Biomaterial Database

Disturbances in the voluntary recruitment order of anterior tibial motor units in ataxia. 1975

L Grimby, and J Hannerz

The recruitment order of motor units was studied with an electromyographic technique for secure identification of single motor unit potentials. It has been shown in previous studies of normal subjects that the recruitment order in sustained voluntary contraction is predominantly stable, and that motor units which increase slowly in discharge rate with increasing contraction strength and which already attain regular discharge intervals at low frequencies are always recruited before motor units which increase more rapidly in discharge rate and which do not attain regular discharge intervals until at higher frequencies. In this study 15 patients with severe cerebellar ataxia were examined. It was shown that the recruitment order in sustained voluntary contraction in attaxia is unstable and that low- and high-frequency motor units may alternate as the unit of lowest threshold.

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
D009435	Synaptic Transmission	The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.	Neural Transmission,Neurotransmission,Transmission, Neural,Transmission, Synaptic
D009469	Neuromuscular Junction	The synapse between a neuron and a muscle.	Myoneural Junction,Nerve-Muscle Preparation,Junction, Myoneural,Junction, Neuromuscular,Junctions, Myoneural,Junctions, Neuromuscular,Myoneural Junctions,Nerve Muscle Preparation,Nerve-Muscle Preparations,Neuromuscular Junctions,Preparation, Nerve-Muscle,Preparations, Nerve-Muscle
D011999	Recruitment, Neurophysiological	The spread of response if stimulation is prolonged. (Campbell's Psychiatric Dictionary, 8th ed.)	Recruitment, Motor Unit,Motor Unit Recruitment,Neurophysiological Recruitment
D002524	Cerebellar Ataxia	Incoordination of voluntary movements that occur as a manifestation of CEREBELLAR DISEASES. Characteristic features include a tendency for limb movements to overshoot or undershoot a target (dysmetria), a tremor that occurs during attempted movements (intention TREMOR), impaired force and rhythm of diadochokinesis (rapidly alternating movements), and GAIT ATAXIA. (From Adams et al., Principles of Neurology, 6th ed, p90)	Adiadochokinesis,Ataxia, Cerebellar,Cerebellar Dysmetria,Dysmetria,Cerebellar Hemiataxia,Cerebellar Incoordination,Hypermetria,Adiadochokineses,Ataxias, Cerebellar,Cerebellar Ataxias,Cerebellar Dysmetrias,Cerebellar Hemiataxias,Cerebellar Incoordinations,Dysmetria, Cerebellar,Dysmetrias,Dysmetrias, Cerebellar,Hemiataxia, Cerebellar,Hemiataxias, Cerebellar,Hypermetrias,Incoordination, Cerebellar,Incoordinations, Cerebellar
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
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man