Multimodal analysis reveals cellular diversity and divergent circuits of the zona incerta
Ontology highlight
ABSTRACT: The zona incerta (ZI) plays an important role in diverse behavioral functions and is an emerging clinical target for deep brain stimulation to treat neurological conditions. Despite their importance, the cell type composition of the ZI and the anatomical circuit organization linking specific ZI cell types to brain-wide circuits remain unclear. In this study, we used single-nucleus RNA-sequencing, spatial RNA profiling, ex vivo electrophysiology, and anatomical circuit mapping to generate a multimodal cellular atlas of the ZI and to characterize the brain-wide monosynaptic inputs to specific ZI cell types. We define four genetically distinct populations of ZI GABAergic neurons that display unique spatial distributions, specialized intrinsic electrophysiological properties, divergent efferent projections, and cell-type dependent synaptic input patterns. Finally, using fiber photometry we reveal response divergence between distinct ZI cell types in a novel behavioral assay that centers around approach-avoid conflict produced by innately appetitive and aversive stimuli. This study thus provides a foundational resource for the design and interpretation of future experiments aimed at understanding the organization and function of the ZI.
Project description:The lateral habenula (LHb) is an epithalamic brain structure critical for processing and adapting to negative action outcomes. However, despite the importance of LHb to behavior and the clear anatomical and molecular diversity of LHb neurons, the neuron types of the habenula remain unknown. Here, we use high-throughput single-cell transcriptional profiling, monosynaptic retrograde tracing, and multiplexed FISH to characterize the cells of the mouse habenula. We find five subtypes of neurons in the medial habenula (MHb) that are organized into anatomical subregions. In the LHb, we describe four neuronal subtypes and show that they differentially target dopaminergic and GABAergic cells in the ventral tegmental area (VTA). These data provide a valuable resource for future study of habenular function and dysfunction and demonstrate neuronal subtype specificity in the LHb-VTA circuit.
Project description:The dorsal raphe nucleus (DRN) is an important source of neuromodulators and has been implicated in a wide variety of behavioral and neurological disorders. The DRN is subdivided into distinct anatomical subregions comprised of multiple cell types, and its complex cellular organization has impeded efforts to investigate the distinct circuit and behavioral functions of its subdomains. Here we used single-cell RNA sequencing, in situ hybridization, anatomical tracing, and spatial correlation analysis to map the transcriptional and spatial profiles of cells from the mouse DRN. Our analysis of 39,411 single-cell transcriptomes revealed at least 18 distinct neuron subtypes and 5 serotonergic neuron subtypes with distinct molecular and anatomical properties, including a serotonergic neuron subtype that preferentially innervates the basal ganglia. Our study lays out the molecular organization of distinct serotonergic and non-serotonergic subsystems, and will facilitate the design of strategies for further dissection the DRN and its diverse functions.
Project description:The complex functions of the neocortex rely on networks of interconnected excitatory and inhibitory interneurons, each of which are composed of multiple neuron types. Prior studies have established rules of local connectivity between major subclasses of inhibitory and excitatory cortical neurons, but the advent of single-cell transcriptomic technologies has revealed a remarkable diversity in transcriptomic neuronal subtypes. Is there specificity of synaptic connections between cortical neurons classified at the level of transcriptomic subtypes, as might be expected if the different types mediate different functions? Here we present a novel method that links transcriptomic cell type to anatomical connectivity, “Single Transcriptome Assisted Rabies Tracing” (START). START combines monosynaptic rabies tracing and single-nuclei RNA sequencing (snRNA-seq) to identify the transcriptomic cell types providing monosynaptic inputs to defined populations of neurons. We employed START in conjunction with Cre driver mouse lines to transcriptomically characterize 35,717 neurons providing monosynaptic input to 5 different layer-specific excitatory cortical neuron populations in mouse V1. At the subclass level, we observed results consistent with findings from prior studies that resolve neuronal subclasses using antibody staining, Cre-expressing mouse lines, or morphological characterization. With improved neuronal subtype granularity achieved with START, we demonstrate transcriptomic subtype specificity of inhibitory inputs to various subclasses of excitatory neurons. These results establish local connectivity rules at the resolution of transcriptomic inhibitory cell types.
Project description:The striatum is the interface between dopamine reward signals and cortico-basal ganglia circuits that mediate diverse behavioral functions. Medium spiny neurons (MSNs) constitute the vast majority of striatal neurons and are traditionally classified as direct- or indirect-pathway neurons. However, that traditional model does not explain the anatomical and functional diversity of MSNs. Here, we defined molecularly distinct MSN types in the primate striatum, including (1) dorsal striatum MSN types associated with striosome and matrix compartments, (2) ventral striatum types associated with the nucleus accumbens shell and olfactory tubercle, and (3) an MSN-like type restricted to mu-opioid receptor rich islands in the ventral striatum. These results lay the foundation for achieving cell type-specific transgenesis in the primate striatum and provide a blueprint for investigating circuit-specific processing.
