There are two types of gamma motor neurons: Dynamic- These focus on Bag1 fibers and enhance dynamic sensitivity. Static- These focus on Bag2 fibers and enhance stretch sensitivity.
418:
project from the primary cortex directly onto motor neurons in the ventral horn of the spinal cord. Their axons synapse on the spinal motor neurons of multiple muscles as well as on spinal
426:
including the relatively independent control of individual fingers. Corticomotorneurons have so far only been found in the primary motor cortex and not in secondary motor areas.
1642:
Fitzpatrick, D. (2001) Lower Motor Neuron
Circuits and Motor Control: Overview. In D. Purves, G.J. Augustine, D. Fitzpatrick, et al. (Ed.), Neuroscience. Retrieved from
951:, depending on the neurotransmitter released and the type of receptor it binds, the response in the muscle fiber could be either excitatory or inhibitory. For
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stimulated to elicit calcium ion release from the sarcoplasmic reticulum. It is this chemical release that causes the target muscle fiber to contract.
1680:
1523:
580:. A single motor neuron may synapse with 150 muscle fibers on average. The motor neuron and all of the muscle fibers to which it connects is a
1105:
908:. As a result, if an action potential arrives before a twitch has completed, the twitches can superimpose on one another, either through
1784:
Manuel, Marin; Zytnicki, Daniel (2011). "Alpha, Beta, and Gamma
Motoneurons: Functional Diversity in the Motor System's Final Pathway".
255:, a gene that causes cell cycle exiting as well as promoting further transcription factors associated with motor neuron development.
1955:
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1710:
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1015:. For any given motor neuron, determining the relative contribution of different input sources is difficult, but advances in
132:(fiber) projects to the spinal cord or outside of the spinal cord to directly or indirectly control effector organs, mainly
1629:
Tortora, G. J., Derrickson, B. (2011). The Spinal Cord and Spinal Nerves. In B. Roesch, L. Elfers, K. Trost, et al. (Ed.),
223:
of motor neurons begin to appear in the fourth week of development from the ventral region of the ventral-dorsal axis (the
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1463:"The Primary Motor Cortex: Upper Motor Neurons That Initiate Complex Voluntary Movements - Neuroscience - NCBI Bookshelf"
1924:
1901:
1499:
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Mack, Sarah; Kandel, Eric R.; Jessell, Thomas M.; Schwartz, James H.; Siegelbaum, Steven A.; Hudspeth, A. J. (2013).
681:, which are involved in facial expression, mastication, phonation, and swallowing. Associated cranial nerves are the
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2509:
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in the spinal cord and occasionally directly onto lower motor neurons. The axons from the lower motor neurons are
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from synaptic vesicles bound to the plasma membrane of the axon terminals. The acetylcholine molecules bind to
415:
199:. Individual twitches can become indistinguishable, and tension rises smoothly eventually reaching a plateau.
2194:
1012:
916:. In summation, the muscle is stimulated repetitively such that additional action potentials coming from the
869:, located in the CNS, synapses onto a ganglionic neuron, located in the PNS, which synapses onto the muscle.
1595:
Isa, T (April 2007). "Direct and indirect cortico-motoneuronal pathways and control of hand/arm movements".
606:, the continuous force generated by noncontracting muscle to oppose stretching. When a muscle is stretched,
2189:
2177:
1948:
880:. Parasympathetic ganglionic neurons are also cholinergic, whereas most sympathetic ganglionic neurons are
480:
422:. They are unique to primates and it has been suggested that their function is the adaptive control of the
62:
1672:
2229:
2167:
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Tortora, G. J., Derrickson, B. (2011). Muscular Tissue. In B. Roesch, L. Elfers, K. Trost, et al. (Ed.),
661:
450:
28:
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271:
1339:"LifeMap Discovery™: The Embryonic Development, Stem Cells, and Regenerative Medicine Research Portal"
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Schacter D.L., Gilbert D.T., and Wegner D.M. (2011) Psychology second edition. New York, NY: Worth
2213:
1941:
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Philippidou, Polyxeni; Walsh, Carolyn; Aubin, Josée; Jeannotte, Lucie; Dasen, Jeremy S. (2012).
1137:
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1972:
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Brachial and lumbar region (both regions are further divided into medial and lateral domains)
267:
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In addition to voluntary skeletal muscle contraction, alpha motor neurons also contribute to
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572:, which are the main force-generating component of a muscle. Their cell bodies are in the
8:
2704:
2549:
2544:
2079:
2012:
1023:
motor neurons. In the fly, motor neurons controlling the legs and wings are found in the
992:
913:
838:(PNS), which themselves directly innervate visceral muscles (and also some gland cells).
