GABAergic Neurons Research Articles

Infralimbic prefrontal cortical projections to the autonomic brainstem: quantification of inputs to cholinergic and adrenergic/noradrenergic nuclei.

The ventromedial prefrontal cortex regulates both emotional and physiological processes. The infralimbic cortex (IL), a prefrontal subregion in rodents, integrates behavioral, neuroendocrine, and autonomic responses to stress. However, the organization of cortical inputs to brainstem nuclei that regulate homeostatic responses are not well defined. We hypothesized that IL projections differentially target pre-ganglionic parasympathetic neurons and adrenergic/noradrenergic nuclei. To quantify IL projections to autonomic brainstem nuclei in male rats, we utilized viral-mediated gene transfer to express yellow fluorescent protein (YFP) in IL glutamatergic neurons. YFP-positive projections to cholinergic and adrenergic/noradrenergic nuclei were then imaged and quantified. Our results indicate that IL glutamate neurons innervated the cholinergic dorsal motor nucleus of the vagus, with low projection density in the nucleus ambiguus. Furthermore, numerous DBH-positive cell groups received IL inputs. The greatest density was to the C2 and A2 regions of the nucleus of the solitary tract with intermediate levels of input to A6 locus coeruleus and throughout the C1 and A1 regions of the ventrolateral medulla. Minimal input was present in the pontine A5. Additionally, IL projections targeted the local GABAergic neurons that regulate activity within preautonomic nuclei. Collectively, our results indicate that IL pyramidal neurons project to vagal preganglionic parasympathetic neurons, presympathetic neurons of the ventrolateral medulla, as well as diffuse homeostatic modulators the nucleus of the solitary tract and locus coeruleus. Ultimately, these findings provide a roadmap for determining circuit-level mechanisms for neural control of homeostasis and autonomic balance.

High-Throughput Neurotoxicity Study of Neonicotinoids in C. elegans: Oxidative Stress and Serotonergic Neuronal Damage as Key Mechanisms.

High-Throughput Neurotoxicity Study of Neonicotinoids in C. elegans: Oxidative Stress and Serotonergic Neuronal Damage as Key Mechanisms.

Temporal control of progenitor competence shapes maturation in GABAergic neuron development in mice.

Diverse types of GABAergic projection neuron and interneurons of the telencephalon derive from progenitors in a ventral germinal zone called the ganglionic eminence. Using single-cell transcriptomics, chromatin accessibility profiling, lineage tracing, birthdating, transplantation across developmental stages and perturbation sequencing in mouse embryos, we investigated how progenitor competence influences the maturation and differentiation of these neurons. We found that the temporal progression of neurogenesis shapes maturation competence in ganglionic eminence progenitors, influencing how their progeny progress toward mature states. By contrast, differentiation competence-defined as the ability of progenitors to produce diverse transcriptomic identities-was maintained throughout neurogenesis. Chromatin remodeling, together with a regulatory module composed of the transcription factor NFIB and its target genes, influenced maturation competence in late-born neurons. These findings reveal how transcriptional programs and chromatin accessibility govern neuronal maturation and the diversification of GABAergic neuron subtypes during neurodevelopment.

Dynamic convergence of neurodevelopmental disorder risk genes across neurodevelopment

ABSTRACTOver three hundred and seventy-three risk genes, broadly enriched for roles in neuronal communication and gene expression regulation, underlie risk for autism spectrum disorder (ASD) and developmental delay (DD). Functional genomic studies of subsets of these genes consistently indicate a convergent role in neurogenesis, but how these diverse risk genes converge on a smaller number of biological pathways in mature neurons is unclear. To uncover shared downstream impacts between neurodevelopmental disorder (NDD) risk genes, here we apply a pooled CRISPR approach to contrast the transcriptomic impacts of targeting 29 NDD loss-of-function genes across human induced pluripotent stem cell (hiPSC)-derived neural progenitor cells, glutamatergic neurons, and GABAergic neurons. Points of convergence vary between the cell types of the brain and are greatest in mature glutamatergic neurons, where they broadly target not just synaptic and epigenetic, but unexpectedly, mitochondrial biology. The strongest convergent networks occur between NDD genes with common co-expression patterns in the post-mortem brain, biological annotations, and clinical associations, suggesting that convergence may one-day inform patient stratification and treatment. Towards this, ten out of eleven drugs tested that were predicted to reverse convergent signatures in human cells and/or arousal and sensory processing behaviors in zebrafish ameliorated at least one behavioral phenotypein vivo. Altogether, robust convergence in post-mitotic neurons represents a clinically actionable therapeutic window.

Orexinergic projections to substantia innominata mediate arousal and analgesia.

Orexinergic projections to substantia innominata mediate arousal and analgesia.

Self-supervised learning analysis of multi-FISH labeled cell-type map in thick brain slices

IntroductionAccurate mapping of the spatial distribution of diverse cell types is essential for understanding the cellular organization of brain. However, the cellular heterogeneity and the substantial cost of manual annotation of cells in volumetric images hinder existing neural networks from achieving high-precision segmentation of multiple cell-types within a unified framework.MethodsTo address this challenge, we introduce a self-supervised learning framework, Voxelwise U-shaped Swin-Mamba network (VUSMamba), for automatic segmentation of multiple neuronal populations in 300 μm thick brain slices. VUSMamba employs contrastive learning and pretext tasks for self-supervised learning on unlabeled data, followed by fine-tuning with minimal annotations. As a proof of concept, we applied the framework to a multi-cell-type dataset obtained using multiplexed fluorescence in situ hybridization (multi-FISH) combined with high-speed volumetric microscopy VISoR.ResultsCompared to state-of-the-art baseline models, VUSMamba achieves higher segmentation accuracy with reduced computational cost. The framework enables simultaneous high-precision segmentation of glutamatergic neurons, GABAergic neurons, and nuclei.DiscussionThis work presents a unified self-supervised neural network framework that offers a standardized pipeline for constructing and analyzing whole-brain cell-type atlases.

Genome-wide analysis reveals pathways important for the development and maturation of excitatory synaptic connections to GABAergic neurons.

A high degree of cell and circuit-specific regulation has presented challenges for efforts to precisely define molecular mechanisms controlling synapse formation and maturation. Here, we pursue an unbiased forward genetic approach to identify C. elegans genes involved in the formation and maturation of cholinergic synaptic connections with GABAergic motor neurons as indicated by the distribution of GFP-tagged postsynaptic AChRs in GABAergic dendrites. We identified mutations in 3 genes that identify key processes in synapse/circuit maturation: postsynaptic receptor assembly, cargo trafficking, and synapse structural organization. Mutation of the RUN domain (RPIP8, UNC-14, and NESCA) cargo adaptor unc-14 dramatically impacted both dendritic spines and overall GABAergic neuron morphology. In contrast, mutation of the nicotinic acetylcholine alpha subunit unc-63 caused a failure in AChR assembly in GABAergic neurons but did not significantly alter dendritic spine structure or abundance. Notably, specific expression of wild type unc-14 cDNA in either GABAergic neurons or presynaptic cholinergic neurons was not sufficient to rescue the unc-14 mutant phenotype while pan neuronal expression provided significant rescue, indicating that disruptions in GABAergic neuron morphology arise from compound effects. Finally, we obtained a mutation in the Liprin-α; synaptic scaffold syd-2 that produces a stop codon in a C-terminal SAM domain and has severe effects on dendritic spines and AChR localization. Our unbiased strategy identified key genes that implicate three distinct cellular processes important for synapse/circuit development and maturation. The identification of these genes from our screen highlights how mechanisms for receptor assembly, cargo trafficking and synapse structural organization each contribute to circuit connectivity.

Multimodal sensory overload in dopamine-deficient larval zebrafish leads to paradoxical kinesia.

