Pyramidal Layer Research Articles

Ultrastructure of rat cerebral cortex cells in normal and experimental dioxin poisoning

Purpose the study of the ultrastructure of the cerebral cortex of rats in normal and experimental poisoning with dioxin.
 Materials and methods. We studied the ultrastructure of the cells of the pyramidal layer of the cerebral cortex of rats of the control and experimental groups that were chronic poisoned with small doses of dioxin (2,3,7,8-tetrachlorodibenzo-para-dioxin or TCDD). Morphometric analysis was carried out to determine the length of synaptic clefts, the number of synapses per unit area, the thickness of the myelin layer of the processes and the number of wrappers of myelin sheaths.
 Results. The pathology of neurons has been observed both at the optical and ultrastructural levels. It is characterized by a decrease in nuclei, cell death, thinning of myelin sheaths and demyelination. The dose of poisoning correlates with the degree of destruction of neurons: with an increase in the dose of dioxin, changes become more significant. The number of synaptic contacts decreases but there is a significant increase in their average length.
 Conclusions. The processes of demyelination, impaired cellular respiration and destruction of synaptic contacts indicate the ability of dioxin to indirectly cause accelerated aging of neurons and their death (apoptosis).

Object Detection Algorithm Based on Improved Feature Pyramid

Feature pyramid network is widely used in advanced object detection. By simply changing the network connection, the performance of small object detection can be greatly improved without increasing the amount of calculation of the original model. However, the algorithm still has some shortcomings. Therefore, a new attention feature pyramid network (attention PFN) is proposed. Firstly, an improved receptive field module is added, which can make full use of global and local context information. Secondly, the connection mode of the pyramid is further optimized. Deconvolution is used to replace the nearest neighbor interpolation in top-down up-sampling and a channel attention module is added to the horizontal connection to highlight important context information. Finally, adaptive fusion and spatial feature balance are used for each feature pyramid, so that the network can learn the weights of different feature layers. Each pyramid layer contains more discrimination information. Attention PFN is tested on Pascal VOC and MS COCO datasets, respectively. The experiment results revealed that the proposed method has better performance than the original algorithm. Therefore, the attention PFN is an effective algorithm.

MLTSP: New 3D Framework, Based on the Multilayer Tensor Spectrum Pyramid

A tensor representation structure based on the multilayer tensor spectrum pyramid (MLTSP) is introduced in this work. The structure is “truncated”, i.e., part of the high-frequency spectrum coefficients is cut-off, and on the retained low-frequency coefficients, obtained at the output of each pyramid layer, a hierarchical tensor SVD (HTSVD) is applied. This ensures a high concentration of the input tensor energy into a small number of decomposition components of the tensors obtained at the coder output. The implementation of this idea is based on a symmetrical coder/decoder. An example structure for a cubical tensor of size 8 × 8 × 8, which is represented as a two-layer tensor spectrum pyramid, where 3D frequency-ordered fast Walsh–Hadamard transform and HTSVD are used, is given in this paper. The analysis of the needed mathematical operations proved the low computational complexity of the new approach, due to a lack of iterative calculations. The high flexibility of the structure in respect to the number of pyramid layers, the kind of used orthogonal transforms, the number of retained spectrum coefficients, and HTSVD components, permits us to achieve the desired accuracy of the restored output tensor, imposed by the application. Furthermore, this paper presents one possible application for 3D object searches in a tensor database. In this case, to obtain the invariant representation of the 3D objects, in the spectrum pyramid, the 3D modified Mellin–Fourier transform is embedded, and the corresponding algorithm is shown.

Heptafluoroisobutyronitrile (C4F7N), a gas used for insulating and arc quenching in electrical switchgear, is neurotoxic in the mouse brain

Fluoronitrile gas (C4F7N, CAS number 42532-60-5) is one of the most promising candidates as insulating and/or breaking medium in high and medium voltage electrical equipment. Besides its promising properties, C4F7N gas is however not devoid of acute toxicity when used pure or in gas mixtures. The toxicity was not extensively analyzed and reported. The aim of the present study was to analyze in mice the consequences of a single exposure to C4F7N gas, at different concentrations and different timepoints after exposure. Male and female Swiss mice were exposed to breathable air or C4F7N gas, at 800 ppmv or 1500 ppmv, for 4 h on day 0. Behavioral tests (spontaneous alternation in the Y-maze and object recognition) were performed on days 1, 7 and 14 to assess memory alterations. The animals were then sacrificed and their brains dissected for biochemical analyses or fixed with paraformaldehyde for histology and immunohistochemistry. Results showed behavioral impairments and memory deficits, with impairments of alternation at days 1 and 7 and object recognition at day 14. Histological alterations of pyramidal neuronal layer in the hippocampus, neuroinflammatory astroglial reaction, and microglial alterations were observed, more marked in female than male mice. Moreover, the biochemical analyses done in the brain of 1500 ppmv exposed female mice showed a reductive stress with decreased lipid peroxidation and release of cytochrome c, leading to apoptosis with increases in caspase-9 cleavage and γ-H2AX/H2AX ratio. Finally, electrophysiological analyses using a multi-electrode array allowed the measure of the extracellular activity of pyramidal neurons in the CA2 area and revealed that exposure to the gas not only prevented the induction of long-term potentiation but even provoked an epileptoid-like activity in some neurons suggesting major alterations of synaptic plasticity. This study therefore showed that an acute exposure of mice to C4F7N gas provoked, particularly in female animals, memory alterations and brain toxicity characterized by a reductive stress, microglial toxicity, loss of synaptic plasticity and apoptosis. Its use in industrial installations must be done with extreme caution.

Multi-Scale Hybrid Network for Polyp Detection in Wireless Capsule Endoscopy and Colonoscopy Images.

The trade-off between speed and precision is a key step in the detection of small polyps in wireless capsule endoscopy (WCE) images. In this paper, we propose a hybrid network of an inception v4 architecture-based single-shot multibox detector (Hyb-SSDNet) to detect small polyp regions in both WCE and colonoscopy frames. Medical privacy concerns are considered the main barriers to WCE image acquisition. To satisfy the object detection requirements, we enlarged the training datasets and investigated deep transfer learning techniques. The Hyb-SSDNet framework adopts inception blocks to alleviate the inherent limitations of the convolution operation to incorporate contextual features and semantic information into deep networks. It consists of four main components: (a) multi-scale encoding of small polyp regions, (b) using the inception v4 backbone to enhance more contextual features in shallow and middle layers, and (c) concatenating weighted features of mid-level feature maps, giving them more importance to highly extract semantic information. Then, the feature map fusion is delivered to the next layer, followed by some downsampling blocks to generate new pyramidal layers. Finally, the feature maps are fed to multibox detectors, consistent with the SSD process-based VGG16 network. The Hyb-SSDNet achieved a 93.29% mean average precision (mAP) and a testing speed of 44.5 FPS on the WCE dataset. This work proves that deep learning has the potential to develop future research in polyp detection and classification tasks.

Stylization of a Seismic Image Profile Based on a Convolutional Neural Network

Seismic data are widely used in oil, gas, and other kinds of mineral exploration and development. However, due to low artificial interpretation accuracy and small sample sizes, seismic data may not meet the needs of convolutional neural network training. There are major differences between optical image and seismic data, making it difficult for a model to learn seismic data characteristics. Therefore, a style transfer network is necessary to make the styles of optical image and seismic data more similar. Since the stylization effect of a seismic section is similar to that of most art styles, based on an in-depth study of image style transfer, this paper compared the effects of various style transfer models, and selected a Laplacian pyramid network to carry out a study of seismic section stylization. It transmits low-resolution global style patterns through a drafting network, revises high-resolution local details through correction networks, and aggregates all pyramid layers to output final stylized images of seismic profiles. Experiments show that this method can effectively convey the whole style pattern without losing the original image content. This style transfer method, based on the Laplacian pyramid network, provides theoretical guidance for the fast and objective application of the model to seismic data features.

The fibro- and cyto-architecture demarcating the border between the dentate gyrus and CA3 in sheep (Ovis aries) and domestic pig (Sus scrofa domesticus).

The hippocampal formation is essential for spatial navigation and episodic memory. The anatomical structure is largely similar across mammalian species, apart from the deep polymorphic layer of the dentate gyrus and the adjacent part of cornu ammonis 3 (CA3) which feature substantial variations. In rodents, the polymorphic layer has a triangular cross‐section abutting on the end of the CA3 pyramidal layer, while in primates it is long and band‐shaped capping the expanded CA3 end, which here lacks a distinct pyramidal layer. This structural variation has resulted in a confusing nomenclature and unclear anatomical criteria for the definition of the dentate‐ammonic border. Seeking to clarify the border, we present here a light microscopic investigation based on Golgi‐impregnated and Timm–thionin‐stained sections of the Artiodactyla sheep and domestic pig, in which the dentate gyrus and CA3 end have some topographical features in common with primates. In short, the band‐shaped polymorphic layer coincides with the Timm‐positive mossy fiber collateral plexus and the Timm‐negative subgranular zone. While the soma and excrescence‐covered proximal dendrites of the mossy cells are localized within the plexus, the peripheral mossy cell dendrites extend outside the plexus, both into the granular and molecular layers, and the CA3. The main mossy fibers leave the collateral plexus in a scattered formation to converge gradually through the CA3 end in between the dispersed pyramidal cells, which are of three subtypes, as in monkey, with the classical apical subtype dominating near the hidden blade, the nonapical subtype near the exposed blade, and the dentate subtype being the only pyramidal cells that extend dendrites into the dentate gyrus. In agreement with our previous study in mink, the findings show that the border between the dentate gyrus and the CA3 end can be more accurately localized by the mossy fiber system than by cyto‐architecture alone.

Mixed-surfactant perovskites with enhanced photostability

Blue and green emitting methylammonium lead bromide perovskite particles with improved UV-light stability have been developed by tuning structure and stabilization with a mixture of different single- and double-tailed surfactants. The ratio of the long alkyl chain surfactants to the methyl ammonium bromide allows for tailoring of the emission color of ready to use perovskite particles without further purification processes. The combination of single and double tailed surfactants exceeds the properties and geometries of the perovskite particles obtainable with a single surfactant. With a mixture of octylammonium bromide and dimethyldioctadecyl bromide, the perovskite particles show a highly anisotropic shape with a layered pyramid structure. The effect of surfactant composition on the perovskite particles’ structure, morphology and light-emitting properties has been elucidated. As these mixed surfactant perovskites are more robust against UV-light than other perovskite particles, they bear great potential for applications in optical devices such as LEDs.

COVID-19 causes neuronal degeneration and reduces neurogenesis in human hippocampus.

Recent investigations of COVID-19 have largely focused on the effects of this novel virus on the vital organs in order to efficiently assist individuals who have recovered from the disease. In the present study we used hippocampal tissue samples extracted from people who died after COVID-19. Utilizing histological techniques to analyze glial and neuronal cells we illuminated a massive degeneration of neuronal cells and changes in glial cells morphology in hippocampal samples. The results showed that in hippocampus of the studied brains there were morphological changes in pyramidal cells, an increase in apoptosis, a drop in neurogenesis, and change in spatial distribution of neurons in the pyramidal and granular layer. It was also demonstrated that COVID-19 alter the morphological characteristics and distribution of astrocyte and microglia cells. While the exact mechanism(s) by which the virus causes neuronal loss and morphology in the central nervous system (CNS) remains to be determined, it is necessary to monitor the effect of SARS-CoV-2 infection on CNS compartments like the hippocampus in future investigations. As a result of what happened in the hippocampus secondary to COVID-19, memory impairment may be a long-term neurological complication which can be a predisposing factor for neurodegenerative disorders through neuroinflammation and oxidative stress mechanisms.

Evaluation of the Antidepressant-like Effect of Chronic Administration of Nigella Fixed Oil Versus Fluoxetine in Rats.

Depression is a group of syndromes characterized by notable and persistent mood disorders, and is one of the most prevalent psychiatric disorders, while the existing treatments have an altered risk-benefit balance. The therapeutic properties of Nigella have been confirmed, suggesting the reliance on phytotherapy. The objective of the present paper is to investigate the antidepressive-like effect of Nigella sativa on rats exposed to the Unpredictable Chronic Mild Stress procedure. Wistar rats were used to investigate the antidepressive-like effect. The stress procedure used in this study combined many stressful conditions. After 6 weeks of treatment, behavioral test (forced swim test) was conducted, and histological changes of the hippocampus were examined. Treatment by nigella and fluoxetine significantly reduced the immobilization time. Histopathological analysis showed that control treatments result in more loosely arranged cells, significant apoptotic neurons characterized by an irregular appearance, and pyknotic hyperchromatic. A preservation of the thickness of the pyramid layer was also observed in the groups treated with nigella and fluoxetine, suggesting that nigella could be used as a treatment or an adjuvant preventing depressive-like disorders.

Autologous skin-derived neural precursor cell therapy reverses canine Alzheimer dementia-like syndrome in a proof of concept veterinary trial

BackgroundOlder companion dogs naturally develop a dementia-like syndrome with biological, clinical and therapeutic similarities to Alzheimer disease (AD). Given there has been no new safe, clinically effective and widely accessible treatment for AD for almost 20 years, an all-new cell therapeutic approach was trialled in canine veterinary patients, and further modelled in aged rats for more detailed neurobiological analysis.MethodsA Phase 1/2A veterinary trial was conducted in N = 6 older companion dogs with definitive diagnosis of Canine Cognitive Dysfunction (CCD). Treatment comprised direct microinjection of 250,000 autologous skin-derived neuroprecursors (SKNs) into the bilateral hippocampus using MRI-guided stereotaxis. Safety was assessed clinically and efficacy using the validated Canine Cognitive Dysfunction Rating Scale (CCDR) at baseline and 3-month post treatment. Intention to treat analysis imputed a single patient that had a surgical adverse event requiring euthanasia. Three dog brains were donated following natural death and histology carried out to quantify Alzheimer pathology as well as immature neurons and synapses; these were compared to a brain bank (N = 12) of untreated aged dogs with and without CCD. Further, an age-related memory dysfunction rat model (N = 16) was used to more closely evaluate intrahippocampal engraftment of canine SKN cells, focusing on mnemonic and synaptic effects as well as donor cell survival, neurodifferentation and electrophysiologic circuit integration in a live hippocampal slice preparation.ResultsFour out-of-five dogs improved on the primary clinical CCDR endpoint, three fell below diagnostic threshold, and remarkably, two underwent full syndromal reversal lasting up to 2 years. At post mortem, synaptic density in the hippocampus specifically was nine standard deviations above non-treated dogs, and intensity of new neurons also several fold higher. There was no impact on AD pathology or long-term safety signals. Modelling in aged rats replicated the main canine trial findings: hippocampally-dependent place memory deficits were reversed and synaptic depletion rescued. In addition, this model confirmed donor cell survival and migration throughout the hippocampus, neuronal differentiation in situ, and physiologically-correct integration into pyramidal layer circuits.ConclusionsWith further development, SKN cell therapy may have potential for treating carefully chosen AD patients based on neurosynaptic restoration in the hippocampus.

Three-dimensional anatomical structure formed by granule cell layer and pyramidal cell layer in human hippocampus.

In the human hippocampus, the pyramidal layer consists of the inferior aspect of the hippocampus which is organized segmentally. Each segment, together with granule layer of the dentate gyrus, exhibits structural unity. In humans, ellipsoidal protrusions called pyramidal hillocks (PHs), which consist of a thick pyramidal cell layer (PL), are present in the inferior aspect of the hippocampus, and are segmentally organized along a longitudinal axis. It is also known that the granule cell layer (GL) of the dentate gyrus (DG) is not a smooth but undulated structure. However, the cytoarchitectural relationships between the protrusions and undulation have yet to be studied well. Here, we aimed to clarify the three-dimensional cytoarchitecture of the PL and GL of human hippocampus. For that purpose, the GL and PL were three-dimensionally reconstructed from serial sections of human hippocampus stained with hematoxylin and eosin. The GL was shaped as tubing with an opening in the dorsal part, and undulated especially in the medial part, forming digit-like processes. In the base of a digit-like process, protrusions of the GL extended laterally, with longer ones reaching the lateral edge, whereas shorter ones disappeared around the medial 1/3 of the GL. Consequently, the lateral part of the GL was undulated loosely. In the ventral view of the PL, the ellipsoidal PHs were sagittally aligned, whereas in the top view, each PH formed an ellipsoidal trough. Each structural unit was formed by a trough of the PH along the bottom, and had a longer GL protrusion in the upper-center, and shorter GL protrusions located between the longer protrusions and the lateral edge of the GL. A digit-like process extended into a dens. It is concluded that a unit of the PH and the GL comprises the longitudinal segmental formation of the hippocampus.

The Hybrid Drive: a chronic implant device combining tetrode arrays with silicon probes for layer-resolved ensemble electrophysiology in freely moving mice

Objective. Understanding the function of brain cortices requires simultaneous investigation at multiple spatial and temporal scales and to link neural activity to an animal’s behavior. A major challenge is to measure within- and across-layer information in actively behaving animals, in particular in mice that have become a major species in neuroscience due to an extensive genetic toolkit. Here we describe the Hybrid Drive, a new chronic implant for mice that combines tetrode arrays to record within-layer information with silicon probes to simultaneously measure across-layer information. Approach. The design of our device combines up to 14 tetrodes and 2 silicon probes, that can be arranged in custom arrays to generate unique areas-specific (and multi-area) layouts. Main results. We show that large numbers of neurons and layer-resolved local field potentials can be recorded from the same brain region across weeks without loss in electrophysiological signal quality. The drive’s lightweight structure (≈3.5 g) leaves animal behavior largely unchanged, compared to other tetrode drives, during a variety of experimental paradigms. We demonstrate how the data collected with the Hybrid Drive allow state-of-the-art analysis in a series of experiments linking the spiking activity of CA1 pyramidal layer neurons to the oscillatory activity across hippocampal layers. Significance. Our new device fits a gap in the existing technology and increases the range and precision of questions that can be addressed about neural computations in freely behaving mice.

Ameliorative Effects of EUK-134, a Superoxide Dismutase and Catalase Mimetic, in a Rat Model of D-Galactose-Induced Oxidative Stress and Accelerated Aging

Background and Aim: EUK-134, a synthetic superoxide dismutase/catalase mimetic, is a salen-manganese complex that exhibits the catalytic actions of both superoxide dismutase and catalase, important antioxidant enzymes biosynthesized by cells. In the current study, we evaluated the protection effects of EUK-134 against D-galactose-induced oxidative stress and accelerated aging in rats. Methods: D-galactose was sub-cutaneously injected at a dose of 100 mg/kg on the back of rats once daily for 42 days and simultaneously EUK-134 was administered to the rats by intra-abdominal injection at a dose of 5 mg/kg once daily. As a positive control, donepezil was administered to the rats by oral feeding at a dose of 1 mg/ kg once daily. Following behavioral tests (eight-arm radial maze test and Morris water maze test), animals were sacrificed on day 42, and their brains were used for histopathological and biochemical assessments of oxidative stress. Results: We found that the administration of EUK-134 (5 mg/kg, i.a.) significantly reversed the spatial memory deficits, the brain weight loss, the reduced cerebral cortex thickness, the decreased pyramidal neuron density and the pyramidal layer in brain hippocampus, the decreased superoxide dismutase activity, the decreased catalase activity, the increased malondialdehyde level, the increased acetylcholine esterase activity and the decreased acetylcholine level in the brain hippocampus and prefrontal cortex of D-gal-induced aging rats, as did the administration of donepezil (1 mg/ kg, oral). Conclusion: These results indicated that EUK-134 possesses neuroprotective effects against D-galactose-induced senescence, probably due to its antioxidant enzyme activities and this shows the availability of EUK-134 in the prevention and treatment of neurodegenerative diseases such as Alzheimer’s disease.

STEREOMETRIC ANALYSIS OF GLIAL AND VASCULAR COMPONENTS IN THE MICROSTRUCTURE OF HUMAN NEOCORTEX REGIONS INVOLVED IN VISUAL-SPATIAL PERCEPTION

Visual-spatial perception in children and adolescents is largely determined by age-specific features of the structure and hemodynamics in the associative areas of the cerebral cortex. Aim. The aim of the study was to investigate the quantitative ratios of vascular and glial components in the oculomotor area 8 of the prefrontal cortex and the 37aс subarea of the posterior associative cortex involved in visual-spatial analysis. Methods. We studied 27 left large hemispheres of the brains in male subjects aged 10 to 17 years, grouped in annual intervals. We studied specific volumes of intracortical blood vessels and gliocytes in the external pyramidal layer on paraffin-embedded cortical slices impregnated with silver nitrate according to Peters with Nissl dyeing using a stereometric method. Results. We found that microstructural changes in the adolescent neocortex resulted in a decrease in the relative content of intracortical microvessels and an increase in the specific volume of gliocytes. The structural changes occur heterochronously: in the oculomotor area 8 of the prefrontal cortex, at 11-12 years of age, and in the subarea 37aс, at 12-13 years of age. Conclusion. The data obtained testify to a significant morpho-functional restructuring of trophic support and metabolic processes in the associative areas of the neocortex controlling visual-spatial perception.

Prenatal development of the human entorhinal cortex.

Little is known about the development of the human entorhinal cortex (EC), a major hub in a widespread network for learning and memory, spatial navigation, high-order processing of object information, multimodal integration, attention and awareness, emotion, motivation, and perception of time. We analyzed a series of 20 fetal and two adult human brains using Nissl stain, acetylcholinesterase (AChE) histochemistry, and immunocytochemistry for myelin basic protein (MBP), neuronal nuclei antigen (NeuN), a pan-axonal neurofilament marker, and synaptophysin, as well as postmortem 3T MRI. In comparison with other parts of the cerebral cortex, the cytoarchitectural differentiation of the EC begins remarkably early, in the 10th week of gestation (w.g.). The differentiation occurs in a superficial magnocellular layer in the deep part of the marginal zone, accompanied by cortical plate (CP) condensation and multilayering of the deep part of CP. These processes last until the 13-14th w.g. At 14 w.g., the superficial lamina dissecans (LD) is visible, which divides the CP into the lamina principalis externa (LPE) and interna (LPI). Simultaneously, the rostral LPE separates into vertical cell-dense islands, whereas in the LPI, the deep LD emerges as a clear acellular layer. In the 16th w.g., the LPE remodels into vertical cell-dense and cell-sparse zones with a caudorostral gradient. At 20 w.g., NeuN immunoreactivity is most pronounced in the islands of layer II cells, whereas migration and differentiation inside-out gradients are seen simultaneously in both the upper (LPE) and the lower (LPI) pyramidal layers. At this stage, the EC adopts for the first time an adult-like cytoarchitectural organization, the superficial LD becomes discernible by 3T MRI, MBP-expressing oligodendrocytes first appear in the fimbria and the perforant path (PP) penetrates the subiculum to reach its molecular layer and travels along through the Cornu Ammonis fields to reach the suprapyramidal blade of the dentate gyrus, whereas the entorhinal-dentate branch perforates the hippocampal sulcus about 2-3weeks later. The first AChE reactivity appears as longitudinal stripes at 23 w.g. in layers I and II of the rostrolateral EC and then also as AChE-positive in-growing fibers in islands of superficial layer III and layer II neurons. At 40 w.g., myelination of the PP starts as patchy MBP-immunoreactive oligodendrocytes and their processes. Our results refute the possibility of an inside-out pattern of the EC development and support the key role of layer II prospective stellate cells in the EC lamination. As the early cytoarchitectural differentiation of the EC is paralleled by the neurochemical development, these developmental milestones in EC structure and connectivity have implications for understanding its normal function, including its puzzling modular organization and potential contribution to consciousness content (awareness), as well as for its insufficiently explored deficits in developmental, psychiatric, and degenerative brain disorders.

Effect of vestibular stimulation on cold water stress-induced neurological changes in Wistar rats

The current study was undertaken to see the effects of cold-water stress on the brain and to evaluate the beneficial effect of vestibular stimulation on stress-induced brain changes. Healthy, male, Wistar rats, weighing 180 to 250 gm with 3-6 months of age, were used for the study. Stress was induced by making the animals swim in cold water maintained at 100C for 30 min a day, for 14 days. Following cold water swimming stress, bilateral hot water caloric vestibular stimulation was given to the animals using 410C temperature water for 15 days. Rats were sacrificed and histopathological brain changes were studied by Hematoxylin & Eosin staining. Serum corticosterone level has increased significantly after cold water swimming stress (p<0.01). Corticosterone was less in animals that received caloric vestibular stimulation in comparison with the animals which did not receive caloric vestibular stimulation (p<0.05). Coldwater swimming stress had induced focal neuronal atrophy, nuclear pyknosis with congested blood vessels and infiltration of mononuclear inflammatory cells in the hippocampus and hypothalamus. Stressed animals that received caloric vestibular stimulation recovered well and showed the cerebral cortex with the normal neuroglial arrangement. Hypothalamus showed normal morphology and the hippocampus showed a pyramidal layer with a normal thickness in comparison to the animals which did not receive caloric vestibular stimulation. We conclude Caloric vestibular stimulation was effective in reversing the cold-water stress-induced serum corticosterone and histopathological changes in the brain.

Role of NODDI in the MRI Characterization of Hippocampal Abnormalities in Temporal Lobe Epilepsy: Clinico-histopathologic Correlations.

The identification of possible hippocampal alterations is a crucial point for the diagnosis and therapy of patients with unilateral temporal lobe epilepsy (TLE). This study aims to investigate the role of neurite orientation dispersion and density imaging (NODDI) compared to diffusion tensor imaging (DTI) in the comprehension of hippocampal microstructure in TLE. DTI and NODDI metrics were calculated in the hippocampi of adult patients with TLE, with and without histology-confirmed hippocampal sclerosis (HS), and in age/sex-matched healthy controls (HC). Diffusion metrics and hippocampal volumes of the pathologic side were compared within participants and between participants among the HS, non-HS, and HC groups. Diffusion metrics were also correlated with hippocampal volume and patients' clinical features. After surgery, hippocampal specimens were processed for neuropathology examinations. Fifteen patients with TLE (9 with and 6 without HS) and 11 HC were included. Hippocampal analyses resulted in a significant increase in fractional anisotropy (FA) and mean diffusivity (MD; mm2/s × 10-3) and decrease in orientation dispersion index (ODI) comparing the pathologic side of patients with HS and their relative nonpathologic side (0.203 vs 0.183, 0.825 vs 0.724, 0.366 vs 0.443, respectively), the pathologic side of patients without HS (0.203 vs 0.169, 0.825 vs 0.745, 0.366 vs 0.453, respectively), and HC (0.203 vs 0.172, 0.825 vs 0.729, 0.366 vs 0.447, respectively). Moreover, neurite density (ND) was significantly decreased comparing both hippocampi of patients with HS (0.416 vs 0.460). A significant increase in free-water isotropic volume fraction (fiso) was found in the comparison of pathologic hippocampi of patients with HS and nonpathologic hippocampi of patients with HS (0.323 vs 0.258) and HC (0.323 vs 0.226). Hippocampal volume of all patients with TLE negatively correlated with MD (r = -0.746, p = 0.0145) and positively correlated with ODI (r = 0.719, p = 0.0145). Fiso and ND of sclerotic hippocampi positively correlated with disease duration (r = 0.684, p = 0.0424 and r = 0.670, p = 0.0486, respectively). Immunohistochemistry in sclerotic hippocampal specimens revealed neuronal loss in the pyramidal layer and fiber reorganization at the level of stratum lacunosum-moleculare, confirming ODI and ND metrics. This study shows the capability of diffusion MRI metrics to detect hippocampal microstructural alterations. Among them, ODI seems to better highlight the fiber reorganization observed by neuropathology in sclerotic hippocampi.

