Neuroscience Research

Neurotropic virus tracers, particularly those with low toxicity and high efficient tracing, are powerful tools for structural and functional dissections of neural circuits. The retrograde trans-mono-synaptic technology based on rabies virus CVS-N2c strain has reduced cytotoxicity and enhanced efficiency, attains long-term gene manipulation for functional studies, but suffers from difficult preparation and low yield. To overcome these shortcomings, an improved production system was established for rapid rescue and preparation of CVS-N2c-{Delta}G virus, CVS-N2c-{Delta}G with the same titer as SAD-B19-{Delta}G can be prepared within a short time. Meanwhile, we found that N2cG coated CVS-N2c-{Delta}G allows efficient retrograde access to projection neurons, and further expand its application in VTA/SNc to DLS pathway that unaddressed by rAAV9-Retro, and the efficiency is 6 folds higher than that of rAAV9-Retro. Then the trans-synaptic efficiency of CVS-N2c-{Delta}G virus was evaluated. Results showed that the trans-mono-synaptic efficiency of oG-mediated CVS-N2c-{Delta}G was 2-3 folds higher than that of oG-mediated SAD-B19-{Delta}G, but there was no difference between oG-mediated and N2cG-mediated CVS-N2c-{Delta}G system. In addition, codon modified N2cG (optiG) did not increase the efficiency of CVS-N2c-{Delta}G tracing. Finally, we found that the CVS-N2c-{Delta}G produced by the improved method can be used for monitoring neural activity of projection neurons, and the time window can be maintained for 3 weeks, and it can also express sufficient recombinases for efficient transgene recombination. That is, the virus produced by the improved production system does not affect its own function, paving the way for its further optimization, popularization and application in structural and functional studies of neural circuits.

Acoustic simulations of cochlear implants (CIs) allow for studies of perceptual performance with minimized effects of large CI individual variability. Different from conventional simulations using continuous sinusoidal or noise carriers, the present study employs pulsatile Gaussian-enveloped tones (GETs) to simulate several key features in modern CIs. Subject to the time-frequency uncertainty principle, the GET has a well-defined tradeoff between its duration and bandwidth. Two types of GET vocoders were implemented and evaluated in normal-hearing listeners. In the first implementation, constant 100-Hz GETs were used to minimize within-channel temporal overlap while different GET durations were used to simulate electric channel interaction. This GET vocoder could produce vowel and consonant recognition similar to actual CI performance. In the second implementation, 900-Hz/channel pulse trains were directly mapped to 900-Hz GET trains to simulate the maxima selection and amplitude compression of a widely-used n-of-m processing strategy, or the Advanced Combination Encoder. The simulated and actual implant performance of speech-in-noise recognition was similar in terms of the overall trend, absolute mean scores, and standard deviations. The present results suggest that the pulsatile GET vocoders can be used as alternative vocoders to simultaneously simulate several key CI processing features and result in similar speech perception performance to that with modern CIs.

Golgi defects including Golgi fragmentation are pathological features of Alzheimer disease (AD). As a pathogenic factor of AD, amyloid precursor protein (APP) induces Golgi fragmentation in soma. However, how APP regulates Golgi outposts (GOs) in dendrites remains unclear. Given that APP resided and affected GOs movements, especially reversed the distribution of multi-compartment GOs (mcGOs), we investigated the regulatory mechanism of mcGOs movements in Drosophila larvae. Knockdown experiments showed the bidirectional mcGOs movements were cooperatively controlled by dynein heavy chain (Dhc) and kinesin heavy chain subunits. Notably, only Dhc mediated APPs regulation on mcGOs movements. Further, by loss-of-function screening, the adaptor protein Sunday driver (Syd) was identified to mediate APP-induced alteration of the direction of mcGOs movements, and dendritic defects. Collectively, by elucidating a model of bidirectional mcGOs movements, we revealed the mechanism of APPs regulation on the direction of mcGOs movements. It provides new insights into AD pathogenesis.

