Working memory deficits in Parkinson's disease mouse model / 中国药理学与毒理学杂志

OBJECTIVE Parkinson's disease(PD)is a progressive neurodegenerative disease clinically char-acterized by dyskinesia,tremor,rigidity,abnormal gait,whereas 90%of patients with PD suffer from defects of the sense of smell before the appearance of the motor dysfunctions.However,the mechanism of olfactory disor-der is still not clear.METHODS We utilized olfaction based delayed paired association task in head-fixed mice.We focused on functional role of neural circuit using opto-genetic techniques.In addition,we viewed the synaptic transmission by slice physiological recording and count-ed the cell number of targeted circuits.RESULTS AND CONCLUSION In our experiments,olfactory working memory impairments were found in the PD mice,and the working memory impairment appeared before motor dys-functions.Furthermore,we also investigated the functional role of neural circuit for olfactory working memory in PD mice.Meanwhile,the excitatory post synaptic currents were decreased as a result of presynaptic release proba-bility suppression in PD mice.However cell loss wasn't found in working memory related circuit recently.These will provide a new idea of clinic diagnosis for PD.

Dissecting the role of subicular circuit in temporal lobe epilepsy / 中国药理学与毒理学杂志

OBJECTIVE Epilepsy is considered a cir-cuit-level dysfunction associated with imbalanced excita-tion-inhibition,it is therapeutically necessary to identify key brain regions and related circuits in epilepsy.The subic-ulum is an essential participant in epileptic seizures,but the circuit mechanism underlying its role remains largely elusive.METHODS Here we deconstruct the diversity of subicular circuits in mouse models of epilepsy.Fiber pho-tometry was used to detect intrinsic activities of subicular PV,SST-positive interneurons and CaMK Ⅱ α-positive pyramidal neurons.Optogenetics and chemogenetics were used to selectively active or inactive subicular neu-rons or their projecting terminals.We also used in vivo and in vitro electrophysiology to record membrane charac-teristics of single neuron in distinct sub-regions of the subiculum.Finally,single pulse test was used to detect synaptic transmission strength between the subiculum and its downstream target.RESULTS First,we found that two majority of subicular interneurons,which inner-vate local pyramidal neurons to constrain their excitability,PV and SST-positive neurons showcase distinct calcium dynamics during hippocampal seizures.This could be attributed to distinct neural inputs from para-hippocampal regions of these two neuronal types.During epileptogen-esis,PV and SST neurons undergo different circuit reor-ganization patterns,that is,remarkable increase of exter-nal input to subicular PV neurons are seen after seizures,while SST cells receive decimated neural input.As their downstream targets,excitatory subicular pyramidal neu-rons are also intrinsically activated during hippocampal seizures.Moreover,we found that the subiculum hetero-geneously controls the generalization of hippocampal sei-zures by projecting to different downstream regions.No-tably,anterior thalamus projecting subicular neurons bidi-rectionally mediate seizures,while entorhinal cortex-pro-jecting subicular neurons act oppositely in seizure modu-lation.These two subpopulations are structurally and functionally dissociable.An intrinsically enhanced hyper-polarization-activated current and robust bursting intensity in anterior thalamus-projecting neurons facilitate synaptic transmission,thus contributing to the generalization of hippocampal seizures.CONCLUSION These results demonstrate that subicular neurons and circuits have diverse roles in epilepsy,suggesting the necessity to pre-cisely target specific subicular circuits for effective treat-ment of epilepsy.

Neurophilic herpesvirus: a powerful tool for neuroscience research / 生物工程学报

Viruses are powerful tools for the study of modern neurosciences. Most of the research on the connection and function of neurons were done by using recombinant viruses, among which neurotropic herpesvirus is one of the most important tools. With the continuous development of genetic engineering and molecular biology techniques, several recombinant neurophilic herpesviruses have been engineered into different viral tools for neuroscience research. This review describes and discusses several common and widely used neurophilic herpesviruses as nerve conduction tracers, viral vectors for neurological diseases, and lytic viruses for neuro-oncology applications, which provides a reference for further exploring the function of neurophilic herpesviruses.

