Journal of neurophysiology最新文献

{"title":"High-altitude hypoxia alters the visual control of standing balance in lowlanders and Tibetan highlanders.","authors":"Jessica A Dickenson, Taylor S Harman, Ajaya J Kunwar, Nilam Thakur, Sunil Dhungel, Nima Sherpa, Abigail W Bigham, Tom D Brutsaert, Trevor A Day, Nicholas D J Strzalkowski","doi":"10.1152/jn.00607.2025","DOIUrl":"10.1152/jn.00607.2025","url":null,"abstract":"<p><p>High-altitude hypoxia affects both visual function and postural control, yet the influence of optic-flow perturbations on standing balance under hypoxic stress remains unclear. Tibetan highlanders (TH) exhibit adaptations to chronic hypoxia, but whether their visually driven postural responses differ from those of lowlanders (LL) has not been investigated. We examined how high-altitude exposure and acclimatization influence static and dynamic visual contributions to balance by delivering sinusoidal optic-flow perturbations in virtual reality at low altitude (1,400 m) and after incremental ascent to high altitude (4,300 m) in acclimatizing LL (<i>n</i> = 15) and TH (<i>n</i> = 14). Anteroposterior center of pressure (AP CoP) velocity and mean power frequency (MPF) were measured during three visual-field conditions (full-, central-, and peripheral-vision) and two optic-flow velocities (peak 1 m/s and 8 m/s at 0.25 Hz). At high altitude, both groups showed attenuated responses to optic flow compared with 1,400 m, reflected by reduced AP CoP velocity and lower MPF across visual-field conditions, consistent with reduced responsiveness to dynamic visual-motion cues under high altitude hypoxia. In contrast, during eyes-open quiet stance [no virtual reality (VR)], TH but not LL exhibited increased AP CoP velocity and MPF at 4,300 m, and no altitude effect was observed with eyes-closed in either group. This finding indicates that TH adopt a visually dependent postural strategy at altitude, whereas LL show minimal changes in static visual balance control but reduced responsiveness to fast dynamic motion. Together, these findings demonstrate that high-altitude hypoxia disrupts dynamic visual processing for balance control in both groups, while revealing group differences in the use of static visual cues during quiet stance.<b>NEW & NOTEWORTHY</b> This is the first study to investigate how high-altitude hypoxia alters visually driven postural control using virtual reality (VR) optic-flow perturbations. We show that hypoxia attenuates sway responses to optic-flow in both lowlanders and Tibetan highlanders, and that visual weighting differs between these groups. These findings reveal altitude- and population-related changes in sensory weighting during standing balance, advancing sensorimotor understanding of postural control in hypoxia.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1110-1120"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147972989","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":"Dissociable roles of primary motor and supplementary motor cortex in shaping the neural drive to muscle.","authors":"Yori R Escalante, Owen N Beck, Yuming Lei","doi":"10.1152/jn.00014.2026","DOIUrl":"10.1152/jn.00014.2026","url":null,"abstract":"<p><p>The primary motor cortex (M1) and supplementary motor area (SMA) are critical for motor execution and planning, yet their distinct causal contributions to modulating the neural drive to muscles remain incompletely understood. To dissociate their roles, we applied low-frequency (1-Hz) transcranial magnetic stimulation (TMS) over M1, SMA, or a sham condition in 75 healthy participants and characterized the activity of single motor units from high-density EMG recorded during a sustained isometric contraction. Our results revealed a clear functional divergence. Applying TMS over M1 produced a direct failure of motor output, causing a rapid force decline compared with sham, which was strongly correlated with a reduction in motor unit firing rates. Conversely, TMS over SMA did not impair net force. Instead, it altered the fundamental structure of the motor command, compelling a compensatory strategy characterized by a reliance on smaller-amplitude motor units with lower firing rates and a marked degradation of the low-frequency (delta-band) coherence that organizes stable output. These results provide direct causal evidence that M1 directly dictates the magnitude of motor output via population firing rates, while SMA orchestrates the composition and temporal structure of the active motor unit pool to generate an efficient and stable command.<b>NEW & NOTEWORTHY</b> Using causal brain stimulation, we demonstrate that the primary motor cortex (M1) and supplementary motor area (SMA) serve distinct roles. Targeted M1 disruption impairs force magnitude by reducing motor unit firing rates. Conversely, modulating SMA spares net force but disrupts the motor plan, forcing compensatory reliance on smaller units and degrading delta-band coherence. By showing M1 governs power while SMA organizes strategy, this study informs personalized neurorehabilitation for specific cortical deficits.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1121-1132"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148794274","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":"Functional identification of language-responsive sensors in individual participants in MEG investigations.","authors":"Mathias Huybrechts, Rose Bruffaerts, Alvincé Le Arnz Pongos, Cory Shain, Benjamin Lipkin, Matthew Siegelman, Vincent Wens, Martin Sjøgård, Idan Asher Blank, Serge Goldman, Xavier De Tiège, Evelina Fedorenko","doi":"10.1152/jn.00628.2025","DOIUrl":"10.1152/jn.00628.2025","url":null,"abstract":"<p><p>Making meaningful inferences about the functional architecture of the language system requires the ability to refer to the same neural units across individuals and studies. Traditional brain imaging approaches align and average brains together in a common space. However, lateral frontal and temporal cortices, where the language system resides, are characterized by high structural and functional interindividual variability, which reduces the sensitivity and functional resolution of group-averaging analyses. This issue is compounded by the fact that language areas lie in close proximity to regions of other large-scale networks with different functional profiles. A solution inspired by vision neuroscience is to identify language areas functionally in each individual brain using a \"localizer\" task (e.g., a language comprehension task). This approach has proven productive in fMRI, yielding a number of robust and replicable findings about the language system. Here, we extend this approach to MEG. Across two experiments (one in Dutch speakers, <i>n</i> = 19; one in English speakers, <i>n</i> = 23), we examined neural responses to the processing of sentences and a control condition (nonword sequences). We demonstrate that the sensor and source topography of neural responses to language is spatially stable within individuals but varies across individuals. Consequently, analyses that take this interindividual variability into account are characterized by greater sensitivity, compared with the group-level analyses. In summary, similar to fMRI, functional identification within individuals yields benefits in MEG, thus opening the door to future investigations of language processing, including questions where whole brain coverage and temporal resolution are both critical.<b>NEW & NOTEWORTHY</b> Language areas vary across individuals, challenging traditional group-averaged brain-imaging approaches. Using an fMRI-based strategy, this study validates that functionally localizing language responses within individuals improves sensitivity in magnetoencephalography (MEG). Across Dutch and English speakers, language-related sensor and source topographies were stable within individuals but varied between individuals. Individual-level functional identification thus enhances MEG analyses, enabling precise investigations of language processing with both high temporal resolution and whole brain coverage.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1075-1085"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13615564/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148794316","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":"Cholinergic premotor modulation of hypoglossal motor activity identified from combined \"opto-dialysis\" in vivo.","authors":"Raina Amin Ladha, Carolina da Silveira Scarpellini, Wen-Ying Liu, Hattie Liu, Kevin Patrick Grace, Gaspard Montandon, Richard L Horner","doi":"10.1152/jn.00634.2024","DOIUrl":"10.1152/jn.00634.2024","url":null,"abstract":"<p><p>A muscarinic acetylcholine receptor (MAchR) mechanism at the hypoglossal motor nucleus (HMN) can suppress tongue motor activity, and anti-MAchR agents are a component of pharmacotherapy for obstructive sleep apnea. However, the source and operation of cholinergic modulation of HMN activity are unknown in vivo. Here, we identify tongue motor responses to optical stimulation of cholinergic neurons at the HMN and intermediate reticular nucleus (IRt) in isoflurane-anesthetized transgenic mice (ChAT-ChR2(H134R)-EYFP) with and without pharmacological manipulation of the HMN. The IRt constitutes a major source of cholinergic input to the HMN and relay station for transmission of respiratory drive. In response to 2-s pulsed (10 ms at 10 Hz, 0-20 mW, <i>n</i> = 15) or tonic (\"square-wave\", 0-20 mW, <i>n</i> = 9) optical stimulation of the HMN or IRt, there was a power-dependent increase in tongue motor responses with lesser responses from the IRt (all <i>P</i> < 0.05). During tonic IRt stimulation, we identified that MAchR antagonism at the HMN (scopolamine, 2 mM, <i>n</i> = 7) increased endogenous respiratory tongue motor activity at higher stimulation intensities (20 mW, <i>P</i> = 0.030), whereas addition of nicotinic (N) AchR antagonism (mecamylamine, 200 µM) decreased respiratory tongue activity at lower stimulation intensities (5 mW, <i>P</i> = 0.012). These data identify opposing inhibitory and excitatory MAchR- and NAchR-dependent modulation of respiratory hypoglossal motor output. In contrast, MAchR antagonism alone or combined with NAchR antagonism at the HMN decreased evoked tonic motor activity (10 and 20 mW, <i>P</i> < 0.034), identifying reduction of a tonic excitatory effect. Together, these data identify cholinergic modulation of IRt-evoked HMN activity that shapes tonic and respiratory hypoglossal motor outputs in vivo.<b>NEW & NOTEWORTHY</b> The intermediate reticular nucleus (IRt) provides the largest innervation of the hypoglossal motor nucleus (HMN), including its cholinergic input, and serves as the critical relay for transmission of the respiratory input. Here, we combined optical stimulation of light-sensitive cation channels at the cholinergic IRt with pharmacological manipulation at the HMN in anesthetized transgenic mice in vivo. We identify differential opposing inhibitory and excitatory modulation of IRt-evoked HMN activity that shape tonic and respiratory hypoglossal motor outputs.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"912-942"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148549408","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":"Arm cycling modulates corticospinal transmission in the biceps brachii: potential involvement of premotoneuronal networks.","authors":"Kyosuke Hanafusa, Tsuyoshi Nakajima, Shinya Suzuki, Tomoyoshi Komiyama, Yukari Ohki, Tomoaki Atomi","doi":"10.1152/jn.00135.2026","DOIUrl":"10.1152/jn.00135.2026","url":null,"abstract":"<p><p>Rhythmic arm movements have been reported to improve motor function in individuals with stroke and spinal cord injury. However, the underlying mechanism remains unclear, particularly whether this benefit involves modulation of corticospinal transmission via premotoneuronal systems, which have been implicated in motor recovery in previous animal studies. Therefore, we investigated how arm cycling modulates the activities of presumed premotoneuronal networks receiving inputs from the corticospinal tract (CST) and the ulnar nerve (NERVE). Nineteen healthy volunteers participated in the study. Electromyographic activity was collected from elbow and shoulder muscles. Arm cycling was performed clockwise at 60 rpm. The CST was stimulated using transcranial magnetic stimulation (TMS) applied over the contralateral motor cortex. During arm cycling, single TMS-induced motor-evoked potentials (MEPs) in the biceps brachii were significantly facilitated during the elbow flexion phase (2-7 o'clock the crank position) compared with the static condition. At the 2 o'clock crank position, combined stimulation (CS) of NERVE and TMS (interstimulus intervals of 7.5 to 12 ms, NERVE ahead) produced significantly greater MEP facilitation (CS-induced MEP facilitation) than the algebraic sum of responses elicited by TMS alone and NERVE alone, in both static and arm cycling tasks. Importantly, CS-induced MEP facilitation during arm cycling was significantly greater than during the static task at 2 o'clock. Furthermore, enhancement of CS-induced MEP facilitation was observed exclusively during the flexion phase but was suppressed during extension. These findings suggest that arm cycling modulates indirect CST outputs via presumed premotoneuronal networks in a task- and phase-dependent manner.<b>NEW & NOTEWORTHY</b> Rhythmic arm movements have been reported to improve motor function in individuals with stroke and spinal cord injury. However, the underlying mechanism remains unclear. The current study demonstrated that arm cycling modulates the activation of presumed premotoneuronal networks within the corticospinal tract, which has been implicated in motor recovery in animal studies. Therefore, this rhythmic movement may represent a beneficial strategy for efficient and targeted activation of these premotoneuronal systems in clinical situations.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"943-958"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148630596","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":"Competitive preordering during planning persists in kinematically fused sequential movements.","authors":"Helena Wright-Wieckowski, Jason Friedman, Joseph M Galea, Katja Kornysheva","doi":"10.1152/jn.00422.2025","DOIUrl":"10.1152/jn.00422.2025","url":null,"abstract":"<p><p>Results in human and nonhuman primates have shown that elements of a movement sequence are preordered in parallel competitively before execution, a process known as competitive queueing (CQ). However, it is unclear whether the preplanning of individual movements persists in continuous skilled actions that involve greater biomechanical integration and is associated with the formation of new motor primitives (neural fusion). We investigated how kinematics impact sequence planning in a handwriting-like task asking whether fusing velocity curves between adjacent movements affects movement preparation. Participants were trained and tested for two days to perform two sequences of four sequential center-out-and-back movements from memory in a delayed sequence production task using a stylus on a Wacom tablet. To manipulate kinematic fusion between subsequent strokes, participants were assigned to one of three groups that were trained to perform the sequences either with acute, right, or obtuse angles between sequential targets. Probe trials assessed the availability of constituent movement elements for fast and accurate execution toward each target during planning. Movement elements associated with later sequence positions were less available than earlier movements, regardless of kinematic fusion, in line with CQ findings for discrete typing sequences in humans. Importantly, a more pronounced CQ gradient was associated with higher fusion, faster initiation, and greater accuracy of sequence production. These findings indicate that kinematically fused sequential actions do not result in the formation of new movement primitives (neural fusion) with a single movement plan. Instead, they continue to be planned separately and are associated with skilled performance.<b>NEW & NOTEWORTHY</b> When we fluidly string actions together like in cursive handwriting, does the brain fuse those movements into a single, unbreakable unit? By manipulating movement co-articulation (fusion) in a handwriting-like task, we challenge this view. Contrary to the assumption that behavioral fusion reflects the emergence of a singular, novel motor primitive, we demonstrate that even under high levels of kinematic fusion, individual sequence elements remain distinctly represented and competitively preordered based on their sequence position.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"975-992"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148579101","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":"Ventral cervical epidural electrical stimulation failed to increase respiratory activity in anesthetized humans during opioid-induced respiratory depression.","authors":"Ruyi Huang, Yan Zhou, Jordan Peyer, Erika L Galer, Aakash Patel, Meghna A Madhavan, Timothy Le, Harry V Vinters, Noriko Salamon, Marc R Nuwer, Irene Wu, James C Leiter, Daniel C Lu","doi":"10.1152/jn.00588.2025","DOIUrl":"10.1152/jn.00588.2025","url":null,"abstract":"<p><p>Respiratory depression is the leading cause of death during opioid overdoses. Epidural electrical stimulation (EES) may facilitate rhythmic motor activities such as locomotion and respiration. We investigated whether tonic, submotor threshold, EES of the ventral cervical spinal cord would activate muscles innervated by motor neurons outside the ventral cervical spinal site of stimulation and increase tidal volume, respiratory frequency, and decrease end-tidal Pco₂, or activate a more restricted set of muscles innervated by motor neurons near the stimulating electrodes. We studied 24 patients who were anesthetized with propofol and low-dose or high-dose remifentanil for treatment of anterior cervical spinal impingement. Cervical EES was delivered between cervical levels 3 to 7 (C3 to C7) for up to 90 s at an intensity ranging from 0.5 mA to 5 mA and a frequency of 5, 30, or 90 Hz at each dose of remifentanil. Ventral cervical EES did not reset the respiratory rhythm. There were no significant changes, on average, in tidal volume, respiratory frequency, or end-tidal Pco₂ during or after ventral cervical EES. In contrast, dorsal cervical EES reset the respiratory rhythm, augmented respiratory activity beyond the period of stimulation, and increased both tidal volume and respiratory frequency and decreased end-tidal Pco₂ in a similar, previous study in anesthetized humans. These observations suggest that the mild to moderate intensity, ventral cervical EES at frequencies < 100 Hz cannot access ventral motor neurons directly or activate interneuronal circuits that might increase motor neuron output indirectly during opioid-induced respiratory depression.<b>NEW & NOTEWORTHY</b> Submotor threshold, dorsal cervical epidural stimulation increased ventilation during opioid-induced respiratory depression by augmenting afferent information that accessed the pontomedullary and spinal circuits driving respiratory motor neurons. Ventral cervical epidural stimulation was unable to achieve a similar effect; ventral stimulation, at the field strength and frequencies tested, did not access or augment ventral respiratory motor neurons during opioid-induced respiratory depression.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1213-1230"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148794507","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":"Predicting nitrogen narcosis using the electroencephalogram recorded from experienced divers.","authors":"Keegan W James, Lachlan D Barnes, Hanna van Waart, Simon J Mitchell, Jamie W Sleigh, Luke E Hallum, Xavier C E Vrijdag","doi":"10.1152/jn.00167.2026","DOIUrl":"10.1152/jn.00167.2026","url":null,"abstract":"<p><p>Nitrogen narcosis causes acute cognitive impairment in divers breathing compressed air at depth, increasing injury and fatality risk. Susceptibility varies widely between individuals, making real-time cortical monitoring a potential safety tool. We recorded 32-channel electroencephalography (EEG) from 45 divers (both sexes; aged 20-55 yr) at rest across four randomized crossover hyperbaric studies. We manipulated pressure (101-811 kPa) and breathing gas (air or heliox) to create two classes of recordings: narcotic (high-pressure air) or non-narcotic (low-pressure air; heliox at any pressure); our outcome was therefore gas composition, not direct cognitive impairment. We extracted 2,720 features (17 feature types × 32 channels × 5 frequency subbands) from preprocessed EEG epochs, trained six machine-learning classifiers using leave-one-participant-out cross-validation on a training set (24 participants), and evaluated the best-performing model on a test set (9 participants) and hold-out set (12 participants). Linear discriminant analysis (LDA) achieved a Matthews correlation coefficient (MCC) of 0.50 (chance ≈ 0; <i>P</i> = 0.001) and accuracy of 82% (baseline 76%; <i>P</i> = 0.001) on the test set, and MCC of 0.25 (chance ≈ 0; <i>P</i> = 0.001) and accuracy of 69% (baseline 69%; <i>P</i> = 0.77) on the hold-out set collected years later. Feature elimination retained 157 features; feature importance analysis identified zero-crossing rate, Hjorth mobility, and Katz fractal dimension at delta-band frequencies (< 4 Hz) over the anterior and posterior midline as the most important features. Easily computed EEG features with an LDA classifier can detect neurophysiological signatures of nitrogen narcosis, potentially enabling real-time passive monitoring of divers.<b>NEW & NOTEWORTHY</b> Nitrogen narcosis can impair a diver's cognitive performance in highly variable ways, influenced by multiple factors. To address this, real-time brain monitoring is desirable to inform divers of their cognitive state. By leveraging machine learning to detect subtle patterns in electroencephalography (EEG) signals, we can develop interpretable algorithms that may support a future monitoring and warning system.