Journal of neurophysiology最新文献

{"title":"Effects of noisy galvanic vestibular stimulation on reactive postural and neuromuscular responses to surface perturbations.","authors":"Mohammad Mahmud, Zaeem Hadi, Isha Sohail, Barry M Seemungal, Toby J Ellmers","doi":"10.1152/jn.00235.2025","DOIUrl":"10.1152/jn.00235.2025","url":null,"abstract":"<p><p>Postural control requires continuous sensorimotor feedback to maintain balance and prevent falls. Noisy galvanic vestibular stimulation (nGVS), a weak stochastic electrical stimulus applied to the peripheral vestibular apparatus, can reduce postural sway during unperturbed steady standing. Although nGVS is proposed to modulate balance by enhancing vestibular-mediated feedback control, the specific underlying neural mechanisms are unknown. Whether nGVS modulates balance during destabilizing perturbations has not been explored. We therefore interrogated the effect of nGVS on dynamic balance in response to a discrete perturbation to posture. We further assessed electromyographic (EMG) activity to provide insight into the neuromuscular mechanisms driving any observed behavioral effects. A randomized double-blinded, sham-controlled trial of 30 healthy young adults was conducted. Perturbations consisted of discrete forward platform movement (peak acceleration = 0.1 g, maximum forward displacement = 24.5 cm). Random noise GVS or sham was delivered continuously during each experimental condition. Initial backward trunk angular velocity in response to the perturbation was used as the primary kinematic outcome. EMG activity of the tibialis anterior and medial gastrocnemius was assessed both pre- and postperturbation. Reduced initial backward trunk angular velocity [<i>P</i> = 0.021 (Holm-Bonferroni corrected)] was observed during nGVS compared with sham. nGVS did not significantly alter any assessed postperturbation EMG outcomes; however, tonic preperturbation tibialis anterior and medial gastrocnemius activity was significantly increased during nGVS. Our findings provide evidence that nGVS can modulate postural responses to perturbations, with the sustained elevation of preperturbation ankle EMG activity indicating a shift in tonic vestibulospinal drive.<b>NEW & NOTEWORTHY</b> Noisy galvanic vestibular stimulation (nGVS) has previously been shown to reduce postural sway during quiet standing. But whether nGVS can modify balance during destabilizing perturbations is unknown. We demonstrate that nGVS reduces the initial backward trunk angular velocity in response to discrete perturbations. These effects occurred without changes in perturbation-evoked muscle responses, but with increased preperturbation ankle muscle activity. These findings suggest that nGVS alters preperturbation tonic vestibulospinal output, as evidenced by elevated preperturbation ankle EMG, rather than reactive feedback gain.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1296-1304"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148813385","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":"Reflex and functional responses to distal tibial/medial plantar nerve electrical stimulation in the treadmill-locomoting spinal cat.","authors":"Bernard J Krasnisky, David P Kowalski, Karen Ollivier-Lanvin, Daniel J Reiners, Boris I Prilutsky, Michel A Lemay","doi":"10.1152/jn.00445.2025","DOIUrl":"10.1152/jn.00445.2025","url":null,"abstract":"<p><p>Low-intensity electrical stimulation of the distal tibial nerve innervating the plantar foot with pulse trains promotes extensor activity in reduced animal preparations when delivered during the extensor phase. Since enhancing extensor activity could potentially improve weight support after spinal cord injury (SCI), we evaluated whether electrical stimulation of the distal tibial nerve or its medial plantar branch enhances/prolongs extensor activity in a locomotor-trained feline model of SCI. With stimulation trains at levels activating large-diameter afferents (low-threshold cutaneous/muscle group I afferents) we found no effects on the activity of the extensors and flexors during walking, whereas stimulation levels activating smaller fibers (higher-threshold cutaneous/muscle group II) were found to increase swing height for stimuli delivered in late stance/early swing. A further increase in stimulus intensity to levels recruiting noxious afferents terminated ongoing stance and produced a flexor withdrawal response of the paw. Muscle reflex responses to low-intensity single-pulse stimuli during walking showed a short-latency inhibition in extensor muscles followed by a longer-latency excitatory response when stimulation was delivered during stance and limited responses when delivered during swing. Flexors showed an early-latency excitatory response followed by a weak inhibitory response for stimulation delivered throughout most of the walking cycle. These reflex responses to single-pulse stimulation agreed with prior studies. The absence of extensor activity enhancement with low-intensity train stimulation of the distal tibial nerve during stance observed in other preparations may be partially explained by changes in spinal neuronal properties and locomotor networks in chronic spinal cats.