Neuronal guidance genes in health and diseases

Neurons migrate from their birthplaces to the destinations, and extending axons navigate to their synaptic targets by sensing various extracellular cues in spatiotemporally controlled manners. These evolutionally conserved guidance cues and their receptors regulate multiple aspects of neural development to establish the highly complex nervous system by mediating both short- and long-range cell-cell communications. Neuronal guidance genes (encoding cues, receptors, or downstream signal transducers) are critical not only for development of the nervous system but also for synaptic maintenance, remodeling, and function in the adult brain. One emerging theme is the combinatorial and complementary functions of relatively limited classes of neuronal guidance genes in multiple processes, including neuronal migration, axonal guidance, synaptogenesis, and circuit formation. Importantly, neuronal guidance genes also regulate cell migration and cell-cell communications outside the nervous system. We are just beginning to understand how cells integrate multiple guidance and adhesion signaling inputs to determine overall cellular/subcellular behavior and how aberrant guidance signaling in various cell types contributes to diverse human diseases, ranging from developmental, neuropsychiatric, and neurodegenerative disorders to cancer metastasis. We review classic studies and recent advances in understanding signaling mechanisms of the guidance genes as well as their roles in human diseases. Furthermore, we discuss the remaining challenges and therapeutic potentials of modulating neuronal guidance pathways in neural repair.

Hippocampus: Molecular, Cellular, and Circuit Features in Anxiety / 神经科学通报·英文版

Anxiety disorders are currently a major psychiatric and social problem, the mechanisms of which have been only partially elucidated. The hippocampus serves as a major target of stress mediators and is closely related to anxiety modulation. Yet so far, its complex anatomy has been a challenge for research on the mechanisms of anxiety regulation. Recent advances in imaging, virus tracking, and optogenetics/chemogenetics have permitted elucidation of the activity, connectivity, and function of specific cell types within the hippocampus and its connected brain regions, providing mechanistic insights into the elaborate organization of the hippocampal circuitry underlying anxiety. Studies of hippocampal neurotransmitter systems, including glutamatergic, GABAergic, cholinergic, dopaminergic, and serotonergic systems, have contributed to the interpretation of the underlying neural mechanisms of anxiety. Neuropeptides and neuroinflammatory factors are also involved in anxiety modulation. This review comprehensively summarizes the hippocampal mechanisms associated with anxiety modulation, based on molecular, cellular, and circuit properties, to provide tailored targets for future anxiety treatment.

An Anterior Cingulate Cortex-to-Midbrain Projection Controls Chronic Itch in Mice / 神经科学通报·英文版

Itch is an unpleasant sensation that provokes the desire to scratch. While acute itch serves as a protective system to warn the body of external irritating agents, chronic itch is a debilitating but poorly-treated clinical disease leading to repetitive scratching and skin lesions. However, the neural mechanisms underlying the pathophysiology of chronic itch remain mysterious. Here, we identified a cell type-dependent role of the anterior cingulate cortex (ACC) in controlling chronic itch-related excessive scratching behaviors in mice. Moreover, we delineated a neural circuit originating from excitatory neurons of the ACC to the ventral tegmental area (VTA) that was critically involved in chronic itch. Furthermore, we demonstrate that the ACC→VTA circuit also selectively modulated histaminergic acute itch. Finally, the ACC neurons were shown to predominantly innervate the non-dopaminergic neurons of the VTA. Taken together, our findings uncover a cortex-midbrain circuit for chronic itch-evoked scratching behaviors and shed novel insights on therapeutic intervention.

Control of Emotion and Wakefulness by Neurotensinergic Neurons in the Parabrachial Nucleus / 神经科学通报·英文版

The parabrachial nucleus (PBN) integrates interoceptive and exteroceptive information to control various behavioral and physiological processes including breathing, emotion, and sleep/wake regulation through the neural circuits that connect to the forebrain and the brainstem. However, the precise identity and function of distinct PBN subpopulations are still largely unknown. Here, we leveraged molecular characterization, retrograde tracing, optogenetics, chemogenetics, and electrocortical recording approaches to identify a small subpopulation of neurotensin-expressing neurons in the PBN that largely project to the emotional control regions in the forebrain, rather than the medulla. Their activation induces freezing and anxiety-like behaviors, which in turn result in tachypnea. In addition, optogenetic and chemogenetic manipulations of these neurons revealed their function in promoting wakefulness and maintaining sleep architecture. We propose that these neurons comprise a PBN subpopulation with specific gene expression, connectivity, and function, which play essential roles in behavioral and physiological regulation.

