ArticleJournal of neurophysiology2015
Distinguishing intrinsic from extrinsic factors underlying firing rate saturation in human motor units.
Article in Journal of neurophysiology, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 38 papers.
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Who cites it
38 citing papers in PubMed.
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- Comparison of human motor unit firing rates in the vastus intermedius and vastus lateralis during isometric knee extension.European journal of applied physiology · 2026Article
- Yank-related changes in corticospinal recruitment gain in humans.Brain research · 2026Article
- Ventral intraspinal microstimulation alters neural population-level nociceptive activity in rats including after spinal cord injury.Pain reports · 2026Article
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- A direct spinal cord-computer interface enables the control of the paralysed hand in spinal cord injury.Brain : a journal of neurology · 2024Article
- Motor unit firing rates increase in prepubescent youth following linear periodization resistance exercise training.European journal of applied physiology · 2024Article
- Onion skin is not a universal firing pattern for spinal motoneurons: simulation study.Journal of neurophysiology · 2024Article
- The neural control of movement: a century of in vivo motor unit recordings is the legacy of Adrian and Bronk.The Journal of physiology · 2024Review
- Motor unit-based synergies in a non-compartmentalized muscle.Experimental brain research · 2023Article
- Decoding firings of a large population of human motor units from high-density surface electromyogram in response to transcranial magnetic stimulation.The Journal of physiology · 2023Article
- A geometric approach to quantifying the neuromodulatory effects of persistent inward currents on individual motor unit discharge patterns.Journal of neural engineering · 2023Article
- The control and training of single motor units in isometric tasks are constrained by a common input signal.eLife · 2022Article
- The Cellular Basis for the Generation of Firing Patterns in Human Motor Units.Advances in neurobiology · 2022Article
- Electrical Properties of Adult Mammalian Motoneurons.Advances in neurobiology · 2022Article
- Motor Unit Discharge Patterns in Response to Focal Tendon Vibration of the Lower Limb in Cats and Humans.Frontiers in integrative neuroscience · 2022Article
- Firing rate trajectories of human occipitofrontalis motor units in response to triangular voluntary contraction intensity.Experimental brain research · 2021Article
- Ischemic stroke-induced polyaxonal innervation at the neuromuscular junction is attenuated by robot-assisted mechanical therapy.Experimental neurology · 2021Article
- Force variability is mostly not motor noise: Theoretical implications for motor control.PLoS computational biology · 2021Article
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3 authors.
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Abstract
During voluntary contraction, firing rates of individual motor units (MUs) increase modestly over a narrow force range beyond which little additional increase in firing rate is seen. Such saturation of MU discharge may be a consequence of extrinsic factors that limit net synaptic excitation acting on motor neurons (MNs) or may be due to intrinsic properties of the MNs. Two sets of experiments involving recording of human biceps brachii MUs were carried out to evaluate saturation. In the first set, the extent of saturation was quantified for 136 low-threshold MUs during isometric ramp contractions. Firing rate-force data were best fit by a saturating function for 90% of MUs recorded with a maximum rate of 14.8 ± 2.0 impulses/s. In the second set of experiments, to distinguish extrinsic from intrinsic factors underlying saturation, we artificially augmented descending excitatory drive to biceps MNs by activation of muscle spindle afferents through tendon vibration. We examined the change in firing rate caused by tendon vibration in 96 MUs that were voluntarily activated at rates below and at saturation. Vibration had little effect on the discharge of MUs that were firing at saturation frequencies but strongly increased firing rates of the same units when active at lower frequencies. These results indicate that saturation is likely caused by intrinsic mechanisms that prevent further increases in firing rate in the presence of increasing synaptic excitation. Possible intrinsic cellular mechanisms that limit firing rates of motor units during voluntary effort are discussed.
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