The role of ventral hippocampal-medial prefrontal glutamatergic pathway on the non-affected side in post-stroke cognitive impairment.

Elucidate the pathogenesis mechanism of post-stroke cognitive impairment (PSCI) can help to develop precision interventions. In this study, we established a mouse model of PSCI using the photochemical method, and behavioral tests including Y-maze and Novel object recognition task for accessing cognitive impairment were observed at week 2 post-stroke. Besides, synaptic plasticity, theta nerve oscillatory and the activity of glutamatergic neurons related to the ventral hippocampal-medial prefrontal glutamatergic neural pathway in the non-affected hemisphere (contralateral hemisphere to the lesion site) were observed. The result indicated the cognitive function declined at week 2 post-stroke. Synaptic plasticity, theta nerve oscillatory synchronization and the activity of glutamatergic neurons of the ventral hippocampal-medial prefrontal glutamatergic neural pathway in the non-affected hemisphere was down-regulated in the PSCI group compared to those of the SHAM group. Therefore we concluded that the declined function of the ventral hippocampal-medial prefrontal glutamatergic pathway in the non-affected hemisphere is a biomarker in the occurrence of cognitive dysfunction after stroke.

Nociceptive transient receptor potential ankyrin 1 (TRPA1) in sensory neurons are targets of the antifungal drug econazole.

BACKGROUND: Econazole is a widely used imidazole derivative antifungal for treating skin infections. The molecular targets for its frequent adverse effects of skin irritation symptoms, such as pruritus, burning sensation, and pain, have not been clarified. Transient receptor potential (TRP) channels, non-selective cation channels, are mainly expressed in peripheral sensory neurons and serve as sensors for various irritants. METHODS: We investigated the effect of econazole on TRP channel activation by measuring intracellular calcium concentration ([Ca2+]i) through fluorescent ratio imaging in mouse dorsal root ganglion (DRG) neurons isolated from wild-type, TRPA1(-/-) and TRPV1(-/-) mice, as well as in heterologously TRP channel-expressed cells. A cheek injection model was employed to assess econazole-induced itch and pain in vivo. RESULTS: Econazole evoked an increase in [Ca2+]i, which was abolished by the removal of extracellular Ca2+ in mouse DRG neurons. The [Ca2+]i responses to econazole were suppressed by a TRPA1 blocker but not by a TRPV1 blocker. Attenuation of the econazole-induced [Ca2+]i responses was observed in the TRPA1(-/-) mouse DRG neurons but was not significant in the TRPV1(-/-) neurons. Econazole increased the [Ca2+]i in HEK293 cells expressing TRPA1 (TRPA1-HEK) but not in those expressing TRPV1, although at higher concentrations, it induced Ca2+ mobilization from intracellular stores in untransfected naïve HEK293 cells. Miconazole, which is a structural analog of econazole, also increased the [Ca2+]i in mouse DRG neurons and TRPA1-HEK, and its nonspecific action was larger than econazole. Fluconazole, a triazole drug failed to activate TRPA1 and TRPV1 in mouse DRG neurons and TRPA1-HEK. Econazole induced itch and pain in wild-type mice, with reduced responses in TRPA1(-/-) mice. CONCLUSIONS: These findings suggested that the imidazole derivatives econazole and miconazole may induce skin irritation by activating nociceptive TRPA1 in the sensory neurons. Suppression of TRPA1 activation may mitigate the adverse effects of econazole.

Dynamics and synchronization control of fractional conformable neuron system.

Dynamic analysis, electrical coupling and synchronization control of the conformable FitzHugh-Nagumo neuronal models have been presented in this work. Firstly, equations of the Adomian-Decomposition-Method and conformable neuron model have been introduced. The Adomian-Decomposition-Method has been employed for the numerical simulation analysis, since it converges fast and provides serial solutions. Fractional order and external current stimulus have been considered as bifurcation parameters and their effects on neuron model dynamics have been examined in detail. Then, the electrical coupling of the two conformable neuronal models without any controller has been revealed and the significance of the coupling strength parameter has been evaluated. To eliminate impact of the coupling strength parameter on synchronization status of neurons, Lyapunov control method has been employed for synchronization control. In the last step, the numerical simulation studies have been experimentally verified using the Texas Instrument Delfino digital signal processor board. Numerical simulation results together with experimental validation have showed that the types of dynamics of the related neuron model are not affected from the change of the fractional order of conformable derivative, but the frequency of the dynamic response of the neuronal model is changed from the alteration of the fractional order. The frequency of response of the neuron model increases with decreasing values of the fractional order. On the other hand, if there is no synchronization control method, the coupled neuron models exhibit response ranging from synchronous to asynchronous depending on the sign and value of the coupling parameter. Additionally, decreasing values of the fractional order may allow the coupled neurons to enter the synchronous state more quickly due to increasing frequency of response of the neuronal model. Finally, the coupled neuron models could exhibit synchronous behavior, that is determined by calculating the standard deviation results, regardless of the value of the coupling parameter by using the Lyapunov control method.

Biomimetic design and integrated biofabrication of an in-vitro three-dimensional multi-scale multilayer cortical model.

The lack of accurate and reliable in vitro brain models hinders the development of brain science and research on brain diseases. Owing to the complex structure of the brain tissue and its highly nonlinear characteristics, the construction of brain-like in vitro tissue models remains one of the most challenging research fields in the construction of living tissues. This study proposes a multi-scale design of a brain-like model with a biomimetic cortical structure, which includes the macroscopic structural features of six layers of different cellular components, as well as micrometer-scale continuous fiber structures running through all layers vertically. To achieve integrated biomanufacturing of such a complex multi-scale brain-like model, a multi-material composite printing/culturing integrated bioprinting platform was developed in-house by integrating cell-laden hydrogel ink direct writing printing and electrohydrodynamic fiber 3D printing technologies. Through integrated bioprinting, multi-scale models with different cellular components and fiber structural parameters were prepared to study the effects of macroscopic and microscopic structural features on the directionality of neural cells, as well as the interaction between glial cells and neurons within the tissue model in a three-dimensional manner. The results revealed that the manufactured in vitro biomimetic cortical model achieved morphological connections between the layers of neurons, reflecting the structure and cellular morphology of the natural cortex. Micrometer-scale (10 µm) cross-layer fibers effectively guided and controlled the extension length and direction of the neurites of surrounding neural cells but had no significant effect on the migration of neurons. In contrast, glial cells significantly promoted the migration of surrounding PC12 cells towards the glial layer but did not contribute to the extension of neurites. This study provides a basis for the design and manufacture of accurate brain-like models for the functionalization of neuronal tissues.

Adrenocorticotropic hormone therapy alters Q-albumin ratios in patients with infantile epileptic spasms syndrome of unknown etiology.

PURPOSE: Infantile epileptic spasms syndrome (IESS) with epileptic spasms as the main seizure type, is treated with adrenocorticotropic hormone (ACTH). This study, for the first time, examines the effects of epileptic spasms and ACTH on blood-brain barrier (BBB) permeability in patients with IESS of unknown etiology. METHODS: We prospectively evaluated the changes in BBB permeability in patients with IESS of unknown etiology at the Saitama Children's Medical Center between February 2012 and February 2024. We compared the levels of serum-albumin, cerebrospinal fluid (CSF)-albumin, Q-albumin, and CSF-neuron-specific enolase (NSE) before and after ACTH therapy. We also assessed the correlation between the frequency of epileptic spasms and these markers. RESULTS: Overall, 16 patients with IESS (8 males) were included in the study. The median age at IESS onset was 5 (range, 2-9) months. The median duration between the epileptic spasms onset and the serum and CSF sample examination before ACTH therapy was 26 (range, 1-154) days. After ACTH therapy, CSF-albumin and Q-albumin levels significantly decreased (CSF-albumin: 13.5 (9.0-32.0) mg/dL vs 11.0 (7.0-19.0) mg/dL, p = 0.001. Q-albumin: 3.7× 10-3 (2.2 × 10-3-7.3 × 10-3) vs 2.8× 10-3 (1.9 × 10-3-4.5 × 10-3), p = 0.003). No correlation was observed between the epileptic spasms frequency and levels of serum-albumin, CSF-albumin, Q-albumin, and CSF-NSE (Spearman's coefficient: r = 0.291, r = 0.141, r = 0.094, and r = -0.471, respectively). CONCLUSION: ACTH therapy is one of the factors that play a role in restoring BBB permeability in patients with IESS of unknown etiology. Our findings may be useful in elucidating the mechanism of ACTH action and IESS pathophysiology.