A Deep Mesencephalic Nucleus Circuit Regulates Licking Behavior / 神经科学通报·英文版

Licking behavior is important for water intake. The deep mesencephalic nucleus (DpMe) has been implicated in instinctive behaviors. However, whether the DpMe is involved in licking behavior and the precise neural circuit behind this behavior remains unknown. Here, we found that the activity of the DpMe decreased during water intake. Inhibition of vesicular glutamate transporter 2-positive (VGLUT2+) neurons in the DpMe resulted in increased water intake. Somatostatin-expressing (SST+), but not protein kinase C-δ-expressing (PKC-δ+), GABAergic neurons in the central amygdala (CeA) preferentially innervated DpMe VGLUT2+ neurons. The SST+ neurons in the CeA projecting to the DpMe were activated at the onset of licking behavior. Activation of these CeA SST+ GABAergic neurons, but not PKC-δ+ GABAergic neurons, projecting to the DpMe was sufficient to induce licking behavior and promote water intake. These findings redefine the roles of the DpMe and reveal a novel CeASST-DpMeVGLUT2 circuit that regulates licking behavior and promotes water intake.

A Neural Circuit Mechanism Controlling Breathing by Leptin in the Nucleus Tractus Solitarii / 神经科学通报·英文版

Leptin, an adipocyte-derived peptide hormone, has been shown to facilitate breathing. However, the central sites and circuit mechanisms underlying the respiratory effects of leptin remain incompletely understood. The present study aimed to address whether neurons expressing leptin receptor b (LepRb) in the nucleus tractus solitarii (NTS) contribute to respiratory control. Both chemogenetic and optogenetic stimulation of LepRb-expressing NTS (NTSLepRb) neurons notably activated breathing. Moreover, stimulation of NTSLepRb neurons projecting to the lateral parabrachial nucleus (LPBN) not only remarkably increased basal ventilation to a level similar to that of the stimulation of all NTSLepRb neurons, but also activated LPBN neurons projecting to the preBötzinger complex (preBötC). By contrast, ablation of NTSLepRb neurons projecting to the LPBN notably eliminated the enhanced respiratory effect induced by NTSLepRb neuron stimulation. In brainstem slices, bath application of leptin rapidly depolarized the membrane potential, increased the spontaneous firing rate, and accelerated the Ca2+ transients in most NTSLepRb neurons. Therefore, leptin potentiates breathing in the NTS most likely via an NTS-LPBN-preBötC circuit.

Research progress of chronic ethanol consumption on neural circuits of cerebellum and behaviors / 中华行为医学与脑科学杂志

Ethanol is one of the most widely used and abused psychoactive substances in the world. Long-term and excessive intake of alcohol can damage the central nervous system and lead to impairment of its function. As an important component of the central nervous system, cerebellum is one of the main target organs damaged by ethanol. Acute and chronic ethanol intake can damage human motor coordination, motor learning and some cognitive functions. Its damage mechanism is generally believed to be caused by the abnormal function of cerebellar cortical neural circuit caused by ethanol intake. Combined with recent studies on the mouse model of long-term ethanol intake, this article reviews the cerebellar neural network mechanism of long-term ethanol intake from various aspects, with a view to providing research and development in behavioral movement, motor coordination, cognitive function, depression, and offers new ideas with the rise of precision medicine for treatment. People are increasingly interested in exploring the mechanism of long-term ethanol intake on the cerebellar neural network. How to improve or block the corresponding mechanism based on the mechanism of action found in existing research is an important proposition in future research.

Advances in neuroimaging studies of cerebral small vessel disease combined with depression / 中华行为医学与脑科学杂志

Depression is a common psychiatric symptom in cerebral small vessel disease (CSVD), which has a certain relationship with impairment of cognitive function and can significantly increase the mortality and morbidity of CSVD patients. The occurrence of CVSD-associated depression is less related to psychological stress, but is associated with the impairment of the brain's emotional circuit. This article reviewed the correlation between the imaging features of CVSD and the occurrence and development of depression in recent years, and the neuroimaging mechanism of depression associated with CVSD. Many literatures have shown that deep white matter hyperintensities and asymptomatic lacunar infarction in the basal ganglia are independent risk factors for depression in CSVD, and the reduction of local brain volume is associated with depression. The neuroimaging mechanism of depression associated with CSVD suggests that the occurrence of depressive symptoms is related to the neural circuits in the lobar cortex-subcortical limbic area. These findings provide clues for exploring the neuropathological mechanisms and specific treatment methods of depression associated with CVSD.

