Journal of Physiology-London最新文献

{"title":"Transcutaneous spinal random noise stimulation enhances motor memory consolidation and corticospinal transmission in humans.","authors":"Mitsuhiro Nito, Daisuke Kudo, Tadaki Koseki, Ippei Nojima, Shigeo Tanabe, Tomofumi Yamaguchi","doi":"10.1113/JP287804","DOIUrl":"https://doi.org/10.1113/JP287804","url":null,"abstract":"<p><p>Stochastic resonance sensory input modulates the central nervous system's excitability, thereby possibly influencing motor skill learning and retention. We investigated the effects of transcutaneous spinal random noise stimulation (tsRNS) at the cervical level on motor skill learning and corticospinal transmission in healthy humans. Participants performed a 20 min visuomotor tracking training task requiring rapid shifts in pinch force, with motor performance tests conducted before, immediately after, 1 day after and 7 days after the training to assess motor skill learning and retention. During the task, participants received real or sham tsRNS for 20 and 0.5 min, respectively. Motor performance improved equally in both groups immediately after training; however, the real tsRNS group showed a higher performance than the sham group at 1 and 7 days post-training. Beta-band corticomuscular coherence increased immediately after training in both groups, and higher performance on 1 day after the training was positively correlated with a greater change in corticomuscular coherence. To elucidate the mechanisms contributing to the enhanced motor memory retention induced by tsRNS, we investigated its effects on cortical and spinal excitability. We observed increased intracortical facilitation and somatosensory evoked potential amplitude following tsRNS; however, the efficacy of cortico-motoneuronal synaptic transmissions and the excitability of spinal motoneurons remained unchanged. Collectively, tsRNS can enhance the corticospinal drive to spinal motoneurons indirectly by increasing the ascending afferent input strength and cortical excitability via the augmented activity of facilitatory interneurons, resulting in improved motor memory retention. Thus, tsRNS may have important clinical applications for rehabilitation after central nervous system lesions. KEY POINTS: Stochastic resonance sensory input modulates the excitability of the central nervous system and may influence motor skill learning and motor memory retention. Transcutaneous spinal random noise stimulation (tsRNS) applied at the cervical level can enhance motor skill learning and motor memory retention in healthy humans. tsRNS can increase the ascending afferent input to the cortex and the excitability of the intracortical circuits rather than directly modulating the descending motor output, resulting in improved motor memory retention. These findings suggest that tsRNS is an effective strategy for promoting functional motor recovery of the upper limb after the development of central nervous system lesions.</p>","PeriodicalId":50088,"journal":{"name":"Journal of Physiology-London","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144745844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"C-tactile afferents: The mystery of human emotional touch has been hidden hair-deep.","authors":"Ingvars Birznieks","doi":"10.1113/JP289528","DOIUrl":"https://doi.org/10.1113/JP289528","url":null,"abstract":"","PeriodicalId":50088,"journal":{"name":"Journal of Physiology-London","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144745843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"State-dependent neural representations of muscle synergies in the spinal cord revealed by optogenetic stimulation.","authors":"Borong H E, Paola Salmas, Jing Zhang, Xiaojie Duan, Vincent C K Cheung","doi":"10.1113/JP288073","DOIUrl":"https://doi.org/10.1113/JP288073","url":null,"abstract":"<p><p>The central nervous system controls movement by combining neuromotor modules, known as muscle synergies. Previous studies suggest that spinal premotor interneurons (PreM-INs) contribute to the encoding of stable muscle synergies for voluntary movement. But descending and sensory inputs also influence motor outputs through the spinal interneuronal network, which may be configured by its inputs to encode different sets of muscle synergies depending on the network state, thereby recruiting different selections of synergies. Here we tested this possibility of state-dependent synergy encoding by examining the muscle synergies represented by the same upstream spinal interneurons under different activity states induced by various optogenetic stimulation patterns. Lumbosacral spinal units and electromyographic (EMG) activities of hindlimb muscles were simultaneously recorded from anaesthetized Thy1-ChR2 mice as the spinal cord was stimulated by one or two optic fibres at different intensities. The synergy encoded by each unit was revealed as a 'muscle field' derived from spike-triggered averages of EMG, whereas the entire muscle synergy set was factorized from the EMG. We found that although the muscle synergy set remained stable across stimulation conditions, the muscle fields of the same units