530:
411:
252:
196:
37:
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Purves D, Augustine GJ, Fitzpatrick D, et al., editors: Neuroscience. 2nd edition, 2001
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1004:
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Motor neurons receive synaptic input from premotor neurons. Premotor neurons can be 1)
905:
637:
565:
491:
387:
184:
169:
161:
145:
141:
932:. Upon adequate stimulation, the motor neuron releases a flood of acetylcholine (Ach)
498:
According to their targets, motor neurons are classified into three broad categories:
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2007:
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1997:
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1417:
1406:"Sustained Hox5 Gene Activity is Required for Respiratory Motor Neuron Development"
1376:
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1271:(11th ed.). Philadelphia: Lippincott William & Wilkins. pp. 299–301.
956:
933:
858:
682:
526:
442:
395:
1838:"Tools for comprehensive reconstruction and analysis of Drosophila motor circuits"
219:
cells are specified to either the rostral-caudal axis or ventral-dorsal axis. The
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2300:
2124:
1913:
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842:
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690:
41:
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work by acting on the motor neurons that innervate muscles (by decreasing their
2749:
2719:
2676:
2496:
2454:
2432:
2352:
2235:
2059:
1964:
1750:
1645:"Lower Motor Neuron Circuits and Motor Control - Neuroscience - NCBI Bookshelf"
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indistinguishable, and tension rises smoothly eventually reaching a plateau.
885:
877:
720:
259:
212:
251:(Shh). The OLIG2 gene being the most important due to its role in promoting
2644:
2479:
2360:
2290:
2069:
1992:
1813:
1616:
1573:
1447:
1390:
1322:
1016:
1008:
937:
780:
438:
391:
117:
374:
227:). This homeodomain is known as the motor neural progenitor domain (pMN).
2659:
2474:
2378:
2336:
2268:
2263:
2084:
2022:
2017:
1987:
1544:
Lemon, Roger N. (April 4, 2008). "Descending
Pathways in Motor Control".
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1295:
Davis-Dusenbery, BN; Williams, LA; Klim, JR; Eggan, K (February 2014).
924:
The interface between a motor neuron and muscle fiber is a specialized
581:
33:
215:, and motor function continues to develop well into childhood. In the
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2278:
2129:
2102:
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403:
121:
113:
45:
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2034:
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1165:(3rd ed.). Oxford: Oxford University Press. pp. 151–153.
811:
275:
1242:(14th ed.). New Jersey: John Wiley & Sons, Inc. pp.
1136:(14th ed.). New Jersey: John Wiley & Sons, Inc. pp.
1106:"Afferent vs. Efferent: AP® Psych Crash Course Review | Albert.io"
2671:
2632:
2524:
1933:
925:
897:
857:, which synapses onto the muscle. Comparatively, the command of
819:
815:
807:
176:
1294:
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neuromuscular junctions, rather than on the muscles themselves.
2331:
2286:
2051:
984:
410:. The axons of these cells descend from the cortex to form the
244:
240:
133:
109:
1403:
1060:
522:
423:
236:
137:
2370:
1732:(pp. 305-307, 311). New Jersey: John Wiley & Sons, Inc.
232:
220:
129:
1489:
1335:
1834:
40:
showing motor neurons with their characteristic coarse
1633:(pp. 443-468). New Jersey: John Wiley & Sons, Inc.
191:
and twitches can become superimposed as a result of
1919:(2nd ed.). Menlo Park, CA: Benjamin/Cummings.
258:Further specification of motor neurons occurs when
160:to the effectors. Types of lower motor neurons are
1912:
1193:
1191:
1161:Pocock, Gillian; Richards, Christopher D. (2006).
970:
529:(such as the muscles of the limbs, abdominal, and
1235:
1129:
793:
672:
576:of the spinal cord and they are sometimes called
2766:
1896:(4th ed.). Pacific Grove, CA: Brooks-Cole.
1751:"The Motor Unit - Neuroscience - NCBI Bookshelf"
1329:
1188:
983:that convey information from the periphery and
1783:
1160:
584:. Motor units are split up into 3 categories:
378:Location of lower motor neurons in spinal cord
148:. Axons from upper motor neurons synapse onto
1949:
1910:
1224:https://www.ncbi.nlm.nih.gov/books/NBK554616/
1163:Human physiology : the basis of medicine
979:that have cell bodies in the spinal cord, 2)
884:, that is, they release the neurotransmitter
876:, that is, they release the neurotransmitter
553:to indicate the flow of information from the
1494:. Kandel, Eric R. (5th ed.). New York.
1700:
1236:Tortora, Gerard; Derrickson, Bryan (2011).
1130:Tortora, Gerard; Derrickson, Bryan (2014).
