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Biology subjects

Bal, R.

Publications and source records attributed to Bal, R..

2 recordsLinked to original sources

Expert drummers replicate neuromechanical signatures of physiological tremor at extreme movement frequencies.

This study investigates the neuromechanical characteristics associated with expert drummers ability to achieve unilateral ankle oscillation frequencies of up to 10 Hz, surpassing known limits for lower-body movements. Eighteen experienced drummers performed trials at various frequencies, using a protocol combining H-reflex measurement, motion analysis, and electromyography. Our findings closely parallel neuromechanical signatures observed in ankle tremors, with an average movement frequency of 6.3 Hz (SD: 0.5 Hz), and a modulation range of 5.5-7.3 Hz. Oscillatory behavior may result from the interplay between muscle-tendon mechanics and stretch reflex loops. At 6.3 Hz, soleus activation lasts 56.2 ms, shortening by 2.5 ms/Hz (p < 0.001), while tibialis anterior activation lasts 52.7 ms, decreasing by 5.3 ms/Hz (p < 0.001). The latency between ankle dorsiflexion and soleus activation is 48.5 ms at 6.3 Hz, matching the short-latency stretch reflex, and decreases by 11 ms/Hz (p<0.001). Limiting factors for the drummers maximal frequency are soleus and tibialis anterior co-activation, reducing ankle movement, and high levels of activation in hip and back muscles, associated with discomfort and pain. Drummers with higher maximal frequencies (above 7.5 Hz, n = 6) show shorter tibialis anterior activation durations (34.3 ms vs. 53.2 ms, p = 0.0013) and reduced tensor fascia latae activation (6.2% vs. 21.0%, p = 0.0135). These findings highlight phenomenological similarities between the ankle technique and physiological tremors, in terms of neuromechanical timing and oscillatory patterns. Precise tibialis anterior timing and relaxed proximal muscle activation are critical for performance, while injury prevention strategies remain essential. Significance StatementThis study provides a neuromechanical analysis of expert metal drummers producing exceptionally high-frequency ankle movements--up to 10 Hz--that surpass known limits for lower-body movements, and draws parallels with physiological action tremors. By comparing their motor patterns to those reported in tremor literature, this work highlights the role of neuromuscular timing and mechanical adaptations, such as stretch reflex dynamics and muscle-tendon interactions. The findings demonstrate that precise tibialis anterior timing and relaxed proximal muscles are critical for performance, while stabilization demands increase the risk of musculoskeletal disorders in the lower back and hips. These insights bridge performance science, biomechanics, and injury prevention, offering valuable perspectives for optimizing high-frequency movements in music, sports, and rehabilitation.

physiology↗

Transgenic Mouse Models Establish a Protective Role of Type 1 IFN Response in SARS-CoV-2 infection-related Immunopathology

Type 1 interferon (IFN-I) response is the first line of host defense against invading viruses. In the absence of definite mouse models, the role of IFN-I in SARS-CoV-2 infections remained to be perplexing. Here, we developed two mouse models, one with constitutively high IFN-I response (hACE2; Irgm1-/-) and the other with dampened IFN-I response (hACE2; Ifnar1-/-) to comprehend the role of IFN-I response during SARS-CoV-2 invasion. We found that hACE2; Irgm1-/- mice were resistant to lethal SARS-CoV-2 infection with substantially reduced cytokine storm and immunopathology. In striking contrast, a severe SARS-CoV-2 infection along with immune cells infiltration, inflammatory response, and enhanced pathology was observed in the lungs of hACE2; Ifnar1-/- mice. Additionally, hACE2; Ifnar1-/- mice were highly susceptible to SARS-CoV-2 neuroinvasion in the brain accompanied by immune cell infiltration, microglia/astrocytes activation, cytokine response, and demyelination of neurons. The hACE2; Irgm1-/- Ifnar1-/- double knockout mice or hACE2; Irgm1-/- mice treated with STING or RIPK2 pharmacological inhibitors displayed loss of the protective phenotypes observed in hACE2; Irgm1-/- mice suggesting that heightened IFN-I response accounts for the observed immunity. Taken together, we explicitly demonstrate that IFN-I protects from lethal SARS-CoV-2 infection, and Irgm1 (IRGM) could be an excellent therapeutic target. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=133 SRC="FIGDIR/small/520843v1_ufig1.gif" ALT="Figure 1"> View larger version (51K): org.highwire.dtl.DTLVardef@a3aad4org.highwire.dtl.DTLVardef@12452fcorg.highwire.dtl.DTLVardef@1c43dc0org.highwire.dtl.DTLVardef@b2167d_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