Paradoxical kinesia-the temporary alleviation of motor deficits by powerful, urgent stimuli in Parkinson's disease (PD)-remains poorly understood at the neural circuit level. Through chemo-genetic ablation of tyrosine hydroxylase-expressing neurons in larval zebrafish and brain-wide calcium imaging under head-fixed, tail-free conditions, we uncovered a neural mechanism underlying this phenomenon. While catecholamine (CA)-deficient larvae exhibited severe locomotor deficits during free swimming, they showed paradoxical recovery of tail movements during whole-brain neural activity imaging. This locomotor recovery was accompanied by a significantly increased number of active neurons in the midbrain and hindbrain, but with reduced firing rates. Further analyses across 2158 anatomically defined regions allowed us to uncover a subset of regions, genes, and neurotransmitter types. GABAergic neurons were found to primarily account for the hyperactivity in the hindbrain, while glutamatergic neurons accounted for the hyperactivity in the midbrain. Hierarchical clustering of neuronal activity with tail movements revealed distinct motor- and non-motor-associated hyperactive clusters in the hindbrain and midbrain, respectively. We identified the Mesencephalic Locomotor Region (MLR) sandwiched between these domains, with enhanced glutamatergic firing rate and cholinergic activation. Furthermore, we found that Telencephalic corticotropin-releasing factor b (crhb) expressing neurons play a crucial role in mediating stress-response to the tectum, which in turn triggers a cascade of neuronal hyperactivity downstream via MLR. These findings reveal a neural mechanism that links stress-induced sensory processing with motor control systems in the absence of regulatory feedback from catecholaminergic neurons, suggesting a direct, unmodulated pathway that bypasses typical inhibitory controls.

Inter-brain neural dynamics in biological and artificial intelligence systems.

Social interaction can be regarded as a dynamic feedback loop between interacting individuals as they act and react to each other1,2. Here, to understand the neural basis of these interactions, we investigated inter-brain neural dynamics across individuals in both mice and artificial intelligence systems. By measuring activities of molecularly defined neurons in the dorsomedial prefrontal cortex of socially interacting mice, we find that the multi-dimensional neural space within each individual can be partitioned into two distinct subspaces-a shared neural subspace that represents shared neural dynamics across animals and a unique neural subspace that represents activity unique to each animal. Notably, compared with glutamatergic neurons, GABAergic (γ-aminobutyric acid-producing) neurons in the dorsomedial prefrontal cortex contain a considerably larger shared neural subspace, which arises from behaviours of both self and others. We extended this framework to artificial intelligence agents and observed that, as social interactions emerged, so too did shared neural dynamics between interacting agents. Importantly, selectively disrupting the neural components that contribute to shared neural dynamics substantially reduces the agents' social actions. Our findings suggest that shared neural dynamics represent a fundamental and generalizable feature of interacting neural systems present in both biological and artificial agents and highlight the functional significance of shared neural dynamics in driving social interactions.

Downregulation of Mfn2 Contributes to Chronic Postsurgical Pain via Inducing the Pyroptosis of GABAergic Neurons in the Spinal Cord.

Chronic postoperative pain (CPSP) is a significant public health issue due to the complex pathophysiological mechanism. Existing evidence has pointed out that the loss of gamma-aminobutyric acid-ergic (GABAergic) neurons played a critical role in various neuropathic pain models. Previous studies also found that pyroptosis-mediated neuroinflammation was involved in neuropathological pain. However, it remains unclear what the relationship is between pyroptosis and the loss of spinal GABAergic neurons in CPSP. This study aimed to investigate the role and mechanism of GABAergic neuron pyroptosis in CPSP. We used skin/muscle incision and retraction (SMIR) to establish the CPSP model in rats. Mechanical allodynia was assessed using the Von Frey test. Western blotting, quantitative real-time polymerase chain reaction (qRT-PCR), immunofluorescence, biochemical assay, and transmission electron microscope (TEM) were employed to investigate the role and mechanism of GABAergic neuron pyroptosis during CPSP. We observed the pyroptosis of GABAergic neurons in the spinal cord following SMIR. Intrathecal administration of the GSDMD inhibitor decreased the pyroptosis of GABAergic neurons in the spinal cord and reversed SMIR-induced mechanical allodynia. In addition, we found that SMIR induced a significant decrease in the level of Mfn2 in the neurons, accompanied by mitochondrial dysfunction and reactive oxygen species (ROS) accumulation in SMIR rats. Intrathecal injection of the Mfn2 activator reduced mitochondrial dysfunction and ROS, alleviated the pyroptosis of GABAergic neurons in the spinal cord, which alleviated the SMIR-induced mechanical allodynia. Our study demonstrated that downregulation of Mfn2 leads to mitochondrial dysfunction and ROS accumulation, which promotes the pyroptosis of spinal GABAergic neurons and the development of chronic pain.

Multiomics-based analysis of key genes, metabolites and pathways unveils mechanism associated with social rank in Chickens.

