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.

Facilitation of behavioral and cortical emergence from isoflurane anesthesia by GABAergic neurons in basal forebrain / 中国药理学与毒理学杂志

OBJECTIVE To reveal the role of the basal forebrain(BF)GABAergic neurons in the regulation of isoflurane anesthesia and to elucidate the underlying neural pathways.METHODS The activity of BF GABAer-gic neurons was monitored during isoflurane anesthesia using a genetically encoded calcium indicator in Vgat-Cre mice of both sexes.The activity of BF GABAer-gic neurons was manipulated by chemogenetic and opto-genetic approaches.Sensitivity,induction time and emer-gence time of isoflurane anesthesia were estimated by righting reflex.The electroencephalogram(EEG)power and burst-suppression were monitored by EEG recording.The effects of activation of GABAergic BF-thalamic reticu-lar nucleus(TRN)pathway on isoflurane anesthesia were investigated with optogenetics.RESULTS The activity of BF GABAergic neurons was generally inhibited during isoflurane anesthesia,obviously decreased during the induction of anesthesia and gradually restored during the emergence from anesthesia.Activation of BF GABAergic neurons with chemogenetics and optogenetics promoted behavioral emergence from isoflurane anesthesia,with decreased sensitivity to isoflurane,delayed induction and accelerated emergence from isoflurane anesthesia.Optogenetic activation of BF GABAergic neurons prom-oted cortical activity during isoflurane anesthesia,with decreased EEG delta power and burst suppression ratio during 0.8%and 1.4%isoflurane anesthesia,respectively.Similar to the effects of activating BF GABAergic cell bod-ies,photostimulation of BF GABAergic terminals in the TRN also strongly promoted cortical activation and behav-ioral emergence from isoflurane anesthesia.CONCLU-SION The GABAergic neurons in the BF is a key neural substrate for general anesthesia regulation that facilitates behavioral and cortical emergence from general anesthe-sia via the BF-TRN pathway.

Chemogenetic and Optogenetic Manipulations of Microglia in Chronic Pain / 神经科学通报·英文版

Chronic pain relief remains an unmet medical need. Current research points to a substantial contribution of glia-neuron interaction in its pathogenesis. Particularly, microglia play a crucial role in the development of chronic pain. To better understand the microglial contribution to chronic pain, specific regional and temporal manipulations of microglia are necessary. Recently, two new approaches have emerged that meet these demands. Chemogenetic tools allow the expression of designer receptors exclusively activated by designer drugs (DREADDs) specifically in microglia. Similarly, optogenetic tools allow for microglial manipulation via the activation of artificially expressed, light-sensitive proteins. Chemo- and optogenetic manipulations of microglia in vivo are powerful in interrogating microglial function in chronic pain. This review summarizes these emerging tools in studying the role of microglia in chronic pain and highlights their potential applications in microglia-related neurological disorders.

Characterization and application of several lysis cassettes / 生物工程学报

Lysis is a common functional module in synthetic biology and is widely used in genetic circuit design. Lysis could be achieved by inducing expression of lysis cassettes originated from phages. However, detailed characterization of lysis cassettes hasn't been reported yet. Here, we first adopted arabinose- and rhamnose-inducible systems to develop inducible expression of five lysis cassettes (S105, A52G, C51S S76C, LKD, LUZ) in Escherichia coli Top10. By measuring OD600, we characterized the lysis behavior of strains harboring different lysis cassettes. These strains were harvested at different growth stages, induced with different concentrations of chemical inducers, or contained plasmids with different copy numbers. We found that although all five lysis cassettes could induce bacterial lysis in Top10, lysis behaviors differed a lot at various conditions. We further found that due to the difference in background expression levels between strain Top10 and Pseudomonas aeruginosa PAO1, it was hard to construct inducible lysis systems in strain PAO1. The lysis cassette controlled by rhamnose-inducible system was finally inserted into the chromosome of strain PAO1 to construct lysis strains after careful screen. The results indicated that LUZ and LKD were more effective in strain PAO1 than S105, A52G and C51S S76C. At last, we constructed an engineered bacteria Q16 using an optogenetic module BphS and the lysis cassette LUZ. The engineered strain was capable of adhering to target surface and achieving light-induced lysis by tuning the strength of ribosome binding sites (RBSs), showing great potential in surface modification.