were matched to different synergies within the set in different states. Thus the interneurons may flexibly adjust their connectivity with the motoneurons of the muscles as descending and sensory afferents impose different states on the spinal network. State-dependent encoding of muscle synergies may allow different synergies to be selected for producing stable movement in an ever-changing workspace environment. KEY POINTS: Muscle synergies for locomotion can be represented by spinal interneurons, as revealed by the interneurons' muscle fields derived from spike-triggered averages of EMG. The muscle field of a single spinal interneuron may vary under different stimulation conditions, as demonstrated by optogenetic stimulation. Encoding of muscle synergies is dependent on the state of spinal activities, thus facilitating the selection of appropriate synergies in different dynamic environments.</p>","PeriodicalId":50088,"journal":{"name":"Journal of Physiology-London","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144734990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Post-exercise hot water immersion enhances haemodynamic and vascular benefits of exercise without further improving cardiorespiratory fitness, glucose, lipids or inflammation.","authors":"Charles J Steward, Mathew Hill, Campbell Menzies, Sophie L Russell, C Douglas Thake, Christopher J A Pugh, Tom Cullen","doi":"10.1113/JP288873","DOIUrl":"https://doi.org/10.1113/JP288873","url":null,"abstract":"&lt;p&gt;&lt;p&gt;There is considerable overlap between the mechanisms underlying the health benefits of exercise training and heat therapy. However, it remains unclear whether combining heat therapy with exercise can enhance improvements in cardiovascular and metabolic health. The present study investigated whether post-exercise hot water immersion (EX+HWI) could augment improvements in cardiorespiratory fitness, cardiovascular and metabolic health compared to post-exercise thermoneutral water immersion (EX+TWI). Twenty-four physically inactive middle-aged adults (age: 58 ± 5 years; body mass index: 28 ± 3 kg m&lt;sup&gt;-&lt;/sup&gt; &lt;sup&gt;2&lt;/sup&gt;; 13 females) were randomly allocated to 8 weeks of supervised EX+HWI (n = 12) or EX+TWI (n = 12). Moderate-intensity aerobic exercise (65-75% maximum heart rate) was performed for 30 min followed by 30 min of immersion at 40°C or 34°C, two to four times per week (total 24 sessions). Cardiorespiratory fitness, brachial artery flow-mediated dilatation, aortic pulse wave velocity, blood pressure and circulating lipids, glucose and inflammatory markers were assessed pre- and post-intervention. Between-group differences showed that EX+HWI resulted in greater reductions in mean arterial pressure (P = 0.029, η&lt;sup&gt;2&lt;/sup&gt; &lt;sub&gt;p&lt;/sub&gt; = 0.207, mean difference: -4 mmHg) and an increase in brachial artery flow-mediated dilatation (P = 0.030, η&lt;sup&gt;2&lt;/sup&gt; &lt;sub&gt;p&lt;/sub&gt; = 0.206, 2.33%). In addition, there were greater improvements in perceived physical health (P = 0.036, η&lt;sup&gt;2&lt;/sup&gt; &lt;sub&gt;p&lt;/sub&gt; = 0.211, 5 a.u.). No between-group differences were observed for cardiorespiratory fitness, aortic stiffness, circulating glucose, lipids and inflammatory markers. Taken together, post-exercise hot water immersion enhances blood pressure and brachial artery endothelial function, in the absence of improvements in cardiorespiratory fitness, circulating glucose, lipids and inflammatory markers. KEY POINTS: Hot water immersion replicates some of the physiological adaptations to exercise, but it is unclear whether post-exercise hot water immersion can augment exercise-derived improvements in cardiovascular health. This is the first study to assess whether 8 weeks of supervised exercise followed by hot water immersion can augment improvements in cardiovascular and metabolic health compared to post-exercise thermoneutral water immersion in physically inactive middle-aged adults. We demonstrate that 30 min of moderate-intensity aerobic exercise, followed by 40°C water immersion, on average three times a week for 8 weeks, reduces diastolic and mean arterial blood pressure more than exercise followed by thermoneutral immersion at 34°C, and increases brachial artery flow-mediated dilatation. These findings provide novel evidence that post-exercise hot water immersion lowers diastolic blood pressure and mean arterial pressure, and improves brachial artery endothelial function, without further enhancing cardiorespiratory fitness, glucose, lipids or inflamm","PeriodicalId":50088,"journal":{"name":"Journal of Physiology-London","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144734988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SAF-guarding the cuff: Could shoulder fat cells combat fibrosis?","authors":"Lukas Blaas, Leonardo Matta","doi":"10.1113/JP289055","DOIUrl":"https://doi.org/10.1113/JP289055","url":null,"abstract":"","PeriodicalId":50088,"journal":{"name":"Journal of Physiology-London","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144734989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Current advances in large-pore channels: From structure-function to physiology and disease.","authors":"Jorge E Contreras","doi":"10.1113/JP289286","DOIUrl":"https://doi.org/10.1113/JP289286","url":null,"abstract":"","PeriodicalId":50088,"journal":{"name":"Journal of Physiology-London","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2025-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144719030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metabolite-sensitive cross-bridge models of human atria reveal the impact of diabetes on muscle mechanoenergetics.","authors":"Julia H Musgrave, June-Chiew Han, Marie-Louise Ward, Andrew J Taberner, Kenneth Tran","doi":"10.1113/JP288463","DOIUrl":"https://doi.org/10.1113/JP288463","url":null,"abstract":"<p><p>Type 2 diabetes is associated with a range of adverse health outcomes, including metabolic dysfunction and increased risk of heart failure. Although the interactions between diabetes and heart disease are complex and incompletely understood, they can be more effectively investigated using multiscale, biophysically based models of the underlying physiological processes. In this study, experimental data from non-diabetic and diabetic human atrial muscles were used to develop metabolite-sensitive cross-bridge models representing each group. The parameterisation of these cross-bridge models revealed that reduced muscle stress development and a leftward shift of the complex modulus measured in the diabetic muscles could be attributed to reduced cross-bridge stiffness and slower cross-bridge detachment rates, respectively. These cross-bridge models were also integrated into muscle models to investigate the effects of diabetic cross-bridge function, Ca²⁺ handling and altered metabolite availability on isometric and physiological work-loop contractions. The diabetic model produced isometric twitches with lower amplitude and prolonged duration and, in response to lowered ATP concentration, the diastolic stress increased notably. In work-loop simulations, the diabetic model exhibited slower shortening, reduced work output and lower power of shortening. However, it was also more efficient and had a less pronounced negative response to increases in P_i concentration. These simulations demonstrate that while experimentally measured differences in diabetic cardiac tissues can lead to impaired function during physiological contractions, they may also offer compensatory advantages. The insights of this study offer clear mechanisms of mechanoenergetic dysfunction in diabetic heart muscle, identifying potential therapeutic targets to improve cardiac outcomes for individuals with diabetes. KEY POINTS: We used multiscale mathematical models to investigate the interaction between mechanical and energetic systems in diabetic cardiomyopathy. Using previously collected data from human atrial tissues, we developed models of non-diabetic and diabetic cross-bridge function. The models confirmed that the mechanisms underlying slower cycling and lower force production in the diabetic tissues were slower cross-bridge detachment rates and lower cross-bridge stiffness. Integrating into muscle models and predicting the behaviour under different types of contraction revealed that these differences lead to longer force twitches with lower amplitude, less work done, slower shortening and lower power generation in the diabetic muscles. This modelling study presents novel human atrial cross-bridge models and offers clear mechanisms of mechanical and energetic dysfunction in diabetic heart muscle with potential pathways for treatment.</p>","PeriodicalId":50088,"journal":{"name":"Journal of Physiology-London","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144734987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Birds of a feather are lysed together: NPY joins the club of vasoconstriction pathways that get no sympathy during exercise.","authors":"Jeremy K Alpenglow, Jarred J Iacovelli","doi":"10.1113/JP289396","DOIUrl":"https://doi.org/10.1113/JP289396","url":null,"abstract":"","PeriodicalId":50088,"journal":{"name":"Journal of Physiology-London","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144719029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Now and then: Development of spinal Shox2 neurons.","authors":"Mohini Sengupta","doi":"10.1113/JP289015","DOIUrl":"https://doi.org/10.1113/JP289015","url":null,"abstract":"","PeriodicalId":50088,"journal":{"name":"Journal of Physiology-London","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144719031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Do brainstem astrocytes function as cerebral perfusion pressure sensors, as cerebral perfusion sensors or as sensors of specific consequences of cerebral hypoperfusion?","authors":"Elapulli Sankaranarayanan Prakash","doi":"10.1113/JP289430","DOIUrl":"https://doi.org/10.1113/JP289430","url":null,"abstract":"","PeriodicalId":50088,"journal":{"name":"Journal of Physiology-London","volume":" ","pages":""},"PeriodicalIF":4.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144709716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}