Overexpression of Sirt6 ameliorates sleep deprivation induced-cognitive impairment by modulating glutamatergic neuron function

Sleep benefits the restoration of energy metabolism and thereby suppo rts neuronal plasticity and cognitive behaviors.Sirt6 is a NAD+-dependent protein deacetylase that has been recognized as an essential regulator of energy metabolism because it modulates various transcriptional regulators and metabolic enzymes.The aim of this study was to investigate the influence of Sirt6 on cerebral function after chronic sleep deprivation(CSD).We assigned C57BL/6J mice to control or two CSD groups and subjected them to AAV2/9-CMV-EGFP or AAV2/9-CMV-Sirt6-EGFP infection in the prelimbic cortex(PrL).We then assessed cerebral functional connectivity(FC) using resting-state functional MRI,neuron/astrocyte metabolism using a metabolic kinetics analysis;dendritic spine densities using sparse-labeling;and miniature excitato ry postsynaptic currents(mEPSCs) and action potential(AP) firing rates using whole-cell patchclamp recordings.In addition,we evaluated cognition via a comprehensive set of behavioral tests.Compared with controls,Sirt6 was significantly decreased(P<0.05) in the PrL after CSD,accompanied by cognitive deficits and decreased FC between the PrL and accumbens nucleus,piriform cortex,motor co rtex,somatosensory co rtex,olfactory tubercle,insular cortex,and cerebellum.Sirt6 ove rexpression reve rsed CSD-induced cognitive impairment and reduced FC.Our analysis of metabolic kinetics using [1-13C] glucose and [2-13C] acetate showed that CSD reduced neuronal Glu4and GABA2synthesis,which could be fully restored via forced Sirt6 expression.Furthermore,Sirt6 ove rexpression reversed CSD-induced decreases in AP firing rates as well as the frequency and amplitude of mEPSCs in PrL pyramidal neurons.These data indicate that Sirt6 can improve cognitive impairment after CSD by regulating the PrL-associated FC network,neuronal glucose metabolism,and glutamatergic neurotransmission.Thus,Sirt6 activation may have potential as a novel strategy for treating sleep disorder-related diseases.

Brain-wide N2cG compensation permits glycoprotein-deleted rabies virus to trace neural circuits across multiple synapses

Rabies-viruses-based retrograde tracers can spread across multiple synapses in a retrograde direction in the nervous system of rodents and primates,making them powerful tools for determining the structure and function of the complicated neural circuits of the brain.However,they have some limitations,such as posing high risks to human health and the inability to retrograde trans-synaptic label inputs from genetically-de¯ned starter neurons.Here,we established a new retrograde trans-multi-synaptic tracing method through brain-wide rabies virus glycoprotein(RVG)compensation,followed by glycoprotein-deleted rabies virus(RV-△G)infection in specific brain regions.Furthermore,in combination with the avian tumor virus receptor A(TVA)controlled by a cell-type-specific promoter,we found that EnvA-pseudotyped RV-△G can mediate e±cient retrograde trans-multi-synaptic transduction from cell-type-specific starter neurons.This study provides new alternative methods for neuroscience researchers to analyze the input neural networks of rodents and nonhuman primates.

Mapping the Behavioral Signatures of Shank3b Mice in Both Sexes

Autism spectrum disorders(ASD)are characterized by social and repetitive abnormalities.Although the ASD mouse model with Shank3b mutations is widely used in ASD research,the behavioral phenotype of this model has not been fully elucidated.Here,a 3D-motion capture system and linear discriminant analysis were used to comprehensively record and analyze the behavioral patterns of male and female Shank3b mutant mice.It was found that both sexes replicated the core and accompanied symptoms of ASD,with significant sex differences.Further,Shank3b heterozygous knockout mice exhibited distinct autistic behaviors,that were significantly different from those those observed in the wild type and homozygous knockout groups.Our findings provide evidence for the inclusion of both sexes and experimental approaches to efficiently characterize heterozygous transgenic models,which are more clinically relevant in autistic studies.

Viral Tools for Neural Circuit Tracing

Neural circuits provide an anatomical basis for functional networks.Therefore,dissecting the structure of neural circuits is essential to understanding how the brain works.Recombinant neurotropic viruses are important tools for neural circuit tracing with many advantages over non-viral tracers:they allow for anterograde,retrograde,and trans-synaptic delivery of tracers in a cell type-specific,circuit-selective manner.In this review,we summarize the recent developments in the viral tools for neural circuit tracing,discuss the key principles of using viral tools in neuroscience research,and highlight innovations for developing and optimizing viral tools for neural circuit tracing across diverse animal species,including nonhuman primates.

Divergent Projection Patterns Revealed by Reconstruction of Individual Neurons in Orbitofrontal Cortex

The orbitofrontal cortex(OFC)is involved in diverse brain functions via its extensive projections to multiple target regions.There is a growing understanding of the overall outputs of the OFC at the population level,but reports of the projection patterns of individual OFC neurons across different cortical layers remain rare.Here,by combining neuronal sparse and bright labeling with a whole-brain florescence imaging system(fMOST),we obtained an uninterrupted three-dimensional whole-brain dataset and achieved the full morphological reconstruction of 25 OFC pyramidal neurons.We compared the wholebrain projection targets of these individual OFC neurons in different cortical layers as well as in the same cortical layer.We found cortical layer-dependent projections characterized by divergent patterns for information delivery.Our study not only provides a structural basis for understanding the principles of laminar organizations in the OFC,but also provides clues for future functional and behavioral studies on OFC pyramidal neurons.

Cortical Organization of Centrifugal Afferents to the Olfactory Bulb: Mono-and Trans-synaptic Tracing with Recombinant Neurotropic Viral Tracers

Sensory processing is strongly modulated by different brain and behavioral states,and this is based on the top-down modulation.In the olfactory system,local neural circuits in the olfactory bulb(OB)are innervated by centrifugal afferents in order to regulate the processing of olfactory information in the OB under different behavioral states.The purpose of the present study was to explore the organization of neural networks in olfactory-related cortices and modulatory nuclei that give rise to direct and indirect innervations to the glomerular layer(GL)of the OB at the whole-brain scale.Injection of different recombinant attenuated neurotropic viruses into the GL showed that it received direct inputs from each layer in the OB,centrifugal inputs from the ipsilateralanterior olfactory nucleus(AON),anterior piriform cortex(Pir),and horizontal limb of diagonal band of Broca(HDB),and various indirect inputs from bilateral cortical neurons in the AON,Pir,amygdala,entorhinal cortex,hippocampus,HDB,dorsal raphe,median raphe and locus coeruleus.These results provide a circuitry basis that will help further understand the mechanism by which olfactory informationprocessing in the OB is regulated.

Rabies Virus Pseudotyped with CVS-N2C Glycoprotein as a Powerful Tool for Retrograde Neuronal Network Tracing

Efficient viral vectors for mapping and manipulating long-projection neuronal circuits are crucial in structural and functional studies of the brain. The SAD strain rabies virus with the glycoprotein gene deleted pseudotyped with the N2 C glycoprotein(SAD-RV(DG)-N2 C(G)) shows strong neuro-tropism in cell culture, but its in vivo efficiency for retrograde gene transduction and neuro-tropism have not been systematically characterized.We compared these features in different mouse brain regions for SAD-RV-N2 C(G) and two other widely-used retrograde tracers, SAD-RV(DG)-B19(G) and r AAV2-retro. We found that SAD-RV(DG)-N2 C(G) enhanced the infection efficiency of long-projecting neurons by^10 times but with very similar neuro-tropism, compared with SAD-RV(DG)-B19(G). On the other hand, SAD-RV(DG)-N2 C(G) had an infection efficiency comparable with r AAV2-retro, but a more restricted diffusion range, and broader tropism to different types and regions of longprojecting neuronal populations. These results demonstrate that SAD-RV(DG)-N2 C(G) can serve as an effective retrograde vector for studying neuronal circuits.