A single-cell transcriptomic census of mammalian olfactory epithelium aging.

Mammalian olfactory epithelium has the capacity of self-renewal throughout life. Aging is one of the major causes leading to the olfactory dysfunction. Here, we performed single-cell RNA sequencing (scRNA-seq) analysis on young and aged murine olfactory epithelium (OE) and identified aging-related differentially expressed genes (DEGs) throughout 21 cell types. Aging led to the presence of activated horizontal basal cells (HBCs) in the OE and promoted cellular interaction between HBCs and neutrophils. Aging enhanced the expression of Egr1 and Fos in sustentacular cell differentiation from multipotent progenitors, whereas Bcl11b was downregulated during the sensory neuronal homeostasis in the aged OE. Egr1 and Cebpb were predictive core regulatory factors of the transcriptional network in the OE. Overexpression of Egr1 in aged OE organoids promoted cell proliferation and neuronal differentiation. Moreover, aging altered expression levels and frequencies of olfactory receptors. These findings provide a cellular and molecular framework of OE aging at the single-cell resolution.

Alzheimer's disease protective allele of Clusterin modulates neuronal excitability through lipid-droplet-mediated neuron-glia communication.

Genome-wide association studies (GWAS) of Alzheimer's disease (AD) have identified a plethora of risk loci. However, the disease variants/genes and the underlying mechanisms remain largely unknown. For a strong AD-associated locus near Clusterin (CLU), we tied an AD protective allele to a role of neuronal CLU in promoting neuron excitability through lipid-mediated neuron-glia communication. We identified a putative causal SNP of CLU that impacts neuron-specific chromatin accessibility to transcription-factor(s), with the AD protective allele upregulating neuronal CLU and promoting neuron excitability. Transcriptomic analysis and functional studies in induced pluripotent stem cell (iPSC)-derived neurons co-cultured with mouse astrocytes show that neuronal CLU facilitates neuron-to-glia lipid transfer and astrocytic lipid droplet formation coupled with reactive oxygen species (ROS) accumulation. These changes cause astrocytes to uptake less glutamate thereby altering neuron excitability. Our study provides insights into how CLU confers resilience to AD through neuron-glia interactions.

Culturing Primary Cortical Neurons for Live-Imaging.

Primary neuronal cultures allow for in vitro analysis of early developmental processes such as axon pathfinding and growth dynamics. When coupled with methods to visualize and measure microtubule dynamics, this methodology enables an inside look at how the cytoskeleton changes in response to extracellular signaling cues. Here, we describe the culturing conditions and tools required to extract primary cortical neurons from postnatal mouse brains and visualize cytoskeletal components.

Electron Microscopy of Neurons on Biomimetic Substrates.

Recent advancements in nano- and microfabrication techniques have led to the development of highly biomimetic patterned substrates able to guide neuronal sprouting, routing, elongation, and branching. Such substrates, recapitulating shapes and geometries found in the native brain, may pave the way toward the development of cell instructive paradigms able to guide morphogenesis at the neuron-material interface. In this scenario, high-resolution electron microscopy approaches, owing to their ability of discerning the details of neural morphogenesis at a nanoscale resolution, may play a crucial role in unravelling the fine ultrastructure of neurons interfacing with biomimetic structured substrates.

DNeuroMAT: A Deep-Learning-Based Neuron Morphology Analysis Toolbox.

Digital reconstruction of neuronal structures from 3D neuron microscopy images is critical for the quantitative investigation of brain circuits and functions. Currently, neuron reconstructions are mainly obtained by manual or semiautomatic methods. However, these ways are labor-intensive, especially when handling the huge volume of whole brain microscopy imaging data. Here, we present a deep-learning-based neuron morphology analysis toolbox (DNeuroMAT) for automated analysis of neuron microscopy images, which consists of three modules: neuron segmentation, neuron reconstruction, and neuron critical points detection.

Analysis of Microtubule Polymerization During Axon Outgrowth Using Fluorescently Labeled Microtubule Plus-End Tracking Proteins.

