Journal of neurophysiology最新文献

{"title":"Transcutaneous stimulation of the cervical spinal cord facilitates motoneuron firing and improves hand-motor function after spinal cord injury.","authors":"Nikhil Verma, Jeonghoon Oh, Ernesto Bedoy, Nikole Chetty, Alexander G Steele, Seo Jeong Park, Jaime R Guerrero, Amir H Faraji, Douglas Weber, Dimitry G Sayenko","doi":"10.1152/jn.00422.2024","DOIUrl":"https://doi.org/10.1152/jn.00422.2024","url":null,"abstract":"<p><p>Spinal cord injury (SCI) interrupts signal transmission between the brain and muscles, often leading to permanent motor impairments. Improving hand function is the highest priority for people with tetraplegia. Electrically engaging spinal circuits using spinal cord stimulation has been demonstrated to improve hand function in people with paralysis post-SCI. Here, we utilized a non-invasive intervention - transcutaneous spinal cord stimulation (tSCS) to facilitate voluntary hand function after SCI. We used a multi-cathode tSCS array to study recruitment patterns across various upper-limb muscles, including forearm subcompartments, in five neurologically intact (NI) participants and five participants with SCI. Our primary objectives was to employ tSCS over the cervical spinal cord to delineate the stimulation-evoked response patterns and assess the effects of tSCS on hand motor function in both groups. We demonstrated that tonic tSCS targeting hand muscles enhanced muscle activity (by up to 21%), increased grip strength (by up to 55%), and improved activation patterns in the participants with SCI. Furthermore, using high-density electromyography-based extraction of motor unit activity, we provided experimental evidence that tSCS can transsynaptically modulate the activity of individual motor units, enabling integration of supraspinal inputs within these networks. Our results indicate that targeted tSCS can immediately improve hand motor function after SCI and suggest potential mechanisms for its facilitatory effects. Similar facilitation of motor unit activity, enhanced muscle activation(up to 65%), and, in some cases, grip strength increases of up to 66%, were also observed in NI participants, indicating that cervical tSCS engages spinal sensorimotor circuits consistently across populations.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144266380","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":"Flexible tapping synchronization in macaques: dynamic switching of timing strategies within rhythmic sequences.","authors":"Ameyaltzin Castillo-Almazán, Oswaldo Pérez, Luis Prado, Nori Jacoby, Hugo Merchant","doi":"10.1152/jn.00158.2025","DOIUrl":"https://doi.org/10.1152/jn.00158.2025","url":null,"abstract":"<p><p>The ability to synchronize bodily movements with regular auditory rhythm across a broad range of tempos underlies humans' capacity for playing music and dancing. This capability is prevalent across human cultures but relatively uncommon among non-human species. Recent research indicates that monkeys can predictively synchronize to regular, isochronous metronomes, exhibiting a preference for visual rather than auditory sequences. In this study, we trained macaques to perform a visual synchronization tapping task, testing their synchronization abilities over a wide tempo range and characterizing their precision and accuracy in timing intervals throughout rhythmic sequences. Additionally, we investigated whether the macaques employed priors or error correction strategies to maintain synchrony with the metronome. Our findings demonstrate that, following sufficient training, macaques exhibit a remarkable capability to synchronize across diverse tempos. Through an inference model analysis, we identified two distinct timing control strategies used by the macaques: an initial strong regression-to-the-mean effect transitioning dynamically into a more precise error correction approach at their preferred tempo. These results provide compelling evidence that primates possess sophisticated rhythmic timing mechanisms, effectively leveraging internal and external cues to regulate their tapping behavior according to task demands.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144258294","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":"Respiratory Sinus Arrhythmia Reactivity in Children: Implications for Emotion Regulation and Dyadic Approaches.","authors":"Minella Aghajani, Amber Efthemiou, Emily Manasian","doi":"10.1152/jn.00193.2025","DOIUrl":"https://doi.org/10.1152/jn.00193.2025","url":null,"abstract":"<p><p>Respiratory sinus arrhythmia (RSA) has been implicated in emotional responding in children and is susceptible to the influences of contextual factors. There are mixed findings regarding adaptive changes in RSA reactivity in response to stressors and challenges. This review identifies contextual factors that contribute to the variation in adaptive responses to emotional stressors and provides an outlet for the utility of dyadic approaches in understanding these patterns in children.