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2. Vestibular control of deep and superficial lumbar muscles

Author

Gallina, A., Abboud, J., Blouin, J.-S., Gallina, A., Abboud, J., and Blouin, J.-S.

Abstract

The active control of the lumbar musculature provides a stable platform critical for postures and goal-directed movements. Voluntary and perturbation-evoked motor commands can recruit individual lumbar muscles in a task-specific manner according to their presumed biomechanics. Here, we investigated the vestibular control of the deep and superficial lumbar musculature. Ten healthy participants were exposed to noisy electrical vestibular stimulation while balancing upright with their head facing forward, left, or right to characterize the differential modulation in the vestibular-evoked lumbar extensor responses in generating multidirectional whole body motion. We quantified the activation of the lumbar muscles on the right side using indwelling [deep multifidus, superficial multifidus, caudal longissimus (L4), and cranial longissimus (L1)] and high-density surface recordings. We characterized the vestibular-evoked responses using coherence and peak-to-peak cross-covariance amplitude between the vestibular and electromyographic signals. Participants exhibited responses in all lumbar muscles. The vestibular control of the lumbar musculature exhibited muscle-specific modulations: responses were larger in the longissimus (combined cranio-caudal) compared with the multifidus (combined deep-superficial) when participants faced forward (P < 0.001) and right (P = 0.011) but not when they faced left. The high-density surface recordings partly supported this observation: the location of the responses was more lateral when facing right compared with left (P < 0.001). The vestibular control of muscle subregions within the longissimus or the multifidus was similar. Our results demonstrate muscle-specific vestibular control of the lumbar muscles in response to perturbations of vestibular origin. The lack of differential activation of lumbar muscle subregions suggests the vestibular control of these subregions is co-regulated for standing balance. NEW & NOTEWORTHY We inves

Published
2024

4. Detection of TPSAB1 copy number variation for the diagnosis of hereditary alpha‐tryptasemia by quantitative PCR.

Author

Docquier, M., Nouspikel, T., Blouin, J. L., Abramowicz, M., Seebach, J. D., and Spoerl, D.

Subjects
NUCLEIC acids, DIAGNOSIS, MAST cell disease, MEDICAL laws, TRYPTASE, ANAPHYLAXIS
Abstract

This document presents the findings of a study comparing two methods, quantitative PCR (qPCR) and digital droplet PCR (ddPCR), for diagnosing hereditary alpha-tryptasemia (HAT). The study found that qPCR had a sensitivity of 100% and specificity of 87.50% in identifying patients with HAT. However, there were some discrepancies between the two methods, and ddPCR is still considered the gold standard. The authors suggest that qPCR could be used as an alternative in facilities where ddPCR is not easily accessible. [Extracted from the article]

Published
2024
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22. A task-relevant experimental pain model to target motor adaptation

Author

Gallina, A., Abboud, J., Blouin, J. S., Gallina, A., Abboud, J., and Blouin, J. S.

Abstract

Key points: Motor adaptation is thought to be a strategy to avoid pain. Current experimental pain models do not allow for consistent modulation of pain perception depending on movement. We showed that low-frequency sinusoidal stimuli delivered at painful intensity result in minimal habituation of pain perception (over 60 s) and minimal stimulation artefacts on electromyographic signals. When the amplitude of the low-frequency sinusoidal stimuli was modulated based on the vertical force participants applied to the ground with their right leg while standing upright, we demonstrated a strong association between perceived pain and motor adaptation. By enabling task-relevant modulation of perceived pain intensity and the recording electromyographic signals during electrical painful stimulation, our novel pain model will permit direct experimental testing of the relationship between pain and motor adaptation. Abstract: Contemporary pain adaptation theories predict that motor adaptation occurs to limit pain. Current experimental pain models, however, do not allow for pain intensity modulation according to one's posture or movements. We developed a task-relevant experimental pain model using low-frequency sinusoidal electrical stimuli applied over the infrapatellar fat pad. In fourteen participants, we compared perceived pain habituation and stimulation-induced artefacts in vastus medialis electromyographic recordings elicited by sinusoidal (4, 10, 20 and 50 Hz) and square electrical waveforms delivered at constant peak stimulation amplitude. Next, we simulated a clinical condition where perceived knee pain intensity is proportional to the load applied on the leg by controlling sinusoidal current amplitude (4 Hz) according to the vertical force the participants applied with their right leg to the ground while standing upright. Pain ratings habituated over a 60 s period for 50 Hz sinusoidal and square waveforms but not for low-frequency sinusoidal stimuli (P < 0.001). EMG

Published
2021

41. Posterpräsentation

Author

Wirthner, D., Germond, M., De Grandi, P., Paul, Janecek, Brunner, A., Linder, H. R., Hänggi, W., Birkhäuser, M. H., Macas, E., Imthurn, B., Münch, M., Rosselli, M., Keller, P. J., Dombi, V. H., DeLozier-Blanchet, C., Blouin, J. -L., Guerne, P. A., Antonarakis, S. E., Haller, U., Walt, H., Schär, G., Köchli, O. R., Fink, D., Bajka, M., Haller, U., Fanger G., Keel B., Peschers U., Vodusek D., Schär G., and Schüßler B.

Published
1995
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47. Directional control of rapid arm movements: the role of the kinetic visual feedback system

Author

Blouin, J., Teasdale, N., Bard, C., and Fleury, M.

Subjects
Human mechanics -- Research, Motor ability -- Research, Visual perception -- Research, Feedback (Psychology) -- Research, Psychology and mental health
Abstract

Vision has long been considered as a single feedback system providing information about the static and the dynamic features of motor behaviors and of the environment where they take place. However, recent models for oculomanual movements have included multichanneling of visual cues (Goodale & Milner, 1992; Jeannerod, 1981; 1984; Paillard, 1980, 1982). According to Paillard's model, a kinetic system, mostly sensitive to dynamic cues, provides directional information of the movement in the rapid distance-covering phase, and a static system, highly sensitive to position cues, provides positional signal errors. The present experiment gives kinematic evidence for the significant contribution of vision during the initial phase of rapid pointing movements when this phase is under the control of the kinetic channel. Movements having directional requirements were more accurate (directional precision) when vision of the initial portion of the trajectory was available. Times-to-peak acceleration and velocity were all shorter and their respective amplitudes were generally higher when vision was available for the first third of the trajectory than when it was not. Further, vision of the entire trajectory did not yield better precision then when vision was available for the initial phase of the movements only. Overall, the data support the existence of two corrective visual feedback systems.

Published
1993

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