<b>NEW & NOTEWORTHY</b> Contrary to prior results in the decerebrated feline, there was no enhancement of hindlimb extensor activity in response to activation of low-threshold cutaneous and proprioceptive afferents from the plantar foot by stimulation trains applied to the distal tibial nerve during stance in locomotor-trained spinal cats. This result may be partially explained by changes in spinal neural networks and suggests limited applicability of plantar foot stimulation for enhancing body weight support in locomotor-trained individuals with spinal injury.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1246-1265"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13560884/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148794449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Large-scale in vivo electrophysiology analysis reveals opposing thalamic and hippocampal excitability after third-trimester-equivalent alcohol exposure in mice.","authors":"Mitchell D Morningstar, Gabriela Acosta, Sam A McKenzie, Carlos F Valenzuela, Ben J Clark, David N Linsenbardt","doi":"10.1152/jn.00189.2026","DOIUrl":"10.1152/jn.00189.2026","url":null,"abstract":"<p><p>Acute, binge-like alcohol exposure during the third-trimester-equivalent period (TTAE) produces apoptotic neurodegeneration in brain regions critical for spatial learning and memory, including the anterior thalamic nuclei (ATN), which are necessary for contextual learning and memory. To investigate the neural mechanisms underlying spatial cognition deficits following developmental alcohol exposure, we performed high-density electrophysiological recordings in and around the ATN of behaving mice, sampling 7,490 neurons across multiple, predominantly thalamic depths. To model acute binge-like TTAE, C57BL/6J mice received two injections of 2.5 g/kg ethanol (or saline) on <i>postnatal day</i> (<i>PND</i>) <i>7</i>. In young adulthood (><i>PND 60</i>), mice were implanted with silicon or multi-wire electrode arrays and allowed to explore a circular arena (40 cm diameter) under dim red light with two wall-mounted light-emitting diode (LED) cues that rotated pseudo-randomly. Spike timing and waveform features were extracted from each putative single unit. Across the recorded population, firing rates were generally reduced following TTAE, although responses were heterogeneous. To characterize this variability, neuronal features were embedded using uniform manifold approximation and projection (UMAP). Logistic regression classified saline- and TTAE-exposed neurons based on electrophysiological properties and UMAP coordinates, achieving 80% accuracy. Cluster-based comparisons showed weak correspondence between physiological similarity and treatment response, suggesting TTAE effects are driven primarily by anatomical location. This study presents the first large-scale in vivo electrophysiological recordings in a freely behaving mouse model of fetal alcohol spectrum disorders, revealing divergent circuit adaptations marked by hippocampal hyperexcitability and thalamic dysfunction.<b>NEW & NOTEWORTHY</b> The present study is one of the first to look at large-scale in vivo electrophysiological features following third-trimester equivalent alcohol exposure. By functionally grouping our neurons, we report a variety of alcohol-related deficits. One particularly striking feature is a bidirectional impact on excitability, with hippocampal neurons generally increasing their excitability and thalamic neurons generally decreasing.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1171-1182"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13552330/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148794461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deep learning reveals cross-modal neural representations of auditory and visual mental imagery in MEG.","authors":"Alina Schüller, Constantin Jehn, Marietta Stegmaier, Jasmin Riegel, Tobias Reichenbach","doi":"10.1152/jn.00563.2025","DOIUrl":"10.1152/jn.00563.2025","url":null,"abstract":"<p><p>Mental imagery provides a unique window into the brain's ability to internally simulate sensory experiences, offering valuable insights for both cognitive neuroscience and brain-computer interface (BCI) research. This study examined the neural representations of imagined auditory and visual stimuli using magnetoencephalography (MEG) and assessed the ability of machine learning models to decode these mental processes. MEG data were recorded from 18 right-handed participants during auditory and visual imagery tasks and source reconstructed within modality-specific cortical regions of interest. We compared a convolutional neural network (CNN) and a linear logistic regression model within a subject-specific classification framework. Both approaches achieved above-chance decoding accuracies, with the CNN outperforming the linear model in both tasks, yielding a mean decoding accuracy of >70% for the visual imagery task. Notably, the CNN achieved significant decoding performance even when trained on nontask-relevant cortical regions, indicating that imagined stimuli are represented in distributed and partially overlapping neural networks across modalities. This cross-modal decoding capability highlights the potential of deep learning models to capture complex, multimodal neural patterns and suggests that future brain-computer interfaces could benefit from integrating auditory and visual information. These findings advance our understanding of cross-modal mental imagery and point toward more flexible and personalized approaches in BCI design.