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144258295","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":"Complementary functional profiles of mismatch responses mediated by adaptation and deviance detection point to two distinct auditory short-term memory systems.","authors":"Tobias Teichert, Hank Jedema, Zjihun Zhen, Kate Gurnsey","doi":"10.1152/jn.00515.2024","DOIUrl":"https://doi.org/10.1152/jn.00515.2024","url":null,"abstract":"<p><p><i>Mismatch negativity is a macroscopic EEG deflection in response to potentially informative auditory events, e.g., rare or unexpected sounds. Mismatch negativity reflects</i> two processes: (i) adaptation, a reduction of responses to repeated sounds and (ii) deviance detection, an enhancement of responses to sounds violating an expected pattern, likely mediated by predictive coding. <i>Adaptation and deviance detection both reflect information about past sounds and are thus dependent on an auditory memory trace. While the two processes have been distinguished theoretically, computationally and anatomically, it is not known if they use information from the same or different memory systems. To answer this question, macaque monkeys listened to a modified roving standard paradigm with a many-standard control condition designed to split mismatch responses into adaptation and deviance detection as a function of delay and frequency difference. Using computational modelling, we confirm that the requirements for isolating adaptation and deviance detection are met. We show that micro- and macroscopic mismatch responses were dominated by adaptation at short latencies but included a meaningful contribution of deviance detection at longer latencies. Most importantly, we show that mismatch responses mediated by adaptation have a short temporal scope and narrow frequency tuning consistent with its dependence on echoic memory. In contrast, mismatch responses mediated by deviance detection have a longer temporal scope but broader frequency tuning, thus pointing to a different memory system. These clearly distinct functional profiles shed light on the evolutionary need for two separate but complementary mechanisms for guiding attention to potentially informative auditory events.</i></p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144258293","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":"Risk optimization during ongoing movement: Insights from movement and gaze behavior in throwing.","authors":"Stephan Zahno, Damian Beck, Ralf Kredel, André Klostermann, Ernst-Joachim Hossner","doi":"10.1152/jn.00606.2024","DOIUrl":"https://doi.org/10.1152/jn.00606.2024","url":null,"abstract":"<p><p>Handling motor noise is fundamental to successful sensorimotor behavior, especially in high-risk situations. Research using finger-pointing tasks shows that humans account for motor noise and costs of potential outcomes in movement planning. However, does this mechanism generalize to more complex movement tasks? Here, we investigate sensorimotor behavior under risk in a virtual reality throwing task across three experiments with 20 participants each. Their task was to throw balls at a target circle, partially overlapped by a penalty circle. In the experiments, penalty magnitude and the distance between the circles were manipulated. We measured the location of their final gaze fixation before movement-as an indicator of their planned aiming point-and the ball's impact location. Without penalty, the final gaze fixation and the ball's impact location were both centered on the target. In the penalty condition, the location of the participants' final gaze fixations and the ball's impact shifted away from the penalty circle, with larger shifts for higher penalties and smaller distances. Interestingly, the shifts in the ball's impact locations were not only larger (\"less risk seeking\") but also closer to the statistically optimal (expected gain-maximizing) location compared to the fixated aim points. Movement trajectory analyses show that, in penalty conditions, the shifts away from the penalty zone increased until the final phases of the movement. Based on these results, we propose the hypothesis that risk evaluation is not completed in a pre-movement planning phase but is further optimized during movement execution.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144248363","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":"Ineffective cues for contextual saccade adaptation.","authors":"Maxime Martel, Laurent Madelain","doi":"10.1152/jn.00148.2025","DOIUrl":"https://doi.org/10.1152/jn.00148.2025","url":null,"abstract":"<p><p>Contextual saccadic adaptation is investigated through a variant of the double-step paradigm, where two directions of intra-saccadic steps are signaled by two cues. This enables the simultaneous induction of two distinct saccadic adaptations. Surprisingly, contextual adaptation is effective only with motor-related cues, whereas visual cues such as target color and shape do not elicit significant adaptation. We tested nine different contextual cues to signal intra-saccadic steps in a contextual double-step paradigm: visual stimulus duration, lateralization of a sound, various statistical regularities across trials, symbolic cues, starting location of the target, as well as the amplitude of the first step or the target color and shape. Robust systematic contextual learning was found under the amplitude and the starting location experiments, while no learning occurred with any other