Despite the importance of sleep to the cerebral cortex, how much sleep changes cortical neuronal firing remains unclear due to complicated firing behaviors. Here we quantified firing of cortical neurons using Hawkes process modeling that can model sequential random events exhibiting temporal clusters. "Intensity" is a parameter of Hawkes process that defines the probability of an event occurring. We defined the appearance of repetitive firing as the firing intensity corresponding to "intensity" in Hawkes process. Firing patterns were quantified by the magnitude of firing intensity, the time constant of firing intensity, and the background firing intensity. The higher the magnitude of firing intensity, the higher the likelihood that the spike will continue. The larger the time constant of firing intensity, the longer the repetitive firing lasts. The higher the background firing intensity, the more likely neurons fire randomly. The magnitude of firing intensity was inversely proportional to the time constant of firing intensity, and non-REM sleep increased the magnitude of firing intensity and decreased the time constant of firing intensity. The background firing intensity was not affected by the sleep/wake state. Our findings suggest that the cortex is organized such that neurons with a higher probability of repetitive firing have shorter repetitive firing periods. In addition, our results suggest that repetitive firing is ordered to become high frequency and short term during non-REM sleep, while unregulated components of firing are independent of the sleep/wake state in the cortex. Hawkes process modeling of firing will reveal novel properties of the brain.

Accumulating evidence indicates that the molecular circadian clock underlies the mating behavior of Drosophila melanogaster. However, information about which gene affects circadian mating behavior is poorly understood in animals. The present study found that feeding Myo-inositol enhanced the close-proximity (CP) rhythm of D. melanogaster mating behavior and lengthened the period of the CP rhythm. Then, to understand a role for inositol synthesis to fly mating behavior, we established the Inos (Myo-inositol 1-phosphate synthase) gene knock down fly strains with RNAi. Interestingly, the CP behavior of this three-different driver knock down strains was arrhythmic, but the locomotor rhythm was rhythmic. The data of three-different Inos knock down strains suggests that Inos gene expression of upper LNd, l-LNV, 5ths-LNv in brain is necessary for proper CP rhythm generation in D. melanogaster. The data indicated that the Inos gene is involved in the role for the circadian rhythm of D. melanogaster mating behavior.

The looming stimulus-evoked flight response is an experimental paradigm for studying innate defensive behaviors. However, how the visual looming stimulus is transmitted from the retina to the brain remains poorly understood. Here, we report that superior colliculus (SC)-projecting RGCs transmit the looming signal from the retina to the brain to mediate the looming-evoked flight behavior by releasing GABA. In the mouse retina, GABAergic RGCs are capable of projecting to many brain areas, including the SC. Superior colliculus (SC)-projecting GABAergic RGCs (spgRGCs) are mono-synaptically connected to the parvalbumin-positive SC neurons known to be required for the looming-evoked flight response. Optogenetic activation of spgRGCs triggers GABA-mediated inhibition in SC neurons. The ablation or silence of spgRGCs compromises looming-evoked flight response but not image-forming functions. Therefore, this study shows that spgRGCs control the looming-evoked flight response by regulating SC neurons via GABA, providing novel insight into the regulation of innate defensive behaviors.

Chicken embryos are a powerful and widely used animal model in developmental biology studies. After the development of CRISPR technology, gene-edited chickens have been generated by transferring primordial germ cells (PGCs) after genetic modifications. However, the low inheritance caused by the competition between host germ cells and the transferred ones is the most common complication and largely reduces the production efficiency in this way. Here, we generated a gene-edited chicken, in which germ cells can be ablated in a drug-dependent manner, as recipients for gene-edited PGC transfer. We used the nitroreductase/metronidazole (NTR/Mtz) system for cell ablation, in which NTR produces cytotoxic alkylating agents from administered Mtz, causing cell apoptosis. The chicken Vasa homolog (CVH) gene locus is used to drive the expression of the NTR gene in a germ cell-specific manner. In addition, a fluorescent protein gene, mCherry, was also placed in the CVH locus to visualize the PGCs. We named this system germ cell-Specific AutonoMoUs RemovAl Induction (gSAMURAI). gSAMURAI chickens will be an ideal recipient to produce offspring derived from transplanted exogenous germ cells.