537:. The three types of these neurons are the
1956:
1942:
1522:: CS1 maint: location missing publisher (
1202:. Toronto: Nelson Education. p. 946.
891:
644:Regulatory factors of lower motor neurons
27:
1437:
1380:
1362:
1312:
1200:Biology - Exploring the Diversity of Life
896:A single motor neuron may innervate many
798:These motor neurons indirectly innervate
361:
175:A single motor neuron may innervate many
140:. There are two types of motor neuron –
1891:
1703:Human Physiology: An Integrated Approach
849:involving only one motor neuron, either
773:
588:oxygen. They are also called red fibers.
512:
373:
365:
211:Motor neurons begin to develop early in
1894:Human Physiology: From Cells to Systems
1197:
517:Somatic motor neurons originate in the
2767:
1558:10.1146/annurev.neuro.31.060407.125547
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1537:
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1133:Principles of Anatomy & Physiology
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1937:
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1665:
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1260:
841:In consequence, the motor command of
1730:Principles of Anatomy and Physiology
1631:Principles of Anatomy and Physiology
1290:
1288:
900:and a muscle fibre can undergo many
179:and a muscle fibre can undergo many
16:Nerve cell sending impulse to muscle
1911:Marieb, E. N.; Mallatt, J. (1997).
1786:Journal of Integrative Neuroscience
1594:
1530:
1480:
13:
1963:
1768:
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1719:
1662:
1623:
1297:"How to make spinal motor neurons"
1154:
274:, are integrated into the various
14:
2791:
1701:Silverthorn, Dee Unglaub (2010).
1285:
991:that convey information from the
985:synapse directly onto motoneurons
872:All vertebrate motor neurons are
1239:Principles of Anatomy Physiology
1216:
2120:Oligodendrocyte progenitor cell
1828:
1757:from the original on 2018-06-05
1694:
1683:from the original on 2017-11-05
1651:from the original on 2018-06-05
1636:
1588:
1469:from the original on 2018-06-05
1454:
1397:
971:Synaptic input to motor neurons
904:in the time taken for a single
701:
654:Persistent Inward Current (PIC)
429:
187:. Innervation takes place at a
183:in the time taken for a single
1229:
1179:
1123:
1098:
794:General visceral motor neurons
786:Motor neuron neurotransmitters
673:Special visceral motor neurons
508:General visceral motor neurons
505:Special visceral motor neurons
283:Motor columns of spinal cord
206:
1:
1546:Annual Review of Neuroscience
1091:
867:general visceral motor neuron
398:. The cells that make up the
1492:Principles of neural science
1364:10.1371/journal.pone.0066629
1269:Langman's medical embryology
481:Anterior corticospinal tract
461:Lateral reticulospinal tract
327:Preganglionic motor column
156:that carry signals from the
7:
2230:Postganglionic nerve fibers
1034:
865:involving two neurons: the
699:
495:divided in sub-categories.
471:Medial reticulospinal tract
451:Lateral corticospinal tract
10:
2796:
2225:Preganglionic nerve fibers
1885:
1609:10.1152/physiol.00045.2006
1019:have made it possible for
88:Excitatory projection (to
2735:Olfactory receptor neuron
2690:
2631:
2624:
2560:
2490:
2447:
2407:
2399:Neurofibril/neurofilament
2369:
2351:
2344:
2330:
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2249:
2155:
2146:
2093:
2050:
2043:
1980:
1971:
1846:10.1101/2022.12.15.520299
1798:10.1142/S0219635211002786
845:and branchial muscles is
836:peripheral nervous system
533:), which are involved in
247:, which are regulated by
84:
76:
58:
53:
26:
21:
1705:. Pearson. p. 398.
824:autonomic nervous system
818:onto neurons located in
677:These are also known as
628:intrafusal muscle fibers
592:are called white fibers.
570:extrafusal muscle fibers
437:are bundles of axons as
294:Location in spinal cord
264:fibroblast growth factor
1198:Russell, Peter (2013).
892:Neuromuscular junctions
679:branchial motor neurons
316:Hypaxial motor column
44:("tigroid" cytoplasm).
2682:Neuromuscular junction
2545:III or Aδ or fast pain
1869:Cite journal requires
999:. The synapses can be
930:neuromuscular junction
918:somatic nervous system
555:central nervous system
547:gamma efferent neurons
539:alpha efferent neurons
519:central nervous system
379:
371:
362:Anatomy and physiology
349:Phrenic motor column
333:Sympathetic ganglion
308:Present entire length
189:neuromuscular junction
1892:Sherwood, L. (2001).
1840:: 2022.12.15.520299.
