Immobility and F‐waves: Impact on lower motor neuron excitability

2020 ◽  
Vol 61 (4) ◽  
pp. 480-484
Author(s):  
Mariana Pereira ◽  
Michael Swash ◽  
Mamede Carvalho
Keyword(s):  
Motor Neuron ◽  
Lower Motor Neuron ◽  
Neuron Excitability ◽  
Motor Neuron Excitability

scholarly journals A genetic manipulation of motor neuron excitability does not alter locomotor output in Drosophila larvae

2014 ◽  
Author(s):  
Erin C. McKiernan
Keyword(s):  
Motor Neuron ◽  
Motor Neurons ◽  
Motor Behavior ◽  
Genetic Manipulation ◽  
Motor Output ◽  
Membrane Properties ◽  
Neuron Excitability ◽  
Motor Neuron Excitability ◽  
The Face

Motor activity, like that producing locomotion, is generated by networks of neurons. At the last output level of these networks are the motor neurons, which send signals to the muscles, causing them to contract. Current research in motor control is focused on finding out how motor neurons contribute to shaping the timing of motor behaviors. Are motor neurons just passive relayers of the signals they receive? Or, do motor neurons shape the signals before passing them on to the muscles, thereby influencing the timing of the behavior? It is now well accepted that motor neurons have active, intrinsic membrane properties - there are ion channels in the cell membrane that allow motor neurons to respond to input in non-linear and diverse ways. However, few direct tests of the role of motor neuron intrinsic properties in shaping motor behavior have been carried out, and many questions remain about the role of specific ion channel genes in motor neuron function. In this study, two potassium channel transgenes were expressed in Drosophila larvae, causing motor neurons to fire at lower levels of current stimulation and at higher frequencies, thereby increasing excitability. Mosaic animals were created in which some identified motor neurons expressed the transgenes while others did not. Motor output underlying crawling was compared in muscles innervated by control and experimental neurons in the same animals. Counterintuitively, no effect of the transgenic manipulation on motor output was seen. Future experiments are outlined to determine how the larval nervous system produces normal motor output in the face of altered motor neuron excitability.

scholarly journals The Inhibitory Tendon-Evoked Reflex Is Increased in the Torque-Enhanced State Following Active Lengthening Compared to a Purely Isometric Contraction

2019 ◽  
Vol 10 (1) ◽  
pp. 13 ◽  
Author(s):  
Vincenzo S. Contento ◽  
Brian H. Dalton ◽  
Geoffrey A. Power
Keyword(s):  
Steady State ◽  
Motor Neuron ◽  
Muscle Length ◽  
Intrinsic Property ◽  
Current Data ◽  
Afferent Feedback ◽  
Matching Task ◽  
Neuron Excitability ◽  
Important Relationship ◽  
Motor Neuron Excitability

Residual torque enhancement (rTE) is a history-dependent property of muscle, which results in an increase in steady-state isometric torque production following an active lengthening contraction as compared to a purely isometric (ISO) contraction at the same muscle length and level of activation. Once thought to be only an intrinsic property of muscle, recent evidence during voluntary contractions indicates a neuromechanical coupling between motor neuron excitability and the contractile state of the muscle. However, the mechanism by which this occurs has yet to be elucidated. The purpose of this study was to investigate inhibition arising from tendon-mediated feedback (e.g., Golgi tendon organ; GTO) through tendon electrical stimulation (TStim) in the ISO and rTE states during activation-matching and torque-matching tasks. Fourteen male participants (22 ± 2 years) performed 10 activation-matching contractions at 40% of their maximum tibialis anterior electromyography amplitude (5 ISO/5 rTE) and 10 torque-matching contractions at 40% of their maximum dorsiflexion torque (5 ISO/5 rTE). During both tasks, 10 TStim were delivered during the isometric steady state of all contractions, and the resulting tendon-evoked inhibitory reflexes were averaged and analyzed. Reflex amplitude increased by ~23% in the rTE state compared to the ISO state for the activation-matching task, and no differences were detected for the torque-matching task. The current data indicate an important relationship between afferent feedback in the torque-enhanced state and voluntary control of submaximal contractions. The history-dependent properties of muscle is likely to alter motor neuron excitability through modifications in tension- or torque-mediated afferent feedback arising from the tendon.

Cortical motor neuron excitability during cutaneous silent period

1998 ◽  
Vol 109 (4) ◽  
pp. 364-368 ◽  
Author(s):  
Kazuo Kaneko ◽  
Shinya Kawai ◽  
Toshihiko Taguchi ◽  
Yasunori Fuchigami ◽  
Hiroshi Yonemura ◽  
...  
Keyword(s):  
Motor Neuron ◽  
Silent Period ◽  
Cortical Motor ◽  
Neuron Excitability ◽  
Cutaneous Silent Period ◽  
Motor Neuron Excitability

Effect of the inhibitory phenomenon following magnetic stimulation of cortex on brainstem motor neuron excitability and on the cortical control of brainstem reflexes

1993 ◽  
Vol 16 (12) ◽  
pp. 1351-1358 ◽  
Author(s):  
A. Arturo Leis ◽  
Markus Kofler ◽  
Dobrivoje S. Stokic ◽  
Gert J. Grubwieser ◽  
J. Scott Delapassebme
Keyword(s):  
Motor Neuron ◽  
Magnetic Stimulation ◽  
Cortical Control ◽  
Neuron Excitability ◽  
Motor Neuron Excitability ◽  
Stimulation Of

scholarly journals Cortical Motor Neuron Excitability in Patients with Peripheral Nerve Injury.

2002 ◽  
Vol 51 (2) ◽  
pp. 367-369
Author(s):  
Kazuo Kaneko ◽  
Toshihiko Taguchi ◽  
Koichirou Toyoda ◽  
Akira Ofuji ◽  
Hiroyasu Ueno ◽  
...  
Keyword(s):  
Peripheral Nerve ◽  
Motor Neuron ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Cortical Motor ◽  
Neuron Excitability ◽  
Motor Neuron Excitability
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