The study of microtubules arrangements and dynamics during axon outgrowth and pathfinding has gained scientific interest during the last decade, and numerous technical resources for its visualization and analysis have been implemented. In this chapter, we describe the cell culture protocols of embryonic cortical and retinal neurons, the methods for transfecting them with fluorescent reporters of microtubule polymerization, and the procedures for time-lapse imaging and quantification in order to study microtubule dynamics during axon morphogenesis.

Visualization and Quantification of Organelle Axonal Transport in Cultured Neurons.

The specialized function and extreme geometry of neurons necessitates a unique reliance upon long-distance microtubule-based transport. Appropriate trafficking of axonal cargos by motor proteins is essential for establishing circuitry during development and continuing function throughout a lifespan. Visualizing and quantifying cargo movement provides valuable insight into how axonal organelles are replenished, recycled, and degraded during the dynamic dance of outgoing and incoming axonal traffic. Long-distance axonal trafficking is of particular importance as it encompasses a pathway commonly disrupted in developmental and degenerative disease states. Here, we describe neuronal organelles and outline methods for live imaging and quantifying their movement throughout the axon via transient expression of fluorescently labeled organelle markers. This resource provides recommendations for target proteins/domains and appropriate acquisition time scales for visualizing distinct neuronal cargos in cultured neurons derived from human induced pluripotent stem cells (iPSCs) and primary rat neurons.

Morphological Analysis of Neurons and Glia Using Mosaic Analysis with Double Markers.

Mosaic Analysis with Double Markers (MADM) is a powerful genetic method typically used for lineage tracing and to disentangle cell autonomous and tissue-wide roles of candidate genes with single cell resolution. Given the relatively sparse labeling, depending on which of the 19 MADM chromosomes one chooses, the MADM approach represents the perfect opportunity for cell morphology analysis. Various MADM studies include reports of morphological anomalies and phenotypes in the central nervous system (CNS). MADM for any candidate gene can easily incorporate morphological analysis within the experimental workflow. Here, we describe the methods of morphological cell analysis which we developed in the course of diverse recent MADM studies. This chapter will specifically focus on methods to quantify aspects of the morphology of neurons and astrocytes within the CNS, but these methods can broadly be applied to any MADM-labeled cells throughout the entire organism. We will cover two analyses-soma volume and dendrite characterization-of physical characteristics of pyramidal neurons in the somatosensory cortex, and two analyses-volume and Sholl analysis-of astrocyte morphology.

[Electrodiagnostic support in an atypical form of amyotrophic lateral sclerosis (Vulpian-Bernhardt syndrome)]. / Apoyo del electrodiagnóstico en una forma atípica de esclerosis lateral amiotrófica (síndrome de Vulpian-Bernhardt).

Background: Vulpian-Bernhardt syndrome is an atypical form of the motor neuron disease described since the 19th century. The importance of a timely diagnosis lies in the increased survival present in this variant. Due to the clinical rarity and complex diagnosis we report a clinical case of this disease, which is why we describe the typical clinical presentation, the diagnostic approach, and we make a bibliographic review of this neurodegenerative disorder as well. Clinical case: Latin American man whose clinical case onset was characterized by thoracic asymmetric and increasing limb weakness, showing affection from distal to proximal upper limbs area. Subsequently, symptoms worsened to the point of limiting day-to-day activities and conditioning patient's physical independence. Physical examination was consistent with motor neuron disease. Nerve conduction studies were performed and confirmed findings compatible with motor neuron involvement limited to thoracic limbs. Conclusion: Vulpian-Bernhardt syndrome is an uncommon form of motor neuron disease. Due to the rarity of its presentation, it is frequent to confuse clinical profile even for trained physicians. The importance of electrodiagnosis relies in identifying the neurogenic origin of the disease, as well as the active denervation and reinnervation data. Considering that with this syndrome patients have a longer survival than with the classic form of amyotrophic lateral sclerosis, it is important to have a clear diagnosis approach in order to provide a better quality of life and supportive treatment.