Project description:The hypothalamic suprachiasmatic (SCN) clock contains several neurochemically defined cell groups that contribute to the genesis of circadian rhythms. Using cell specific and genetically-targeted approaches we have confirmed an indispensable role for vasoactive intestinal polypeptide expressing SCN (SCNVIP) neurons in generating the mammalian locomotor activity (LMA) circadian rhythm. Optogenetic-assisted circuit mapping revealed functional, di-synaptic connectivity between SCNVIP neurons and dorsomedial hypothalamic neurons, providing a circuit substrate by which SCNVIP neurons may regulate LMA rhythms. In vivo photometry revealed that while SCNVIP neurons are acutely responsive to light, their activity is otherwise behavioral state invariant. Single-nuclei RNA-sequencing revealed SCNVIP neurons comprise two transcriptionally distinct subtypes, including putative pacemaker and non-pacemaker populations. Given that SCNVIP neurons constitute ~10% of the total SCN population, and that other cell groups were unable to sustain coherent circadian LMA rhythms following SCNVIP disruption, our findings demonstrate a disproportionately large influence of the SCNVIP cell population on pacemaker function.
Project description:As the primary source of norepinephrine (NE) in the brain, the locus coeruleus (LC) regulates both arousal and stress responses, but how neuromodulatory inputs contribute to LC modulation remains incompletely understood. In this study, we isolated a network of transcriptionally diverse inhibitory pericoerulear (peri-LC) GABAergic neurons that integrate distant stimuli and modulate modes of LC firing. To define the peri-LC anatomy, we used viral tracing, single-nuclei and high-resolution spatial RNA transcriptomics to molecularly characterize both LC and peri-LC cell types. We complemented this approach with techniques in electrophysiology, photometry, optogenetics, and chemogenetics to probe the function of peri-LC neurons in behaving mice. These findings indicate that LC and peri-LC neurons comprise transcriptionally heterogenous neuronal groups which integrate diverse inputs to influence behavioral arousal states and avoidance. We used snRNAseq to characterize the peri-LC and LC brain regions. Our dataset contains 30,838 cells, of which 12,278 are neurons.
Project description:Whilst reward pathologies e.g., anhedonia and apathy, are major and common in stress-related neuropsychiatric disorders, their neurobiological bases and therefore treatment are poorly understood. Functional imaging studies in humans with reward pathology indicate that attenuated BOLD activity in nucleus accumbens (NAc) occurs during reward anticipation/expectancy but not reinforcement; potentially, this is dopamine (DA) related. In mice, chronic social stress (CSS) leads to reduced reward learning and effortful motivation and, here, DA-sensor fibre photometry was used to investigate whether these behavioural deficits co-occur with altered NAc DA activity during reward anticipation and/or reinforcement. In CSS mice relative to controls: (1) Reduced discriminative learning of the sequence, tone-on + appetitive behaviour = tone-on + sucrose reinforcement, co-occurred with attenuated NAc DA activity throughout tone-on and sucrose reinforcement. (2) Reduced effortful motivation during the sequence, operant behaviour = tone-on + sucrose delivery + tone-off / appetitive behaviour = sucrose reinforcement, co-occurred with attenuated NAc DA activity at tone-on and typical activity at sucrose reinforcement. (3) Reduced effortful motivation during the sequence, operant behaviour = appetitive behaviour + sociosexual reinforcement co-occurred with typical NAc DA activity at female reinforcement. Therefore, in CSS mice attenuated NAc DA activity is specific to reward anticipation and as such potentially causal to deficits in learning and motivation. CSS did not impact on the transcriptome of ventral tegmentum DA neurons, suggesting that its stimulus-specific effects on NAc DA activity originate elsewhere in the neural circuitry of reward processing.
2024-07-31 | GSE268460 | GEO
Project description:Brain-wide monosynaptic connectivity mapping with ROInet-seq
Project description:The central amygdala (CEA) is a brain region that consists of primarily GABAergic neurons. It has been widely investigated for its role in many innate and adaptive behaviors, such as appetitive and defensive behaviors. Despite the complex functions of CEA, the molecular diversity of CEA neurons has not been systemically examined. Here, we performed single-cell RNA-sequencing (scRNA-Seq) in the CEA to classify the molecularly defined neuron types in this region.