Journal of neurophysiology最新文献

{"title":"Third-order entropy for spatiotemporal neural network characterization.","authors":"Sarita S Deshpande, Wim van Drongelen","doi":"10.1152/jn.00108.2024","DOIUrl":"10.1152/jn.00108.2024","url":null,"abstract":"<p><p>The human brain comprises an intricate web of connections that generate complex neural networks capable of storing and processing information based on factors such as network structure, connectivity strength, and interactions. To further unravel and understand this information, we introduce third-order entropy, a new metric grounded in the Triple Correlation Uniqueness (TCU) theorem. Triple correlation, which provides a complete and unique characterization of the network, relates three nodes separated by up to two spatiotemporal lags. Based on these four lags, we evaluate third-order entropy from the spatiotemporal lag probability distribution function (PDF) of the network activity's triple correlation. Given a spike raster, we compute triple correlation by iterating over time and space. Summing the contributions to the triple correlation over each of the spatial and temporal lag combinations generates a 4-D spatiotemporal frequency histogram, from which we estimate a PDF and compute entropy. To validate our approach, we first estimate third-order entropy from feedforward motifs in a simulated spike raster and then simulate the effects of adding increasing motif-class structure to a Poisson-modeled spike raster. Finally, we apply this methodology to spiking activity recorded from rat cortical cultures and compare our results to previously published results of pairwise entropy over time. Although first- and second-order metrics of activity (spike rate and cross-correlation) show agreement with previously published results, our TCU-based third-order entropy computation is a more complete tool for neural network characterization and reveals a greater depth of underlying network organization compared with pairwise entropy.<b>NEW & NOTEWORTHY</b> Here, we present third-order entropy built from triple correlation, which measures spatiotemporal interactions among up to three neurons. Per the Triple Correlation Uniqueness theorem, third-order entropy is based on a complete and unique characterization of the network. We first outline and validate the method and then apply it to an experimental dataset of rat cortical cultures. We show that the third-order entropy metric provides greater insight into network activity compared with pairwise entropy.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1234-1244"},"PeriodicalIF":2.1,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143649227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Postural strategy for two potential targets considering motor costs for postural stabilization and probabilistic information.","authors":"Ryo Watanabe, Takahiro Higuchi","doi":"10.1152/jn.00308.2024","DOIUrl":"10.1152/jn.00308.2024","url":null,"abstract":"<p><p>When an intended action has multiple potential goals, individuals should consider multiple possibilities about future events to react successfully. Previous studies on arm reaching using a \"go-before-you-know\" paradigm have found that hand trajectories under multiple potential targets were spatially averaged between targets and biased based on probabilistic information about the targets. Using a target-stepping task while standing, we recently observed that a prestep posture was planned more advantageously for stepping to the target with higher motor costs for postural stabilization. The present study aimed to examine whether such a postural strategy would be selected when the probability of a potential target with higher motor costs being selected as the true target was low. Fourteen participants (mean age 23.2 ± 4.6 yr) initiated stepping movements knowing only the probability of two potential targets and took a step onto a target revealed after step initiation. The results showed that the participants prepared their mediolateral posture state more advantageously to take a step onto the target with higher costs, even when it was selected with a lower probability. Prestep postures were also affected by the probability information, although the effects were small. Our simulations demonstrated that the postural strategy prioritizing motor costs was mechanically beneficial for affording time to take a step toward the true target while maintaining an upright posture. These findings suggest that, when maintaining postural stability is critical, the central nervous system considers the motor costs for postural stabilization in addition to probability information under multiple potential targets.<b>NEW & NOTEWORTHY</b> Recent studies using a target-reaching task under a \"go-before-you-know\" paradigm have shown that individuals use probabilistic information when planning a motor strategy under multiple potential goals. We introduced this paradigm to a target-stepping task performed while standing and found that motor costs for postural stabilization were considered for initial posture planning under uneven probabilistic targets. These findings indicated that the central nervous system considers motor costs when planning postural strategies to minimize instability.