<b>NEW & NOTEWORTHY</b> By comparing linear and deep classifiers, this work shows that convolutional networks capture rich, cross-modal neural representations of auditory and visual mental imagery in magnetoencephalography (MEG). Significant decoding from nontask-relevant regions indicates distributed cortical engagement, highlighting deep learning's potential for robust, modality-independent brain-computer interfaces.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1183-1195"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148396448","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":"Excitability of posterior root reflex evoked by transcutaneous spinal stimulation is distinct from the H-reflex in the soleus muscle: a pulse duration study.","authors":"Matthias J Krenn, Elizabeth A Gordineer, Dobrivoje S Stokic","doi":"10.1152/jn.00147.2026","DOIUrl":"10.1152/jn.00147.2026","url":null,"abstract":"<p><p>Transcutaneous spinal stimulation studies of the lumbosacral posterior root reflex (PRR) have commonly used a 1-ms pulse duration adopted from soleus Hoffmann reflex (H-reflex) protocols. However, it remains unknown whether the excitability characteristics of the PRR and H-reflex vary with pulse duration. Twelve neurologically intact participants underwent tibial nerve stimulation to evoke soleus M waves and H-reflexes, and lumbosacral transcutaneous spinal stimulation to evoke soleus PRRs. Recruitment curve data were collected across eight pulse durations (50-2,000 µs). Stimulation intensities corresponding to 50% of the maximum H-reflex were used to construct strength-duration curves for each response type. Rheobase and chronaxie were estimated using the Weiss-Lapicque equation. Maximum peak-to-peak amplitudes of the M wave, H-reflex, and PRR did not differ significantly across pulse duration (with increased stimulation intensity at shorter pulse durations). However, when normalized to the maximum M wave, the PRR was 12.3% larger than the H-reflex. The strength-duration curves were well described by a hyperbolic function, with the PRR exhibiting a substantially higher rheobase (50.8 mA) and shorter chronaxie (338 µs) than the H-reflex (6.7 mA; 874 µs) and M wave (12.5 mA; 545 µs). The maximum soleus PRR and H-reflex do not differ across pulse durations from 50 to 2,000 µs, although shorter pulses require higher stimulation intensities. The differences in PRR and H-reflex rheobase and chronaxie values are likely due to specific electrode configurations, tissue properties, and sites of activation. The excitability characteristics of the soleus PRR and H-reflex have implications for selecting stimulators and their parameters.<b>NEW & NOTEWORTHY</b> Direct comparison of the soleus PRR and H-reflex excitability reveals that the PRR activates a larger proportion of the motoneuron pool and exhibits a markedly higher rheobase and shorter chronaxie, reflecting differences in tissue properties and stimulation geometry. The shorter PRR chronaxie implies that PRR can be efficiently elicited with a pulse duration of less than 1 ms, as adopted from H-reflex protocols.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1133-1145"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13571212/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148794333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deliberation is a controllable process governed by desirability and cognitive effort.","authors":"Jan A Calalo, Seth R Sullivan, Nicholas R Muscara, John Buggeln, Truc Ngo, Matthew R Short, Michael J Carter, Isaac Kurtzer, Joshua G A Cashaback","doi":"10.1152/jn.00193.2026","DOIUrl":"10.1152/jn.00193.2026","url":null,"abstract":"<p><p>Humans spend a lifetime making decisions based on incoming sensory information and goals. Prominent theories of perceptual decision-making have described the components of the deliberation process, yet they lack a unifying principle that governs what the nervous system considers to tune deliberation. Desirability (reward) and effort (energy) are major determinants in governing a broad range of human and animal behavior, such as foraging, walking, and decisions. Here, we develop a theory where desirability and cognitive effort tune the control gains that govern deliberation. Several hallmark features of decision behavior simply emerge from the model, with the deliberation process closely resembling low-dimensional neural dynamics. We also predict and provide a novel mechanistic explanation for \"choking-under-pressure,\" where extremely large rewards lead to performance deficits. Our principled framework explains both behavioral and neural phenomena while providing a path to unify disparate fields.<b>NEW & NOTEWORTHY</b> Desirability and effort are fundamental objectives that drive human and animal behavior. Information processing accounts of decision-making do not consider biologically plausible objectives and thus fail to explain what tunes deliberation. Here, we propose a novel theory where deliberation is a controllable process governed by desirability and cognitive effort. This theoretical model captures classic decision phenomena while the emergent process bears a striking resemblance to complex neural dynamics.