1046:Central chromatolysis
810:( the muscles of the
543:beta efferent neurons
513:Somatic motor neurons
502:Somatic motor neurons
466:Vestibulospinal tract
377:
369:
344:Muscles of the limbs
338:Lateral motor column
229:Transcription factors
213:embryonic development
154:efferent nerve fibers
2700:Meissner's corpuscle
2665:Postsynaptic density
2562:Efferent nerve fiber
2550:IV or C or slow pain
2492:Afferent nerve fiber
2318:Satellite glial cell
1081:Efferent nerve fiber
1076:Afferent nerve fiber
1056:Motor neuron disease
1027:, homologous to the
961:electrophysiological
400:primary motor cortex
305:Median motor column
71:cranial nerve nuclei
2705:Merkel nerve ending
1410:Nature Neuroscience
1355:2013PLoSO...866629E
1267:Sadler, T. (2010).
977:spinal interneurons
914:tetanic contraction
638:Gamma motor neurons
566:Alpha motor neurons
531:intercostal muscles
492:Lower motor neurons
487:Lower motor neurons
416:Corticomotorneurons
412:corticospinal tract
388:Upper motor neurons
383:Upper motor neurons
284:
197:tetanic contraction
170:gamma motor neurons
162:alpha motor neurons
146:lower motor neurons
142:upper motor neurons
38:hypoglossal nucleus
2740:Photoreceptor cell
2710:Pacinian corpuscle
2641:Electrical synapse
2595:Lower motor neuron
2590:Upper motor neuron
2311:Internodal segment
2251:Connective tissues
2221:Autonomic ganglion
1314:10.1242/dev.097410
1025:ventral nerve cord
989:descending neurons
834:), located in the
775:*Except fibers to
662:Hyper-polarization
624:Beta motor neurons
578:ventral horn cells
549:. They are called
406:, which are giant
380:
372:
370:Spinal cord tracts
322:Body wall muscles
282:
166:beta motor neurons
116:is located in the
2762:
2761:
2758:
2757:
2725:Free nerve ending
2692:Sensory receptors
2620:
2619:
2535:Ib or Golgi or Aα
2443:
2442:
2326:
2325:
2203:Ramus communicans
2142:
2141:
2138:
2137:
2008:Commissural fiber
2003:Association fiber
1998:Projection fibers
1712:978-0-321-55980-7
1416:(12): 1636–1644.
1278:978-0-7817-9069-7
1253:978-1-118-34500-9
1209:978-0-17-665133-6
1172:978-0-19-856878-0
1147:978-1-118-34500-9
1051:Motor dysfunction
934:neurotransmitters
902:action potentials
791:
790:
709:Neurotransmitter
476:Tectospinal tract
456:Rubrospinal tract
443:action potentials
390:originate in the
359:
358:
181:action potentials
94:
93:
89:
80:Projection neuron
46:H&E-LFB stain
2787:
2775:Efferent neurons
2655:Synaptic vesicle
2650:Chemical synapse
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1826:
1825:
1781:
1766:
1765:
1763:
1762:
1746:
1733:
1726:
1717:
1716:
1698:
1692:
1691:
1689:
1688:
1669:
1660:
1659:
1657:
1656:
1640:
1634:
1627:
1621:
1620:
1592:
1586:
1585:
1541:
1528:
1527:
1521:
1513:
1487:
1478:
1477:
1475:
1474:
1458:
1452:
1451:
1441:
1401:
1395:
1394:
1384:
1366:
1333:
1327:
1326:
1316:
1292:
1283:
1282:
1264:
1258:
1257:
1233:
1227:
1220:
1214:
1213:
1195:
1186:
1183:
1177:
1176:
1158:
1152:
1151:
1127:
1121:
1120:
1118:
1117:
1110:Albert Resources
1102:
963:activity) or on
957:muscle relaxants
859:visceral muscles