Preoperative Acute Sleep Deprivation Causes Postoperative Pain Hypersensitivity and Abnormal Cerebral Function

Preoperative sleep loss can amplify post-operative mechanical hyperalgesia.However,the underlying mechanisms are still largely unknown.In the current study,rats were randomly allocated to a control group and an acute sleep deprivation(ASD)group which experienced 6 h ASD before surgery.Then the variations in cerebral function and activity were investigated with multi-modal techniques,such as nuclear magnetic resonance,functional magnetic resonance imaging,c-Fos immunofluorescence,and electrophysiology.The results indicated that ASD induced hyperalgesia,and the metabolic kinetics were remarkably decreased in the striatum and midbrain.The functional connectivity(FC)between the nucleus accumbens(NAc,a subregion of the ventral striatum)and the ventrolateral periaqueductal gray(vLPAG)was significantly reduced,and the c-Fos expression in the NAc and the vLPAG was suppressed.Furthermore,the electrophysiological recordings demonstrated that both the neuronal activity in the NAc and the vLPAG,and the coherence of the NAc-vLPAG were suppressed in both resting and task states.This study showed that neuronal activity in the NAc and the vLPAG were weakened and the FC between the NAc and the vLPAG was also suppressed in rats with ASD-induced hyperalgesia.This study highlights the importance of preoperative sleep management for surgical patients.

Rapid and Sparse Labeling of Neurons Based on the Mutant Virus-Like Particle of Semliki Forest Virus

Sparse labeling of neurons contributes to uncovering their morphology, and rapid expression of a fluorescent protein reduces the experiment range. To achieve the goal of rapid and sparse labeling of neurons in vivo, we established a rapid method for depicting the fine structure of neurons at 24 h post-infection based on a mutant viruslike particle of Semliki Forest virus. Approximately 0.014 fluorescent focus-forming units of the mutant virus-like particle transferred enhanced green fluorescent protein into neurons in vivo, and its affinity for neurons in vivo was stronger than for neurons in vitro and BHK21(baby hamster kidney) cells. Collectively, the mutant virus-likeparticle provides a robust and convenient way to reveal the fine structure of neurons and is expected to be a helper virus for combining with other tools to determine their connectivity. Our work adds a new tool to the approaches for rapid and sparse labeling of neurons in vivo.

Reviews and prospects of human factors research on curve driving

In order to fully understand the research progress of human factors and traffic safety in curve driving,from the perspective of driver-vehicle-road-environment dynamic traffic system,this paper explored the current research status and development trend of human factors of curve driving,and displayed the development process and structural relationship of human factors research of curve driving by using scientific knowledge map.Through the core collection database of Web of Science,1408 English literatures related to human factors research of curve driving published from 2012 to 2022(as of October 1,2022)were obtained,and the literatures in this field were sorted and analyzed based on the VOSviewer visualization software.The results show that China,Tongji University and Accident Analysis and Prevention are the country,institution and journal with the largest contribution rate in the field of human factors research on curve driving.Co-citation analysis shows that the research contents in this field are divided into 5 clusters:driver’s visual characteristics,risk of collision,vehicle dynamics characteristics,the influence of traffic engineering facilities on driving behavior,selection of driving speed.The co-occurrence analysis of keywords shows that the topics of curve geometry design and vehicle dynamics,driving behavior and risk,driving speed and safety,behavior prediction and intervention measures are the current research hotspots in the research field.It is found that the development trend of traffic safety improvement in curves is to construct a continuous,consistent,multi-level visual reference frame conforming to driving expectation through visual guiding technology,and summarizes the technical concept of linear visual guidance.This study can provide a reference for the study of human factors of curve driving.

Visualization and correction of social abnormalities-associated neural ensembles in adult MECP2 duplication mice

Duplications of MECP2-containing genomic segments led to severe autistic symptoms in male. Transgenic mice overexpressing the human MECP2 gene exhibit autistic-like behaviors. Neural circuits underlying social defects in MECP2 transgenic(MECP2-TG) mice remain unknown. To observe neural activity of MECP2-TG mice in vivo, we performed calcium imaging by implantation of microendoscope in the hippocampal CA1 regions of MECP2-TG and wild type(WT) mice. We identified neurons whose activities were tightly associated with social interaction, which activity patterns were compromised in MECP2-TG mice. Strikingly, we rescued the social-related neural activity in CA1 and social defects in MECP2-TG mice by deleting the human MECP2 transgene using the CRISPR/Cas9 method during adulthood.Our data points to the neural circuitry responsible for social interactions and provides potential therapeutic targets for autism in adulthood.

Imaging and Spectral Characteristics of Amyloid Plaque Autofluorescence in Brain Slices from the APP/PS1 Mouse Model of Alzheimer’s Disease

Amyloid deposits are one of the hallmark pathological lesions of Alzheimer's disease(AD). They can be visualized by thioflavin-S, silver impregnation,Congo red staining, and immunohistochemical reactions.However, that amyloid deposits generate blue autofluorescence(auto-F) has been ignored. Here, we report that visible light-induced auto-F of senile plaques(SPs) was detected and validated with conventional methods. Brain slices from APP/PS1(amyloid precursor protein/presenilin1) transgenic mice were mounted on slides, rinsed,coverslipped and observed for details of the imaging and spectral characteristics of the auto-F of SPs. Then the slices were treated with the above classic methods for comparative validation. We found that the SP auto-F was greatest under blue-violet excitation with a specific emission spectrum, and was much easier, more sensitive, and reliable than the classic methods. Because it does not damage slices, observation of auto-F can be combined with all post-staining techniques in slices and for brain-wide imaging in AD.

Regional Metabolic Patterns of Abnormal Postoperative Behavioral Performance in Aged Mice Assessed by XH-NMR Dynamic Mapping Method

Abnormal postoperative neurobehavioral performance(APNP)is a common phenomenon in the early postoperative period.The disturbed homeostatic status of metabolites in the brain after anesthesia and surgery might make a significant contribution to APNP.The dynamic changes of metabolites in different brain regions after anesthesia and surgery,as well as their potential association with APNP are still not well understood.Here,we used a battery of behavioral tests to assess the effects of laparotomy under isoflurane anesthesia in aged mice,and investigated the metabolites in 12 different sub-regions of the brain at different time points using proton nuclear magnetic resonance('H-NMR)spectroscopy.The abnormal neurobehavioral performance occurred at 6 h and/or 9 h,and recovered at 24 h after anesthesia/surgery.Compared with the control group,the altered metabolite of the model group at 6 h was aspartate(Asp),and the difference was mainly displayed in the cortex;while significant changes at 9 h occurred predominantly in the cortex and hippocampus,and the corresponding metabolites were Asp and glutamate(Glu).All changes returned to baseline at 24 h.The altered metabolic changes could have occurred as a result of the acute APNP,and the metabolites Asp and Glu in the cortex and hippocampus could provide preliminary evidence for understanding the APNP process.

Mutation inε-Sarcoglycan Induces a Myoclonus-Dystonia Syndrome-Like Movement Disorder in Mice

Myoclonus dystonia syndrome(MDS)is an inherited movement disorder,and most MDS-related mutations have so far been found in theε-sarcoglycan(SGCE)coding gene.By generating SGCE-knockout(KO)and human 237 C>T mutation knock-in(KI)mice,we showed here that both KO and KI mice exerted typical movement defects similar to those of MDS patients.SGCE promoted filopodia development in vitro and inhibited excitatory synapse formation both in vivo and in vitro.Loss of function of SGCE leading to excessive excitatory synapses that may ultimately contribute to MDS pathology.Indeed,using a zebrafish MDS model,we found that among 1700 screened chemical compounds,Vigabatrin was the most potent in readily reversing MDS symptoms of mouse disease models.Our study strengthens the notion that mutations of SGCE lead to MDS and most likely,SGCE functions to brake synaptogenesis in the CNS.

