Experimental Physiology最新文献

{"title":"The perception of the position of an unseen limb: Investigation of the effect of thixotropic conditioning on drift and accuracy.","authors":"Simon C Gandevia, Georgia Fisher, Joanna Diong, Annie A Butler, Martin E Héroux","doi":"10.1113/EP092686","DOIUrl":"https://doi.org/10.1113/EP092686","url":null,"abstract":"<p><p>Proprioceptive judgements can be divided into two broad categories: low-level and high-level. Low-level judgements of limb position require a person to detect, discriminate or match the position of a body part, whereas high-level judgements require a person to report the position of an unseen body part relative to the external world. It has been suggested that muscle thixotropy - the influence of recent contraction or stretch on the passive properties of a muscle - impacts both the accuracy of low-level judgements of limb position and the degree to which these judgements drift over time. However, high-level proprioceptive judgements of upper limb position and the degree to which they drift over time may not be affected by thixotropy. This was investigated here. Twenty-five healthy adult participants made visual judgements about the perceived position of their hidden index finger after their elbow muscles had been conditioned with a flexion or extension contraction, or after a series of large passive elbow movements. After conditioning contractions, participants made small errors (∼2°) in perceived index finger position in the direction of elbow flexion, regardless of the contraction type. There was little to no effect of either contraction type on drift in perceived index-finger position in our test. Our results support the view that high-level proprioceptive judgements of hand position can be minimally affected by the effects of muscle thixotropy. Thus, we suggest that muscle spindle signals do not dominate the central, cross-modal transformations of sensory information that are required for high-level proprioceptive judgements.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144265782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surgery in space: The ultimate frontier.","authors":"Mohamad Bashir, Ali Murtada, Matti Jubouri, Adam Bashir, Ian Williams, Damian Bailey","doi":"10.1113/EP092765","DOIUrl":"https://doi.org/10.1113/EP092765","url":null,"abstract":"","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144265781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aortic and cardiovascular remodelling after thoracic endovascular aortic repair for blunt traumatic aortic injury in younger patients: A narrative review of physiological and clinical outcomes.","authors":"Marco David Bokobza De la Rosa, Matti Jubouri, Thurkga Moothathamby, Mohamed Refaie, Ali Murtada, Idhrees Mohammed, Ian M Williams, Damian M Bailey, Mohamad Bashir","doi":"10.1113/EP092615","DOIUrl":"https://doi.org/10.1113/EP092615","url":null,"abstract":"<p><p>Blunt traumatic aortic injury (BTAI) is severe, often fatal in younger populations due to high-energy deceleration mechanisms. Thoracic endovascular aortic repair (TEVAR) has revolutionised BTAI treatment, surpassing the previously standard open surgical repair in mortality and complication rates. Despite its success, concerns arise regarding TEVAR's long-term effects, especially in younger BTAI patients. Key physiological changes following TEVAR include alterations in aortic size, shape, compliance and flow dynamics, leading to loss of the Windkessel effect and a consequent increased pulse wave velocity and decreased radial strain, which can contribute to the development of hypertension. These alterations also predispose patients to changes in cardiovascular flow (increased reverse systolic flow, reduced maximum velocity and altered helical flow), potentially increasing the risk of left ventricular dysfunction and coronary artery disease. Physiological changes also increase the likelihood of complications such as graft migration. Clinical outcomes of TEVAR for BTAI have generally been favourable, with significant reductions in mortality and cerebrovascular accident rates compared to open surgical repair. However, long-term complications, including the need for re-interventions, remain a concern, though studies suggest these are infrequent. The durability of TEVAR in younger patients, who may experience decades of device use, poses unique challenges, particularly due to the natural progression of aortic morphology over time. Therefore, adapting TEVAR to the physiological needs of younger BTAI patients is essential. Developing more compliant endografts and using shorter stents with improved materials can help minimise structural and haemodynamic changes and enhance cardiovascular outcomes, supporting the long-term health of this vulnerable population.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144257664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Size, more than oxygen need, determines the number of capillaries around a muscle fibre.","authors":"Christopher S Fry, Carlo Reggiani","doi":"10.1113/EP092911","DOIUrl":"https://doi.org/10.1113/EP092911","url":null,"abstract":"","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144247096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diffusion and physical constraints limit oxidative capacity, capillary supply and size of muscle fibres in mice and humans.","authors":"Hans Degens, Guy A M Messa, Jason Tallis, Alessandra Bosutti, Tomas Venckunas, Ismail Adeniran, Rob C I Wüst, Paul W Hendrickse","doi":"10.1113/EP092750","DOIUrl":"https://doi.org/10.1113/EP092750","url":null,"abstract":"<p><p>It has been suggested that angiogenesis during skeletal muscle fibre hypertrophy allows escape from the 'size constraint', which is the inverse relationship between oxidative capacity and muscle fibre cross-sectional area (FCSA). It is, however, not known whether there are any limitations to the combinations of FCSA, oxidative capacity and capillary supply to an individual fibre. We determined the FCSA, oxidative capacity and capillary supply to fibres from highly resistance-trained men before and after superimposed endurance training, recreationally active men and women, and different mouse muscles. Both the oxidative capacity and the number of capillaries around a fibre (CAF) per FCSA (CAF/FCSA) showed an upper limit at each FCSA, irrespective of species, muscle origin or training status. The upper limit of fibre oxidative capacity was likely determined by diffusion constraints. The upper limit of CAF/FCSA was determined by physical constraints where (i) there is no further reduction in maximal diffusion distance to the core of a fibre beyond a CAF of 2, and (ii) the reduction in fibre area supplied by a capillary diminishes exponentially with an increase in CAF. The calculated upper limits of oxidative capacity and CAF/FCSA of a fibre of a given FCSA were linearly related. Irrespective of species, sex, muscle of origin and training status, our data indicate that diffusion limitations and physical limitations to capillary placement around a fibre place an upper limit on the oxidative capacity and capillary supply to a fibre of a given size, respectively.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144247095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ageing exacerbates the adverse effects of respiratory muscle fatigue on vascular function, locomotor muscle fatigue and exercise performance in males.","authors":"Valentin Mons, Colin Lavigne, Olivier Meste, Benjamin Mauroy, Gregory M Blain","doi":"10.1113/EP092897","DOIUrl":"https://doi.org/10.1113/EP092897","url":null,"abstract":"<p><p>This study investigated the effect of respiratory muscle fatigue on cardiovascular function, locomotor muscle fatigue and exercise performance in young and master athletes, a model of successful ageing. Ten young male (YA, 27.4 ± 4.4 years) and 11 male master endurance athletes (MA, 65.0 ± 5.1 years) performed, on separate days, two constant workload cycling tests at 90% of peak power to exhaustion (CWT) following a fatiguing inspiratory loading task at 60% (ILT_60%) and a sham task at 2% (ILT_2%) of their maximal inspiratory pressure. On a third day, the sham task was replicated but CWT was interrupted at the time equal to that performed during CWT_ILT60% (CWT_ILT2%-ISO). Quadriceps fatigue was assessed by changes in maximal voluntary isometric contraction (MVC), potentiated twitch force (QT_SINGLE) and voluntary activation (VA) from 15 s to 15 min post-exercise. Mean arterial pressure (MAP) was measured using finger pulse photoplethysmography. Blood flow (Q̇_L) and limb vascular conductance (LVC) were measured using Doppler ultrasound. During ILT_60%, MA demonstrated reduced Q̇_L (P = 0.036), a greater increase in MAP (P < 0.001) and a larger decrease in LVC (P = 0.044) compared to YA. During CWT_ILT60%, MA experienced a larger decrease in time to exhaustion (-39.7 ± 14.0%) than YA (-15.5 ± 13.9%, P = 0.010). Exercise-induced reductions in MVC and QT_SINGLE (both P < 0.039) were also more pronounced during CWT_ILT60% compared to CWT_ILT2%-ISO in MA. Ageing exacerbates the adverse effects of respiratory muscle fatigue on limb vascular function and locomotor muscle fatigue during subsequent exercise, resulting in greater impairments in exercise performance.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144233641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Caffeine in cerebrovascular research: To withdraw or not to withdraw?","authors":"Brooke R Shepley, Kevin J Milne, Anthony Richard Bain","doi":"10.1113/EP092703","DOIUrl":"https://doi.org/10.1113/EP092703","url":null,"abstract":"","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144224853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deep-learning models of the ascending proprioceptive pathway are subject to illusions.","authors":"Adriana Perez Rotondo, Merkourios Simos, Florian David, Sebastian Pigeon, Olaf Blanke, Alexander Mathis","doi":"10.1113/EP092313","DOIUrl":"https://doi.org/10.1113/EP092313","url":null,"abstract":"<p><p>Proprioception is essential for perception and action. Like any other sense, proprioception is also subject to illusions. In this study, we model classic proprioceptive illusions in which tendon vibrations lead to biases in estimating the state of the body. We investigate these illusions with task-driven models that have been trained to infer the state of the body from distributed sensory muscle spindle inputs (primary and secondary afferents). Recent work has shown that such models exhibit representations similar to the neural code along the ascending proprioceptive pathway. Importantly, we did not train the models on illusion experiments and simulated muscle-tendon vibrations by considering their effect on primary afferents. Our results demonstrate that task-driven models are indeed susceptible to proprioceptive illusions, with the magnitude of the illusion depending on the vibration frequency. This work illustrates that primary afferents alone are sufficient to account for these classic illusions and provides a foundation for future theory-driven experiments.