783:
738:Parasympathetic
727:Parasympathetic
700:
527:skeletal muscles
521:, project their
396:precentral gyrus
352:Cervical region
330:Thoracic region
319:Thoracic region
285:
281:
31:
19:
18:
2795:
2794:
2790:
2789:
2788:
2786:
2785:
2784:
2765:
2764:
2763:
2754:
2686:
2616:
2565:
2556:
2540:II or Aβ and Aγ
2495:
2486:
2439:
2429:Apical dendrite
2424:Dendritic spine
2403:
2365:
2335:
2322:
2306:Node of Ranvier
2301:Myelin incisure
2273:
2245:
2134:
2125:Oligodendrocyte
2108:Ependymal cells
2089:
2039:
1967:
1962:
1927:
1904:
1888:
1883:
1882:
1870:
1868:
1859:
1858:
1833:
1829:
1782:
1769:
1760:
1758:
1749:
1747:
1736:
1727:
1720:
1713:
1699:
1695:
1686:
1684:
1671:
1670:
1663:
1654:
1652:
1643:
1641:
1637:
1628:
1624:
1593:
1589:
1542:
1531:
1515:
1514:
1502:
1488:
1481:
1472:
1470:
1461:
1459:
1455:
1422:10.1038/nn.3242
1402:
1398:
1334:
1330:
1293:
1286:
1279:
1265:
1261:
1254:
1234:
1230:
1221:
1217:
1210:
1196:
1189:
1184:
1180:
1173:
1159:
1155:
1148:
1128:
1124:
1115:
1113:
1104:
1103:
1099:
1094:
1037:
1013:neuromodulatory
981:sensory neurons
973:
894:
832:parasympathetic
796:
784:
774:
675:
632:muscle spindles
608:sensory neurons
515:
489:
432:
408:pyramidal cells
394:located in the
385:
364:
253:Ngn2 expression
209:
106:efferent neuron
90:
49:
42:Nissl substance
17:
12:
11:
5:
2793:
2783:
2782:
2777:
2760:
2759:
2756:
2755:
2753:
2752:
2750:Taste receptor
2747:
2742:
2737:
2732:
2727:
2722:
2720:Muscle spindle
2717:
2715:Ruffini ending
2712:
2707:
2702:
2696:
2694:
2688:
2687:
2685:
2684:
2679:
2677:Ribbon synapse
2674:
2669:
2668:
2667:
2662:
2657:
2647:
2637:
2635:
2626:
2622:
2621:
2618:
2617:
2615:
2614:
2613:
2612:
2607:
2602:
2592:
2587:
2582:
2577:
2571:
2569:
2558:
2557:
2555:
2554:
2553:
2552:
2547:
2542:
2537:
2532:
2522:
2517:
2512:
2507:
2501:
2499:
2497:Sensory neuron
2488:
2487:
2485:
2484:
2483:
2482:
2472:
2467:
2465:Pseudounipolar
2462:
2457:
2451:
2449:
2445:
2444:
2441:
2440:
2438:
2437:
2436:
2435:
2433:Basal dendrite
2426:
2421:
2413:
2411:
2405:
2404:
2402:
2401:
2396:
2391:
2386:
2384:Axon terminals
2381:
2375:
2373:
2367:
2366:
2364:
2363:
2357:
2355:
2346:
2339:
2328:
2327:
2324:
2323:
2321:
2320:
2315:
2314:
2313:
2308:
2303:
2298:
2283:
2281:
2275:
2274:
2272:
2271:
2266:
2261:
2255:
2253:
2247:
2246:
2244:
2243:
2238:
2236:Nerve fascicle
2233:
2227:
2218:
2217:
2216:
2211:
2199:
2198:
2197:
2192:
2182:
2181:
2180:
2175:
2170:
2159:
2157:
2150:
2144:
2143:
2140:
2139:
2136:
2135:
2133:
2132:
2127:
2122:
2117:
2116:
2115:
2105:
2099:
2097:
2091:
2090:
2088:
2087:
2082:
2077:
2072:
2067:
2062:
2056:
2054:
2045:
2041:
2040:
2038:
2037:
2032:
2027:
2026:
2025:
2020:
2015:
2010:
2005:
2000:
1990:
1984:
1982:
1975:
1969:
1968:
1965:Nervous tissue
1961:
1960:
1953:
1946:
1938:
1932:
1931:
1925:
1908:
1902:
1887:
1884:
1881:
1880:
1871:|journal=
1827:
1792:(3): 243–276.
1767:
1734:
1718:
1711:
1693:
1673:"CHAPTER NINE"
1661:
1635:
1622:
1603:(2): 145–152.
1587:
1552:(1): 195–218.
1529:
1500:
1479:
1453:
1396:
1328:
1307:(3): 491–501.