Pyramidal Ownership and SOE Innovation

AbstractHow can state‐owned enterprises (SOEs) become more innovative in emerging economies where market competition emerges and state socialism remains? Rooted in a state socialism logic that traditionally prioritizes central planning, SOEs are increasingly challenged by a market competition logic espousing efficiency and innovation. We posit that the challenge, stemming from the grip of the state as the ultimate owner, may be mitigated for some SOEs under pyramidal ownership. A pyramid features SOEs being organized into chains of firms, creating indirect ownership and control through pyramidal layers. Such layers insulate state intervention in lower‐tier SOEs, loosening the grip of the state socialism logic and facilitating corresponding SOEs’ acceptance of the market competition logic, as reflected in more innovation. Leveraging a sample of SOEs in China, we find that SOEs innovate more when the number of pyramidal layers between them and the state increases. In addition, the innovation‐facilitating role of pyramidal ownership hinges on industry regulations and institutional development. Overall, this paper integrates research on institutional logics and pyramidal ownership to deepen our understanding of SOE innovation.

Spatial distribution of beta-klotho mRNA in the mouse hypothalamus, hippocampal region, subiculum, and amygdala.

Beta-klotho (KLB) is a coreceptor required for endocrine fibroblast growth factor (FGF) 15/19 and FGF21 signaling in the brain. Klb is prominent within the hypothalamus, which is consistent with its metabolic functions, but diverse roles for Klb are now emerging. Central Klb expression is low but discrete and may govern FGF-targeted sites. However, given its low expression, it is unclear if Klb mRNA is more widespread. We performed in situ hybridization to label Klb mRNA to generate spatial maps capturing the distribution and levels of Klb within the mouse hypothalamus, hippocampal region, subiculum, and amygdala. Semiquantitative analysis revealed that Klb-labeled cells may express low, medium, or high levels of Klb mRNA. Hypothalamic Klb hybridization was heterogeneous and varied rostrocaudally within the same region. Most Klb-labeled cells were found in the lateral hypothalamic zone, but the periventricular hypothalamic region, including the suprachiasmatic nucleus, contained the greatest proportion of cells expressing medium or high Klb levels. We also found heterogeneous Klb hybridization in the amygdala and subiculum, where Klb was especially distinct within the central amygdalar nucleus and ventral subiculum, respectively. By contrast, Klb-labeled cells in the hippocampal region only expressed low levels of Klb and were typically found in the pyramidal layer of Ammon's horn or dentate gyrus. The Klb-labeled regions identified in this study are consistent with reported roles of Klb in metabolism, taste preference, and neuroprotection. However, additional identified sites, including within the hypothalamus and amygdala, may suggest novel roles for FGF15/19 or FGF21 signaling.