Introduction: The post-inhibition excitatory phase (E3) of the cutaneous silent period (CSP) is attributed to the resynchronization of motoneuron activity following the inhibitory period but there is also evidence that a somatosensory startle reflex may contribute to this phase. We hypothesized that the startle reflex component contained in E3 will decrease during vibration.
Methods: Sixteen healthy individuals were included in the study. CSP was recorded from slightly contracted right thenar muscles after painful index finger stimulation, before, during, and immediately after vibration. The values of the percentage change of E3 relative to pre-stimulus baseline (E3%) were compared before, during, and after vibration for each individual.
Results: There was a reduction in E3% during vibration and the values returned to normal immediately after vibration (153.1 ± 43.5%, 115.2 ± 30.2%, 154.9 ± 68.2%, respectively; p = 0.030).
Discussion: E3 is reduced during vibration in healthy individuals, presumably due to suppression of a reflex component, which is superimposed upon the known resynchronization of motoneurons.
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http://dx.doi.org/10.1007/s10072-020-04557-5 | DOI Listing |
Rev Physiol Biochem Pharmacol
January 2025
Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, UK.
Pre- and post-synaptic events are regulated by liquid-liquid phase separation and this phenomenon requires multiple electrical forces. Both axonal transport and the organization of postsynaptic excitatory and inhibitory receptors are regulated by LLPS, with its mandatory electrical drivers ultimately determining our cognitive health and capacity.
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January 2025
Biorobotics Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
This study introduces a novel neuromechanical model employing a detailed spiking neural network to explore the role of axial proprioceptive sensory feedback, namely stretch feedback, in salamander locomotion. Unlike previous studies that often oversimplified the dynamics of the locomotor networks, our model includes detailed simulations of the classes of neurons that are considered responsible for generating movement patterns. The locomotor circuits, modeled as a spiking neural network of adaptive leaky integrate-and-fire neurons, are coupled to a three-dimensional mechanical model of a salamander with realistic physical parameters and simulated muscles.
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View Article and Find Full Text PDFCerebellum
January 2025
Department of Neurology, Pusan National University Hospital, Pusan National University School of Medicine and Biomedical Research Institute, Busan, South Korea.
Alexander's law states that spontaneous nystagmus increases when looking in the direction of fast-phase and decreases during gaze in slow-phase direction. Disobedience to Alexander's law is occasionally observed in central nystagmus, but the underlying neural circuit mechanisms are poorly understood. In a retrospective analysis of 2,652 patients with posterior circulations stroke, we found a violation of Alexander's law in one or both directions of lateral gaze in 17 patients with lesions of unilateral lateral medulla affecting the vestibular nucleus.
View Article and Find Full Text PDFScience
January 2025
Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA.
Synapses are organized by trans-synaptic adhesion molecules that coordinate assembly of pre- and postsynaptic specializations, which, in turn, are composed of scaffolding proteins forming liquid-liquid phase-separated condensates. Presynaptic teneurins mediate excitatory synapse organization by binding to postsynaptic latrophilins; however, the mechanism of action of teneurins, driven by extracellular domains evolutionarily derived from bacterial toxins, remains unclear. In this work, we show that only the intracellular sequence, a dimerization sequence, and extracellular bacterial toxin-derived latrophilin-binding domains of Teneurin-3 are required for synapse organization, suggesting that teneurin-induced latrophilin clustering mediates synaptogenesis.
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