cues. This lack of contextual learning further confirms that the prediction of the intra-saccadic steps depends on the nature of the context. In two additional experiments replicating those using target color and shape, as well as symbolic cues, participants were periodically prompted to explicitly report the contextual cue they had just experienced. Again, no systematic contextual adaptation was observed despite participants achieving reporting the contextual cue accurately. This dissociation between perceptual reports and motor tasks involving the same visual information aligns with previous results on the constraints for contextual learning. The saccadic system, evolutionarily specialized for spatial targeting, exhibits selective learning that prioritizes localization cues, effectively ignoring non-motor cues in its learning processes, even when such cues are explicitly perceived.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144225755","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":"Enhanced amygdala inhibitory neurotransmission and its vulnerability to hyperthermic stress in <i>Atp1a2</i>-deficient heterozygous mice.","authors":"Shin'Ichiro Satake, Shigefumi Yokota, Keiko Ikeda","doi":"10.1152/jn.00157.2025","DOIUrl":"https://doi.org/10.1152/jn.00157.2025","url":null,"abstract":"<p><p>The sodium pump (Na,K-ATPase, NKA) is a membrane-bound enzyme crucial for maintaining Na⁺/K⁺ electrochemical gradients across plasma membranes. NKA constitutes catalytic α and auxiliary β subunits, of which four α and three β isoforms have been identified. The physiological roles of the isoforms are not fully understood; nevertheless, mutations in the human α2 subunit gene <i>ATP1A2</i> have been linked to various neurological disorders, including familial hemiplegic migraine type 2 (FHM2), alternating hemiplegia of childhood (AHC), and epilepsy syndromes, with symptoms typically triggered by physical and psychological stressors. Mice lacking <i>Atp1a2</i> die of respiratory failure at birth, whereas heterozygous fetuses (<i>Atp1a2^+/-</i>) survive and exhibit increased c-Fos expression in the principal excitatory neurons of the amygdala, suggesting increased neuronal activity. We compared neurotransmission properties in the basolateral amygdala (BLA) between juvenile <i>Atp1a2^+/-</i> mice and their wild-type (WT) littermates using acute brain slices to elucidate the physiological significance of α2-NKA. Focal electrical stimulation elicited inhibitory and excitatory postsynaptic currents (IPSCs and EPSCs) in regularly spiking principal neurons within the BLA. Both IPSC and EPSC amplitudes increased linearly with stimulation intensity. IPSCs were consistently larger in <i>Atp1a2^+/-</i> compared to WT, whereas EPSCs were comparable between the two groups. Notably, the enhanced inhibitory neurotransmission observed in <i>Atp1a2^+/-</i> was abolished under hyperthermic stress. The disrupted balance between inhibition and excitation in BLA neuronal networks may be a key pathophysiological mechanism underlying α2-NKA-related disorders.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144225754","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":"Investigating motor unit firing rates during arm cycling compared to intensity-matched isometric contractions in humans.","authors":"Daniel C Basile, Alysha D Wira, Charles L Rice, Kevin E Power","doi":"10.1152/jn.00128.2025","DOIUrl":"https://doi.org/10.1152/jn.00128.2025","url":null,"abstract":"<p><p>Studies in humans have not assessed motor unit firing rates (MUFR) recorded from intramuscular electromyography (EMG) during a rhythmic locomotor output. Using arm cycling as a model of locomotor generated activity, the purpose was to determine whether MUFR differed during arm cycling compared to intensity-matched isometric contractions. We hypothesized that MUFR would be greater during arm cycling than isometric contractions, assessed at various working intensities. Young males (n=10) and females (n=4) completed arm cycling bouts and isometric contractions of the biceps brachii. Indwelling fine-wire electrodes were inserted into the biceps brachii to record MUFR during arm cycling with combinations of two power outputs (25 and 50 W) and cadences (30 and 60 RPM), and subsequently compared to intensity-matched isometric contractions. Motor unit recordings were analyzed during the flexion phase of arm cycling when biceps brachii EMG activity was high, and with the forearms in a neutral grip position. Results indicated that MUFR were significantly higher during arm cycling compared to isometric contractions (p=0.003), and MUFR increased with greater cycling intensity (p<0.001). Higher MUFR demonstrated during arm cycling were likely influenced by greater descending drive and/or enhanced spinal motoneuron excitability, facilitated through CPG-mediated changes to intrinsic motoneuron properties. Thus, different neural control strategies are used during rhythmic locomotor output compared with isometric contractions in humans.