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1191-1204"},"PeriodicalIF":2.1,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143585928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hip posture affects the firing properties of motor units in the tibialis anterior muscle.","authors":"Tetsuya Hirono, Taian M Vieira, Alberto Botter, Kohei Watanabe","doi":"10.1152/jn.00448.2024","DOIUrl":"10.1152/jn.00448.2024","url":null,"abstract":"<p><p>In this study, we contend the firing properties of motor units change due to nonphysiological sources. We specifically ask whether changes in the fibular nerve length, without a concurrent change in tibialis anterior architecture, affect motor unit firing and recruitment strategies. We tested this hypothesis based on high-density surface electromyograms (EMGs) collected from the tibialis anterior of 18 healthy young adults for two hip postures, flexed and extended. To control for changes in peripheral nerve length, conduction time between electrical stimulation and generation of compound action potentials in extensor digitorum brevis was measured for the two hip postures during rest. Motor units were decomposed from EMGs obtained during sustained isometric dorsiflexion at 10% of the maximal voluntary contraction (MVC), and during ramp isometric contractions up to 20% MVC. Individual motor unit firings were identified and tracked between the two postures. Nerve conduction time was significantly shorter in hip flexed than in hip extended posture (<i>P</i> < 0.01), suggesting that peripheral nerve was stretched in the flexed hip posture. MVC torque was not different between flexed and extended postures (<i>P</i> = 0.254). Motor unit firing rates during sustained contraction at 10% of MVC, and during ramp-up contraction to 20% of MVC were significantly lower during flexed hip posture than during extended hip posture (<i>P</i> < 0.05). Hip flexion posture, which likely result in a stretching of the fibular nerve, was observed to reduce the average firing rate of active motor units during relatively low contractions.<b>NEW & NOTEWORTHY</b> Peripheral nerve condition can affect motor unit activations. Sciatic and fibular nerves are stretched by ankle dorsiflexion, knee extension, and hip flexion. Hip flexion posture, which likely result in a stretching of the fibular nerve, was observed to reduce the average firing rate of active motor units during relatively low contraction. Proximal joint posture, which does not directly influence muscle architecture, should be considered to interpret neural input properties.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1074-1082"},"PeriodicalIF":2.1,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143557169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How sub-optimal are the neural representations: show me your null model.","authors":"Movitz Lenninger, Arvind Kumar","doi":"10.1152/jn.00085.2025","DOIUrl":"10.1152/jn.00085.2025","url":null,"abstract":"","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1083-1085"},"PeriodicalIF":2.1,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143515793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Whole body coarticulation reflects expertise in sport climbing.","authors":"Antonella Maselli, Lisa Musculus, Riccardo Moretti, Andrea d'Avella, Markus Raab, Giovanni Pezzulo","doi":"10.1152/jn.00341.2024","DOIUrl":"10.1152/jn.00341.2024","url":null,"abstract":"<p><p>Taking sport climbing as a testbed, we explored coarticulation in naturalistic motor-behavior at the level of whole body kinematics. Participants were instructed to execute a series of climbing routes, each composed of two initial foot-moves equal in all routes, and two subsequent hand-moves differing across routes in a set of eight possible configurations. The goal was assessing whether climbers modulate the execution of a given move depending on which moves come next in the plan. Coarticulation was assessed by training a set of classifiers and estimating how well the whole body (or single-joint) kinematics during a given stage of the climbing execution could predict its future unfolding. Results showed that most participants engage in coarticulation, with temporal and bodily patterns that depend on expertise. Nonclimbers tend to prepare the next-to-come move right before its onset and only after the end of the previous move. Rather, expert-climbers (and to a smaller extent, beginner-climbers) show early coarticulation during the execution of the previous move and engage in adjustments that involve the coordination of a larger number of joints across the body. These results demonstrate coarticulation effects in whole body naturalistic motor behavior and as a function of expertise. Furthermore, the enhanced coarticulation found in expert-climbers provides hints for experts engaging in more refined mental processes converting abstract instructions (e.g., move the right hand to a given location) into motor simulations involving whole body coordination. Overall, these results contribute to advancing our current knowledge of the rich interplay between cognition and motor control.<b>NEW & NOTEWORTHY</b> The current study explores the way in which having formed a plan for a sequential motor task affects its execution. We showed that climbing expertise increases the extent to which participants adjust their motor execution based on the moves that follow in a planned route. These results provide evidence of coarticulation in naturalistic motor behavior and suggest enhanced skills in mentalizing forward motor control and optimal-control strategies in expert climbers.