IntroductionIn China, standard smoking cessation practices are rarely used by healthcare service providers (HSPs). WeChat, a popular social media app, has been widely used in China. MethodsIn this single-blind, randomized trial, undertaken in China with 8-week interventions and follow-up to 52 weeks, about 2,200 providers from different health care settings will be randomly selected to the intervention or control group. This trial will be conducted in China between June 2018 to October 2019. The intervention group will receive regular smoking cessation training program messages by the professional team to 8 weeks and follow to 52 weeks. A hard copy of the manual will be sent to each provider from the intervention group by mail after randomization. The Control group will only communicate by themselves and receive thanks messages for 8 weeks, and follow-up to 52 weeks. The trial will be carried out in two phases. The first phase is the pilot study (n=200, 8-week intervention and follow-up to 16 weeks) and the second is the main study (n=2000, 8-week intervention and follow-up to 52 weeks). The primary outcome measure will be the utilization rate of behavioural and pharmacotherapy interventions for smoking patients from 8 to 52 weeks. This trial is registered at ClinicalTrials.gov (number NCT03556774). ConclusionsThis program will be the first evidence-based educational program in smoking cessation designed specifically for the improvement of Chinese HSPs utilization of behavioural and pharmacotherapy interventions for cigarette smoking cessation in health care settings by the WeChat WeQuit program. ImplicationsThis protocol may show that WeChat WeQuit training program will be effective in increasing the provision of effective tobacco cessation interventions by Chinese-speaking HSPs, especially therapists, to patients with cigarette smoking, which will provide valuable insights into bridging the gap between need and services for smoking cessation in China. Overall, we believe this program will be likely to have very substantial public health benefits if it would provide a widely accessible and efficacious smoking cessation information for Chinese HSPs.

Cranial irradiation is used for prophylactic brain radiotherapy as well as treatment of primary brain tumors. Despite its high efficiency, it often induces unexpected side effects, including cognitive dysfunction. Herein, we observed that mice exposed to cranial irradiation exhibited cognitive dysfunction, including altered spontaneous behavior, decreased spatial memory, and reduced novel object recognition. Analysis of actin cytoskeleton revealed that ionizing radiation (IR) disrupted the filamentous/globular actin (F/G-actin) ratio and downregulated the actin turnover signaling pathway p21-activated kinase 3 (PAK3)-LIM kinase 1 (LIMK1)-cofilin. Furthermore, we found that IR could upregulate microRNA-206-3p (miR-206-3p) targeting PAK3. As the inhibition of miR-206-3p through antagonist (antagomiR), IR-induced disruption of PAK3 signaling is restored. In addition, intranasal administration of antagomiR-206-3p recovered IR-induced cognitive impairment in mice. Our results suggest that cranial irradiation-induced cognitive impairment could be ameliorated by regulating PAK3 through antagomiR-206-3p, thereby affording a promising strategy for protecting cognitive function during cranial irradiation, and promoting quality of life in patients with radiation therapy.

Autism spectrum disorder (ASD) is a class of severe neurodevelopmental disorders with a high incidence in young children, and its pathogenesis remains elusive. There is no effective treatment, and ASD children usually have a hard time in integrating into society and leading a normal life, which places a heavy burden on the families and society. Studies have shown that in addition to genetic factors, environmental factors are another important risk contributing to the pathogenesis of ASD. Early environmental adversity, which can lead to abnormal brain development and affect cognition and behavior, greatly increases the incidence of a variety of brain developmental diseases including ASD. However, studies on this aspect are inadequate at present, and no clear conclusions can be drawn. We explored whether early adversity could trigger ASD core clinical symptoms in macaques by modeling early adversity through maternal separation. In this study, we conducted a rigorous behavioral analysis of 12 male macaques (1.5-2 years old) that underwent maternal separation and 9 male normal macaques of the same age that had been mother raised, and found that maternal separation could induce a small number of the young individuals to develop three core symptoms of ASD, including social impairment, stereotyped behaviors, and restricted interest simultaneously. According to DSM-V and ASD clinical diagnostic criteria, these individuals should be ASD macaques for having all the three core ASD symptoms at the same time., For the first time, this study reveals that early environmental adversity can lead to ASD pathogenesis in monkeys, and provides a new approach for future ASD studies and modeling ASD monkeys.

