Food Addiction and Its Neural Circuitry Regulation Mechanism / 生物化学与生物物理进展

Food addiction refers to the individual dependence on certain specific foods (high-calorie foods) to the extent that it becomes difficult to control and manifests a series of addictive-like behavioral changes. Food addiction is an important factor in the development of human obesity and is also a core factor that most people cannot maintain weight loss or adhere to restrictive diets to maintain a healthy weight. A deeper understanding of food addiction and its neurobiological mechanisms will provide accurate targets for intervening in food addiction to improve obesity. Food addiction is characterized by compulsive, chronic and repetitive nature. The Yale Food Addiction Scale (YFAS), a scale specifically designed to assess food addiction, was developed in 2009 by modeling all the DSM-IV for substance dependence to be applicable to eating behavior. In 2016, Gearhardt developed the Yale Food Addiction Scale 2.0, which contains 35 survey questions, to align the YFAS scale with the diagnostic criteria for addictive disorders in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders. One of the most valid and used animal models for food addiction is the mouse food self-administration model. The mouse food self-administration model was modified according to the rat cocaine addiction model, and the food addiction status of the animals was evaluated based on three behaviors: persistence of feeding response, feeding motivation, and compulsive feeding. Studies have shown that the neural circuits of the lateral hypothalamus-ventral tegmental area-nucleus accumbens and ventral tegmental area-prelimbic-nucleus accumbens are key neurobiological mechanisms that regulate food addiction. Dopaminergic neurons in the ventral tegmental area project to the nucleus accumbens (NAc) to facilitate food reinforcement, food reward, and food addiction. The corticotropin-releasing factor (CRF) secreted by the hypothalamus may mediate chronic stress-induced VTA-nucleus accumbens reward system dysfunction and promote food addiction in mice. Meanwhile, the nucleus accumbens receives glutamatergic projections from the prelimbic cortex, an integral part of the reward system. Specific inhibition of the PL-NAc neural circuit develops a food addiction-susceptible phenotype in mice. Furthermore, dopaminergic projections from the ventral tegmental area to the prelimbic cortex specifically inhibited the PL-NAc neural circuit to promote a food-addicted phenotype in mice. Additionally, neurotensin-positive neurons in the lateral septum (LSNts) project to the tuberal nucleus (TU) via GABA signaling to suppress hedonic feeding.

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.

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.

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.

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.

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.

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.

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.

Circuit-Specific Control of Blood Pressure by PNMT-Expressing Nucleus Tractus Solitarii Neurons / 神经科学通报·英文版

The nucleus tractus solitarii (NTS) is one of the morphologically and functionally defined centers that engage in the autonomic regulation of cardiovascular activity. Phenotypically-characterized NTS neurons have been implicated in the differential regulation of blood pressure (BP). Here, we investigated whether phenylethanolamine N-methyltransferase (PNMT)-expressing NTS (NTSPNMT) neurons contribute to the control of BP. We demonstrate that photostimulation of NTSPNMT neurons has variable effects on BP. A depressor response was produced during optogenetic stimulation of NTSPNMT neurons projecting to the paraventricular nucleus of the hypothalamus, lateral parabrachial nucleus, and caudal ventrolateral medulla. Conversely, photostimulation of NTSPNMT neurons projecting to the rostral ventrolateral medulla produced a robust pressor response and bradycardia. In addition, genetic ablation of both NTSPNMT neurons and those projecting to the rostral ventrolateral medulla impaired the arterial baroreflex. Overall, we revealed the neuronal phenotype- and circuit-specific mechanisms underlying the contribution of NTSPNMT neurons to the regulation of BP.

A Neural Circuit Controlling Virgin Female Aggression Induced by Mating-related Cues in Drosophila / 神经科学通报·英文版

Females increase aggression for mating opportunities and for acquiring reproductive resources. Although the close relationship between female aggression and mating status is widely appreciated, whether and how female aggression is regulated by mating-related cues remains poorly understood. Here we report an interesting observation that Drosophila virgin females initiate high-frequency attacks toward mated females. We identify 11-cis-vaccenyl acetate (cVA), a male-derived pheromone transferred to females during mating, which promotes virgin female aggression. We subsequently reveal a cVA-responsive neural circuit consisting of four orders of neurons, including Or67d, DA1, aSP-g, and pC1 neurons, that mediate cVA-induced virgin female aggression. We also determine that aSP-g neurons release acetylcholine (ACh) to excite pC1 neurons via the nicotinic ACh receptor nAChRα7. Together, beyond revealing cVA as a mating-related inducer of virgin female aggression, our results identify a neural circuit linking the chemosensory perception of mating-related cues to aggressive behavior in Drosophila females.