Introducción: el síndrome de Vulpian-Bernhardt es una forma atípica de la enfermedad de la motoneurona descrita desde el siglo XIX. La importancia de un diagnóstico oportuno radica en la mayor supervivencia que presenta esta variante. Debido a la rareza clínica y al diagnóstico complejo presentamos un caso clínico de esta enfermedad, por lo que describimos el cuadro clínico típico, el abordaje diagnóstico y hacemos una revisión bibliográfica de este trastorno neurodegenerativo. Caso clínico: hombre de origen latinoamericano que comenzó su padecimiento con debilidad de miembros torácicos, asimétrica y progresiva de distal a proximal. Los síntomas progresaron hasta limitar sus actividades de la vida diaria y su independencia física. La exploración física fue compatible con enfermedad de motoneurona. Se hicieron estudios de extensión y neuroconducción que confirmaron hallazgos compatibles con afectación en motoneurona limitada a miembros torácicos. Conclusión: el síndrome Vulpian-Bernhardt es una forma clínica poco común. Debido a su rareza, es fácil confundir el cuadro clínico, incluso por parte de experimentados. La importancia del electrodiagnóstico radica en identificar el origen neurogénico de la enfermedad, los datos de denervación activa y reinervación. Al ser una forma en la que se presenta una supervivencia mayor que en la forma clásica, es importante el diagnóstico claro para dar una mejor calidad de vida y tratamiento de soporte.

Spectral resonance in Fitzhugh-Nagumo neuron system: relation with stochastic resonance and its role in EMG signal characterization.

This paper examines the existence of spectral resonance in the Fitzhugh-Nagumo (FHN) system driven by periodical signal and unbounded noise having Gaussian distribution. It is newly revealed that if the inter-spike-interval (ISI) distribution is accumulated on a single cluster, there exists a dual relationship between stochastic resonance and spectral resonance determined by commonly used metric normalized standard deviation of ISI. Furthermore, the ISI distribution is also concentrated on more than one cluster depending on different driving signal frequency. Consequently, the apparent regular spiking behavior is observed to occur at specified driving signal frequencies which result in a local minimum in entropy function indicating spectral resonance. Therefore it is proposed that occurrence of spectral resonance strongly depends on the shape of ISI distribution tuned by the stochastic and deterministic driving signal parameters and conventional metrics may not indicate entire resonance behavior. Correspondingly, the entropy function is utilized in this paper as an alternative metric to enable the detection of the spectral resonance occurrence. The ISI distribution obtained from the FHN system is investigated to relate the real electromyography (EMG) measurements under different conditions such as myokymia and neuromyotonia. It is seen that ISI distribution observed from myokymic EMG exhibits notably close behavior as in the case of spectral resonance generated by FHN whereas a wider distribution is monitored in the case of neuromyotonia. It is contributed that the modeling and parameterization based on ISI distribution can be potentially used to identify different neural activities.

Energy and synchronization between two neurons with nonlinear coupling.

Consensus and synchronous firing in neural activities are relative to the physical properties of synaptic connections. For coupled neural circuits, the physical properties of coupling channels control the synchronization stability, and transient period for keeping energy diversity. Linear variable coupling results from voltage coupling via linear resistor by consuming certain Joule heat, and electric synapse coupling between neurons derives from gap junction connection under special electrophysiological condition. In this work, a voltage-controlled electric component with quadratic relation in the i-v (current-voltage) is used to connect two neural circuits composed of two variables. The energy function obtained by using Helmholtz theorem is consistent with the Hamilton energy function converted from the field energy in the neural circuit. Chaotic signals are encoded to approach a mixed signal within certain frequency band, and then its amplitude is adjusted to excite the neuron for detecting possible occurrence of nonlinear resonance. External stimuli are changed to trigger different firing modes, and nonlinear coupling activates changeable coupling intensity. It is confirmed that nonlinear coupling behaves functional regulation as hybrid synapse, and the synchronization transition between neurons can be controlled for reaching possible energy balance. The nonlinear coupling is helpful to keep energy diversity and prevent synchronous bursting because positive and negative feedback is switched with time. As a result, complete synchronization is suppressed and phase lock is controlled between neurons with energy diversity.

Coincidence detection and integration behavior in spiking neural networks.

