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Full-Text Articles in Medicine and Health Sciences
Persistent Inward Currents In Tibialis Anterior Motoneurons Can Be Reliably Estimated Within The Same Session, Thomas Lapole, Ricardo N.O. Mesquita, Stéphane Baudry, Robin Souron, Eleanor K. O'Brien, Callum G. Brownstein, Vianney Rozand
Persistent Inward Currents In Tibialis Anterior Motoneurons Can Be Reliably Estimated Within The Same Session, Thomas Lapole, Ricardo N.O. Mesquita, Stéphane Baudry, Robin Souron, Eleanor K. O'Brien, Callum G. Brownstein, Vianney Rozand
Research outputs 2022 to 2026
The response of spinal motoneurons to synaptic input greatly depends on the activation of persistent inward currents (PICs), the contribution of which can be estimated through the paired motor unit technique. Yet, the intra-session test–retest reliability of this measurement remains to be fully established. Twenty males performed isometric triangular dorsiflexion contractions to 20 and 50 % of maximal torque at baseline and after a 15-min resting period. High-density electromyographic signals (HD-EMG) of the tibialis anterior were recorded with a 64-electrode matrix. HD-EMG signals were decomposed, and motor units tracked across time points to estimate the contribution of PICs to motoneuron …
Excitatory Drive To Spinal Motoneurones Is Necessary For Serotonin To Modulate Motoneurone Excitability Via 5-Ht2 Receptors In Humans, Tyler T. Henderson, Janet L. Taylor, Jacob R. Thorstensen, Justin J. Kavanagh
Excitatory Drive To Spinal Motoneurones Is Necessary For Serotonin To Modulate Motoneurone Excitability Via 5-Ht2 Receptors In Humans, Tyler T. Henderson, Janet L. Taylor, Jacob R. Thorstensen, Justin J. Kavanagh
Research outputs 2022 to 2026
Serotonin modulates corticospinal excitability, motoneurone firing rates and contractile strength via 5-HT2 receptors. However, the effects of these receptors on cortical and motoneurone excitability during voluntary contractions have not been explored in humans. Therefore, the purpose of this study was to investigate how 5-HT2 antagonism affects corticospinal and motoneuronal excitability with and without descending drive to motoneurones. Twelve individuals (aged 24 ± 4 years) participated in a double-blind, placebo-controlled, crossover study, whereby the 5-HT2 antagonist cyproheptadine was administered. Transcranial magnetic stimulation (TMS) was delivered to the motor cortex to produce motor evoked potentials (MEPs), and electrical stimulation at the cervicomedullary …
Contrast Detection Is Enhanced By Deterministic, High-Frequency Transcranial Alternating Current Stimulation With Triangle And Sine Waveform, Weronika Potok, Onno Van Der Groen, Sahana Sivachelvam, Marc Bächinger, Flavio Fröhlich, Laszlo B. Kish, Nicole Wenderoth
Contrast Detection Is Enhanced By Deterministic, High-Frequency Transcranial Alternating Current Stimulation With Triangle And Sine Waveform, Weronika Potok, Onno Van Der Groen, Sahana Sivachelvam, Marc Bächinger, Flavio Fröhlich, Laszlo B. Kish, Nicole Wenderoth
Research outputs 2022 to 2026
Stochastic resonance (SR) describes a phenomenon where an additive noise (stochastic carrier-wave) enhances the signal transmission in a nonlinear system. In the nervous system, nonlinear properties are present from the level of single ion channels all the way to perception and appear to support the emergence of SR. For example, SR has been repeatedly demonstrated for visual detection tasks, also by adding noise directly to cortical areas via transcranial random noise stimulation (tRNS). When dealing with nonlinear physical systems, it has been suggested that resonance can be induced not only by adding stochastic signals (i.e., noise) but also by adding …
Can Local Vibration Alter The Contribution Of Persistent Inward Currents To Human Motoneuron Firing?, T. Lapole, Ricardo N. O. Mesquita, S. Baudry, R. Souron, C. G. Brownstein, V. Rozand
Can Local Vibration Alter The Contribution Of Persistent Inward Currents To Human Motoneuron Firing?, T. Lapole, Ricardo N. O. Mesquita, S. Baudry, R. Souron, C. G. Brownstein, V. Rozand
Research outputs 2022 to 2026
The response of spinal motoneurons to synaptic input greatly depends on the activation of persistent inward currents (PICs), which in turn are enhanced by the neuromodulators serotonin and noradrenaline. Local vibration (LV) induces excitatory Ia input onto motoneurons and may alter neuromodulatory inputs. Therefore, we investigated whether LV influences the contribution of PICs to motoneuron firing. This was assessed in voluntary contractions with concurrent, ongoing LV, as well as after a bout of prolonged LV. High-density surface electromyograms (HD-EMG) of the tibialis anterior were recorded with a 64-electrode matrix. Twenty males performed isometric, triangular, dorsiflexion contractions to 20% and 50% …
5-Ht2 Receptor Antagonism Reduces Human Motoneuron Output To Antidromic Activation But Not To Stimulation Of Corticospinal Axons, Jacob R. Thorstensen, Janet L. Taylor, Justin J. Kavanagh
5-Ht2 Receptor Antagonism Reduces Human Motoneuron Output To Antidromic Activation But Not To Stimulation Of Corticospinal Axons, Jacob R. Thorstensen, Janet L. Taylor, Justin J. Kavanagh
Research outputs 2022 to 2026
The intrinsic electrical properties of motoneurons strongly affect motoneuron excitability to fast-acting excitatory ionotropic inputs. Serotonin (5-HT) is a neurochemical that alters the intrinsic properties of motoneurons, whereby animal models and in vitro experiments indicate that 5-HT increases motoneuron excitability by activating 5-HT2 receptors on the somato-dendritic compartment. In the current study, we examined how antagonism of the 5-HT2 receptor affects motoneuron excitability in humans. We hypothesised that motoneuron excitability would be reduced. The 5-HT2 antagonist cyproheptadine was administered to 10 healthy participants in a double-blinded, placebo-controlled, crossover trial. Electrical cervicomedullary stimulation was used to deliver a synchronised excitatory volley …