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144215373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Eccentric training at long muscle lengths induces greater corticospinal and spinal reflex plasticity than eccentric training at short muscle lengths.","authors":"Julian Colard, Yohan Betus, Tristan Tallio, Baptiste Bizet, Antoine Nordez, Marc Jubeau, Thomas Cattagni","doi":"10.1113/EP092470","DOIUrl":"https://doi.org/10.1113/EP092470","url":null,"abstract":"<p><p>It is well-established that resistance training generates neural adaptations. These may be greater when exercises mainly include eccentric contractions or when muscles are trained at long length. However, it remains to be clarified whether the length at which muscles are trained influences neural adaptation following eccentric training. We trained 28 healthy young individuals with eccentric exercises for 9 weeks (24 sessions) at either short (n = 13) or long (n = 15) plantar flexor lengths. Participants were assessed once before and once after this training. Estimates of corticospinal excitability and short-interval intracortical inhibition were obtained using transcranial magnetic stimulation and by analysing conditioned or non-conditioned motor evoked potentials. Effectiveness of Ia afferents to discharge α-motoneurons, and post-activation depression induced by primary afferent depolarization were estimated using peripheral tibial nerve stimulation conditioned or not by fibular nerve stimulation, and by analysing Hoffmann reflex amplitude. Maximal plantar flexor torque and voluntary activation were also assessed. The increase in corticospinal excitability and effectiveness of Ia afferents to discharge α-motoneurons were significantly greater after training at long muscle length than at short muscle length (+24.03% and +16.1%, respectively, P < 0.001), without between-group differences in adaptations for short-interval intracortical inhibition, post-activation depression by primary afferent depolarization, maximal torque or voluntary activation level. These results suggest that eccentric training performed at long muscle lengths induces greater adaptations in corticospinal and spinal reflex plasticity. It is crucial to consider muscle length during eccentric training to optimize neuronal plasticity and potentially enhance daily task performances.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144198631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Acute alterations in blood lactate in the setting of transient stress induced myocardial ischaemia.","authors":"Jamie M O'Driscoll, Elliot Smith, Matchel Bibat, Jamie J Edwards, Claire Compton, Konstantina Kipourou, Damian Coleman, Jonathan Wiles, Eliane Cunliffe, Anna Marciniak, Rajan Sharma","doi":"10.1113/EP092429","DOIUrl":"https://doi.org/10.1113/EP092429","url":null,"abstract":"<p><p>An elevation in resting venous blood lactate ([La^-]_b) levels in conditions of myocardial hypoperfusion is associated with adverse prognosis and survival. This investigation aimed to assess changes in venous [La^-]_b levels induced by dobutamine stress in the presence and absence of myocardial ischaemia and adverse outcomes at 1 year. Four hundred and four consecutive patients (mean age 70 ± 10 years, 243 male) reporting chest pain underwent dobutamine stress echocardiography (DSE) and were categorised as ischaemic (IS) or non-ischaemic (NI) responders. Conventional and global longitudinal strain (GLS) echocardiographic measures were recorded at rest. Venous [La^-]_b samples were acquired at rest, peak stress and 1, 3, 5 and 10 min into recovery using a commercially available Lactate Pro 2 device. There were no significant differences in [La^-]_b concentrations between IS (1.75 ± 0.76 mmol L^-1) and NI (1.73 ± 0.60 mmol L^-1) responders at baseline (P = 0.592). However, [La^-]_b concentrations were significantly greater at peak stress (1.83 ± 0.57 vs. 1.68 ± 0.60 mmol L^-1), 1 (1.90 ± 0.56 vs. 1.73 ± 0.71 mmol L^-1), 3 (1.97 ± 0.56 vs. 1.73 ± 0.71 mmol L^-1), 5 (1.98 ± 0.60 vs. 1.74 ± 0.70 mmol L^-1) and 10 min (2.01 ± 0.63 vs. 1.76 ± 0.71 mmol L^-1) into recovery between IS and NI responders (all P < 0.001). GLS was significantly lower in IS compared to NI (-15.5 ± 2.9 vs. -16.2% ± 2.7%, P = 0.02) responders at baseline. In patients who experienced an adverse cardiac event during 1 year of follow-up, GLS (-14.4 ± 2.7 vs. -16.1% ± 2.8%, P < 0.001) and [La^-]_b concentrations were significantly lower at baseline (1.54 ± 0.55 vs. 1.78 ± 0.70 mmol L^-1, P = 0.02), as were [La^-]_b concentrations at 5 (1.68 ± 0.55 vs. 1.88 ± 0.68 mmol L^-1, P = 0.04) and 10 min (1.70 ± 0.56 vs. 1.93 ± 0.71 mmol L^-1, P = 0.02) into recovery compared to patients who did not experience an adverse event. GLS (hazard ration (HR) 1.21; 95% CI: 1.11-1.33, P < 0.001) and [La^-]_b concentrations at 10 min into recovery (HR 0.54; 95% CI: 0.33-0.85, P = 0.01) were significant independent predictors of an adverse event. Transient myocardial ischaemia is associated with a significant elevation in [La^-]_b concentrations, which extends into the recovery period, compared to NI responders. A blunted metabolic response to dobutamine stress and attenuated longitudinal myocardial mechanics are independently associated with short-term adverse events.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144208109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}