Biomaterial Database

Inter-trial variation of soleus H reflex in humans: implication for supraspinal influence. 2002

I S Hwang, and I Y Tsai

Department of Physical Therapy, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan. ishwang@mail.ncku.edu.tw

Inter-trial variation in soleus H reflex amplitude for different effort modes, elicited at different test-stimulus intensities, was studied in fifteen healthy subjects. Regardless of test-stimulus intensity, weak isometric plantarflexion and dorsiflexion at 20% of maximum voluntary contraction caused significant potentiation and depression of the H reflex amplitude. In addition, both facilitation and inhibition of the soleus H reflex was associated with considerable inter-trial variability of the H reflex amplitude that varied proportionally with test-stimulus intensity. As inter-variability of the H reflex was independent of that of M response, the results indicate that: 1) supra-spinal input influences loop-gain fluctuations of the monosynaptic-reflex arc; and 2) smaller test stimuli may be more efficacious for exploration of motoneuronal excitability because of reduction in variability in H reflex amplitude.

UI	MeSH Term	Description	Entries
D009046	Motor Neurons	Neurons which activate MUSCLE CELLS.	Neurons, Motor,Alpha Motorneurons,Motoneurons,Motor Neurons, Alpha,Neurons, Alpha Motor,Alpha Motor Neuron,Alpha Motor Neurons,Alpha Motorneuron,Motoneuron,Motor Neuron,Motor Neuron, Alpha,Motorneuron, Alpha,Motorneurons, Alpha,Neuron, Alpha Motor,Neuron, Motor
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D011930	Reaction Time	The time from the onset of a stimulus until a response is observed.	Response Latency,Response Speed,Response Time,Latency, Response,Reaction Times,Response Latencies,Response Times,Speed, Response,Speeds, Response
D012016	Reference Values	The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.	Normal Range,Normal Values,Reference Ranges,Normal Ranges,Normal Value,Range, Normal,Range, Reference,Ranges, Normal,Ranges, Reference,Reference Range,Reference Value,Value, Normal,Value, Reference,Values, Normal,Values, Reference
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
D004576	Electromyography	Recording of the changes in electric potential of muscle by means of surface or needle electrodes.	Electromyogram,Surface Electromyography,Electromyograms,Electromyographies,Electromyographies, Surface,Electromyography, Surface,Surface Electromyographies
D006181	H-Reflex	A monosynaptic reflex elicited by stimulating a nerve, particularly the tibial nerve, with an electric shock.	H Reflex,H-Reflexes,H Reflexes,Reflex, H
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000293	Adolescent	A person 13 to 18 years of age.	Adolescence,Youth,Adolescents,Adolescents, Female,Adolescents, Male,Teenagers,Teens,Adolescent, Female,Adolescent, Male,Female Adolescent,Female Adolescents,Male Adolescent,Male Adolescents,Teen,Teenager,Youths
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults