Is age-related myelinodegenerative change an initial risk factor of neurodegenerative diseases?

Myelination, the continuous ensheathment of neuronal axons, is a lifelong process in the nervous system that is essential for the precise, temporospatial conduction of action potentials between neurons. Myelin also provides intercellular metabolic support to axons. Even minor disruptions in the integrity of myelin can impair neural performance and increase susceptibility to neurological diseases. In fact, myelin degeneration is a well-known neuropathological condition that is associated with normal aging and several neurodegenerative diseases, including multiple sclerosis and Alzheimer's disease. In the central nervous system, compact myelin sheaths are formed by fully mature oligodendrocytes. However, the entire oligodendrocyte lineage is susceptible to changes in the biological microenvironment and other risk factors that arise as the brain ages. In addition to their well-known role in action potential propagation, oligodendrocytes also provide intercellular metabolic support to axons by transferring energy metabolites and delivering exosomes. Therefore, myelin degeneration in the aging central nervous system is a significant contributor to the development of neurodegenerative diseases. Interventions that mitigate age-related myelin degeneration can improve neurological function in aging individuals. In this review, we investigate the changes in myelin that are associated with aging and their underlying mechanisms. We also discuss recent advances in understanding how myelin degeneration in the aging brain contributes to neurodegenerative diseases and explore the factors that can prevent, slow down, or even reverse age-related myelin degeneration. Future research will enhance our understanding of how reducing age-related myelin degeneration can be used as a therapeutic target for delaying or preventing neurodegenerative diseases.

Optogenetic approaches for neural tissue regeneration: A review of basic optogenetic principles and target cells for therapy

Optogenetics has revolutionized the field of neuroscience by enabling precise control of neural activity through light-sensitive proteins known as opsins. This review article discusses the fundamental principles of optogenetics, including the activation of both excitatory and inhibitory opsins, as well as the development of optogenetic models that utilize recombinant viral vectors. A considerable portion of the article addresses the limitations of optogenetic tools and explores strategies to overcome these challenges. These strategies include the use of adeno-associated viruses, cell-specific promoters, modified opsins, and methodologies such as bioluminescent optogenetics. The application of viral recombinant vectors, particularly adeno-associated viruses, is emerging as a promising avenue for clinical use in delivering opsins to target cells. This trend indicates the potential for creating tools that offer greater flexibility and accuracy in opsin delivery. The adaptations of these viral vectors provide advantages in optogenetic studies by allowing for the restricted expression of opsins through cell-specific promoters and various viral serotypes. The article also examines different cellular targets for optogenetics, including neurons, astrocytes, microglia, and Schwann cells. Utilizing specific promoters for opsin expression in these cells is essential for achieving precise and efficient stimulation. Research has demonstrated that optogenetic stimulation of both neurons and glial cells-particularly the distinct phenotypes of microglia, astrocytes, and Schwann cells-can have therapeutic effects in neurological diseases. Glial cells are increasingly recognized as important targets for the treatment of these disorders. Furthermore, the article emphasizes the emerging field of bioluminescent optogenetics, which combines optogenetic principles with bioluminescent proteins to visualize and manipulate neural activity in real time. By integrating molecular genetics techniques with bioluminescence, researchers have developed methods to monitor neuronal activity efficiently and less invasively, enhancing our understanding of central nervous system function and the mechanisms of plasticity in neurological disorders beyond traditional neurobiological methods. Evidence has shown that optogenetic modulation can enhance motor axon regeneration, achieve complete sensory reinnervation, and accelerate the recovery of neuromuscular function. This approach also induces complex patterns of coordinated motor neuron activity and promotes neural reorganization. Optogenetic approaches hold immense potential for therapeutic interventions in the central nervous system. They enable precise control of neural circuits and may offer new treatments for neurological disorders, particularly spinal cord injuries, peripheral nerve injuries, and other neurodegenerative diseases.

Topical administration of GLP-1 eyedrops improves retinal ganglion cell function by facilitating presynaptic GABA release in early experimental diabetes

JOURNAL/nrgr/04.03/01300535-202602000-00048/figure1/v/2025-05-05T160104Z/r/image-tiff Diabetic retinopathy is a prominent cause of blindness in adults, with early retinal ganglion cell loss contributing to visual dysfunction or blindness. In the brain, defects in γ-aminobutyric acid synaptic transmission are associated with pathophysiological and neurodegenerative disorders, whereas glucagon-like peptide-1 has demonstrated neuroprotective effects. However, it is not yet clear whether diabetes causes alterations in inhibitory input to retinal ganglion cells and whether and how glucagon-like peptide-1 protects against neurodegeneration in the diabetic retina through regulating inhibitory synaptic transmission to retinal ganglion cells. In the present study, we used the patch-clamp technique to record γ-aminobutyric acid subtype A receptor-mediated miniature inhibitory postsynaptic currents in retinal ganglion cells from streptozotocin-induced diabetes model rats. We found that early diabetes (4 weeks of hyperglycemia) decreased the frequency of GABAergic miniature inhibitory postsynaptic currents in retinal ganglion cells without altering their amplitude, suggesting a reduction in the spontaneous release of γ-aminobutyric acid to retinal ganglion cells. Topical administration of glucagon-like peptide-1 eyedrops over a period of 2 weeks effectively countered the hyperglycemia-induced downregulation of GABAergic mIPSC frequency, subsequently enhancing the survival of retinal ganglion cells. Concurrently, the protective effects of glucagon-like peptide-1 on retinal ganglion cells in diabetic rats were eliminated by topical administration of exendin-9-39, a specific glucagon-like peptide-1 receptor antagonist, or SR95531, a specific antagonist of the γ-aminobutyric acid subtype A receptor. Furthermore, extracellular perfusion of glucagon-like peptide-1 was found to elevate the frequencies of GABAergic miniature inhibitory postsynaptic currents in both ON- and OFF-type retinal ganglion cells. This elevation was shown to be mediated by activation of the phosphatidylinositol-phospholipase C/inositol 1,4,5-trisphosphate receptor/Ca 2+ /protein kinase C signaling pathway downstream of glucagon-like peptide-1 receptor activation. Moreover, multielectrode array recordings revealed that glucagon-like peptide-1 functionally augmented the photoresponses of ON-type retinal ganglion cells. Optomotor response tests demonstrated that diabetic rats exhibited reductions in visual acuity and contrast sensitivity that were significantly ameliorated by topical administration of glucagon-like peptide-1. These results suggest that glucagon-like peptide-1 facilitates the release of γ-aminobutyric acid onto retinal ganglion cells through the activation of glucagon-like peptide-1 receptor, leading to the de-excitation of retinal ganglion cell circuits and the inhibition of excitotoxic processes associated with diabetic retinopathy. Collectively, our findings indicate that the γ-aminobutyric acid system has potential as a therapeutic target for mitigating early-stage diabetic retinopathy. Furthermore, the topical administration of glucagon-like peptide-1 eyedrops represents a non-invasive and effective treatment approach for managing early-stage diabetic retinopathy.

Neuromodulation technologies improve functional recovery after brain injury: From bench to bedside

Spontaneous recovery frequently proves maladaptive or insufficient because the plasticity of the injured adult mammalian central nervous system is limited. This limited plasticity serves as a primary barrier to functional recovery after brain injury. Neuromodulation technologies represent one of the fastest-growing fields in medicine. These techniques utilize electricity, magnetism, sound, and light to restore or optimize brain functions by promoting reorganization or long-term changes that support functional recovery in patients with brain injury. Therefore, this review aims to provide a comprehensive overview of the effects and underlying mechanisms of neuromodulation technologies in supporting motor function recovery after brain injury. Many of these technologies are widely used in clinical practice and show significant improvements in motor function across various types of brain injury. However, studies report negative findings, potentially due to variations in stimulation protocols, differences in observation periods, and the severity of functional impairments among participants across different clinical trials. Additionally, we observed that different neuromodulation techniques share remarkably similar mechanisms, including promoting neuroplasticity, enhancing neurotrophic factor release, improving cerebral blood flow, suppressing neuroinflammation, and providing neuroprotection. Finally, considering the advantages and disadvantages of various neuromodulation techniques, we propose that future development should focus on closed-loop neural circuit stimulation, personalized treatment, interdisciplinary collaboration, and precision stimulation.

Investigation of epilepsy-related genes in a Drosophila model

Complex genetic architecture is the major cause of heterogeneity in epilepsy, which poses challenges for accurate diagnosis and precise treatment. A large number of epilepsy candidate genes have been identified from clinical studies, particularly with the widespread use of next-generation sequencing. Validating these candidate genes is emerging as a valuable yet challenging task. Drosophila serves as an ideal animal model for validating candidate genes associated with neurogenetic disorders such as epilepsy, due to its rapid reproduction rate, powerful genetic tools, and efficient use of ethological and electrophysiological assays. Here, we systematically summarize the advantageous techniques of the Drosophila model used to investigate epilepsy genes, including genetic tools for manipulating target gene expression, ethological assays for seizure-like behaviors, electrophysiological techniques, and functional imaging for recording neural activity. We then introduce several typical strategies for identifying epilepsy genes and provide new insights into gene‒gene interactions in epilepsy with polygenic causes. We summarize well-established precision medicine strategies for epilepsy and discuss prospective treatment options, including drug therapy and gene therapy for genetic epilepsy based on the Drosophila model. Finally, we also address genetic counseling and assisted reproductive technology as potential approaches for the prevention of genetic epilepsy.

Microglial polarization pathways and therapeutic drugs targeting activated microglia in traumatic brain injury

Traumatic brain injury can be categorized into primary and secondary injuries. Secondary injuries are the main cause of disability following traumatic brain injury, which involves a complex multicellular cascade. Microglia play an important role in secondary injury and can be activated in response to traumatic brain injury. In this article, we review the origin and classification of microglia as well as the dynamic changes of microglia in traumatic brain injury. We also clarify the microglial polarization pathways and the therapeutic drugs targeting activated microglia. We found that regulating the signaling pathways involved in pro-inflammatory and anti-inflammatory microglia, such as the Toll-like receptor 4 /nuclear factor-kappa B, mitogen-activated protein kinase, Janus kinase/signal transducer and activator of transcription, phosphoinositide 3-kinase/protein kinase B, Notch, and high mobility group box 1 pathways, can alleviate the inflammatory response triggered by microglia in traumatic brain injury, thereby exerting neuroprotective effects. We also reviewed the strategies developed on the basis of these pathways, such as drug and cell replacement therapies. Drugs that modulate inflammatory factors, such as rosuvastatin, have been shown to promote the polarization of anti-inflammatory microglia and reduce the inflammatory response caused by traumatic brain injury. Mesenchymal stem cells possess anti-inflammatory properties, and clinical studies have confirmed their significant efficacy and safety in patients with traumatic brain injury. Additionally, advancements in mesenchymal stem cell-delivery methods-such as combinations of novel biomaterials, genetic engineering, and mesenchymal stem cell exosome therapy-have greatly enhanced the efficiency and therapeutic effects of mesenchymal stem cells in animal models. However, numerous challenges in the application of drug and mesenchymal stem cell treatment strategies remain to be addressed. In the future, new technologies, such as single-cell RNA sequencing and transcriptome analysis, can facilitate further experimental studies. Moreover, research involving non-human primates can help translate these treatment strategies to clinical practice.

Respiratory modulation of beta corticomuscular coherence in isometric hand movements

Respiration is a fundamental physiological function in humans, often synchronized with movement to enhance performance and efficiency. Recent studies have underscored the modulatory effects of respiratory rhythms on brain oscillations and various behavioral responses, including sensorimotor processes. In light of this connection, our study aimed to investigate the influence of different respiratory patterns on beta corticomuscular coherence (CMC) during isometric hand flexion and extension. Utilizing electroencephalogram (EEG) and surface electromyography (sEMG), we examined three breathing conditions: normal breathing, deep inspiration, and deep expiration. Two experimental protocols were employed: the first experiment required participants to simultaneously breathe and exert force, while the other involved maintaining a constant force while varying breathing patterns. The results revealed that deep inspiration significantly enhanced beta CMC during respiration-synchronized tasks, whereas normal breathing resulted in higher CMC compared to deep respiration during sustained force exertion. In the second experiment, beta CMC was cyclically modulated by respiratory phase across all breathing conditions. The difference in the outcomes from the two protocols demonstrated a task-specific modulation of respiration on motor control. Overall, these findings indicate the complex dynamics of respiration-related effects on corticomuscular neural communication and provide valuable insights into the mechanisms underpinning the coupling between respiration and motor function.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11571-025-10245-x.

Electrophysiological characterization of sourced human iPSC-derived motor neurons

Induced pluripotent stem cell (iPSC)-derived motor neurons provide a powerful platform for studying motor neuron diseases. These cells enable human-specific modeling of disease mechanisms and high-throughput drug screening. While commercially available iPSC-derived motor neurons offer a convenient alternative to time-intensive differentiation protocols, their electrophysiological properties and maturation require comprehensive evaluation to validate their utility for research and therapeutic applications. In this study, we characterized the electrophysiological properties of commercially available iPSC-derived motor neurons. Immunofluorescence confirmed the expression of motor neuron-specific biomarkers, indicating successful differentiation and maturation. Electrophysiological recordings revealed stable passive membrane properties, maturation-dependent improvements in action potential kinetics, and progressive increases in repetitive firing. Voltage-clamp analyses confirmed the functional expression of key ion channels, including high- and low-voltage-activated calcium channels, TTX-sensitive and TTX-insensitive sodium channels, and voltage-gated potassium channels. While the neurons exhibited hallmark features of motor neuron physiology, high input resistance, depolarized resting membrane potentials, and limited firing capacity suggest incomplete electrical maturation. Altogether, these findings underscore the potential of commercially available iPSC-derived motor neurons as a practical resource for MND research, while highlighting the need for optimized protocols to support prolonged culture and full maturation.

A macro-transection model of brain trauma for neuromaterial testing with functional electrophysiological readouts

JOURNAL/nrgr/04.03/01300535-202512000-00024/figure1/v/2025-01-31T122243Z/r/image-tiff Functional recovery in penetrating neurological injury is hampered by a lack of clinical regenerative therapies. Biomaterial therapies show promise as medical materials for neural repair through immunomodulation, structural support, and delivery of therapeutic biomolecules. However, a lack of facile and pathology-mimetic models for therapeutic testing is a bottleneck in neural tissue engineering research. We have deployed a two-dimensional, high-density multicellular cortical brain sheet to develop a facile model of injury (macrotransection/scratch wound) in vitro . The model encompasses the major neural cell types involved in pathological responses post-injury. Critically, we observed hallmark pathological responses in injury foci including cell scarring, immune cell infiltration, precursor cell migration, and short-range axonal sprouting. Delivering test magnetic particles to evaluate the potential of the model for biomaterial screening shows a high uptake of introduced magnetic particles by injury-activated immune cells, mimicking in vivo findings. Finally, we proved it is feasible to create reproducible traumatic injuries in the brain sheet (in multielectrode array devices in situ ) characterized by focal loss of electrical spiking in injury sites, offering the potential for longer term, electrophysiology plus histology assays. To our knowledge, this is the first in vitro simulation of transecting injury in a two-dimensional multicellular cortical brain cell sheet, that allows for combined histological and electrophysiological readouts of damage/repair. The patho-mimicry and adaptability of this simplified model of brain injury could benefit the testing of biomaterial therapeutics in regenerative neurology, with the option for functional electrophysiological readouts.

The role of beta band phase resetting in audio-visual temporal order judgment

The integration of auditory and visual stimuli is essential for effective language processing and social perception. The present study aimed to elucidate the mechanisms underlying audio-visual (A-V) integration by investigating the temporal dynamics of multisensory regions in the human brain. Specifically, we evaluated inter-trial coherence (ITC), a neural index indicative of phase resetting, through scalp electroencephalography (EEG) while participants performed a temporal-order judgment task that involved auditory (beep, A) and visual (flash, V) stimuli. The results indicated that ITC phase resetting was greater for bimodal (A + V) stimuli compared to unimodal (A or V) stimuli in the posterior temporal region, which resembled the responses of A-V multisensory neurons reported in animal studies. Furthermore, the ITC got lager as the stimulus-onset asynchrony (SOA) between beep and flash approached 0 ms. This enhancement in ITC was most clearly seen in the beta band (13-30 Hz). Overall, these findings highlight the importance of beta rhythm activity in the posterior temporal cortex for the detection of synchronous audiovisual stimuli, as assessed through temporal order judgment tasks.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11571-024-10183-0.

Optimizing non-invasive vagus nerve stimulation for treatment in stroke

Stroke remains a leading cause of long-term disability worldwide. There is an unmet need for neuromodulatory therapies that can mitigate against neurovascular injury and potentially promote neurological recovery. Transcutaneous vagus nerve stimulation has been demonstrated to show potential therapeutic effects in both acute and chronic stroke. However, previously published research has only investigated a narrow range of stimulation settings and indications. In this review, we detail the ongoing studies of transcutaneous vagus nerve stimulation in stroke through systematic searches of registered clinical trials. We summarize the upcoming clinical trials of transcutaneous vagus nerve stimulation in stroke, highlighting their indications, parameter settings, scope, and limitations. We further explore the challenges and barriers associated with the implementation of transcutaneous vagus nerve stimulation in acute stroke and stroke rehabilitation, focusing on critical aspects such as stimulation settings, target groups, biomarkers, and integration with rehabilitation interventions.

Regulation of dentate gyrus pattern separation by hilus ectopic granule cells

The dentate gyrus (DG) in hippocampus is reported to perform pattern separation, converting similar inputs into different outputs and thus avoiding memory interference. Previous studies have found that human and mice with epilepsy have significant pattern separation defects and a portion of adult-born granule cells (abGCs) migrate abnormally into the hilus, forming hilus ectopic granule cells (HEGCs). For the lack of relevant pathophysiological experiments, how HEGCs affect pattern separation remains unclear. Therefore, in this paper, we will construct the DG neuronal circuit and focus on discussing effects of HEGCs on pattern separation numerically. The obtained results showed that HEGCs impaired pattern separation efficiency since the sparse firing of granule cells (GCs) was destroyed. We provided new insights into the underlining mechanisms of HEGCs impairing pattern separation through analyzing two excitatory circuits: GC-HEGC-GC and GC-Mossy cell (MC)-GC, both of which involve the participation of HEGCs within the DG. It is revealed that the recurrent excitatory circuit GC-HEGC-GC formed by HEGCs mossy fiber sprouting significantly enhanced GCs activity, consequently disrupted pattern separation. However, another excitatory circuit had negligible effects on pattern separation due to the direct and indirect influences of MCs on GCs, which in turn led to the GCs sparse firing. Thus, HEGCs impair DG pattern separation mainly through the GC-HEGC-GC circuit and therefore ablating HEGCs may be one of the effective ways to improve pattern separation in patients with epilepsy.

Brain analysis to approach human muscles synergy using deep learning

Brain signals and muscle movements have been analyzed using electroencephalogram (EEG) data in several studies. EEG signals contain a lot of noise, such as electromyographic (EMG) waves. Further studies have been done to improve the quality of the results, though it is thought that the combination of these two signals can lead to a significant improvement in the synergistic analysis of muscle movements and muscle connections. Using graph theory, this study examined the interaction of EMG and EEG signals during hand movement and estimated the synergy between muscle and brain signals. Mapping of the brain diagram was also developed to reconstruct the muscle signals from the muscle connections in the brain diagram. The proposed method included noise removal from EEG and EMG signals, graph feature analysis from EEG, and synergy calculation from EMG. Two methods were used to estimate synergy. In the first method, after calculating the brain connections, the features of the communication graph were extracted and then synergy estimating was made with neural networks. In the second method, a convolutional network created a transition from the matrix of brain connections to the synergistic EMG signal. This study reached the high correlation values of 99.8% and maximum MSE error of 0.0084. Compared to other graph-based methods, this method based on regression analysis had a very significant performance. This research can lead to the improvement of rehabilitation methods and brain-computer interfaces.

Characteristics analysis of a single electromechanical arm driven by a functional neural circuit

From a biological viewpoint, the muscle tissue produces efficient gait behavior that can be adjusted by neural signals. From the physical viewpoint, the limb movement can be simulated by applying a neural circuit to control the artificial electromechanical arm (EA). In this paper, a functional neural circuit is used to excite a single EA, the load circuit attached to the moving beam is driven by a neural circuit, and the Ampere force is activated by the load circuit to control the artificial EA. The dynamic equations of the neural circuit are derived using Kirchhoff's theorem, while the energy and motion equations of the beam are computed through the application of mechanics and related theoretical principles. Furthermore, the dynamic characteristics of the functional neural circuit forced EA are analyzed. The results indicate that the beam movement can be controlled by the electrical activity of this functional neural circuit. This work will provide theoretical guidance to build the electromechanical device for complex gait behaviors.

Uncommon and common roles of inhibitory interneuron and autapse and their cooperations to induce or eliminate epileptiform firing of pyramidal neuron

Different from the common role of inhibitory modulations to suppress firing activities, uncommon roles of inhibitory modulations are observed in recent experiments. For instance, inhibitory autapse can enhance spiking frequency of interneuron, and inhibitory interneuron can enhance spiking of pyramidal neuron to epileptiform firing with high membrane potential and extracellular potassium concentration, presenting possible novel etiology of brain diseases and challenge to excitation-inhibition balance. In the present paper, the uncommon roles, the common roles, and their cooperations are studied in a computation model. Firstly, the inhibitory interneuron with fast instead of slow decay synaptic current plays an uncommon role, and the complex process for the uncommon role is obtained. Compared with slow decay, the fast decay inhibitory synaptic current is strong enough to induce silence with low membrane potential, resulting in long silence and high level of extracellular potassium concentration when firing recovers, initiating positive feedback between firing and potassium concentration to induce the epileptiform firing. Secondly, inhibitory autaptic current with fast rather than slow decay plays an uncommon role to enhance spiking frequency of interneuron. Autaptic current with slow decay causes weak potassium current during downstroke of action potential to induce spike advanced. Finally, different cooperations between the common and uncommon roles of interneuron and autapse are obtained. Especially, fast autapse with great uncommon role can reverse the common role of interneuron, which can induce spiking to the epileptiform firing, and slow autapse with great common role can reverse the uncommon role of interneuron, which can change the epileptiform firing to spiking for the normal state. These findings present explanations to the uncommon roles of inhibitory modulations and multiple feasible measures to modulate the epileptiform firing and brain diseases.

Development of color learning protocol based on music-color association for people with visual impairment

BACKGROUND

This research developed and confirmed the feasibility of a color-learning mobile application for people with visual impairment based on the hypothesis that the music-color association may be synaesthetically induced through emotion.

METHODS

In total, 120 participants with visual impairment, comprising 60 congenital and 60 adventitious cases, were recruited. They underwent sequential procedures: Procedure 1 involved selecting color-music associations and designing tasks; Procedure 2 focused on application development with accessibility features; and Procedure 3 verified usability and effectiveness.

RESULTS

Significant improvements were observed in hue, luminance, and saturation scores following the use of the music-color association application among participants with both congenital and adventitious visual impairment. The effectiveness of the application in facilitating color learning is evident, suggesting its potential utility in enhancing color perception in this population.

CONCLUSIONS

This research introduces a novel framework for color learning among visually impaired individuals using a music-based synesthetic approach. The developed mobile application offers a promising avenue for efficiently improving color perception and learning, thereby addressing the critical need for accessibility and education for this population. Further research should explore the long-term effects and broader applications of synesthetic-induced learning in diverse contexts.

Exploring the potential for gene therapy in Cav1.4-related retinal channelopathies

The visual process begins with photon detection in photoreceptor outer segments within the retina, which processes light signals before transmission to the thalamus and visual cortex. Cav1.4 L-type calcium channels play a crucial role in this process, and dysfunction of these channels due to pathogenic variants in corresponding genes leads to specific manifestations in visual impairments. This review explores the journey from basic research on Cav1.4 L-type calcium channel complexes in retinal physiology and pathophysiology to their potential as gene therapy targets. Moreover, we provide a concise overview of key findings from studies using different animal models to investigate retinal diseases. It will critically examine the constraints these models present when attempting to elucidate retinal channelopathies. Additionally, the paper will explore potential strategies for addressing Cav1.4 channel dysfunction and discuss the current challenges facing gene therapy approaches in this area of research.

Unraveling the functional complexity of the locus coeruleus-norepinephrine system: insights from molecular anatomy to neurodynamic modeling

The locus coeruleus (LC), as the primary source of norepinephrine (NE) in the brain, is central to modulating cognitive and behavioral processes. This review synthesizes recent findings to provide a comprehensive understanding of the LC-NE system, highlighting its molecular diversity, neurophysiological properties, and role in various brain functions. We discuss the heterogeneity of LC neurons, their differential responses to sensory stimuli, and the impact of NE on cognitive processes such as attention and memory. Furthermore, we explore the system's involvement in stress responses and pain modulation, as well as its developmental changes and susceptibility to stressors. By integrating molecular, electrophysiological, and theoretical modeling approaches, we shed light on the LC-NE system's complex role in the brain's adaptability and its potential relevance to neurological and psychiatric disorders.

The dynamic impact of adult neurogenesis on pattern separation within the dentate gyrus neural network

Pattern separation in the dentate gyrus (DG) is crucial for distinguishing similar memories. The DG continues to undergo neurogenesis throughout the lifespan, and adult hippocampus neurogenesis leads to the incorporation of thousands of adult-born granule cells (adult-born GCs) into the existing DG circuitry. These newborn GCs exhibit high excitability and are easier to respond to novel stimuli, which seems to be contrary to the requirement of pattern separation for high input specificity. Meanwhile, the changes brought about by the growth of adult-born GCs can not be ignored. Here, we build a biologically relevant model of the DG containing adult-born GCs and test it using the Modified National Institute of Standards and Technology (MNIST) database. By analyzing this model, the results show that the net effect of adult-born GCs to GCs is inhibition, thereby improving the sparsity of GCs and pattern separation. This provides computational evidence for "indirect encoding" of adult-born GCs. In addition, as adult-born GCs transition toward maturity, they have the following growth characteristics: decreased activity, increased coupling strength with feedback inhibition, and enhanced synaptic plasticity. We find that the decreased activity reduces pattern separation efficiency while the other characteristics increase pattern separation efficiency. Finally, given that the firing rate of entorhinal cortex (EC) neurons is influenced by numerous factors (such as the complexity of memory tasks), the input frequency to the DG should be within a range rather than being fixed. To address this, we gradually increase the input frequency and notice that the presence of adult-born GCs increases the adaptability of the DG neural network and thus improves the robustness of pattern separation.

The GluN3-containing NMDA receptors

N-methyl-D-aspartate receptors (NMDARs) are heterotetrameric ion channels that play crucial roles in brain function. Among all the NMDAR subtypes, GluN1-N3 receptors exhibit unique agonist binding and gating properties. Unlike "conventional" GluN1-N2 receptors, which require both glycine and glutamate for activation, GluN1-N3 receptors are activated solely by glycine. Furthermore, GluN1-N3 receptors display faster desensitization, reduced Ca2+ permeability, and lower sensitivity to Mg2+ blockage compared to GluN1-N2 receptors. Due to these characteristics, GluN1-N3 receptors are thought to play critical roles in eliminating redundant synapses and pruning spines in early stages of brain development. Recent studies have advanced pharmacological tools for specifically targeting GluN1-N3 receptors and provided direct evidence of these glycine-activated excitatory receptors in native brain tissue. The structural basis of GluN1-N3 receptors has also been elucidated through cryo-EM and artificial intelligence. These findings highlight that GluN1-N3 receptors are not only involved in essential brain functions but also present potential targets for drug development.

Nerve root magnetic stimulation regulates the synaptic plasticity of injured spinal cord by ascending sensory pathway

JOURNAL/nrgr/04.03/01300535-202512000-00026/figure1/v/2025-01-31T122243Z/r/image-tiff Promoting synaptic plasticity and inducing functional reorganization of residual nerve fibers hold clinical significance for restoring motor function following spinal cord injury. Neuromagnetic stimulation targeting the nerve roots has been shown to improve motor function by enhancing nerve conduction in the injured spinal cord and restoring the synaptic ultrastructure of both the sensory and motor cortex. However, our understanding of the neurophysiological mechanisms by which nerve root magnetic stimulation facilitates motor function recovery in the spinal cord is limited, and its role in neuroplasticity remains unclear. In this study, we established a model of spinal cord injury in adult male Sprague-Dawley rats by applying moderate compression at the T10 vertebra. We then performed magnetic stimulation on the L5 nerve root for 3 weeks, beginning on day 3 post-injury. At day 22 post-injury, we observed that nerve root magnetic stimulation downregulated the level of interleukin-6 in the injured spinal cord tissue of rats. Additionally, this treatment reduced neuronal damage and glial scar formation, and increased the number of neurons in the injured spinal cord. Furthermore, nerve root magnetic stimulation decreased the levels of acetylcholine, norepinephrine, and dopamine, and increased the expression of synaptic plasticity-related mRNA and proteins PSD95, GAP43, and Synapsin II. Taken together, these results showed that nerve root magnetic stimulation alleviated neuronal damage in the injured spinal cord, regulated synaptic plasticity, and suppressed inflammatory responses. These findings provide laboratory evidence for the clinical application of nerve root magnetic stimulation in the treatment of spinal cord injury.

Regulatory mechanism of inhibitory interneurons with time-delay on epileptic seizures under sinusoidal sensory stimulation

Epilepsy is a neurological disorder in which complex electrophysiological processes are closely linked to inherent nonlinear kinetic properties. This study investigates the effects of sinusoidal sensory stimulation bias and time-delay on the dynamics of epileptic seizures within a corticothalamic neural network model. The results indicate that an increase in sensory stimulation bias can prematurely terminate seizures, and high-frequency stimulation can induce a phenomenon of frequency resonance. Meanwhile, discharge states transitions are associated with the emergence of bifurcation points. Time-delay exerts a significant regulatory influence on pathways with delay embedding (I2-PY), whereas its impact on pathways without delay embedding (I1-I1 and thalamic relay nucleus (TC)-I2) is negligible. Under sinusoidal sensory stimulation, the responses of three pathways (I1-I1, I1-PY, and I2-PY) associated with inhibitory interneurons reveal that the inhibitory properties of interneurons can suppress seizures; however, an excessively strong inhibitory effect may also precipitate seizures and facilitate state transitions. These findings contribute to a deeper understanding of seizure dynamics and may guide future research in the transmission and evolution of seizures.

Home-based strength and balance exercises for fall prevention among older individuals of advanced age: a randomized controlled single-blind study

OBJECTIVE

This research was to explore the effectiveness, safety, and adherence of home-based strength and balance exercises for fall prevention among the self-reliant individuals of advanced age and analyzed the beneficial components.

METHOD

This randomized controlled single-blind study included 124 individuals aged 80 years and over(mean age 84.4±3.2 years). The test group (n=63) performed strength and balance exercises facilitated by sports video training (≥ 3 sessions a week, ≥ 30 minutes per session), while the control group (n=61) maintained their daily routines. We conducted a comprehensive geriatric assessment (self-care ability, muscle strength, mobility, cognition, and psychological status) at baseline and 12 months later and dynamic posture mapping for balance and gait.

RESULTS

The test group had a decreased risk of falls compared to the control group (25.4%vs.44.3%, respectively; RR = 0.747; 95% CI: 0.551-0.975; p = 0.027). There was no statistically significant difference in the fall rate between the two groups (0.48 falls per person-year vs. 0.67 falls per person-year, respectively; IRR: 0.708; 95% CI: 0.394-1.275; p = 0.251). The composite equilibrium score (SOTcom) for vestibular and integrated balance on the Sensory Organization Test (SOT) increased in the test group, while SOTcom decreased in the control group. In the test group, there was a significant improvement in the indexes pertaining to response time, movement speed, directional control, and endpoint offset in some directions. Adherence was better in the test group, with 54.0% exercised ≥ 3 times per week and 28.6% exercised 1-2 times per week on average.

CONCLUSION

Home-based strength and balance exercises improved balance and reduced the risk of falls among the individuals of advanced age. The video-guided, remotely monitored regimen demonstrated effectiveness, safety, and compliance, although scope for improvement remains.

Neuroenhancement by repetitive transcranial magnetic stimulation (rTMS) on DLPFC in healthy adults

The term "neuroenhancement" describes the enhancement of cognitive function associated with deficiencies resulting from a specific condition. Nevertheless, there is currently no agreed-upon definition for the term "neuroenhancement", and its meaning can change based on the specific research being discussed. As humans, our continual pursuit of expanding our capabilities, encompassing both cognitive and motor skills, has led us to explore various tools. Among these, repetitive Transcranial Magnetic Stimulation (rTMS) stands out, yet its potential remains underestimated. Historically, rTMS was predominantly employed in studies focused on rehabilitation objectives. A small amount of research has examined its use on healthy subjects with the goal of improving cognitive abilities like risk-seeking, working memory, attention, cognitive control, learning, computing speed, and decision-making. It appears that the insights gained in this domain largely stem from indirect outcomes of rehabilitation research. This review aims to scrutinize these studies, assessing the effectiveness of rTMS in enhancing cognitive skills in healthy subjects. Given that the dorsolateral prefrontal cortex (DLPFC) has become a popular focus for rTMS in treating psychiatric disorders, corresponding anatomically to Brodmann areas 9 and 46, and considering the documented success of rTMS stimulation on the DLPFC for cognitive improvement, our focus in this review article centers on the DLPFC as the focal point and region of interest. Additionally, recognizing the significance of theta burst magnetic stimulation protocols (TBS) in mimicking the natural firing patterns of the brain to modulate excitability in specific cortical areas with precision, we have incorporated Theta Burst Stimulation (TBS) wave patterns. This inclusion, mirroring brain patterns, is intended to enhance the efficacy of the rTMS method. To ascertain if brain magnetic stimulation consistently improves cognition, a thorough meta-analysis of the existing literature has been conducted. The findings indicate that, after excluding outlier studies, rTMS may improve cognition when compared to appropriate control circumstances. However, there is also a considerable degree of variation among the researches. The navigation strategy used to reach the stimulation site and the stimulation location are important factors that contribute to the variation between studies. The results of this study can provide professional athletes, firefighters, bodyguards, and therapists-among others in high-risk professions-with insightful information that can help them perform better on the job.

Partial face visibility and facial cognition: event-related potential and eye tracking investigation

Face masks became a part of everyday life during the SARS-CoV-2 pandemic. Previous studies showed that the face cognition mechanism involves holistic face processing, and the absence of face features could lower the cognition ability. This is opposed to the experience during the pandemic, when people could correctly recognize faces, although the mask covered a part of the face. This paper clarifies the partial face cognition mechanism of the full and partial faces based on the electroencephalogram (EEG) and eye-tracking data. We observed two event-related potentials, P3a in the frontal lobe and P3b in the parietal lobe, as subcomponents of P300. The amplitude of both P3a and P3b were lowered when the eyes were invisible, and the amplitude of P3a evoked by the nose covered was larger than the full face. The eye-tracking data showed that 16 out of 18 participants focused on the eyes associated with the EEG results. Our results demonstrate that the eyes are the most crucial feature of facial cognition. Moreover, the face with the nose covered might enhance cognition ability due to the visual working memory capacity. Our experiment also shows the possibility of people recognizing faces using both holistic and structural face processing. In addition, we calculated canonical correlation using the P300 and the total fixation duration of the eye-tracking data. The results show high correlation in the cognition of the full face and the face and nose covered (R c = 0.93 ) which resembles the masked face. The finding suggests that people can recognize the masked face as well as the full face in similar cognition patterns.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11571-025-10231-3.

Beta-band oscillations and spike-local field potential synchronization in the motor cortex are correlated with movement deficits in an exercise-induced fatigue mouse model

Fatigue, a complex and multifaceted symptom, profoundly influences quality of life, particularly among individuals suffering from chronic medical conditions or neurological disorders. This symptom not only exacerbates existing conditions but also hinders daily functioning, thereby perpetuating a vicious cycle of worsening symptoms and reduced physical activity. Given the pivotal role of the motor cortex (M1) in coordinating and executing voluntary movements, understanding how the cortex regulates fatigue is crucial. Despite its importance, the neural mechanisms underlying fatigue remain inadequately explored. In this study, we employed electrophysiological recordings in the M1 region of mice to investigate how excitation-inhibition dynamics and neural oscillations are regulated during exercise-induced fatigue. We observed that fatigue led to decreased voluntary physical activity and cognitive performance, manifesting as reduced running wheel distance, mean speed, exercise intensity, and exploratory behaviour. At the neural level, we detected increased firing frequencies for M1 neurons, including both pyramidal neurons and interneurons, along with heightened beta-band oscillatory activity and stronger coupling between beta-band oscillations and interneurons. These findings enhance our understanding of the mechanisms underlying fatigue, offering insights into behavioural, excitability, and oscillatory changes. The results of this study could pave the way for the development of novel intervention strategies to combat fatigue.

Formation of cognitive maps in large-scale environments by sensorimotor integration

Hippocampus in the mammalian brain supports navigation by building a cognitive map of the environment. However, only a few studies have investigated cognitive maps in large-scale arenas. To reveal the computational mechanisms underlying the formation of cognitive maps in large-scale environments, we propose a neural network model of the entorhinal-hippocampal neural circuit that integrates both spatial and non-spatial information. Spatial information is relayed from the grid units in medial entorhinal cortex (MEC) by integrating multimodal sensory-motor signals. Non-spatial, such as object, information is imparted from the visual units in lateral entorhinal cortex (LEC) by encoding visual scenes through a deep neural network. The synaptic weights from the grid units and the visual units to the place units in the hippocampus are learned by a competitive learning rule. We simulated the model in a large box maze. The place units in the model form irregularly-spaced multiple fields across the environment. When the strength of visual inputs is dominant, the responses of place units become conjunctive and egocentric. These results point to the key role of the hippocampus in balancing spatial and non-spatial information relayed via LEC and MEC.

Stage-specific modulation of Drosophila gene expression with muscle GAL4 promoters

The bipartite GAL4/UAS system is the most widely used method for targeted gene expression in Drosophila melanogaster and facilitates rapid in vivo genetic experimentation. Defining precise gene expression patterns for tissues and/or cell types under GAL4 control will continue to evolve to suit experimental needs. However, the precise spatial and temporal expression patterns for some commonly used muscle tissue promoters are still unclear. This missing information limits the precise timing of experiments during development. Here, we focus on three muscle-enriched GAL4 drivers (Mef2-GAL4, C57-GAL4 and G7-GAL4) to better inform selection of the most appropriate muscle promoter for experimental needs. Specifically, C57-GAL4 and G7-GAL4 turn on in the first or second instar larval stages, respectively, and can be used to bypass myogenesis for studies of muscle function after development.

Attenuated heterogeneity of hippocampal neuron subsets in response to novelty induced by amyloid-β

Alzheimer's disease (AD) patients exhibited episodic memory impairments including location-object recognition in a spatial environment, which was also presented in animal models with amyloid-β (Aβ) accumulation. A potential cellular mechanism was the unstable representation of spatial information and lack of discrimination ability of novel stimulus in the hippocampal place cells. However, how the firing characteristics of different hippocampal subsets responding to diverse spatial information were interrupted by Aβ accumulation remains unclear. In this study, we observed impaired novel object-location recognition in Aβ-treated Long-Evans rats, with larger receptive fields of place cells in hippocampal CA1, compared with those in the saline-treated group. We identified two subsets of place cells coding object information (ObjCell) and global environment (EnvCell) during the task, with firing heterogeneity in response to introduced novel information. ObjCells displayed a dynamic representation responding to the introduction of novel information, while EnvCells exhibited a stable representation to support the recognition of the familiar environment. However, the dynamic firing patterns of these two subsets of cells were disrupted to present attenuated heterogeneity under Aβ accumulation. The impaired spatial representation novelty information could be due to the disturbed gamma modulation of neural activities. Taken together, these findings provide new evidence for novelty recognition impairments of AD rats with spatial representation dysfunctions of hippocampal subsets.

Human induced pluripotent stem cell-derived therapies for regeneration after central nervous system injury

In recent years, the progression of stem cell therapies has shown great promise in advancing the nascent field of regenerative medicine. Considering the non-regenerative nature of the mature central nervous system, the concept that "blank" cells could be reprogrammed and functionally integrated into host neural networks remained intriguing. Previous work has also demonstrated the ability of such cells to stimulate intrinsic growth programs in post-mitotic cells, such as neurons. While embryonic stem cells demonstrated great potential in treating central nervous system pathologies, ethical and technical concerns remained. These barriers, along with the clear necessity for this type of treatment, ultimately prompted the advent of induced pluripotent stem cells. The advantage of pluripotent cells in central nervous system regeneration is multifaceted, permitting differentiation into neural stem cells, neural progenitor cells, glia, and various neuronal subpopulations. The precise spatiotemporal application of extrinsic growth factors in vitro, in addition to microenvironmental signaling in vivo, influences the efficiency of this directed differentiation. While the pluri- or multipotency of these cells is appealing, it also poses the risk of unregulated differentiation and teratoma formation. Cells of the neuroectodermal lineage, such as neuronal subpopulations and glia, have been explored with varying degrees of success. Although the risk of cancer or teratoma formation is greatly reduced, each subpopulation varies in effectiveness and is influenced by a myriad of factors, such as the timing of the transplant, pathology type, and the ratio of accompanying progenitor cells. Furthermore, successful transplantation requires innovative approaches to develop delivery vectors that can mitigate cell death and support integration. Lastly, host immune responses to allogeneic grafts must be thoroughly characterized and further developed to reduce the need for immunosuppression. Translation to a clinical setting will involve careful consideration when assessing both physiologic and functional outcomes. This review will highlight both successes and challenges faced when using human induced pluripotent stem cell-derived cell transplantation therapies to promote endogenous regeneration.

Copper homeostasis and neurodegenerative diseases

Copper, one of the most prolific transition metals in the body, is required for normal brain physiological activity and allows various functions to work normally through its range of concentrations. Copper homeostasis is meticulously maintained through a complex network of copper-dependent proteins, including copper transporters (CTR1 and CTR2), the two copper ion transporters the Cu -transporting ATPase 1 (ATP7A) and Cu-transporting beta (ATP7B), and the three copper chaperones ATOX1, CCS, and COX17. Disruptions in copper homeostasis can lead to either the deficiency or accumulation of copper in brain tissue. Emerging evidence suggests that abnormal copper metabolism or copper binding to various proteins, including ceruloplasmin and metallothionein, is involved in the pathogenesis of neurodegenerative disorders. However, the exact mechanisms underlying these processes are not known. Copper is a potent oxidant that increases reactive oxygen species production and promotes oxidative stress. Elevated reactive oxygen species levels may further compromise mitochondrial integrity and cause mitochondrial dysfunction. Reactive oxygen species serve as key signaling molecules in copper-induced neuroinflammation, with elevated levels activating several critical inflammatory pathways. Additionally, copper can bind aberrantly to several neuronal proteins, including alpha-synuclein, tau, superoxide dismutase 1, and huntingtin, thereby inducing neurotoxicity and ultimately cell death. This study focuses on the latest literature evaluating the role of copper in neurodegenerative diseases, with a particular focus on copper-containing metalloenzymes and copper-binding proteins in the regulation of copper homeostasis and their involvement in neurodegenerative disease pathogenesis. By synthesizing the current findings on the functions of copper in oxidative stress, neuroinflammation, mitochondrial dysfunction, and protein misfolding, we aim to elucidate the mechanisms by which copper contributes to a wide range of hereditary and neuronal disorders, such as Wilson's disease, Menkes' disease, Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, and multiple sclerosis. Potential clinically significant therapeutic targets, including superoxide dismutase 1, D-penicillamine, and 5,7-dichloro-2-[(dimethylamino)methyl]-8-hydroxyquinoline, along with their associated therapeutic agents, are further discussed. Ultimately, we collate evidence that copper homeostasis may function in the underlying etiology of several neurodegenerative diseases and offer novel insights into the potential prevention and treatment of these diseases based on copper homeostasis.

A single-cell transcriptomic atlas of sensory-dependent gene expression in developing mouse visual cortex

Sensory experience drives the maturation of neural circuits during postnatal brain development through molecular mechanisms that remain to be fully elucidated. One likely mechanism involves the sensory-dependent expression of genes that encode direct mediators of circuit remodeling within developing cells. To identify potential drivers of sensory-dependent synaptic development, we generated a single-nucleus RNA sequencing dataset describing the transcriptional responses of cells in the mouse visual cortex to sensory deprivation or to stimulation during a developmental window when visual input is necessary for circuit refinement. We sequenced 118,529 nuclei across 16 neuronal and non-neuronal cell types isolated from control, sensory deprived and sensory stimulated mice, identifying 1268 sensory-induced genes within the developing brain. While experience elicited transcriptomic changes in all cell types, excitatory neurons in layer 2/3 exhibited the most robust changes, and the sensory-induced genes in these cells are poised to strengthen synapse-to-nucleus crosstalk and to promote cell type-specific axon guidance pathways. Altogether, we expect this dataset to significantly broaden our understanding of the molecular mechanisms through which sensory experience shapes neural circuit wiring in the developing brain.

Multilevel analysis of the central-peripheral-target organ pathway: contributing to recovery after peripheral nerve injury

Peripheral nerve injury is a common neurological condition that often leads to severe functional limitations and disabilities. Research on the pathogenesis of peripheral nerve injury has focused on pathological changes at individual injury sites, neglecting multilevel pathological analysis of the overall nervous system and target organs. This has led to restrictions on current therapeutic approaches. In this paper, we first summarize the potential mechanisms of peripheral nerve injury from a holistic perspective, covering the central nervous system, peripheral nervous system, and target organs. After peripheral nerve injury, the cortical plasticity of the brain is altered due to damage to and regeneration of peripheral nerves; changes such as neuronal apoptosis and axonal demyelination occur in the spinal cord. The nerve will undergo axonal regeneration, activation of Schwann cells, inflammatory response, and vascular system regeneration at the injury site. Corresponding damage to target organs can occur, including skeletal muscle atrophy and sensory receptor disruption. We then provide a brief review of the research advances in therapeutic approaches to peripheral nerve injury. The main current treatments are conducted passively and include physical factor rehabilitation, pharmacological treatments, cell-based therapies, and physical exercise. However, most treatments only partially address the problem and cannot complete the systematic recovery of the entire central nervous system-peripheral nervous system-target organ pathway. Therefore, we should further explore multilevel treatment options that produce effective, long-lasting results, perhaps requiring a combination of passive (traditional) and active (novel) treatment methods to stimulate rehabilitation at the central-peripheral-target organ levels to achieve better functional recovery.

Inhibitory gamma-aminobutyric acidergic neurons in the anterior cingulate cortex participate in the comorbidity of pain and emotion

Pain is often comorbid with emotional disorders such as anxiety and depression. Hyperexcitability of the anterior cingulate cortex has been implicated in pain and pain-related negative emotions that arise from impairments in inhibitory gamma-aminobutyric acid neurotransmission. This review primarily aims to outline the main circuitry (including the input and output connectivity) of the anterior cingulate cortex and classification and functions of different gamma-aminobutyric acidergic neurons; it also describes the neurotransmitters/neuromodulators affecting these neurons, their intercommunication with other neurons, and their importance in mental comorbidities associated with chronic pain disorders. Improving understanding on their role in pain-related mental comorbidities may facilitate the development of more effective treatments for these conditions. However, the mechanisms that regulate gamma-aminobutyric acidergic systems remain elusive. It is also unclear as to whether the mechanisms are presynaptic or postsynaptic. Further exploration of the complexities of this system may reveal new pathways for research and drug development.

Conformational restriction enables discovering a series of chroman derivatives as potent and selective NaV1.8 inhibitors with improved pharmacokinetic properties

Voltage-gated sodium channel 1.8 (NaV1.8) is a promising analgesic target due to its unique biophysical characteristics and specific role in nociceptive sensation. VX-150 initially completed proof-of-concept studies in clinical trials, but with high dosages and frequent administration. Herein, based on VX-150, we report the design, synthesis and structure-activity relationship (SAR) study aiming to identify novel, potent and selective NaV1.8 inhibitors with improved pharmacokinetic properties. Conformational restriction strategy and subsequent optimization led to the identification of the chroman derivative (R)-40 as the most promising hNaV1.8 inhibitor showing an IC50 value of 5.9 ± 1.0 nM and good selectivity over other tested NaV channels and hERG channel. More importantly, (R)-40 showed good in vitro metabolic stability in liver microsomes across multiple species and excellent in vivo PK profiles in rats and dogs. Notably, (R)-40 exerted dose-dependent analgesic activities in both rat models with postoperative and inflammatory pain, and a wide safety margin in neurotoxicity evaluation. Overall, these results confirmed conformational restriction as an effective strategy to improve PK profile, and our detailed study provided a valuable foundation for developing novel NaV1.8 inhibitors.

Structural insights into the function, dysfunction and modulation of Kv3 channels

The third subfamily of voltage-gated K+ (Kv) channels includes four members, Kv3.1, Kv3.2, Kv3.3 and Kv3.4. Fast gating and activation at relatively depolarized membrane potentials allows Kv3 channels to be major drivers of fast action potential repolarization in the nervous system. Consequently, they help determine the fast-spiking phenotype of inhibitory interneurons and regulate fast synaptic transmission at glutamatergic synapses and the neuromuscular junction. Recent studies from our group and a team of collaborators have used cryo-EM to demonstrate the surprising gating role of the Kv3.1 cytoplasmic T1 domain, the structural basis of a developmental epileptic encephalopathy caused by the Kv3.2-C125Y variant and the mechanism of action of positive allosteric modulators involving unexpected interactions and conformational changes in Kv3.1 and Kv3.2. Furthermore, our recent work has shown that Kv3.4 regulates use-dependent spike broadening in a manner that depends on gating modulation by phosphorylation of the channel's N-terminal inactivation domain, which can impact activity-dependent synaptic facilitation. Here, we review and integrate these studies to provide a perspective on our current understanding of Kv3 channel function, dysfunction and pain modulation in the nervous system.

The dopaminergic system and Alzheimer's disease

Alzheimer's disease is a common neurodegenerative disorder in older adults. Despite its prevalence, its pathogenesis remains unclear. In addition to the most widely accepted causes, which include excessive amyloid-beta aggregation, tau hyperphosphorylation, and deficiency of the neurotransmitter acetylcholine, numerous studies have shown that the dopaminergic system is also closely associated with the occurrence and development of this condition. Dopamine is a crucial catecholaminergic neurotransmitter in the human body. Dopamine-associated treatments, such as drugs that target dopamine receptor D and dopamine analogs, can improve cognitive function and alleviate psychiatric symptoms as well as ameliorate other clinical manifestations. However, therapeutics targeting the dopaminergic system are associated with various adverse reactions, such as addiction and exacerbation of cognitive impairment. This review summarizes the role of the dopaminergic system in the pathology of Alzheimer's disease, focusing on currently available dopamine-based therapies for this disorder and the common side effects associated with dopamine-related drugs. The aim of this review is to provide insights into the potential connections between the dopaminergic system and Alzheimer's disease, thus helping to clarify the mechanisms underlying the condition and exploring more effective therapeutic options.

Predicting and preventing the next viral disease transmitted through food

The ability of viruses to infect humans following oral exposure and disrupt normal physiological or anatomical functions is a hallmark of their potential to cause foodborne disease. While the etiology of the vast majority of foodborne diseases remains undetermined, viruses are often identified as the culprit when the cause is ascertained. Many undiagnosed causes of foodborne illnesses, especially sporadic cases, may go undetected or be caused by yet-to-be-identified viruses. The potential for food to become a transmission vehicle for viral diseases that are not typically acquired following ingestion may be described within the epidemiological paradigm. This model considers the characteristics and interactions of the host (the human), the agent (the virus), and the environment (the food, the food producing animal or the food production environment). Importantly, these factors are not static and evolution of viruses, transformations in agrifood systems, and changes in environmental conditions and human health and behaviour may contribute to increased pathogenicity, virulence, or exposure. In the context of determining the potential for additional viruses to emerge as important causes of foodborne disease, factors that contribute to hazard characterization (e.g., receptor affinity and distribution) and exposure assessment (e.g., prevalence in food animals and food hygiene) are reviewed. Although it is not possible to predict the type, the timing nor the location of the emergence of the next important cause of foodborne viral disease, the deployment and implementation of actions and behaviours related to personal and food hygiene, sanitation, and safe food handling practices can reduce the likelihood and impact of known and emergent viruses on the safety of the food supply and human health.

Neuronal correlates of sleep in honey bees

Honey bees Apis mellifera follow the day-night cycle for their foraging activity, entering rest periods during darkness. Despite considerable research on sleep behaviour in bees, its underlying neurophysiological mechanisms are not well understood, partly due to the lack of brain imaging data that allow for analysis from a network- or system-level perspective. This study aims to fill this gap by investigating whether neuronal activity during rest periods exhibits stereotypic patterns comparable to sleep signatures observed in vertebrates. Using two-photon calcium imaging of the antennal lobes (AL) in head-fixed bees, we analysed brain dynamics across motion and rest epochs during the nocturnal period. The recorded activity was computationally characterised, and machine learning was applied to determine whether a classifier could distinguish the two states after motion correction. Out-of-sample classification accuracy reached 93 %, and a feature importance analysis suggested network features to be decisive. Accordingly, the glomerular connectivity was found to be significantly increased in the rest-state patterns. A full simulation of the AL using a leaky spiking neural network revealed that such a transition in network connectivity could be achieved by weakly correlated input noise and a reduction of synaptic conductance of the inhibitive local neurons (LNs) which couple the AL network nodes. The difference in the AL response maps between awake- and sleep-like states generated by the simulation showed a decreased specificity of the odour code in the sleep state, suggesting reduced information processing during sleep. Since LNs in the bee brain are GABAergic, this suggests that the GABAergic system plays a central role in sleep regulation in bees as in many higher species including humans. Our findings support the theoretical view that sleep-related network modulation mechanisms are conserved throughout evolution, highlighting the bee's potential as an invertebrate model for studying sleep at the level of single neurons.

Implementing feature binding through dendritic networks of a single neuron

A single neuron receives an extensive array of synaptic inputs through its dendrites, raising the fundamental question of how these inputs undergo integration and summation, culminating in the initiation of spikes in the soma. Experimental and computational investigations have revealed various modes of integration operations that include linear, superlinear, and sublinear summation. Interestingly, different types of neurons exhibit diverse patterns of dendritic integration depending on the spatial distribution of dendrites. The functional implications of these specific integration modalities remain largely unexplored. In this study, we employ the Purkinje cell (PC) as a model system to investigate these complex questions. Our findings reveal that PCs generally exhibit sublinear summation across their expansive dendrites. Both spatial and temporal input dynamically modulates the degree of sublinearity. Strong sublinearity necessitates the synaptic distribution in PCs to be globally scattered sensitive, whereas weak sublinearity facilitates the generation of complex firing patterns in PCs. Using dendritic branches characterized by strong sublinearity as computational units, we demonstrate that a neuron can successfully address the feature binding problem. Taken together, these results offer a systematic perspective on the functional role of dendritic sublinearity, inspiring a broader understanding of dendritic integration in various neuronal types.

Internal sensory models allow for balance control using muscle spindle acceleration feedback

Motor control requires sensory feedback, and the nature of this feedback has implications for the tasks of the central nervous system (CNS): for an approximately linear mechanical system (e.g., a freely standing person, a rider on a bicycle), if the sensory feedback does not contain the state variables (i.e., joint position and velocity), then optimal control actions are based on an internal dynamical system that estimates these states from the available incomplete sensory feedback. Such a computational system can be implemented as a recurrent neural network (RNN), and it uses a sensory model to update the state estimates. This is highly relevant for muscle spindle primary afferents whose firing rates scale with acceleration: if fusimotor and skeletomotor control are perfectly coordinated, these firing rates scale with the exafferent joint acceleration component, and in the absence of fusimotor control, they scale with the total joint acceleration (exafferent plus reafferent). For both scenarios, a sensory model exists that expresses the exafferent joint acceleration as a function of the state variables, and for the second scenario, a sensory model exists that corrects for the reafferent joint acceleration. Simulations of standing and bicycle balance control under realistic conditions show that joint acceleration feedback is sufficient for balance control, but only if the reafferent acceleration component is either absent from the feedback or is corrected for in the computational system.

Glucocorticoid receptor signaling in the brain and its involvement in cognitive function

The hypothalamic-pituitary-adrenal axis regulates the secretion of glucocorticoids in response to environmental challenges. In the brain, a nuclear receptor transcription factor, the glucocorticoid receptor, is an important component of the hypothalamic-pituitary-adrenal axis's negative feedback loop and plays a key role in regulating cognitive equilibrium and neuroplasticity. The glucocorticoid receptor influences cognitive processes, including glutamate neurotransmission, calcium signaling, and the activation of brain-derived neurotrophic factor-mediated pathways, through a combination of genomic and non-genomic mechanisms. Protein interactions within the central nervous system can alter the expression and activity of the glucocorticoid receptor, thereby affecting the hypothalamic-pituitary-adrenal axis and stress-related cognitive functions. An appropriate level of glucocorticoid receptor expression can improve cognitive function, while excessive glucocorticoid receptors or long-term exposure to glucocorticoids may lead to cognitive impairment. Patients with cognitive impairment-associated diseases, such as Alzheimer's disease, aging, depression, Parkinson's disease, Huntington's disease, stroke, and addiction, often present with dysregulation of the hypothalamic-pituitary-adrenal axis and glucocorticoid receptor expression. This review provides a comprehensive overview of the functions of the glucocorticoid receptor in the hypothalamic-pituitary-adrenal axis and cognitive activities. It emphasizes that appropriate glucocorticoid receptor signaling facilitates learning and memory, while its dysregulation can lead to cognitive impairment. This provides clues about how glucocorticoid receptor signaling can be targeted to overcome cognitive disability-related disorders.

Emergence of human-like attention and distinct head clusters in self-supervised vision transformers: A comparative eye-tracking study

Visual attention models aim to predict human gaze behavior, yet traditional saliency models and deep gaze prediction networks face limitations. Saliency models rely on handcrafted low-level visual features, often failing to capture human gaze dynamics, while deep learning-based gaze prediction models lack biological plausibility. Vision Transformers (ViTs), which use self-attention mechanisms, offer an alternative, but when trained with conventional supervised learning, their attention patterns tend to be dispersed and unfocused. This study demonstrates that ViTs trained with self-supervised DINO (self-Distillation with NO labels) develop structured attention that closely aligns with human gaze behavior when viewing videos. Our analysis reveals that self-attention heads in later layers of DINO-trained ViTs autonomously differentiate into three distinct clusters: (1) G1 heads (20%), which focus on key points within figures (e.g., the eyes of the main character) and resemble human gaze; (2) G2 heads (60%), which distribute attention over entire figures with sharp contours (e.g., the bodies of all characters); and (3) G3 heads (20%), which primarily attend to the background. These findings provide insights into how human overt attention and figure-ground segregation emerge in visual perception. Our work suggests that self-supervised learning enables ViTs to develop attention mechanisms that are more aligned with biological vision than traditional supervised training.

P2 purinergic signaling and pruritus

Pruritus is a common sensation that triggers scratching. Extracellular nucleotides and nucleosides, along with their receptors, primarily compose the purinergic signaling. The purinergic signaling mechanism in itch remains incompletely understood. Keratinocytes, fibroblasts, Langerhans cells, primary sensory nerve endings in the skin, and neurons and satellite glial cells in primary sensory ganglia (dorsal root ganglia and trigeminal ganglia) have been confirmed to express multiple subtypes of P2X and P2Y receptors. Purinergic signaling in the skin and primary sensory ganglia is involved in the pathological changes of skin pruritus, including atopic dermatitis, psoriasis, systemic sclerosis, diabetes complicated with pruritus, or other pruritus disorders. The interaction between P2 purinergic signaling and histamine receptors, transient receptor potential (TRP) channel receptors, and Mas-related G protein-coupled receptor member A3 (MrgprA3) receptors, which mediate itch signaling, is involved in the pathological process of skin pruritus. P2 purinergic receptor agonists can induce itching behaviors in animals. Targeted antagonism or inhibition of P2 purinergic receptors in the skin and primary sensory ganglia can alleviate pathological changes in skin pruritus. This review summarizes studies concluding that P2 receptors are involved in the pathogenesis of pruritus, with several showing potential as novel therapeutic options for alleviating pruritus.

Targeting harmful effects of non-excitatory amino acids as an alternative therapeutic strategy to reduce ischemic damage

The involvement of the excitatory amino acids glutamate and aspartate in cerebral ischemia and excitotoxicity is well-documented. Nevertheless, the role of non-excitatory amino acids in brain damage following a stroke or brain trauma remains largely understudied. The release of amino acids by necrotic cells in the ischemic core may contribute to the expansion of the penumbra. Our findings indicated that the reversible loss of field excitatory postsynaptic potentials caused by transient hypoxia became irreversible when exposed to a mixture of just four non-excitatory amino acids (L-alanine, glycine, L-glutamine, and L-serine) at their plasma concentrations. These amino acids induce swelling in the somas of neurons and astrocytes during hypoxia, along with permanent dendritic damage mediated by N-methyl-D-aspartate receptors. Blocking N-methyl-D-aspartate receptors prevented neuronal damage in the presence of these amino acids during hypoxia. It is likely that astroglial swelling caused by the accumulation of these amino acids via the alanine-serine-cysteine transporter 2 exchanger and system N transporters activates volume-regulated anion channels, leading to the release of excitotoxins and subsequent neuronal damage through N-methyl-D-aspartate receptor activation. Thus, previously unrecognized mechanisms involving non-excitatory amino acids may contribute to the progression and expansion of brain injury in neurological emergencies such as stroke and traumatic brain injury. Understanding these pathways could highlight new therapeutic targets to mitigate brain injury.

Polyethylene glycol fusion repair of severed sciatic nerves accelerates recovery of nociceptive sensory perceptions in male and female rats of different strains

JOURNAL/nrgr/04.03/01300535-202509000-00028/figure1/v/2024-11-05T132919Z/r/image-tiff Successful polyethylene glycol fusion (PEG-fusion) of severed axons following peripheral nerve injuries for PEG-fused axons has been reported to: (1) rapidly restore electrophysiological continuity; (2) prevent distal Wallerian Degeneration and maintain their myelin sheaths; (3) promote primarily motor, voluntary behavioral recoveries as assessed by the Sciatic Functional Index; and, (4) rapidly produce correct and incorrect connections in many possible combinations that produce rapid and extensive recovery of functional peripheral nervous system/central nervous system connections and reflex (e.g., toe twitch) or voluntary behaviors. The preceding companion paper describes sensory terminal field reorganization following PEG-fusion repair of sciatic nerve transections or ablations; however, sensory behavioral recovery has not been explicitly explored following PEG-fusion repair. In the current study, we confirmed the success of PEG-fusion surgeries according to criteria (1-3) above and more extensively investigated whether PEG-fusion enhanced mechanical nociceptive recovery following sciatic transection in male and female outbred Sprague-Dawley and inbred Lewis rats. Mechanical nociceptive responses were assessed by measuring withdrawal thresholds using von Frey filaments on the dorsal and midplantar regions of the hindpaws. Dorsal von Frey filament tests were a more reliable method than plantar von Frey filament tests to assess mechanical nociceptive sensitivity following sciatic nerve transections. Baseline withdrawal thresholds of the sciatic-mediated lateral dorsal region differed significantly across strain but not sex. Withdrawal thresholds did not change significantly from baseline in chronic Unoperated and Sham-operated rats. Following sciatic transection, all rats exhibited severe hyposensitivity to stimuli at the lateral dorsal region of the hindpaw ipsilateral to the injury. However, PEG-fused rats exhibited significantly earlier return to baseline withdrawal thresholds than Negative Control rats. Furthermore, PEG-fused rats with significantly improved Sciatic Functional Index scores at or after 4 weeks postoperatively exhibited yet-earlier von Frey filament recovery compared with those without Sciatic Functional Index recovery, suggesting a correlation between successful PEG-fusion and both motor-dominant and sensory-dominant behavioral recoveries. This correlation was independent of the sex or strain of the rat. Furthermore, our data showed that the acceleration of von Frey filament sensory recovery to baseline was solely due to the PEG-fused sciatic nerve and not saphenous nerve collateral outgrowths. No chronic hypersensitivity developed in any rat up to 12 weeks. All these data suggest that PEG-fusion repair of transection peripheral nerve injuries could have important clinical benefits.

Learning performance of cerebellar circuit depends on diversity and chaoticity of spiking patterns in granule cells: A simulation study

The cerebellum, composed of numerous neurons, plays various roles in motor control. Although it is functionally subdivided, the cerebellar cortex has a canonical structural pattern in neuronal circuits including a recurrent circuit pattern formed by granule cells (GrCs) and Golgi cells (GoCs). The canonical circuital pattern suggests the existence of a fundamental computational algorithm, although it remains unclear. Modeling and simulation studies are useful for verifying hypotheses about complex systems. Previous models have shown that they could reproduced the neurophysiological data of the cerebellum; however, the dynamic characteristics of the system have not been fully elucidated. Understanding the dynamic characteristics of the circuital pattern is necessary to reveal the computational algorithm embedded in the circuit. This study conducted numerical simulations using the cerebellar circuit model to investigate dynamic characteristics in a simplified model of cerebellar microcircuits. First, the diversity and chaoticity of the patterns of spike trains generated from GrCs depending on the synaptic strength between the GrCs and GoCs were investigated based on cluster analysis and the Lyapunov exponent, respectively. Then the effect of synaptic strength on learning tasks was investigated based on the convergence properties of the output signals from Purkinje cells. The synaptic strength for high learning performance was almost consistent with that for the high diversity of the generated patterns and the edge of chaos. These results suggest that the learning performance of the cerebellar circuit depends on the diversity and the chaoticity of the spiking patterns from the GrC-GoC recurrent circuit.

Investigation of the relationship between 0.5-1200 Hz signal characteristics of cortical high-frequency oscillations and epileptogenicity through multivariate analysis

Fast ripples (FRs) (250-500 Hz) on the electroencephalogram (EEG) are closely related to epileptogenicity and are important to determine cortical regions resected in epilepsy surgery. However, FR-related epileptogenicity may be variable, and may depend on information associated with FRs. We enrolled nine epilepsy patients who had undergone intracranial 5 kHz-sampling-rate EEG for surgical treatment and had final Engel class I outcomes. Three electrodes were selected from each epileptogenic area (EA) and the unlikely EA (the region outside the EA) in each patient. Up to 100 candidate FRs were automatically detected from interictal nocturnal EEG at each of the selected electrodes and were visually reviewed independently by two researchers. Multivariate logistic regression analysis was performed using the frequency and log-power value of the corresponding FRs, presence of concurrent spike, ripple, very-high-frequency oscillations (vHFO)1 (500-600 Hz), and vHFO2 (600-1200 Hz), and whether the timing of the spectral peak of corresponding FRs was in the peak-trough or trough-peak transition of each slow activity (0.5-1, 1-2, 2-3, 3-4, and 4-8 Hz) as independent variables. Factors significantly related to epileptogenicity were FR power, the concurrent presence of spike and vHFO2, coupling with 0.5-1 and 1-2 Hz slow waves in the peak-trough transition, and coupling with 3-4 and 4-8 Hz slow waves in the trough-peak transition. Multifactorial analysis of FRs may increase their usefulness, potentially leading to improved treatment outcomes in epilepsy surgery.

Cortical-subcortical neural networks for motor learning and storing sequence memory

Motor sequence learning relies on the synergistic collaboration of multiple brain regions. However, most existing models for motor sequence learning primarily focus on functional-level analyses of sequence memory mechanisms, providing limited neurophysiological insights into how biological neural systems intrinsically encode the ordering of sequential element. Based on physiological and anatomical evidence, this study establishes a cortico-subcortical neuronal network model that differs from existing functional frameworks, emphasizing the neural mechanisms of sequence learning in the brain. The proposed model is biological plausibility and represents a potential mechanism for human sequential learning. It achieves the sequential selection and learning of elements through the cortico-basal ganglia-thalamic circuit, where the working memory function of the prefrontal cortex serves as the basis for Hebbian learning among cortical neurons, enabling the encoding of sequential order. The model successfully reproduces physiological experimental phenomena, validating its biological rationality. Furthermore, we explore the role of cholinergic interneurons in sequence learning, revealing their ability to enhance the robustness of learning. Finally, we demonstrate the model's applicability by deploying it to control a robotic arm in drawing and handwriting tasks, highlighting its adaptability to complex real-world scenarios. These biologically inspired results aim to offer a mechanistic explanation for sequence learning and memory formation in the human brain, providing valuable insights into brain-like control systems and neural networks.