Multiomics-based analysis of key genes, metabolites and pathways unveils mechanism associated with social rank in Chickens.

Electroacupuncture alleviates the relapse of behaviors associated with pain sensory memory and pain-related aversive memory by activating MORs and inhibiting GABAergic neurons in the insular cortex.

Electroacupuncture alleviates the relapse of behaviors associated with pain sensory memory and pain-related aversive memory by activating MORs and inhibiting GABAergic neurons in the insular cortex.

Bioprinting spatially guided functional 3D neural circuits with agarose-xanthan gum copolymer hydrogels.

Bioprinting spatially guided functional 3D neural circuits with agarose-xanthan gum copolymer hydrogels.

Partial rescue of schizophrenia-related phenotypes in young adult Sp4 hypomorphic mice.

Partial rescue of schizophrenia-related phenotypes in young adult Sp4 hypomorphic mice.

Control of motor coordination by transient receptor potential melastatin 8 through γ-aminobutyric acidergic circuit modulation in the male mouse cerebellum

Transient receptor potential melastatin 8 (TRPM8) is a non-selective cation channel that is activated by mild cooling and chemical agents. Although TRPM8 is widely expressed in the peripheral and central nervous systems, its cerebellar distribution and functional significance remain unexplored. We investigated the expression and role of TRPM8 in motor function using TRPM8-enhanced green fluorescent protein and TRPM8-deficient (TRPM8KO) mice. TRPM8 immunoreactivity was observed in parvalbumin- and vesicular γ-aminobutyric acid (GABA) transporter-labeled interneurons. TRPM8 was also expressed in hyperpolarization-activated cyclic nucleotide-gated potassium channel 1-labeled inhibitory plexuses that enveloped GABAA receptor-expressing Purkinje cell somata and terminated as pinceau. Next, motor functions were assessed in wild-type and TRPM8KO mice. TRPM8KO mice exhibited abnormal motor coordination in the rotarod test. However, TRPM8 deficiency did not affect body balance in the footprint test or general spontaneous activity in the open field test. To explore the importance of TRPM8 in motor coordination, the TRPM8 antagonist RQ-00203078 or vehicle (control) was intracerebrally or intraperitoneally administered; motor responses were analyzed using the rotarod test. Compared with vehicle, RQ-00203078 significantly reduced the rotarod retention time. Our results suggest that TRPM8 channels on inhibitory GABAergic neurons contribute to motor coordination by modulating synaptic transmission in Purkinje cell–interneuron synapses.

Quantitative and site-specific chemoproteomic profiling of O-GlcNAcylation in Drosophila.

Quantitative and site-specific chemoproteomic profiling of O-GlcNAcylation in Drosophila.

Loss-of-consciousness: sources of GABAergic input to the mesopontine tegmental anesthesia area

Exposure of neurons in the brainstem mesopontine tegmental anesthesia area (MPTA) to minute quantities of GABAergic general anesthetics at clinically relevant concentrations is sufficient to induce loss-of-consciousness (LOC), while lesioning this nucleus renders rodents relatively insensitive to these anesthetics delivered systemically. The MPTA thus appears to be a key GABA-receptive target in brain mechanisms of clinical anesthesia. As lesioning the MPTA also affects natural instances of LOC including sleep and fainting, it is of interest to know the source(s) of endogenous GABA present in the MPTA. Here, we used retrograde tracing combined with immunolabeling to locate GABAergic neurons that provide the MPTA with synaptic input. Sources of glycinergic and glutamatergic input were also explored. Abundant GABAergic neurons with axonal projections to the MPTA were found in: (1) deep laminae of the neocortex rostrally, (2) a mesolimbic field ranging from the basal forebrain to the limbic midbrain, and (3) deep cerebellar nuclei and the rostroventromedial medulla (RVM). All three showed ipsilateral predominance. Only modest numbers of glycinergic input neurons were found, mostly in the hindbrain. Glutamatergic sources of MPTA input were mainly in the cortex, the ventral tegmental area and the RVM. The endogenous modulatory input to the MPTA identified here, particularly the GABAergic input, likely plays a significant role in the various natural circumstances that involve LOC. GABAergic anesthetics, in turn, agents that permit pain-free surgery, appear to act by substituting for endogenous GABA in the MPTA and hence co-opting endogenous GABA-receptive brain circuitry related to consciousness and its loss.