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1162-1170"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148604130","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":"Pain threshold induced by local exposure to millimeter waves on human skin.","authors":"Akiko Yuasa, Shintaro Uehara, Kazuki Ushizawa, Sachiko Kodera, Akimasa Hirata, Yohei Otaka","doi":"10.1152/jn.00554.2025","DOIUrl":"10.1152/jn.00554.2025","url":null,"abstract":"<p><p>Exposure to millimeter waves potentially causes pain and tissue damage at the exposed body sites. However, the threshold temperature, especially the pain threshold, remains unclear. In this study, we investigated the perception thresholds of four different types of sensations-warmth, heat, tingling, and pain-and individual physical characteristics associated with the pain perception induced by millimeter-wave exposure. Thirty-five healthy adults were exposed to a 28-GHz millimeter wave on their left middle fingertip at an input power of 8.5 W (incident power density averaged over a 1 cm² area: 1.00 W/cm²) for up to 10 min. The temperature at which the initial subjective perception of each of the four sensation types occurred was determined as the perception threshold for that sensation. When the skin surface temperature exceeded 44°C or when the participant felt pain, the exposure was terminated. The association between participants' physical characteristics and the presence of pain was investigated using logistic regression analysis. Consequently, the perception thresholds increased in the following order: warmth < heat < tingling < pain. A total of 18 (51%) participants perceived pain, and the average pain threshold was 41.9°C. Females were more likely than males to perceive pain (odds ratio, 4.80 [1.15-20.09]), which may be partially explained by sex-related differences in hydration levels and finger circumference. Our results demonstrated that exposure to millimeter waves can induce pain at approximately 42°C and revealed clear sex differences in sensitivity to pain perception under millimeter-wave exposure.<b>NEW & NOTEWORTHY</b> This study investigated the perception thresholds of four types of sensations-warmth, heat, tingling, and pain-when the fingertip was exposed to 28 GHz millimeter waves. The results showed that the perception thresholds followed the order of warmth, heat, tingling, and pain, with the threshold skin temperature for pain at 41.9°C. Notably, females exhibited significantly higher sensitivity to pain than males. These findings provide further evidence supporting the need for protection from millimeter-wave exposure.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1196-1203"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148794482","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":"Action potential-induced changes in O₂ consumption, NADH regeneration, and mitochondrial membrane potential in adult mouse spinal motor neurons.","authors":"John N Barrett, Jonathan E Katz, Ellen F Barrett","doi":"10.1152/jn.00512.2025","DOIUrl":"10.1152/jn.00512.2025","url":null,"abstract":"<p><p>Studies of central neurons suggest that stimulation activates Ca²⁺-dependent processes that increase NADH regeneration and O₂ consumption. This study asked whether similar processes dominate respiratory responses in spinal motor neurons. Lumbar ventral horn segments from adult mice were perfused in a flow-through chamber. Motor neurons were stimulated with trains of action potentials (5-80 Hz for 20-40 s) conducted antidromically from ventral roots. Perfusion solutions contained antagonists of ionotropic cholinergic and glutaminergic receptors to inhibit synaptic transmission. The stimulation-induced increase in O₂ consumption, calculated from changes in the phosphorescence/fluorescence of porphyrin compounds, was inhibited reversibly by procaine and low [K⁺] solutions, and blocked by inhibitors of mitochondrial respiration (rotenone, oligomycin). These findings suggest that the increase in O₂ consumption was due mainly to activation of ATPase pumps to counteract the changes in transmembrane ion gradients produced by repetitive action potential discharge. In glucose, pyruvate, or lactate (1-10 mM), peak O₂ consumption and NADH regeneration increased with action potential workload. For all three tested substrates, a fraction of O₂ consumption (median 12%-40%) was Ca²⁺-dependent; NADH regeneration showed significant Ca²⁺ dependence only in low [lactate] (2.5 mM). Stimulation produced a depolarizing shift in the mitochondrial membrane potential (ΔΨ_m) that increased with workload. The relationship between O₂ consumption and NADH regeneration was flexible, in a manner suggesting that resting NADH is sufficient for the initial respiratory response to stimulation. A scenario consistent with most respiration in glucose is action potential workload →increased pump activity →↑ADP/ATP ratio → ↑ATP synthase activity → ΔΨ_m depolarization→↑O₂ consumption.<b>NEW & NOTEWORTHY</b> In a novel preparation of adult mouse motor neurons stimulated by back-propagated action potentials, the relationship between O₂ consumption and NADH regeneration was flexible. Data suggest a resting reservoir of NADH sufficient to support the response to short-term workloads. In glucose, most O₂ consumption and NADH regeneration were independent of extracellular [Ca²⁺]. The major driver of the respiratory response to stimulation was an increased ADP/ATP ratio, activating ATP synthase, which uses the mitochondrial proton gradient.