Thalamocortical Circuit Controls Neuropathic Pain via Up-regulation of HCN2 in the Ventral Posterolateral Thalamus / 神经科学通报·英文版

The thalamocortical (TC) circuit is closely associated with pain processing. The hyperpolarization-activated cyclic nucleotide-gated (HCN) 2 channel is predominantly expressed in the ventral posterolateral thalamus (VPL) that has been shown to mediate neuropathic pain. However, the role of VPL HCN2 in modulating TC circuit activity is largely unknown. Here, by using optogenetics, neuronal tracing, electrophysiological recordings, and virus knockdown strategies, we showed that the activation of VPL TC neurons potentiates excitatory synaptic transmission to the hindlimb region of the primary somatosensory cortex (S1HL) as well as mechanical hypersensitivity following spared nerve injury (SNI)-induced neuropathic pain in mice. Either pharmacological blockade or virus knockdown of HCN2 (shRNA-Hcn2) in the VPL was sufficient to alleviate SNI-induced hyperalgesia. Moreover, shRNA-Hcn2 decreased the excitability of TC neurons and synaptic transmission of the VPL-S1HL circuit. Together, our studies provide a novel mechanism by which HCN2 enhances the excitability of the TC circuit to facilitate neuropathic pain.

Implantes cocleares ópticos: una herramienta promisoria de tratamiento para la hipoacusia / Optical cochlear implants: a promising treatment tool for hearing loss

La hipoacusia afecta a más de 1.500 millones de personas mundialmente. Los principales medios de rehabilitación usados son los audífonos e implantes cocleares (IC). El IC eléctrico convierte el sonido en impulsos eléctricos que estimulan, directamente, a las neuronas del ganglio espiral para proveer sensación auditiva. Tiene como desventaja una amplia dispersión espacial de la corriente, limitando la resolución espectral y el rango dinámico de codificación sonoro, lo que conduce a una mala comprensión del habla en entornos ruidosos y mala apreciación de la música. En los últimos años se ha estudiado utilizar estimulación óptica en vez de eléctrica, pues emite estímulos con mayor selectividad espacial. Se han descrito IC ópticos usando luz infrarroja y otros con métodos de optogenética, estos últimos requieren de la expresión de proteínas fotosensibles inducidas por virus adenoasociados. Se ha visto que la selectividad espectral de la estimulación optogenética es indistinguible de la acústica, y permitió tasas de disparo casi fisiológicas con buena precisión temporal hasta 250 Hz de estimulación. Estudios que compararon un sistema de IC óptico con uno eléctrico concluyen que el uso de optogenética permitiría una restauración de la audición con una selectividad espectral mejorada en comparación con un IC eléctrico.

Hearing loss affects more than 1.5 billion people worldwide. The main means of rehabilitation used are hearing aids and cochlear implants (CI). The electrical CI converts sound into electrical impulses that directly stimulate neurons in the spiral ganglion to provide auditory sensation; it has the disadvantage of a wide spatial dispersion of the current, limiting the spectral resolution and the dynamic range of sound coding, which leads to a poor understanding of speech in noisy environments and a poor appreciation of music. In recent years, the use of optical stimulation instead of electrical stimulation have been studied since it emits stimuli with greater spatial selectivity. Optical CIs have been described using infrared light and others using optogenetic methods, the latter requiring the expression of photosensitive proteins induced by adeno-associated viruses. The spectral selectivity of optogenetic stimulation has been found to be indistinguishable from acoustic stimulation and allowed near-physiological firing rates with good temporal accuracy up to 250 Hz stimulation. Studies comparing an optical and an electrical CI system conclude that the use of optogenetics would allow hearing restoration with improved spectral selectivity compared to an electrical CI.