The prosperity of electronic nicotine delivery systems (ENDS) or e-cigarette use has been regarded to lead an increasing risk of nicotine addiction, especially among youth. Understanding and evaluating the behaviors induced by ENDS are fundamental to the study of neuropsychiatric effects of e-cigarettes. However, little is known regarding the behavioral features during e-cigarette exposure in mice. Current behavioral assessments for nicotine addiction are based on nicotine withdrawal-induced anxiety which can be only performed after ENDS exposures. Here we developed MiceVAPORDot, a novel high-throughput tool for automated in situ behavioral characterization during e-cigarette exposure. The integration of a deep learning-based animal pose tracking method by MiceVAPORDot allows precise characterization on behavioral phenotypes of e-vapor exposed mice, which were unable revealed by traditional evaluation methodology such as conditioned place preference and elevated plus maze tests. The behavioral fingerprints recognized by MiceVAPORDot can be used for high-throughput screening on incentive nature of e-cigarette flavors as well as medications for smoking cessation.

Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) offer a powerful means for reversible control of neuronal activity through systemic administration of inert actuators. Because chemogenetic control relies on DREADD expression levels, understanding and quantifying the temporal dynamics of their expression is crucial for planning long-term experiments in monkeys. In this study, we longitudinally quantified in vivo DREADD expression in macaque monkeys using positron emission tomography with the DREADD-selective tracer [11C]deschloroclozapine (DCZ), complemented by functional studies. Twenty macaque monkeys were evaluated after being injected with adeno-associated virus vectors expressing the DREADDs hM4Di or hM3Dq, whose expression was quantified as changes in [11C]DCZ binding potential from baseline levels. Expression levels of both hM4Di and hM3Dq peaked around 60 days post-injection, remained stable for about 1.5 years, and declined gradually after two years. Significant chemogenetic control of neural activity and behavior persisted for about two years. The presence of protein tags significantly influenced expression levels, with co-expressed protein tags reducing overall expression levels. These findings provide valuable insights and guidelines for optimizing the use of DREADDs in long-term primate studies and potential therapeutic applications.

The voltage-gated sodium channel Nav1.7 plays a crucial role in the initiation and propagation of pain signals. Our previous study has successfully identified the interacting proteins of mouse Nav1.7 (mNav1.7). In this study, we aimed to further elucidate the protein-protein interactions associated with human Nav1.7 (hNav1.7). Stable epitope (TAP)-tagged HEK293 cells expressing hNaV1.7 were utilized for the identification of hNav1.7-interacting proteins. The hNaV1.7-associated complexes were isolated through tandem affinity purification and further characterized by mass spectrometry. Bioinformatics analysis was carried out using the PANTHER classification system. Electrophysiological recording was performed to assess Nav1.7 current. Tap-tagged hNav1.7 was expressed effectively in HEK293 cells, exhibiting normal functional Nav1.7 currents. A total of 261 proteins were identified as interactors of hNav1.7, mainly located across the cell membrane and cytoplasm, and primarily involved in biological processes related to protein translation and expression. Comparison between human and mouse Nav1.7-interacting proteins revealed shared proteins (such as Eef1a1, Eef2, Tcp1, Cct2, Cct3, Cct5, Cct6a, and Cct7) as well as protein families (such as kinesin and Rab GTPases family). Knockdown of two of the shared interacting proteins, CCT5 and TMED10, resulted in reduced Nav1.7 current density. In conclusion, the protein interactions of hNaV1.7 were successfully mapped in the current work. These novel findings offer essential insights into the regulatory mechanisms that govern Nav1.7 function. Significance statementChronic pain affects approximately 20% of the worlds population and is a global major public health problem. Nav1.7 has been recognized as a promising target for novel analgesics. However, the drug development process for Nav1.7 is challenging. A thorough understanding of the regulatory mechanism of Nav1.7 would greatly assist in the development of its analgesic drugs. Our previous work successfully mapped the mNav1.7 protein interactions. In the current study, the interacting proteins of hNav1.7 were further defined. Our findings provide important implications for the development of Nav1.7-based analgesics for human use.