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1016-1033"},"PeriodicalIF":2.1,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143416732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Visual properties of action consequences and not environments affect context-specific motor learning.","authors":"Shanaathanan Modchalingam, Andrew King, Bernard Marius 't Hart, Denise Y P Henriques","doi":"10.1152/jn.00268.2024","DOIUrl":"10.1152/jn.00268.2024","url":null,"abstract":"<p><p>The human motor system can adapt to perturbations by updating existing internal models of motor control or by creating context-specific motor memories or strategies that can be flexibly activated or deactivated. Using a virtual target-directed ball rolling task, we investigate whether motor learning is context specific when perturbations are applied to either the throw direction of a ball, or the acceleration of the ball postrelease. In addition, by altering the visual slant of the task surface in an immersive virtual-reality environment, we determine whether informative visual cues that predict visual perturbations to expected action consequences affect the propensity for context-specific motor learning. Our findings reveal that perturbations resembling postthrow accelerations enable flexible, context-specific motor adaptation regardless of the presence of the visual slant cues. Perturbations in the throw directions, conversely, lead to the updating of existing internal models. In addition, we find fast implicit visual-context-specific changes in performance during early learning and context switching. Our findings underscore the role of visual properties of both perturbations and environments in flexible and generalizable motor learning. Data and analysis scripts are available at https://osf.io/a5nv3/.<b>NEW & NOTEWORTHY</b> We investigated how the visual features of action consequences, like the trajectory of a thrown ball, influence the brain's ability to adapt motor skills in changing contexts. We show that perturbations mimicking real-world accelerations enable context-specific adaptation, unlike visuomotor rotations. In addition, we found that visual environment context can modulate early implicit motor behavior but does not affect the propensity for updating existing internal models during motor learning.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1176-1190"},"PeriodicalIF":2.1,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143542356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Examining a role for irisin in treating cerebral ischemia.","authors":"Jack Bayfield, Hanna R Elford, Brian R Christie","doi":"10.1152/jn.00027.2025","DOIUrl":"10.1152/jn.00027.2025","url":null,"abstract":"<p><p>Stroke is a leading cause of death and disability, with ischemic stroke representing most cases. Age is the most significant nonmodifiable risk factor for stroke, and with an aging population, there is an urgent need for effective prevention and treatment strategies. Physical inactivity is a strong risk factor for stroke, and exercise has long been held as a promising approach to improve poststroke outcomes. During exercise, the myokine irisin is released as a product of a type 1 membrane protein cleavage that is encoded by the fibronectin type III domain containing 5 (FNDC5) gene. This review summarizes recent literature on irisin's role in ischemic stroke, examining central effects, stroke risk, poststroke functional outcomes, and exogenous administration. Irisin has value as a prognostic marker for risk stratification. Low levels of irisin correlate with worse outcomes and higher mortality in patients with ischemic stroke. Irisin may also be a key to the benefits of exercise, particularly for high-intensity resistance training, which significantly increases irisin levels. Beyond exercise, exogenous irisin is neuroprotective in murine models, reducing brain edema, inflammation, and apoptosis, and increasing blood-brain barrier integrity and brain-derived neurotrophic factor levels. This underscores irisin's potential to mitigate ischemic damage and promote recovery. Human trials are necessary to validate these findings and explore the feasibility of irisin-based interventions in acute stroke care. This review lays a foundation for future research to clarify irisin's therapeutic benefits, establish optimal exercise protocols, and explore exogenous irisin as a novel intervention for ischemic stroke.