Genetic Approaches for Neural Circuits Dissection in Non-human Primates / 神经科学通报·英文版

Genetic tools, which can be used for the morphology study of specific neurons, pathway-selective connectome mapping, neuronal activity monitoring, and manipulation with a spatiotemporal resolution, have been widely applied to the understanding of complex neural circuit formation, interactions, and functions in rodents. Recently, similar genetic approaches have been tried in non-human primates (NHPs) in neuroscience studies for dissecting the neural circuits involved in sophisticated behaviors and clinical brain disorders, although they are still very preliminary. In this review, we introduce the progress made in the development and application of genetic tools for brain studies on NHPs. We also discuss the advantages and limitations of each approach and provide a perspective for using genetic tools to study the neural circuits of NHPs.

Neural Mechanisms Underlying the Coughing Reflex / 神经科学通报·英文版

Breathing is an intrinsic natural behavior and physiological process that maintains life. The rhythmic exchange of gases regulates the delicate balance of chemical constituents within an organism throughout its lifespan. However, chronic airway diseases, including asthma and chronic obstructive pulmonary disease, affect millions of people worldwide. Pathological airway conditions can disrupt respiration, causing asphyxia, cardiac arrest, and potential death. The innervation of the respiratory tract and the action of the immune system confer robust airway surveillance and protection against environmental irritants and pathogens. However, aberrant activation of the immune system or sensitization of the nervous system can contribute to the development of autoimmune airway disorders. Transient receptor potential ion channels and voltage-gated Na+ channels play critical roles in sensing noxious stimuli within the respiratory tract and interacting with the immune system to generate neurogenic inflammation and airway hypersensitivity. Although recent studies have revealed the involvement of nociceptor neurons in airway diseases, the further neural circuitry underlying airway protection remains elusive. Unraveling the mechanism underpinning neural circuit regulation in the airway may provide precise therapeutic strategies and valuable insights into the management of airway diseases.

Role of frontal lobe and its related circuits involved in cognitive flexibility impairment in autism / 中华行为医学与脑科学杂志

Autism spectrum disorder (ASD) is a multifactorial disease, with social difficulties and repetitive behaviors as its core symptoms. With the improvement of diagnostic methods, the detection rate of ASD is increasing year by year.Cognitive flexibility impairment is very obvious in most autistic patients.More and more studies have shown that cognitive flexibility impairment is related to the occurrence and development of core symptoms. However, the mechanism of cognitive flexibility impairment in autism remains unclear. The frontal lobe plays an important role in advanced cognition, and its complete development is related to cognitive function. Recent studies have shown that frontal lobe dysfunction is closely related to cognitive flexibility deficits in autistic patients, and the abnormal changes in the frontal lobe, the associated default mode network dysfunction and frontal striatal circuit defects may be the important mechanisms of cognitive flexibility impairment. Based on the recent clinical and basic studies on cognitive flexibility in autism, this article reviews the mechanisms of frontal lobe and related circuits involved in the impairment of cognitive flexibility in autism.

Recent advance in anxiety related neural circuits regulating by ventral tegmental area / 中华神经医学杂志

As a common emotional and psychogenic disorder, anxiety disorder seriously threats the human physical and mental health. Ventral tegmental area (VTA) is the canter of the mesocortical limbic circuit, with extensive bidirectional connections to forebrain areas, and plays important role in regulating reward, motivation, cognition, and disgust. Besides, VTA is involved in anxiety regulation by forming functional connections with multiple brain regions and connecting external stimulus information and feedback output behaviours. This article briefly summarizes the different cell subsets of VTA and its involvement in anxiety-related neural circuits.

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.

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.

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.

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 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.

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.