Activation of parvalbumin interneurons in anterior cingulate cortex impairs observational fear

The ability to detect conspecific＇s distress is crucial for animal survival. In rodent models, observational fear （OF） occurs when one animal perceives another fear related negative emotions, which may model certain behaviors caused by witnessing traumatic experiences in humans. Anterior cingulate cortex （ACC） has been showed to play a crucial role in OF. However, cellular and neural circuit basis relating to ACC governing OF is poorly understood. Here, we used Designer Receptor Exclusively Activated by a Designer Drug （DREADD） system to investigate the cell type specific circuit mechanism of ACC in OF. Firstly, inhibitory hM4D （Gi） designer receptor together with clozapine N-oxide （CNO） injection was applied to inactivate ACC neurons in the observer mice. We found that, chemogenetic inhibition of ACC resulted in a decreased freezing response in the observer mice. Next, combining PV-ires-Cre mice and Cre-dependent DREADD system, we selectively targeted the ACC parvalbumin （PV） interneurons with the excitatory hM3D （Gq） designer receptor. Activation of ACC PV interneurons following CNO injection reduced freezing response in the observer mice, while had no effect on freezing response in the demon- strator mice. Finally, monosynaptic rabies retrograde tracing revealed that ACC PV interneurons receive inputs from the mediodorsal thalamic nucleus （MD） and the ventromedial thalamic nucleus （VM）, both known for their roles in OF. Taken together, these findings reveal that ACC activation is important for OF, during which PV interneurons in ACC play an important regulatory role. Abnormal function of ACC PV interneurons might contribute to the pathology of empathy- deficits related diseases, such as autism and schizoohrenia.

Research advances in multi-field coupling model for geothermal reservoir heat extraction

As a kind of clean renewable energy,the production and utilization of geothermal resources can make a great contribution to optimizing the energy structure and energy conservation and emission reduction.The circulating heat extraction process of working fluid will disturb the equilibrium state of physical and chemical fields inside the reservoir,and involve the mutual coupling of heat transfer,flow,stress,and chemical reaction.Revealing the coupling mechanism of flow and heat transfer inside the reservoir during geothermal exploitation can provide important theoretical support for the efficient exploitation of geothermal resources.This paper reviews the research advances of the multi-field coupling model in the reservoir during geothermal production over the past 40 years.The thrust of this paper is on objective analysis and evaluation of the importance of each coupling process and its influence on reservoir heat extraction performance.Finally,we discuss the existing challenges and perspectives to promote the future development of the geothermal reservoir multi-field coupling model.An accurate understanding of the multi-field coupling mechanism,an efficient cross-scale modeling method,as well as the accurate characterization of reservoir fracture morphology,are crucial for the multi-field coupling model of geothermal production.

Restoration of FMRP expression in adult V1 neurons rescues visual deficits in a mouse model of fragile X syndrome

Many people affected by fragile X syndrome(FXS)and autism spectrum disorders have sensory processing deficits,such as hypersensitivity to auditory,tactile,and visual stimuli.Like FXS in humans,loss of Fmr1 in rodents also cause sensory,behavioral,and cognitive deficits.However,the neural mechanisms underlying sensory impairment,especially vision impairment,remain unclear.It remains elusive whether the visual processing deficits originate from corrupted inputs,impaired perception in the primary sensory cortex,or altered integration in the higher cortex,and there is no effective treatment.In this study,we used a genetic knockout mouse model(Fmr1^(KO)),in vivo imaging,and behavioral measurements to show that the loss of Fmr1 impaired signal processing in the primary visual cortex(V1).Specifically,Fmr1^(KO) mice showed enhanced responses to low-intensity stimuli but normal responses to high-intensity stimuli.This abnormality was accompanied by enhancements in local network connectivity in V1 microcircuits and increased dendritic complexity of V1 neurons.These effects were ameliorated by the acute application of GABAA receptor activators,which enhanced the activity of inhibitory neurons,or by reintroducing Fmr1 gene expression in knockout V1 neurons in both juvenile and young-adult mice.Overall,V1 plays an important role in the visual abnormalities of Fmr1^(KO) mice and it could be possible to rescue the sensory disturbances in developed FXS and autism patients.