ガンマ運動ニューロン
- 関
- fusimotor neuron
WordNet
- machine that converts other forms of energy into mechanical energy and so imparts motion
- a nonspecific agent that imparts motion; "happiness is the aim of all men and the motor of all action"
- a unit of magnetic field strength equal to one-hundred-thousandth of an oersted
- the 3rd letter of the Greek alphabet
- the act of driving an automobile
- a herd of whales
PrepTutorEJDIC
- (電気の)『モーター』,電動機 / エンジン,(特に)内燃機関 / 《英》自動車(motorcar) / 《名詞の前にのみ用いて》 / モーターの;エンジンの;自動車の / モーター(エンジン)による,自動車による / (神経・筋肉について)運動の / 自動車で行く / …‘を'自動車で運ぶ
- ガンマ(ギリシア語アルファベットの第3字Γ,γ;英語のG,gに相当)
- 自動車運転〈技術〉,ドライブ
- (特に女性の)魅力的な脚,すんなりした脚
- 神経単位,神経細胞,ニューロン,ノイロン
Wikipedia preview
出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2012/09/04 13:29:12」(JST)
[Wiki en表示]
Neuron: Gamma motorneuron |
A muscle spindle, with γ motor and Ia sensory fibers |
NeuroLex ID |
sao1438006234 |
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Gamma motoneurons (γ-motoneurons), also called gamma motor neurons, are the efferent component of the fusimotor system, the system by which the central nervous system controls and modifies muscle spindle sensitivity. The fusimotor system refers to the combination of muscle spindles and γ-motoneurons. The function of the muscle spindle is to provide proprioceptive feedback for the movement, position and extension of muscles.
γ-motoneurons are located in the brainstem and spinal cord and are smaller than their α-motoneuron counterparts, which are responsible for controlling skeletal muscle.
Contents
- 1 Conduction velocity
- 2 Function
- 3 Populations of neurons
- 4 Effects of nuclear chain fibers
- 5 References
- 6 See also
- 7 External links
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Conduction velocity
The axon from a γ-motoneuron is myelinated and has a slower conduction velocity than α-motoneuron axons. The typical conduction velocity for a γ-motoneuron axon is in the region of 4 to 24 m/s.[1][2]
Function
Gamma-motoneurons regulate the gain of the stretch reflex by adjusting the level of tension in the intrafusal muscle fibers of the muscle spindle. This mechanism sets the baseline level of activity in α-motoneurons and helps to regulate muscle length and tone. For example, stimulation of a γ-motoneuron from higher centers contracts the ends of the intrafusal fibres and consequently stretches the middle part of the muscle spindle. This part of the spindle is innervated by type Ia sensory fiber that go on to synapse with alpha-motoneurons, completing the gamma-loop.
Populations of neurons
There are two distinct populations of γ-motoneuron: dynamic γ-motoneurons and static γ-motoneurons.
- Dynamic γ-motoneurons have axons that innervate only dynamic nuclear bag fibres (bag1) .
- Static γ-motoneurons innervate both nuclear chain fibres and static nuclear bag (bag2) fibres.
Effects of nuclear chain fibers
The effect of nuclear chain fibres on primary endings is to drive the discharge up to a frequency of around 60 Hz in a linear fashion, above which the discharge can become irregular. The activities of bag2 fibres show an initial sharp peak in discharge, which gets less as the receptor adapts. Bag2 fibres also reduce the dynamic sensitivity of the Ia afferent and sometimes also reduce the length sensitivity. Activation of bag1 fibres has the effect of increasing both the length sensitivity and the dynamic sensitivity of the primary ending.[3]
It is believed that the secondary sensory endings serve to measure length and muscle contractions of nuclear chain fibres at the pole via the static γ-motoneurons both excite the ending and increase its length sensitivity. Bag1 and bag2 fibres receive very little innervation from secondary endings, and activation of these fibres has a minimal effect on the discharge of the secondary ending.[3]
References
- ^ Andrew BL, Part NJ (1972) Properties of fast and slow motor units in hind limb and tail muscles of the rat. Q J Exp Physiol Cogn Med Sci 57:213-225.
- ^ Russell NJ (1980) Axonal conduction velocity changes following muscle tenotomy or deafferentation during development in the rat. J Physiol 298:347-360.
- ^ a b Boyd I (1980) The action of the three types of intrafusal fibre in isolated cat muscle spindles on the dynamic and length sensitivities of primary and secondary sensory endings. In: Muscle Receptors and Movement (Taylor A, Prochazka A, eds), pp 17 - 32. London: MacMillan.