Recently, the interest in spiking neural networks (SNNs) remarkably increased, as up to now some key advances of biological neural networks are still out of reach. Thus, the energy efficiency and the ability to dynamically react and adapt to input stimuli as observed in biological neurons is still difficult to achieve. One neuron model commonly used in SNNs is the leaky-integrate-and-fire (LIF) neuron. LIF neurons already show interesting dynamics and can be run in two operation modes: coincidence detectors for low and integrators for high membrane decay times, respectively. However, the emergence of these modes in SNNs and the consequence on network performance and information processing ability is still elusive. In this study, we examine the effect of different decay times in SNNs trained with a surrogate-gradient-based approach. We propose two measures that allow to determine the operation mode of LIF neurons: the number of contributing input spikes and the effective integration interval. We show that coincidence detection is characterized by a low number of input spikes as well as short integration intervals, whereas integration behavior is related to many input spikes over long integration intervals. We find the two measures to linearly correlate via a correlation factor that depends on the decay time. Thus, the correlation factor as function of the decay time shows a powerlaw behavior, which could be an intrinsic property of LIF networks. We argue that our work could be a starting point to further explore the operation modes in SNNs to boost efficiency and biological plausibility. Supplementary Information: The online version of this article (10.1007/s11571-023-10038-0) contains supplementary material, which is available to authorized users.

A Temperature Sensory Leaky Integrate-and-Fire Artificial Neuron Based on Chitosan/PNIPAM Bilayer Volatile Complementary Resistive Switching Memristor.

The presence of neurons is crucial in neuromorphic computing systems as they play a vital role in modulating the strength of synapses through the release of either excitatory or inhibitory stimuli. Hence, the development of sensory neurons plays a pivotal role in broadening the scope of brain-inspired neural computing. The present study introduces an artificial sensory neuron, which is constructed using a temperature-sensitive volatile complementary resistance switch memristor based on the functional layer of the chitosan/PNIPAM bilayer. The resistive switching behavior arises from the formation and ionization of oxygen vacancy filaments, whereby the threshold voltage and low resistive resistance of the device exhibit a temperature-dependent increase within the range of 290-410 K. A functional replication of a neuron with leaky integration and firing has been successfully developed, effectively simulating essential biological functions such as firing triggered by threshold, refractory period implementation, and modulation of spiking frequency. The artificial sensory neuron exhibits characteristics similar to those of leaky integrated firing neurons that receive temperature inputs. It has the potential to control the output frequency and amplitude under varying temperature conditions, making it suitable for temperature-sensing applications. This study presents a potential hardware implementation for developing efficient artificial intelligence systems that can support temperature detections.

Early detection of dopaminergic dysfunction and glymphatic system impairment in Parkinson's disease.

PURPOSE: This study aimed to assess the glymphatic function and its correlation with clinical characteristics and the loss of dopaminergic neurons in Parkinson's disease (PD) using hybrid positron emission tomography (PET)-magnetic resonance imaging (MRI) combined with diffusion tensor image analysis along the perivascular space (DTI-ALPS), choroid plexus volume (CPV), and enlarged perivascular space (EPVS) volume. METHODS: Twenty-five PD patients and thirty matched healthy controls (HC) participated in the study. All participants underwent 18F-fluorodopa (18F-DOPA) PET-MRI scanning. The striatal standardized uptake value ratio (SUVR), DTI-ALPS index, CPV, and EPVS volume were calculated. Furthermore, we also analysed the relationship between the DTI-ALPS index, CPV, EPVS volume and striatal SUVR as well as clinical characteristics of PD patients. RESULTS: PD patients demonstrated significantly lower values in DTI-ALPS (t = 3.053, p = 0.004) and larger CPV (t = 2.743, p = 0.008) and EPVS volume (t = 2.807, p = 0.008) compared to HC. In PD group, the ALPS-index was negatively correlated with the Unified Parkinson's Disease Rating Scale III (UPDRS-III) scores (r = -0.730, p < 0.001), and positively correlated with the mean putaminal SUVR (r = 0.560, p = 0.007) and mean caudal SUVR (r = 0.459, p = 0.032). Moreover, the mean putaminal SUVR was negatively associated with the UPDRS-III scores (r = -0.544, p = 0.009). CONCLUSION: DTI-ALPS has the potential to uncover glymphatic dysfunction in patients with PD, with this dysfunction correlating strongly with the severity of disease, together with the mean putaminal and caudal SUVR. PET- MRI can serve as a potential multimodal imaging biomarker for early-stage PD.