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1320-1328"},"PeriodicalIF":2.1,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143710308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of age and feedback modality on the proprioceptive sense of force: insights from motor unit recordings.","authors":"Mélanie Henry, Abdulkerim Darendeli, Taylor Tvrdy, Sajjad Daneshgar, Roger M Enoka","doi":"10.1152/jn.00486.2024","DOIUrl":"10.1152/jn.00486.2024","url":null,"abstract":"<p><p>The primary purpose of our study was to compare the influence of feedback modality (visual vs. auditory) on force-reproduction accuracy in middle-aged and older adults. As a secondary objective, we investigated whether expected differences would be reflected in the neural drive sent to a hand muscle during the task. Participants (<i>n</i> = 42; 40-84 yr) performed a force-reproduction task with the first dorsal interosseus muscle at two target forces [5% and 20% of maximal voluntary contraction (MVC)]. Each trial involved a target phase that was guided by visual or auditory feedback and then a reproduction phase without feedback. The neural drive was characterized by measures of force steadiness and motor unit discharge characteristics during the target phase. Force-reproduction accuracy at the lower target force declined with increasing age and with visual feedback compared with auditory feedback. In contrast, there was no evidence of an effect of age or condition on force-reproduction accuracy at the moderate target force (20% MVC). Force steadiness was worse and motor unit coherence in the delta and beta bands was greater when the task was guided by auditory feedback at both target forces. These findings indicate that greater accuracy during the low-force task in the auditory-feedback condition was accompanied by a noisier control signal and differences in motor unit coherence in the delta and beta bands during the target phase.<b>NEW & NOTEWORTHY</b> The sense of force can be assessed with force-reproduction tasks, which typically involve visual feedback of the applied force during the target phase. Middle-aged and older adults improved force-reproduction accuracy when using auditory instead of visual feedback. This effect was accompanied by an increase in motor unit coherence in the beta band. This provides evidence for different sensorimotor processing of proprioceptive inputs when these sensory modalities are used to provide feedback of the applied force.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1103-1115"},"PeriodicalIF":2.1,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143523712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The influence of postural threat-induced anxiety on locomotor learning and updating: a mini-review.","authors":"Peiqi Lu","doi":"10.1152/jn.00199.2024","DOIUrl":"10.1152/jn.00199.2024","url":null,"abstract":"<p><p>Anxiety, as a multifaced construct encompassing physiological, cognitive, and behavioral responses to perceived stress, is associated with locomotion. This mini-review focuses on a study using the \"broken-escalator phenomenon\" to explore how postural threat-induced anxiety affects locomotor adaptation (learning) and deadaptation (updating). The study sheds light on the significance of perceived safety and appropriate structure of the environment for effective learning. The review also comments on related paths of inquiry and potential future directions.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1205-1207"},"PeriodicalIF":2.1,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143605018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distinct firing responses to synthetic synaptic currents in the adult murine reticular and relay thalamus.","authors":"Isaac Y M Chang, Jeanne T Paz","doi":"10.1152/jn.00052.2025","DOIUrl":"10.1152/jn.00052.2025","url":null,"abstract":"<p><p>Numerous cortical and subcortical inputs innervate the thalamus and robustly control thalamic activity. These synaptic inputs differ in shape and undergo dynamic changes throughout development and disease conditions. How the shape of postsynaptic currents regulates thalamic neuronal firing has been studied mainly in young rodents with immature neural development and function. Here, we use adult mice with mature intrinsic excitability to address this question in two compartments of the thalamus-the nucleus reticularis thalami (nRT) and thalamocortical (TC) relay nuclei. Using whole cell patch-clamp electrophysiology, we simulated synthetic inhibitory (IPSCs) and synthetic excitatory postsynaptic currents (EPSCs), injected them in nRT and TC neurons, and examined how changes in their shape parameters regulated neuronal firing in different electrical states. We found that in response to synthetic IPSCs, TC neurons initiate low-threshold spikes (LTSs) earlier than nRT neurons, and the amplitude of IPSCs regulates the probability of initiating an LTS while the duration of IPSCs regulates the timing at which the LTS initiates. These results show that in the adult thalamus, LTS is regulated by IPSCs similarly to what has been reported for the immature thalamus. In addition, sharp driver-like EPSCs evoke more firing when nRT and TC neurons are silent; whereas slow modulator-like EPSCs evoke more firing when nRT and TC neurons are active. Critically, we have generated a quantitative map of how features of synaptic currents shape neuronal firing in relationship with activity states.<b>NEW & NOTEWORTHY</b> We provide a systematic overview of how the shape parameters (i.e., amplitude, duration, and charge) of synthetic inhibitory and excitatory synaptic currents regulate neuronal firing in the adult murine thalamus across cell types (nRT vs. TC neurons) and electrical states (active vs. silent).</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1329-1340"},"PeriodicalIF":2.1,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143710229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}