See also
- Alpha motor neuron
- Beta motor neuron
- Muscle spindle
- Intrafusal muscle fibre
- Extrafusal muscle fiber
External links
- http://www.lib.mcg.edu/edu/eshuphysio/program/section8/8ch3/s8ch3_20.htm
- Motor+Neurons,+Gamma at the US National Library of Medicine Medical Subject Headings (MeSH)
- NIF Search - Gamma Motor Neuron via the Neuroscience Information Framework
Histology: nervous tissue (TA A14, GA 9.849, TH H2.00.06, H3.11)
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CNS |
General
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Grey matter · White matter (Projection fibers · Association fiber · Commissural fiber · Lemniscus · Funiculus · Fasciculus · Decussation · Commissure) · meninges
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Neuroglia
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Myelination: Oligodendrocyte
Astrocyte (Radial glial cell) · Ependymal cells (Tanycyte) · Microglia
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Other
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Pyramidal · Purkinje · Granule
Neuropil
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PNS |
General
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Posterior (Root, Ganglion, Ramus) · Anterior (Root, Ramus) · rami communicantes (Gray, White) · Autonomic ganglion (Preganglionic nerve fibers · Postganglionic nerve fibers)
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Connective tissues
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epineurium · perineurium · endoneurium · nerve fascicle
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Neuroglia
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Myelination: Schwann cell (Neurolemma, Myelin incisure, Myelin sheath gap, Internodal segment)
Satellite glial cell
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Neurons/
nerve fibers |
Parts
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Perikaryon (Axon hillock)
Axon (Axon terminals, Axoplasm, Axolemma, Neurofibril/neurofilament)
Dendrite (Nissl body, Dendritic spine, Apical dendrite/Basal dendrite)
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Types
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Bipolar · Unipolar · Pseudounipolar · Multipolar · Interneuron (Renshaw)
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Afferent nerve fiber/
Sensory nerve
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GSA · GVA · SSA · SVA
fibers (Ia, Ib or Golgi, II or Aβ, III or Aδ or fast pain, IV or C or slow pain)
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Efferent nerve fiber/
Motor nerve
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GSE · GVE · SVE
Upper motor neuron · Lower motor neuron (α motorneuron, γ motorneuron, β motorneuron)
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Termination |
Synapse
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Electrical synapse/Gap junction · Chemical synapse (Synaptic vesicle, Active zone, Postsynaptic density) · Ribbon synapse · Neuromuscular junction
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Sensory receptors
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Meissner's corpuscle · Merkel nerve ending · Pacinian corpuscle · Ruffini ending · Muscle spindle · Free nerve ending · Olfactory receptor neuron · Photoreceptor cell · Hair cell · Taste bud
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anat(n/s/m/p/4/e/b/d/c/a/f/l/g)/phys/devp
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noco(m/d/e/h/v/s)/cong/tumr, sysi/epon, injr
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proc, drug(N1A/2AB/C/3/4/7A/B/C/D)
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anat(h/r/t/c/b/l/s/a)/phys(r)/devp/prot/nttr/nttm/ntrp
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noco/auto/cong/tumr, sysi/epon, injr
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UpToDate Contents
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English Journal
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- Pitman MJ.
- The Laryngoscope.Laryngoscope.2014 Nov;124(11):2537-43. doi: 10.1002/lary.24749. Epub 2014 Jun 10.
- OBJECTIVES/HYPOTHESIS: To investigate the feasibility of an implantable electrical stimulation device to treat spasmodic dysphonia (SD) by neuromodulation of the muscle spindle gamma loop.STUDY DESIGN: Prospective case series.METHOD: Five subjects underwent daily stimulation of the left thyroaryteno
- PMID 24913352
Japanese Journal
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- 電子情報通信学会技術研究報告. NC, ニューロコンピューティング 111(157), 103-107, 2011-07-18
- 自発行動開始時に第一次運動野において主要な周波数成分がベータ波帯からガンマ波帯に変化することが報告されている。この現象を説明するために、相互抑制結合を持つ二つのWilson-Cowanモデルにおいて、双方の興奮性ニューロン群及び、片方の抑制性細胞群に定常入力を与える計算機実験を行った。その結果、興奮性細胞群に対する入力が増加すると、周波数がステップ関数的に増加した。急激な周波数増加の原因は、二つの …
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- SPP1 expression in spinal motor neurons of the macaque monkey
- YAMAMOTO Tatsuya,HIGO Noriyuki,SATO Akira,NISHIMURA Yukio,OISHI Takao,MURATA Yumi,YOSHINO SAITO Kimika,ISA Tadashi,KOJIMA Toshio
- Neuroscience research : the official journal of the Japan Neuroscience Society 69(1), 81-86, 2011-01-01
- NAID 10028190361
- 皮質神経細胞の不規則発火時系列が示唆する条件付きエントロピー最小化原理(脳活動の計測と解析,生命現象の非線形性,一般)
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- 電子情報通信学会技術研究報告. NC, ニューロコンピューティング 109(125), 33-35, 2009-07-06
- 活動中の動物の大脳皮質神経細胞から記録されるスパイク時系列は不規則であることが知られている.脳の機能を知るためには,この不規則時系列がどのように生成されているかを調べることが重要である.そこで,自発前肢運動課題中のラット大脳皮質運動野の神経細胞から傍細胞記録を行い,スパイク時系列を記録した.その結果,スパイク間隔はべき分布を示した.この結果は,インビボでは発火率が時間変動しその変動がガンマ分布に従 …
- NAID 110007360359
Related Links
- Gamma motor neurons , also called gamma motoneurons, are a type of lower motor neuron that take part in the process of muscle contraction, and represent about 30% of fibers going to the muscle.[1] Like alpha motor neurons, their ...
- Gamma motor neurons (γ motor neurons), also called gamma motoneurons, are a type of lower motor neuron that take part in the process of muscle contraction, and represent about 30% of fibers going to the muscle. [1] Like alpha ...
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- 英
- gamma motor neuron
- 関
- 紡錘運動ニューロン
[★]
- 関
- exercise、kinesis、locomote、locomotive、motility、motion、move、movement
[★]
- 関
- nerve、nervi、nervous、nervus、neural、neuron
[★]
γ ガンマ