Activation of a hypothalamus-habenula circuit by mechanical stimulation inhibits cocaine addiction-like behaviors

Background Mechanoreceptor activation modulates GABA neuron firing and dopamine (DA) release in the mesolimbic DA system, an area implicated in reward and substance abuse. The lateral habenula (LHb), the lateral hypothalamus (LH), and the mesolimbic DA system are not only reciprocally connected, but also involved in drug reward. We explored the effects of mechanical stimulation (MS) on cocaine addiction-like behaviors and the role of the LH-LHb circuit in the MS effects. MS was performed over ulnar nerve and the effects were evaluated by using drug seeking behaviors, optogenetics, chemogenetics, electrophysiology and immunohistochemistry. Results Mechanical stimulation attenuated locomotor activity in a nerve-dependent manner and 50-kHz ultrasonic vocalizations (USVs) and DA release in nucleus accumbens (NAc) following cocaine injection. The MS effects were ablated by electrolytic lesion or optogenetic inhibition of LHb. Optogenetic activation of LHb suppressed cocaine-enhanced 50 kHz USVs and locomotion. MS reversed cocaine suppression of neuronal activity of LHb. MS also inhibited cocaine-primed reinstatement of drug-seeking behavior, which was blocked by chemogenetic inhibition of an LH-LHb circuit. Conclusion These findings suggest that peripheral mechanical stimulation activates LH-LHb pathways to attenuate cocaine-induced psychomotor responses and seeking behaviors.

Dissecting the Neural Circuitry for Pain Modulation and Chronic Pain: Insights from Optogenetics / 神经科学通报·英文版

Pain is an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage. The processing of pain involves complicated modulation at the levels of the periphery, spinal cord, and brain. The pathogenesis of chronic pain is still not fully understood, which makes the clinical treatment challenging. Optogenetics, which combines optical and genetic technologies, can precisely intervene in the activity of specific groups of neurons and elements of the related circuits. Taking advantage of optogenetics, researchers have achieved a body of new findings that shed light on the cellular and circuit mechanisms of pain transmission, pain modulation, and chronic pain both in the periphery and the central nervous system. In this review, we summarize recent findings in pain research using optogenetic approaches and discuss their significance in understanding the pathogenesis of chronic pain.

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.

Optogenetic study of glutamatergic neuron in parasubiculum in visuospatial memory / 中华行为医学与脑科学杂志

Objective:To investigate the function of glutamatergic neuron of the parasubiculum in spatial memory.Methods:Sixteen adult male C57BL/6 mice aged 6-8 weeks were divided into two groups randomly, 0.4 μl AAV5-CaMKⅡα-eNpHR3.0-eYFP was injected into the bilateral parasubiculum respectively in experimental group, equal dose AAV5-CaMKⅡα-eYFP for control group.The optic fiber was implanted 6 weeks after virus injection.The novel object place recognition test was performed one week after optic fiber implantation, continuous yellow light was delivered during the behavioral test to inhibit the function of glutamatergic neuron in the parasubiculum.The standard memory index (D2) was used to evaluate the spatial memory function.SPSS 20.0 software was used to process the data, and the independent-samples t-test and paired-samples t-test were used for data analysis. Results:In the novel object place recognition experiment, the mice showed no preference for either object in both control group(new object: 0.51±0.06, familiar object: 0.49±0.04, t=1.21, P>0.05) and experimental group(new object: 0.49±0.05, familiar object: 0.50±0.04, t=-0.78, P>0.05). Compared with the control group (0.55±0.06), the D2 score of the experimental group (0.26±0.07) was significantly lower ( t=-2.96, P<0.05), and the number of c-fos positive neuron in experimental group (96.33±7.13) was also significantly less than that in control group (127.67±5.24, t=-3.54, P<0.05). Conclusion:Inhibiting glutamatergic neuronal activity in the parasubiculum impairs spatial memory in mice, suggesting that glutamatergic neurons of the parasubiculum play an important role in spatial memory.

Application prospect of common viral tracers in study on brain effect of acupuncture / 中国针灸

The feasibility and prospect of viral tracers and mediating functional components are explored in study on brain effect of acupuncture. In the paper, proceeding with viral tracers, the viral tracers used to analyze the structure of specific neural circuits are introduced, as well as their mediated probes, optical/chemical genetics techniques, Cre-LoxP systems, etc. The viral tracers and their functional components can not only mark specifically nerve cells or neural circuits, but also interfere with the function of specific types of neurons or nuclei. They solve some disadvantage of traditional nerve tracing method that only describes the morphology of neurons of one brain region and the simple projection among brain regions, and the indirect and non-specific absorption. The viral tracers and their functional components play the important approach to decoding the mechanism on brain effect of acupuncture when introduced in experimental acupuncture so as to provide an in vivo, real-time and intuitive novel method for a further analysis of neurobiological mechanism on brain effect of acupuncture.