Currently, calcium imaging allows long-term recording of large-scale neuronal activity in diverse states. However, it remains difficult to extract neuronal dynamics from recorded imaging data. In this study, we propose an improved constrained nonnegative matrix factorization (CNMF)-based algorithm and an effective method to extract cell shapes with fewer false positives and false negatives through image processing. We also show that the evaluation metrics obtained during image and signal processing can be combined and used for false-positive cell determination. For the CNMF algorithm, we combined cell-by-cell regularization and baseline shrinkage estimation, which greatly improved its stability and robustness. We applied these methods to real data and confirmed their effectiveness. Our method is simpler and faster, detects more cells with lower firing rates and signal-to-noise ratios, and enhances the quality of the extracted cell signals. These advances can improve the standard of downstream analysis and contribute to progress in neuroscience.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes Coronavirus disease 2019 (COVID-19) exhibits two major variants based on mutations of its spike protein, i.e., the D614 prototype and G614 variant. Although neurological symptoms have been frequently reported in patients, it is still unclear whether SARS-CoV-2 impairs neuronal activity or function. Here, we show that expression of both D614 and G614 spike proteins is sufficient to induce phenotypes of impaired neuronal morphology, including defective dendritic spines and shortened dendritic length. Using spike protein-specific monoclonal antibodies, we found that D614 and G614 spike proteins show differential S1/S2 cleavage and cell fusion efficiency. Our findings provide an explanation for higher transmission of the G614 variant and the neurological manifestations observed in COVID-19 patients.

Synaptic transmission mediated by various neurotransmitters influences a wide range of behaviors. However, understanding how neuromodulatory transmitters encode diverse behaviors and affect their functions remains challenging. Here, we introduce GESIAP3.0, an advanced, third-generation image analysis program based on genetically encoded sensors. This tool enables precise quantitative analysis of transmission in both awake, freely moving animals and immobilized subjects. GESIAP3.0 incorporates movement correction algorithms that effectively eliminate image displacement in behaving animals while optimizing synaptic information extraction and simplifying computations on commodity computers. Quantitative analysis of cholinergic, dopaminergic, and serotonergic transmission, corrected for tissue movement, revealed synaptic properties consistent with measurements from ex vivo wide-field and in vivo two-photon imaging under stable conditions. This validates the applicability of GESIAP3.0 for analyzing synaptic properties of neuromodulatory transmission in behaving animals.

BackgroundParkinsons disease (PD) is caused by the progressive loss of dopaminergic cells in substantia nigra pars compacta (SNc). The root cause of this cell loss in PD is still not decisively elucidated. A recent line of thinking traces the cause of PD neurodegeneration to metabolic deficiency. Due to exceptionally high energy demand, SNc neurons exhibit a higher basal metabolic rate and higher oxygen consumption rate, which results in oxidative stress. Recently, we have suggested that the excitotoxic loss of SNc cells might be due to energy deficiency occurring at different levels of neural hierarchy. Levodopa (LDOPA), a precursor of dopamine, which is used as a symptom-relieving treatment for PD, leads to outcomes that are both positive and negative. Several researchers suggested that LDOPA might be harmful to SNc cells due to oxidative stress. The role of LDOPA in the course of PD pathogenesis is still debatable. New MethodWe hypothesize that energy deficiency can lead to LDOPA-induced toxicity (LIT) in two ways: by promoting dopamine-induced oxidative stress and by exacerbating excitotoxicity in SNc. We present a multiscale computational model of SNc-striatum system, which will help us in understanding the mechanism behind neurodegeneration postulated above and provides insights for developing disease-modifying therapeutics. ResultsIt was observed that SNc terminals are more vulnerable to energy deficiency than SNc somas. During LDOPA therapy, it was observed that higher LDOPA dosage results in increased loss of somas and terminals in SNc. It was also observed that co-administration of LDOPA and glutathione (antioxidant) evades LDOPA-induced toxicity in SNc neurons. Comparison with Existing MethodsOur proposed multiscale model of SNc-striatum system is first of its kind, where SNc neuron was modelled at biophysical level, and striatal neurons were modelled at spiking level. ConclusionsWe show that our proposed model was able to capture LDOPA-induced toxicity in SNc, caused by energy deficiency.