Research progress of light therapy for mood disorders / 中华行为医学与脑科学杂志

Light therapy, a non-intrusive approach, is now considered as a promising new treatment method for a variety of mood disorders such as depression, bipolar disorder, postpartum depression and so on. However, the neural mechanism of light therapy to regulate emotions is still unclear, and the clinical application of light therapy and its side effects are still controversial. Light therapy regulates mood may be related to the changes of neural circuit mediated by intrinsically photosensitive retinal ganglion cells(ipRGCs), clock gene expression, circadian rhythm and sleep structure. In this paper, the treatment of mood disorders by light has been discussed, and a variety of neural circuits and molecular biological mechanisms of light therapy are introduced, meanwhile, the current situation and side effects of light therapy have been analyzed, in order to provide evidence for the application and promotion of light therapy in the treatment of mood disorders.

Projections from Infralimbic Cortex to Paraventricular Thalamus Mediate Fear Extinction Retrieval / 神经科学通报·英文版

The paraventricular nucleus of the thalamus (PVT), which serves as a hub, receives dense projections from the medial prefrontal cortex (mPFC) and projects to the lateral division of central amygdala (CeL). The infralimbic (IL) cortex plays a crucial role in encoding and recalling fear extinction memory. Here, we found that neurons in the PVT and IL were strongly activated during fear extinction retrieval. Silencing PVT neurons inhibited extinction retrieval at recent time point (24 h after extinction), while activating them promoted extinction retrieval at remote time point (7 d after extinction), suggesting a critical role of the PVT in extinction retrieval. In the mPFC-PVT circuit, projections from IL rather than prelimbic cortex to the PVT were dominant, and disrupting the IL-PVT projection suppressed extinction retrieval. Moreover, the axons of PVT neurons preferentially projected to the CeL. Silencing the PVT-CeL circuit also suppressed extinction retrieval. Together, our findings reveal a new neural circuit for fear extinction retrieval outside the classical IL-amygdala circuit.

HSV-1 H129-Derived Anterograde Neural Circuit Tracers: Improvements, Production, and Applications / 神经科学通报·英文版

Anterograde viral tracers are powerful and essential tools for dissecting the output targets of a brain region of interest. They have been developed from herpes simplex virus 1 (HSV-1) strain H129 (H129), and have been successfully applied to map diverse neural circuits. Initially, the anterograde polysynaptic tracer H129-G4 was used by many groups. We then developed the first monosynaptic tracer, H129-dTK-tdT, which was highly successful, yet improvements are needed. Now, by inserting another tdTomato expression cassette into the H129-dTK-tdT genome, we have created H129-dTK-T2, an updated version of H129-dTK-tdT that has improved labeling intensity. To help scientists produce and apply our H129-derived viral tracers, here we provide the protocol describing our detailed and standardized procedures. Commonly-encountered technical problems and their solutions are also discussed in detail. Broadly, the dissemination of this protocol will greatly support scientists to apply these viral tracers on a large scale.

Illuminating Neural Circuits in Alzheimer’s Disease / 神经科学通报·英文版

Alzheimer’s disease (AD) is the most common neurodegenerative disorder and there is currently no cure. Neural circuit dysfunction is the fundamental mechanism underlying the learning and memory deficits in patients with AD. Therefore, it is important to understand the structural features and mechanisms underlying the deregulated circuits during AD progression, by which new tools for intervention can be developed. Here, we briefly summarize the most recently established cutting-edge experimental approaches and key techniques that enable neural circuit tracing and manipulation of their activity. We also discuss the advantages and limitations of these approaches. Finally, we review the applications of these techniques in the discovery of circuit mechanisms underlying β-amyloid and tau pathologies during AD progression, and as well as the strategies for targeted AD treatments.