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144225756","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":"Temperature-induced shifts and temperature compensation in the tuning of motion-sensitive neurons of bumblebees.","authors":"Bianca Jaske, Keram Pfeiffer","doi":"10.1152/jn.00013.2025","DOIUrl":"10.1152/jn.00013.2025","url":null,"abstract":"<p><p>Bumblebees are poikilothermic insects, i.e., their body temperature generally follows the ambient temperature. However, within certain boundaries, bumblebees are able to increase their body temperature above the ambient temperature through shivering thermogenesis. Biophysical processes, including neuronal activity, depend on temperature. In the past, the influence of temperature on sensory systems and neuronal coding was investigated in different insect species. Most studies described a temperature dependency of neuronal responses, yet some behavioral processes require robust encoding of information. Here we investigated the influence of temperature on the tuning of wide-field motion-sensitive neurons in the central brain of bumblebees. Using multiunit recordings, we examined neuronal tuning properties to translational motion by presenting moving gratings at two head temperature conditions. Although the tuning of most neurons showed a temperature dependency, some neurons stayed unaffected within the tested temperature range. In a third group of neurons the tuning was not affected by temperature for one movement direction of the stimulus, whereas the response to the opposite direction was temperature dependent. These different response types might serve different behavioral functions. Neurons that are involved in the control of self-motion might require temperature-dependent response properties, because bumblebees fly faster at higher temperatures and therefore experience faster optic flow. Other behaviors that rely on optic flow (e.g., measuring distance traveled) require a robust, temperature-independent encoding of optic flow information. Hence, neurons that respond largely independently of temperature are required for this task. Our findings suggest a function-dependent level of temperature compensation in different populations of motion-sensitive neurons.<b>NEW & NOTEWORTHY</b> Bumblebees need to cope with varying temperatures of their body and head, which depend both on ambient temperature and on self-generated heat. To investigate the impact of changing head temperature on response properties of motion-sensitive neurons in the bumblebee central brain we used multiunit recordings to measure responses at different temperatures. We show that the bumblebee central brain comprises both temperature-dependent and temperature-compensated motion-sensitive neurons, which might account for different behavioral functions.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1675-1691"},"PeriodicalIF":2.1,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143972467","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":"Spatiomotor dynamics of hand movements during the drawing of memory-guided trajectories without visual feedback.","authors":"Christopher W Tyler, Kristyo N Mineff, Michael Liang, Lora T Likova","doi":"10.1152/jn.00153.2024","DOIUrl":"10.1152/jn.00153.2024","url":null,"abstract":"<p><p>Although the underlying principles of the spatiomotor dynamics during human movement execution are now broadly understood to conform to a minimum jerk principle, the question addressed in the present analysis is whether different principles operate during human drawing movements without visual input, deriving from studies of the Likova Cognitive-Kinesthetic Memory-Drawing Training. For two groups of participants, completely blind, and sighted but temporarily blindfolded, this analysis shows that the consensus model of arm-motion kinematics as a simple one-third power relationship of drawing speed to the local curvature of the line being drawn is not a sufficient characterization of their coupling. Instead, the drawing dynamics without visual feedback conform to a hyperbolic power relationship, with a coupling power of approximately 1.0 for regions of the highest curvature, asymptoting to curvature-independence for regions of shallow curvature, for both blind and blindfolded groups. Thus, the asymptotic power was much higher than the one-third power predicted by the minimum jerk principle. In detail, the maximum-velocity asymptote for both groups averaged about 6 cm/s for drawing from memory, increasing to more than twice as fast for mindless scribbling. We conclude that the more elaborate operating principle of a hyperbolic saturation function, with a power asymptote of about 1.0, may be interpreted as an adaptive implementation approximating the Minimum Jerk Principle of the simple one-third power law relating velocity and curvature.<b>NEW & NOTEWORTHY</b> This study reevaluates the one-third power law proposed to govern arm-motion kinematics relating drawing speed to the local curvature of the line being drawn. For complex drawings guided by memory without visual feedback, we find that the relationship is better characterized as a steeper power function that asymptotes to a constant speed for shallow curvatures, empirically approximating the predictions of the minimum jerk principle.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1665-1674"},"PeriodicalIF":2.1,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143764130","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}