1284:
1277:
1259:
1252:
1228:
1215:
1208:
1187:
1178:
1171:
1153:
1146:
1122:
1096:
1095:
1093:
1090:
1089:
1088:
1086:Sensory neuron
1083:
1078:
1073:
1068:
1063:
1058:
1053:
1048:
1043:
1036:
1033:
972:
969:
893:
890:
888:. (see Table)
804:smooth muscles
800:cardiac muscle
795:
792:
789:
788:
771:
770:
767:Norepinephrine
764:
761:
757:
756:
755:Acetylcholine
753:
752:Preganglionic
750:
746:
745:
744:Acetylcholine
742:
739:
735:
734:
733:Acetylcholine
731:
730:Preganglionic
728:
724:
723:
718:
715:
711:
710:
707:
704:
674:
671:
670:
669:
668:
667:
657:
651:
648:Size Principle
642:
635:
617:stretch reflex
612:muscle spindle
600:
599:
598:
597:
593:
589:
514:
511:
510:
509:
506:
503:
488:
485:
484:
483:
478:
473:
468:
463:
458:
453:
431:
428:
384:
381:
363:
360:
357:
356:
353:
350:
346:
345:
342:
339:
335:
334:
331:
328:
324:
323:
320:
317:
313:
312:
311:Axial muscles
309:
306:
302:
301:
296:
291:
249:sonic hedgehog
208:
205:
92:
91:
86:
82:
81:
78:
74:
73:
60:
56:
55:
51:
50:
32:
24:
23:
15:
9:
6:
4:
3:
2:
2792:
2781:
2778:
2776:
2773:
2772:
2770:
2751:
2748:
2746:
2743:
2741:
2738:
2736:
2733:
2731:
2728:
2726:
2723:
2721:
2718:
2716:
2713:
2711:
2708:
2706:
2703:
2701:
2698:
2697:
2695:
2693:
2689:
2683:
2680:
2678:
2675:
2673:
2670:
2666:
2663:
2661:
2658:
2656:
2653:
2652:
2651:
2648:
2646:
2642:
2639:
2638:
2636:
2634:
2630:
2627:
2623:
2611:
2610:γ motorneuron
2608:
2606:
2605:β motorneuron
2603:
2601:
2600:α motorneuron
2598:
2597:
2596:
2593:
2591:
2588:
2586:
2583:
2581:
2578:
2576:
2573:
2572:
2570:
2568:
2563:
2559:
2551:
2548:
2546:
2543:
2541:
2538:
2536:
2533:
2531:
2528:
2527:
2526:
2523:
2521:
2518:
2516:
2513:
2511:
2508:
2506:
2503:
2502:
2500:
2498:
2493:
2489:
2481:
2478:
2477:
2476:
2473:
2471:
2468:
2466:
2463:
2461:
2458:
2456:
2453:
2452:
2450:
2446:
2434:
2430:
2427:
2425:
2422:
2420:
2417:
2416:
2415:
2414:
2412:
2410:
2406:
2400:
2397:
2395:
2392:
2390:
2387:
2385:
2382:
2380:
2377:
2376:
2374:
2372:
2368:
2362:
2359:
2358:
2356:
2354:
2350:
2347:
2343:
2340:
2338:
2333:
2329:
2319:
2316:
2312:
2309:
2307:
2304:
2302:
2299:
2297:
2294:
2293:
2292:
2288:
2285:
2284:
2282:
2280:
2276:
2270:
2267:
2265:
2262:
2260:
2257:
2256:
2254:
2252:
2248:
2242:
2239:
2237:
2234:
2231:
2228:
2226:
2222:
2219:
2215:
2212:
2210:
2207:
2206:
2205:
2204:
2200:
2196:
2193:
2191:
2188:
2187:
2186:
2183:
2179:
2176:
2174:
2171:
2169:
2166:
2165:
2164:
2161:
2160:
2158:
2154:
2151:
2149:
2145:
2131:
2128:
2126:
2123:
2121:
2118:
2114:
2111:
2110:
2109:
2106:
2104:
2101:
2100:
2098:
2096:
2092:
2086:
2083:
2081:
2078:
2076:
2073:
2071:
2068:
2066:
2063:
2061:
2058:
2057:
2055:
2053:
2049:
2046:
2042:
2036:
2033:
2031:
2028:
2024:
2021:
2019:
2016:
2014:
2011:
2009:
2006:
2004:
2001:
1999:
1996:
1995:
1994:
1991:
1989:
1986:
1985:
1983:
1979:
1976:
1974:
1970:
1966:
1959:
1954:
1952:
1947:
1945:
1940:
1939:
1936:
1928:
1926:0-8053-4068-8
1922:
1917:
1916:
1915:Human Anatomy
1909:
1905:
1903:0-534-37254-6
1899:
1895:
1890:
1889:
1876:
1863:
1855:
1851:
1847:
1843:
1839:
1831:
1823:
1819:
1815:
1811:
1807:
1803:
1799:
1795:
1791:
1787:
1780:
1778:
1776:
1774:
1772:
1756:
1752:
1745:
1743:
1741:
1739:
1731:
1725:
1723:
1714:
1708:
1704:
1697:
1682:
1678:
1674:
1668:
1666:
1650:
1646:
1639:
1632:
1626:
1618:
1614:
1610:
1606:
1602:
1598:
1591:
1583:
1579:
1575:
1571:
1567:
1563:
1559:
1555:
1551:
1547:
1540:
1538:
1536:
1534:
1525:
1519:
1511:
1507:
1503:
1501:9780071390118
1497:
1493:
1486:
1484:
1468:
1464:
1457:
1449:
1445:
1440:
1435:
1431:
1427:
1423:
1419:
1415:
1411:
1407:
1400:
1392:
1388:
1383:
1378:
1374:
1370:
1365:
1360:
1356:
1352:
1349:(7): e66629.