In Vivo Two-photon Calcium Imaging in Dendrites of Rabies Virus-labeled V1 Corticothalamic Neurons / 神经科学通报·英文版

Monitoring neuronal activity in vivo is critical to understanding the physiological or pathological functions of the brain. Two-photon Ca imaging in vivo using a cranial window and specific neuronal labeling enables real-time, in situ, and long-term imaging of the living brain. Here, we constructed a recombinant rabies virus containing the Ca indicator GCaMP6s along with the fluorescent protein DsRed2 as a baseline reference to ensure GCaMP6s signal reliability. This functional tracer was applied to retrogradely label specific V1-thalamus circuits and detect spontaneous Ca activity in the dendrites of V1 corticothalamic neurons by in vivo two-photon Ca imaging. Notably, we were able to record single-spine spontaneous Ca activity in specific circuits. Distinct spontaneous Ca dynamics in dendrites of V1 corticothalamic neurons were found for different V1-thalamus circuits. Our method can be applied to monitor Ca dynamics in specific input circuits in vivo, and contribute to functional studies of defined neural circuits and the dissection of functional circuit connections.

Modulating neural circuits in substance addiction with repetitive transcranial magnetic stimulation / 上海交通大学学报（医学版）

Substance addiction is a chronic and recurrent disorder and may be related to complex neural circuits. However, there is no optimally effective treatment for substance addiction currently. Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive, safe and easy-to-operate neuro-electrophysiological technique, which is becoming an emerging therapeutic option for many mental disorders. The effect of rTMS on substance addiction is closely related to the stimulation of neural circuits. However, the mechanism is still unknown. The review summarizes recent research progress on the application of rTMS and its application combined with other therapies in substance addiction, as well as the regulation of rTMS on substance addiction-related neural circuits.

Trans-synaptic Neural Circuit-Tracing with Neurotropic Viruses / 神经科学通报·英文版

A central objective in deciphering the nervous system in health and disease is to define the connections of neurons. The propensity of neurotropic viruses to spread among synaptically-linked neurons makes them ideal for mapping neural circuits. So far, several classes of viral neuronal tracers have become available and provide a powerful toolbox for delineating neural networks. In this paper, we review the recent developments of neurotropic viral tracers and highlight their unique properties in revealing patterns of neuronal connections.

Recent Advances in the Genetic Dissection of Neural Circuits in Drosophila / 神经科学通报·英文版

Nervous systems endow animals with cognition and behavior. To understand how nervous systems control behavior, neural circuits mediating distinct functions need to be identified and characterized. With superior genetic manipulability, Drosophila is a model organism at the leading edge of neural circuit analysis. We briefly introduce the state-of-the-art genetic tools that permit precise labeling of neurons and their interconnectivity and investigating what is happening in the brain of a behaving animal and manipulating neurons to determine how behaviors are affected. Brain-wide wiring diagrams, created by light and electron microscopy, bring neural circuit analysis to a new level and scale. Studies enabled by these tools advances our understanding of the nervous system in relation to cognition and behavior.

Abnormality of resting-state functional network in a rat animal model of sepsis-associated encephalopathy / 临床麻醉学杂志

Objective To explore changes in the functional network in an animal model of SAE induced by lipopolysaccharide (LPS) challenge.Methods Thirty male Sprague-Dawley rats were randomly allocated into control group and group SAE.SAE model was established by intraperitoneal injection of LPS 1 mg/kg in group SAE, while the same amount of saline.was injected in the control group.Firstly, we used regional homogeneity (ReHo) method to exam abnormal brain regions between the control and SAE groups and then considered them as seeds for functional connectivity analysis, and behavioral tests were performed at 48 hours after LPS intraperitoneal injection.Results Compared with the control group, our study showed LPS impaired mood function, as reflected by depression-like behavior of prolonged immobility[ (38.93± 13.84) s vs (22.06± 6.75) s, P<0.05]in the forced swim test;LPS induced significantly increased ReHo values in the anterior cingulate cortex (ACC) and caudate putamen (CPu) of (1.21±0.07 vs 0.97±0.12, P<0.05) and (1.34±0.09 vs 1.17±0.16, P<0.05) respectively;the ACC seed showed increased functional connectivity with the retrosplenial cortex (0.45 ± 0.06 vs 0.11 ± 0.02, P<0.05) ;the right CPu seed showed increased functional connectivity with the left Cpu (0.33±0.07 vs 0.07±0.01, P<0.05) ;the depression-like behavior was associated with increased ReHo values in the ACC and right CPu as well as increased functional connectivity between the right CPu and left CPu.Conclusion This study suggests that the impaired mood function in SAE is associated with increased ReHo values in the ACC and right CPu as well as increased functional connectivity between the right CPu and left CPu, indicating that the abnormality of resting-state functional network may be a potential mechanism involved in SAE.