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1286-1295"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148818681","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":"Magnetoencephalography detects rectification of abnormal brain hypercorrelations following abstinence from alcohol in chronic alcoholism.","authors":"Scott M Lewis, Arthur C Leuthold, Gihyun Yoon, Katie Thompson, Peka Christova, Apostolos P Georgopoulos","doi":"10.1152/jn.00288.2026","DOIUrl":"10.1152/jn.00288.2026","url":null,"abstract":"<p><p>Here, we used magnetoencephalography (MEG) to investigate changes in brain functional organization and their time course following alcohol abstinence in chronic alcoholic patients. Eighteen male veterans (10 control and 8 currently alcohol-dependent) participated in this study. MEG in alcoholic participants was obtained on various days, starting at <i>day 3</i> of alcohol abstinence. A MEG scan consisted of a 45-s data acquisition period from 248 whole head axial gradiometers at a frequency of 1.017 kHz. All 30,628 pairwise zero-lag cross-correlations (CC0) between prewhitened sensor time courses per scan were computed and analyzed. We found the following. At <i>day 3</i> post abstinence, the mean |CC0| was 2.1× higher than that of controls, indicating a strongly hypercorrelated state. This hypercorrelation decreased gradually in a logarithmic fit, both for negative and positive CC0, which became less negative and less positive with time, respectively. These results demonstrate the power of MEG as a sensitive tool to detect, quantify, and track functional brain status during alcohol detoxification.<b>NEW & NOTEWORTHY</b> Here, we report on the hypercorrelation status of the chronic alcoholic brain assessed using magnetoencephalography (MEG) comprising strong negative and positive cross-correlations between 248 MEG sensors in a 45-s duration of data acquisition in the resting state. The strong correlations were reduced over time with the logarithm of the day in abstinence and were estimated to return to the levels of controls in 564-577 days, attesting to the potential for functional brain network recovery during abstinence.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"969-974"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148673777","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 HCN4 channel modulates external tufted cell burst firing.","authors":"Adam C Puche, Fu-Wen Zhou","doi":"10.1152/jn.00194.2026","DOIUrl":"10.1152/jn.00194.2026","url":null,"abstract":"<p><p>Hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels are expressed widely in various brain regions and cardiac tissue. The HCN channel conductance, named as <i>I</i>_h (in neurons), plays a controlling role in neuronal excitability and rhythmic oscillatory activity in individual neurons and neuronal networks. Immunohistochemical studies in the literature show HCN channel isoforms are expressed in the olfactory bulb, but relative isoform expression levels are unknown. HCN channels are encoded by four genes (HCN1-4). The expression and function of those isoforms in the five types of mitral/tufted cells are not well known. Here, we examined HCN1-4 protein and channel conductance in olfactory bulb output neurons. HCN1, 2, 3, and 4 isoforms were expressed in the olfactory bulb, with HCN4 the most abundant. HCN channel-mediated <i>I</i>_h conductance was present in the different classes of output neurons with the highest level in external tufted cells and low to none in mitral cells. To isolate specific contributions of the isoforms to the rhythmic firing of external tufted cells, we used cell-specific pharmacology infusing antagonists or isoform-specific blocking antisera into single neurons. Only the HCN4-blocking antisera terminated external tufted cell burst firing, whereas other antisera had no significant effect on spiking. Those results indicate that HCN4 in external tufted cells controls burst firing in these cells. Since burst firing of external tufted cells is a key regulator of activity in the olfactory bulb, this suggests HCN4 and the resulting <i>I</i>_h conductance are key circuit regulators.<b>NEW & NOTEWORTHY</b> External tufted cells in olfactory bulb are pacemaker neurons that fire rhythmic bursts. This study demonstrates that the pacemaker action of external tufted cells is critically dependent on <i>I</i>_h from HCN4 channel providing feedforward excitation to generate long-lasting depolarizations in the mitral cells. Since mitral/tufted cells play important roles in odor discrimination and olfactory learning, we speculate that HCN4 is a key regulatory channel in driving overall network activity and function of the olfactory bulb.</p>","PeriodicalId":16563,"journal":{"name":"Journal of neurophysiology","volume":" ","pages":"1204-1212"},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13616201/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148794441","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}