An Infrared Touch System for Automatic Behavior Monitoring / 神经科学通报·英文版

Key requirements of successful animal behavior research in the laboratory are robustness, objectivity, and high throughput, which apply to both the recording and analysis of behavior. Many automatic methods of monitoring animal behavior meet these requirements. However, they usually depend on high-performing hardware and sophisticated software, which may be expensive. Here, we describe an automatic infrared behavior-monitor (AIBM) system based on an infrared touchscreen frame. Using this, animal positions can be recorded and used for further behavioral analysis by any PC supporting touch events. This system detects animal behavior in real time and gives closed-loop feedback using relatively low computing resources and simple algorithms. The AIBM system automatically records and analyzes multiple types of animal behavior in a highly efficient, unbiased, and low-cost manner.

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.

Application and research progress of optogenetic technology in retinal diseases / 中华实验眼科杂志

Optogenetics is a technique combining optics and the power of light with genetics; it uses light-mediated protein-protein interactions to control the open/closed state of channels or the activation/inactivation states of signaling components within live cells.Recently developed optogenetic tools offer exciting opportunities by enabling signaling regulation with superior temporal and spatial resolution.The eye is a light-bioelectric conversion system.Compared with diseases of other organs, there are great advantages to apply optogenetics to the treatment of ophthalmic conditions, as new optical genetic tools are rapidly emerging.This article will focus on the main methods of optogenetic control of cells and the current status and outlook of its application in retinal diseases.

The Cre-loxP system and its derivative systems: methodology research and applications in neuroscience / 药学学报

In scientific research, it is often needed to knock in, knock out, knock down, or overexpress a specific gene in model organisms or specific types of cells to achieve precise regulation of experimental independent variables. In this case, various transgenic mice are required. The cyclization recombinase (Cre) can directly interact with different loxP (locus X over P1) DNA sequences without any cofactors to perform specific gene knock-in or knock-out at specific targets. Because of its advantages of simple action principles, high spatial specificity, and high reorganization efficiency, the Cre-loxP system is widely used in scientific research. Furthermore, the CreERT2 system (mutant of the fusion protein of Cre and estrogen receptor ligand binding domain) and the tetracycline (Tet)-on/off system, derived from the Cre-loxP system, have made the recombination of the target gene occur in temporal-specificity on the basis of spatial-specificity. This dual specificity of time and space is indispensable for research in specific directions such as fear memory and engram cells on the basis of reducing the impacts on experimental animals. Therefore, these derived systems have broad application prospects.

Application and research progress of optogenetic technology in retinal diseases / 中华实验眼科杂志

Optogenetics is a technique combining optics and the power of light with genetics;it uses light-mediated protein-protein interactions to control the open/closed state of channels or the activation/inactivation states of signaling components within live cells.Recently developed optogenetic tools offer exciting opportunities by enabling signaling regulation with superior temporal and spatial resolution.The eye is a light-bioelectric conversion system.Compared with diseases of other organs,there are great advantages to apply optogenetics to the treatment of ophthalmic conditions,as new optical genetic tools are rapidly emerging.This article will focus on the main methods of optogenetic control of cells and the current status and outlook of its application in retinal diseases.

Medial Preoptic Area Modulates Courtship Ultrasonic Vocalization in Adult Male Mice / 神经科学通报·英文版

Adult male mice emit highly complex ultrasonic vocalizations (USVs) in response to female conspecifics. Such USVs, thought to facilitate courtship behaviors, are routinely measured as a behavioral index in mouse models of neurodevelopmental and psychiatric disorders such as autism. While the regulation of USVs by genetic factors has been extensively characterized, the neural mechanisms that control USV production remain largely unknown. Here, we report that optogenetic activation of the medial preoptic area (mPOA) elicited the production of USVs that were acoustically similar to courtship USVs in adult mice. Moreover, mPOA vesicular GABA transporter-positive (Vgat +) neurons were more effective at driving USV production than vesicular glutamate transporter 2-positive neurons. Furthermore, ablation of mPOA Vgat+ neurons resulted in altered spectral features and syllable usage of USVs in targeted males. Together, these results demonstrate that the mPOA plays a crucial role in modulating courtship USVs and this may serve as an entry point for future dissection of the neural circuitry underlying USV production.