1348:
1344:
1340:
1332:
1324:
1320:
1315:
1310:
1306:
1302:
1298:
1291:
1289:
1280:
1274:
1270:
1263:
1255:
1249:
1245:
1241:
1240:
1232:
1225:
1219:
1211:
1205:
1201:
1194:
1192:
1182:
1174:
1168:
1164:
1157:
1149:
1143:
1139:
1138:406, 502, 541
1135:
1134:
1126:
1111:
1107:
1101:
1097:
1087:
1084:
1082:
1079:
1077:
1074:
1072:
1069:
1067:
1066:Sensory nerve
1064:
1062:
1059:
1057:
1054:
1052:
1049:
1047:
1044:
1042:
1039:
1038:
1032:
1030:
1026:
1022:
1018:
1014:
1010:
1006:
1002:
998:
994:
990:
986:
982:
978:
968:
966:
962:
958:
954:
950:
949:invertebrates
945:
942:
939:
935:
931:
927:
922:
919:
915:
911:
907:
906:muscle twitch
903:
899:
898:muscle fibres
889:
887:
886:noradrenaline
883:
882:noradrenergic
879:
878:acetylcholine
875:
870:
868:
864:
860:
856:
852:
848:
844:
839:
837:
833:
829:
825:
821:
817:
813:
809:
805:
801:
787:
782:
781:blood vessels
778:
772:
768:
765:
762:
759:
758:
754:
751:
748:
747:
743:
740:
737:
736:
732:
729:
726:
725:
722:
721:Acetylcholine
719:
716:
713:
712:
708:
705:
703:Branch of NS
702:
698:
696:
692:
688:
684:
680:
665:
663:
658:
655:
652:
649:
646:
645:
643:
639:
636:
633:
629:
625:
622:
621:
620:
618:
613:
609:
605:
594:
590:
586:
585:
583:
579:
575:
571:
567:
564:
563:
562:
560:
557:(CNS) to the
556:
552:
548:
544:
540:
536:
532:
528:
524:
520:
507:
504:
501:
500:
499:
496:
493:
482:
479:
477:
474:
472:
469:
467:
464:
462:
459:
457:
454:
452:
449:
448:
447:
444:
441:, that carry
440:
436:
427:
425:
421:
417:
413:
409:
405:
401:
397:
393:
389:
376:
368:
354:
351:
348:
347:
343:
340:
337:
336:
332:
329:
326:
325:
321:
318:
315:
314:
310:
307:
304:
303:
300:
297:
295:
292:
290:
287:
286:
280:
277:
273:
269:
265:
261:
260:retinoic acid
256:
254:
250:
246:
242:
238:
234:
231:here include
230:
226:
222:
218:
214:
204:
200:
198:
194:
190:
186:
185:muscle twitch
182:
178:
177:muscle fibres
173:
171:
167:
163:
159:
155:
151:
147:
143:
139:
135:
131:
127:
123:
119:
115:
111:
107:
103:
99:
87:
83:
79:
75:
72:
68:
64:
61:
57:
52:
47:
43:
39:
35:
30:
25:
22:Motor neurons
20:
2780:Motor system
2645:Gap junction
2567:Motor neuron
2566:
2361:Axon hillock
2337:nerve fibers
2291:Schwann cell
2201:
2184:
2162:
2080:Medium spiny
1993:White matter
1981:Tissue Types
1914:
1893:
1862:cite journal
1830:
1789:
1785:
1759:. Retrieved
1729:
1702:
1696:
1685:. Retrieved
1676:
1653:. Retrieved
1638:
1630:
1625:
1600:
1596:
1590:
1549:
1545:
1491:
1471:. Retrieved
1456:
1413:
1409:
1399:
1346:
1342:
1331:
1304:
1300:
1268:
1262:
1238:
1231:
1218:
1199:
1181:
1162:
1156:
1132:
1125:
1114:. Retrieved
1112:. 2019-12-02
1109:
1100:
1017:connectomics
974:
946:
938:postsynaptic
923:
895:
871:
866:
862:
854:
850:
847:monosynaptic
846:
840:
797:
785:
779:and certain
777:sweat glands
760:Sympathetic
749:Sympathetic
678:
676:
659:
653:
647:
601:
577:
574:ventral horn
546:
542:
538:
516:
497:
490:
439:white matter
435:Nerve tracts
433:
430:Nerve tracts
420:interneurons
392:motor cortex
386:
298:
293:
289:Motor column
288:
257:
210:
201:
174:
150:interneurons
128:, and whose
118:motor cortex
105:
101:
98:motor neuron
97:
95:
63:Ventral horn
2660:Active zone
2625:Termination
2475:Interneuron
2379:Telodendron
2287:Myelination
2269:Endoneurium
2264:Perineurium
2085:Interneuron