Effects of uniform rocking motion on VLPO regional GABA/Glu contents and sleep in rats

Abstract Recent research has found that rocking promotes sleep in mice, but there is a lack of information on whether rocking also promotes sleep in rats and the neurophysiological mechanisms involved. The purpose of the present experiment was to elucidate the effects of rocking on sleep–wake staging in rats. EEG recordings were made on a platform with a frequency of 1.5 HZ and a displacement of 20 mm for 12 h of rocking and 12 h of stillness in rats, and the proportion of each sleep phase in the 24-h EEG was analyzed. The contents of glutamate and GABA in the VLPO region of rats were measured during shaking. The results showed that at a shaking frequency of 1.5 HZ, the proportion of non-rapid eye movement (REM) sleep increased and wakefulness decreased in the first 12 h of the rats, and there was no significant effect in the last 12 h. In the experiments, GABA levels in the VLPO region of awake rats gradually increased after the onset of uniform rocking exercise and began to decrease after reaching a peak at 20 min. After 40 min, GABA levels leveled off and did not change significantly above 60 min, but had no effect on glutamate levels. These results suggest that 1.5 HZ of rocking promotes NREM sleep and reduces wakefulness in rats, and that rocking may be related to GABAergic neurons in promoting sleep in rats.

An alternative neural basis underlying leptin resistance.

An alternative neural basis underlying leptin resistance.

A hypothalamic circuit for circadian regulation of corticosterone secretion

The secretion of cortisol in humans and corticosterone (Cort) in rodents follows a daily rhythm which is important in readying the individual for daily activity. This rhythm is orchestrated by the suprachiasmatic nucleus (SCN), but how it ultimately regulates the circadian rhythm of activity of neurons in the paraventricular nucleus of the hypothalamus that produce corticotropin-releasing hormone (PVHCRH neurons) is not known. We hypothesized that the SCN may exert this influence by projections to the subparaventricular zone (SPZ), which in turn innervates neurons in the dorsomedial nucleus of the hypothalamus (DMH) that regulate PVHCRH neurons. First, we found that ablating SPZVgat neurons eliminates the circadian rhythm of Cort secretion, but that deleting Vgat from them does not, suggesting that they predominantly use some other transmitter. Next, we found that either ablating or acutely inhibiting the DMH glutamatergic (DMHVglut2) neurons resulted in a 40–70% reduction in the daily peak of Cort. Deletion of the Vglut2 gene within the DMH produced a similar effect, highlighting the indispensable role of glutamatergic signaling. Chemogenetic stimulation of DMHVglut2 neurons led to an increase of Cort levels, and optogenetic activation of their terminals in the PVH in hypothalamic slices directly activated PVHCRH neurons through glutamate action on AMPA receptors (the DMHVglut2 → PVHCRH pathway). Similar to the disruption of DMHVglut2 neurons, ablating, inhibiting, or disrupting GABA transmission by DMH GABAergic (DMHVgat) neurons diminished the circadian peak of Cort, particularly under constant darkness conditions. Chemogenetic stimulation of rostral DMHVgat neurons increased Cort, although with a lower magnitude compared to DMHVglut2 neuron stimulation, suggesting a role in disinhibiting PVHCRH neurons. Supporting this hypothesis, we found that rostral DMHVgat neurons project directly to GABAergic neurons in the caudal ventral part of the PVH and adjacent peri-PVH area (cvPVH), which directly inhibit PVHCRH neurons, and that activating the rostral DMHVgat terminals in the cvPVH in brain slices reduced GABAergic afferent input onto the PVHCRH neurons. Finally, ablation of cvPVHVgat neurons resulted in increased Cort release at the onset of the active phase, affirming the pivotal role of the DMHVgat → cvPVHVgat → PVHCRH pathway in Cort secretion. In summary, our study delineates two parallel pathways transmitting temporal information to PVHCRH neurons, collectively orchestrating the daily surge in Cort in anticipation of the active phase. These findings are crucial to understand the neural circuits regulating Cort secretion, shedding light on the mechanisms governing this physiological process and the coordinated interplay between the SCN, SPZ, DMH, and PVH.