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"893-911"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148436835","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":"Imaging fast neural circuit activity in brain and nerve with electrical impedance tomography: review and neurophysiological applications.","authors":"David Holder, Kai Mason, Kirill Aristovich","doi":"10.1152/jn.00069.2026","DOIUrl":"10.1152/jn.00069.2026","url":null,"abstract":"<p><p>Neural engineering has become topical with widespread publicity for projects such as implanted devices for recording and intelligent stimulation of the cerebral cortex. Unfortunately, the brain has many billions of neurons, with thousands of synaptic connections, and functions with millisecond-scale graded depolarization; there are substantial limitations in sampling this adequately, even with modern technology. Electrical impedance tomography (EIT) is a novel medical imaging technique that has the capability to image fast electrical activity in the brain or nerve over milliseconds at a mesoscopic scale of millimeters in the rat or several in the human brain. This enables tomographic images of the electrical properties of a subject to be produced with electrode arrays, by imaging the impedance changes that occur as ion channels open during neuronal depolarization. A small, safe, insensible electrical current at a few kilohertz is applied, usually serially, to pairs of electrodes. Images are reconstructed from the many transfer impedances recorded by measuring resulting voltages at other electrodes. Currently, this is accomplished with intracranial or perineural electrode arrays and requires averaging to a repeated trigger over several minutes. With this, images of neural activity with a resolution of 200 µm and 1 ms can be produced during evoked activity or epileptic seizures in rat cerebral cortex or fascicular compound action potentials in pig or human vagus nerve. Work is in progress to extend this to real-time noninvasive imaging of fast neural activity in humans using multiple-frequency current injection with frequency division multiplexing and recording with atomic magnetometers.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1045-1057"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148604113","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":"Motor-evoked modules obtained from transcranial magnetic stimulation.","authors":"Takuya Morishita, Martina Coscia, Mirea Bacigalupo, Michael Lassi, Camille E Proulx, Lisa Fleury, Friedhelm C Hummel","doi":"10.1152/jn.00122.2026","DOIUrl":"10.1152/jn.00122.2026","url":null,"abstract":"<p><p>As a noninvasive neuromodulation technique, transcranial magnetic stimulation (TMS) offers insights into motor system physiology through motor-evoked potentials (MEPs). In the present study, we applied a factorization approach to multimuscle MEPs to characterize the pattern-level structure of corticospinal outputs beyond conventional per-muscle amplitude measures. To evaluate this approach, we analyzed multimuscle MEP datasets from three experiments in healthy young adults focusing on different stimulus parameters: stimulus intensity (<i>experiment 1: n</i> = 40), motor mapping size (<i>experiment 2: n</i> = 35), and activation of intracortical circuits by a paired-pulse TMS paradigm (<i>experiment 3: n</i> = 20). We extracted motor-evoked modules (MEMs) using non-negative matrix factorization (NMF) and compared their structure across different stimulus conditions. MEM structure was impacted by stimulus intensity, and these findings indicate that stimulus intensity shapes the pattern-level structure of corticospinal outputs. Varying motor mapping size had only a minor impact on MEM structure, suggesting that the pattern-level structure of corticospinal outputs elicited by TMS was stable across mapping extents. Activation of intracortical inhibition appeared to alter MEM structure compared with single-pulse TMS. These findings suggest that paired-pulse activation of intracortical inhibition may alter the pattern-level structure of corticospinal outputs. The MEM framework allows us to characterize the pattern-level structure of corticospinal outputs beyond single-muscle MEPs; thus, MEMs obtained from TMS complement well-established single-muscle MEP analyses and offer a novel perspective for investigating the motor system.<b>NEW & NOTEWORTHY</b> The study introduces a framework to assess the pattern-level structure of corticospinal outputs using motor-evoked modules (MEMs) obtained from transcranial magnetic stimulation (TMS). MEMs were extracted from multimuscle motor-evoked potentials (MEPs) through non-negative matrix factorization (NMF). MEM structure was impacted by stimulus intensity, and intracortical inhibition appeared to alter MEM structure compared with single-pulse TMS. The framework complements well-established single-muscle MEP analyses and offers a novel perspective for investigating the motor system.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1058-1074"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148673803","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}