Neuroimmune interactions and kidney disease

The autonomic nervous system plays critical roles in maintaining homeostasis in humans, directly regulating inflammation by altering the activity of the immune system. The cholinergic anti-inflammatory pathway is a well-studied neuroimmune interaction involving the vagus nerve. CD4-positive T cells expressing β2 adrenergic receptors and macrophages expressing the alpha 7 subunit of the nicotinic acetylcholine receptor in the spleen receive neurotransmitters such as norepinephrine and acetylcholine and are key mediators of the cholinergic anti-inflammatory pathway. Recent studies have demonstrated that vagus nerve stimulation, ultrasound, and restraint stress elicit protective effects against renal ischemia-reperfusion injury. These protective effects are induced primarily via activation of the cholinergic anti-inflammatory pathway. In addition to these immunological roles, nervous systems are directly related to homeostasis of renal physiology. Whole-kidney three-dimensional visualization using the tissue clearing technique CUBIC (clear, unobstructed brain/body imaging cocktails and computational analysis) has illustrated that renal sympathetic nerves are primarily distributed around arteries in the kidneys and denervated after ischemia-reperfusion injury. In contrast, artificial renal sympathetic denervation has a protective effect against kidney disease progression in murine models. Further studies are needed to elucidate how neural networks are involved in progression of kidney disease.

Research progress on ophthalmologic optogenetics / 中华实验眼科杂志

Optogenetics is a genetic technique that applies illumination with certain wavelength to modulate the biological activity of cells or subcellular components accurately.This technique is friendly to researchers of ophthalmology due to characteristics of the eyes including transparency, accessibility and comparative independence.Optogenetics can be used in retinal neurons, such as retinal ganglion cells (RGCs), even extended to vascular endothelial cells, immune cells and other ocular cells or cell substructures, which can further our understanding of ocular physiology and provide potential, therapeutic approaches for neurodegenerative diseases, vascular diseases, inflammation and other eye-related diseases.Improvement in effectiveness, safety and comfort is pivotal for this technique to expand application in ophthalmology and for its function to reach the physiology state of nomal eyes.In this review, a comprehensive analysis of optogenetics progress in ophthalmology was performed.Challenges in imaging including light sensitivity, spatial resolution and temporal resolution, and problems in expression involving local and systemic safety, specificity and persistence were reviewed.

PET imaging on neurofunctional changes after optogenetic stimulation in a rat model of panic disorder / 医学前沿

Panic disorder (PD) is an acute paroxysmal anxiety disorder with poorly understood pathophysiology. The dorsal periaqueductal gray (dPAG) is involved in the genesis of PD. However, the downstream neurofunctional changes of the dPAG during panic attacks have yet to be evaluated in vivo. In this study, optogenetic stimulation to the dPAG was performed to induce panic-like behaviors, and in vivo positron emission tomography (PET) imaging with F-flurodeoxyglucose (F-FDG) was conducted to evaluate neurofunctional changes before and after the optogenetic stimulation. Compared with the baseline, post-optogenetic stimulation PET imaging demonstrated that the glucose metabolism significantly increased (P < 0.001) in dPAG, the cuneiform nucleus, the cerebellar lobule, the cingulate cortex, the alveus of the hippocampus, the primary visual cortex, the septohypothalamic nucleus, and the retrosplenial granular cortex but significantly decreased (P < 0.001) in the basal ganglia, the frontal cortex, the forceps minor corpus callosum, the primary somatosensory cortex, the primary motor cortex, the secondary visual cortex, and the dorsal lateral geniculate nucleus. Taken together, these data indicated that in vivo PET imaging can successfully detect downstream neurofunctional changes involved in the panic attacks after optogenetic stimulation to the dPAG.