Assessment of motor neuron excitability in parkinsonian rigidity by the F wave

1985 ◽  
Vol 232 (4) ◽  
pp. 246-249 ◽  
Author(s):  
Giovanni Abbruzzese ◽  
Marco Vische ◽  
Sandro Ratto ◽  
Michele Abbruzzese ◽  
Emilio Favale
Keyword(s):  
Motor Neuron ◽  
Neuron Excitability ◽  
Motor Neuron Excitability ◽  
F Wave

scholarly journals Thenar Muscle Motor Imagery Increases Spinal Motor Neuron Excitability of the Abductor Digiti Minimi Muscle

2021 ◽  
Vol 15 ◽  
Author(s):  
Yoshibumi Bunno ◽  
Toshiaki Suzuki
Keyword(s):  
Motor Neuron ◽  
Muscle Activity ◽  
Emg Activity ◽  
Thenar Muscle ◽  
Spinal Motor Neuron ◽  
Spinal Motor ◽  
Neuron Excitability ◽  
Motor Neuron Excitability ◽  
F Wave ◽  
Rest Condition

When a person attempts intended finger movements, unintended finger movement also occur, a phenomenon called “enslaving”. Given that motor imagery (MI) and motor execution (ME) share a common neural foundation, we hypothesized that the enslaving effect on the spinal motor neuron excitability occurs during MI. To investigate this hypothesis, electromyography (EMG) and F-wave analysis were conducted in 11 healthy male volunteers. Initially, the EMG activity of the left abductor digiti minimi (ADM) muscle during isometric opposition pinch movement by the left thumb and index finger at 50% maximal effort was compared with EMG activity during the Rest condition. Next, the F-wave and background EMG recordings were performed under the Rest condition, followed by the MI condition. Specifically, in the Rest condition, subjects maintained relaxation. In the MI condition, they imagined isometric left thenar muscle activity at 50% maximal voluntary contraction (MVC). During ME, ADM muscle activity was confirmed. During the MI condition, both F-wave persistence and the F-wave/M-wave amplitude ratio obtained from the ADM muscle were significantly increased compared with that obtained during the Rest condition. No difference was observed in the background EMG between the Rest and MI conditions. These results suggest that MI of isometric intended finger muscle activity at 50% MVC facilitates spinal motor neuron excitability corresponding to unintended finger muscle. Furthermore, MI may induce similar modulation of spinal motor neuron excitability as actual movement.

Do F-wave measurements detect changes in motor neuron excitability?

2004 ◽  
Vol 30 (3) ◽  
pp. 289-294 ◽  
Author(s):  
Jenny Z. Lin ◽  
Mary Kay Floeter
Keyword(s):  
Motor Neuron ◽  
Wave Measurements ◽  
Neuron Excitability ◽  
Motor Neuron Excitability ◽  
F Wave

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.

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