2075:Von Economo
2023:Decussation
2018:Nerve tract
1988:Grey matter
1677:www.unc.edu
1301:Development
1071:Motor nerve
1029:spinal cord
965:cholinergic
953:vertebrates
928:called the
874:cholinergic
828:sympathetic
763:Ganglionic
741:Ganglionic
695:hypoglossal
610:within the
604:muscle tone
225:basal plate
217:neural tube
207:Development
158:spinal cord
126:spinal cord
67:spinal cord
2769:Categories
2730:Nociceptor
2470:Multipolar
2419:Nissl body
2296:Neurilemma
2259:Epineurium
2044:Cell Types
1761:2017-09-05
1687:2017-12-08
1655:2017-11-30
1597:Physiology
1473:2017-11-30
1116:2021-04-25
1092:References
1009:electrical
1005:inhibitory
1001:excitatory
863:disynaptic
683:oculomotor
626:innervate
582:motor unit
568:innervate
535:locomotion
404:Betz cells
355:Diaphragm
102:motoneuron
34:Micrograph
2745:Hair cell
2279:Neuroglia
2241:Funiculus
2130:Microglia
2103:Astrocyte
2060:Pyramidal
2013:Lemniscus
1854:254736092
1806:0219-6352
1566:0147-006X
1518:cite book
1510:795553723
1430:1097-6256
1373:1932-6203
1244:1090–1099
1041:Betz cell
1021:fruit fly
997:brainstem
941:receptors
910:summation
855:branchial
706:Position
691:trochlear
559:periphery
193:summation
122:brainstem
114:cell body
2530:Ia or Aα
2460:Unipolar
2409:Dendrite
2394:Axolemma
2389:Axoplasm
2173:Ganglion
2113:Tanycyte
2065:Purkinje
2052:Neuronal
2035:Meninges
2030:Neuropil
1822:21582283
1814:21960303
1755:Archived
1681:Archived
1649:Archived
1617:17420305
1582:16139768
1574:18558853
1467:Archived
1448:23103965
1391:23874394
1343:PLOS ONE
1323:24449832
1035:See also
843:skeletal
814:): they
812:arteries
714:Somatic
697:nerves.
687:abducens
551:efferent
85:Function
59:Location
2672:Autapse
2633:Synapse
2480:Renshaw
2455:Bipolar
2332:Neurons
2185:Ventral
2156:General
2070:Granule
1886:Sources
1439:3676175
1382:3714290
1351:Bibcode
926:synapse
851:somatic
822:of the
820:ganglia
816:synapse
808:viscera
806:of the
596:energy.
245:Nkx-6.2
241:Nkx-6.1
134:muscles
124:or the
108:) is a
69:, some
65:of the
54:Details
36:of the
2525:fibers
2163:Dorsal
1923:
1900:
1852:
1820:
1812:
1804:
1709:
1615:
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1169:
1144:
693:, and
660:After
545:, and
299:Target
270:, and
243:, and
168:, and
138:glands
112:whose
110:neuron
2448:Types
2345:Parts
2214:White
2195:Ramus
2178:Ramus
2095:Glial
1850:S2CID
1818:S2CID
1578:S2CID
1061:Nerve
1011:, or
993:brain
987:, 3)
912:or a
664:(AHP)
523:axons
424:hands
237:OLIG2
221:axons
195:or a
77:Shape
2371:Axon
2353:Soma
2209:Gray
2190:Root
2168:Root
1921:ISBN
1898:ISBN
1875:help
1810:PMID
1802:ISSN
1707:ISBN
1613:PMID
1570:PMID
1562:ISSN
1524:link
1506:OCLC
1496:ISBN
1444:PMID
1426:ISSN
1387:PMID
1369:ISSN
1319:PMID
1273:ISBN
1248:ISBN
1204:ISBN
1167:ISBN
1142:ISBN
995:and
830:and
802:and
717:n/a
402:are
272:TGFb
268:Wnts
233:Pax6
144:and
136:and
130:axon
100:(or
2585:SVE
2580:GVE
2575:GSE
2520:SVA
2515:SSA
2510:GVA
2505:GSA
2148:PNS
1973:CNS
1842:doi
1794:doi
1605:doi
1554:doi
1434:PMC
1418:doi
1377:PMC
1359:doi
1309:doi
1305:141
947:In
861:is
853:or
630:of
525:to
276:Hox
104:or
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1864:}}
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96:A
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