The elegant functions of the brain are facilitated by sophisticated connections between neurons, the architecture of which is frequently characterized by one nucleus connecting to multiple targets via projection neurons. Delineating the sub-nucleus fine architecture of projection neurons in a certain nucleus could greatly facilitate its circuit, computational, and functional resolution. Here, we developed multi-fluorescent rabies virus to delineate the fine organization of corticothalamic projection neuron subsets in the primary visual cortex (V1). By simultaneously labeling multiple distinct subsets of corticothalamic projection neurons in V1 from their target nuclei in thalamus (dLGN, LP, LD), we observed that V1-dLGN corticothalamic neurons were densely concentrated in layer VI, except for several sparsely scattered neurons in layer V, while V1-LP and V1-LD corticothalamic neurons were localized to both layers V and VI. Meanwhile, we observed a fraction of V1 corticothalamic neurons targeting multiple thalamic nuclei, which was further confirmed by fMOST whole-brain imaging. We further conceptually proposed an upgraded sub-nucleus tracing system with higher throughput (21 subsets) for more complex architectural tracing. The multi-fluorescent RV tracing tool can be extensively applied to resolve architecture of projection neuron subsets, with a strong potential to delineate the computational and functional organization of these nuclei.

Alcohol use disorder (AUD) is known to have a significant genetic component, yet there remains a substantial gap between its heritability and findings from genome-wide association studies. One potential factor contributing to this gap may be genetic interactions, or epistasis, a largely unexplored aspect in the context of AUD. The aim of this study was to investigate the role of epistasis in AUD susceptibility and severity among American Indians, a population that exhibits the highest rates of AUD among all ethnic groups in the U.S. We began by identifying genes previously linked to alcohol dependence and AUD, then expanded this gene set through biological networks, ultimately comprising 3,736 genes and regulatory elements. The final gene set was mapped to over 476K variants in an American Indian cohort of 742 individuals. We performed a pairwise genetic interaction association analysis on the variant set, followed by a bi-clustering procedure to group the interacting SNP pairs into interacting intervals. A total of 114 interacting pairs of genes and regulatory elements were identified to be significantly associated with AUD severity. These genes were enriched for immune system, cell adhesion, neuronal, and disease pathways. Their expressions were particularly enriched in midbrain GABAergic neurons. Our study represents the first large-scale genetic interaction study of AUD in any population. Our findings suggest that epistasis may significantly contribute to the development and progression of AUD.

This study elucidates the molecular mechanisms underlying the axonal localization of the sex peptide receptor, a pivotal G-protein coupled receptor in the Drosophila melanogaster post-mating response cascade. Utilizing transgenic expression, neuronal labeling, and bioinformatics analyses, we demonstrate that the N-terminal domain of SPR is indispensable for its axonal targeting in both Drosophila larval ventral nerve cord neurons and mouse hippocampal neurons. Deletion of the N-terminal domain abolished axonal localization, highlighting its critical role in this process. Intriguingly, the C-terminal domain of SPR appears to play a subordinate role in axonal targeting. Bioinformatical analysis revealed a striking homology between the N-terminus of SPR and the Broad-complex, Tramtrack, and Bric-a-brac/poxvirus and zinc finger family of proteins. The BTB domain, a conserved protein-protein interaction domain within this family, is implicated in diverse cellular processes and axonal targeting. Further investigation into the role of the BTB domain-like region in SPR could provide valuable insights into the molecular underpinnings of axonal targeting and post-mating responses in Drosophila. This research contributes to our understanding of the intricate mechanisms governing GPCR localization and function in the context of reproductive biology and neuronal signaling.