The interface barrier between the brain surface and the adjacent meninges is important for regulating exchanges of fluid, protein, and immune cells between the CNS and periphery. However, the cell types that form this important interface are not yet fully defined. To address this limitation, we used single-cell RNA sequencing (scRNA-seq) and single-cell spatial transcriptomics together with morphological lineage tracing and immunostaining to describe the cell types forming the interface barrier of the adult murine cortex. We show that the cortical interface is composed of three major cell types, leptomeningeal cells, border astrocytes, and tissue-resident macrophages. On the nonparenchymal side, the interface is composed of transcriptionally distinct PDGFRα-positive leptomeningeal cells that are intermingled with macrophages. This leptomeningeal layer is lined by a population of transcriptionally distinct border astrocytes. The interface neighborhood is rich in growth factor mRNAs, including many leptomeni...

In the article “A Preprocessing Toolbox for 2-Photon Subcellular Calcium Imaging,” by Anqi Jiang, Chong Zhao, and Mark E. J. …

The degeneration of midbrain dopamine (DA) neurons disrupts the neural control of natural behavior, such as walking, posture, and gait in Parkinson's disease. While some aspects of motor symptoms can be managed by DA replacement therapies, others respond poorly. Recent advancements in machine learning-based technologies offer opportunities to better understand the organizing principles of behavior modules at fine timescales and its dependence on dopaminergic modulation. In the present study, we applied the motion sequencing (MoSeq) platform to study the spontaneous locomotor activities of neurotoxin and genetic mouse models of parkinsonism as the midbrain DA neurons progressively degenerate. We also evaluated the treatment efficacy of levodopa (l-DOPA) on behavioral modules at fine timescales. We revealed robust changes in the kinematics and usage of the behavioral modules that encode spontaneous locomotor activity. Further analysis demonstrates that fast behavioral modules with higher velocities were more...

Interoception and associated subjective states shape adaptive behaviors. In humans, interoceptive information is hierarchically processed in the insular cortex (IC), being integrated first in the posterior IC (PIC) and then processed in the anterior IC (AIC) to generate subjective states. However, it has not been established whether this is the case in other species nor whether utilization of interoceptive states to guide behavior is also specifically associated with functional engagement of the AIC, as suggested by this hierarchical model. We investigated in male Sprague Dawley rats whether the use of pharmacologically induced internal states to guide instrumental behavior in a discrimination task functionally engages the AIC as opposed to the mere experience of such states. Rats trained to use the interoceptive state produced by the centrally acting GABAA receptor antagonist pentylenetetrazol (PTZ) or the peripherally acting β-adrenoreceptor agonist isoproterenol to guide their behavior performed as well...

The two main cell types in the striatum, dopamine receptor 1 and adenosine receptor 2a spiny projection neurons (D1-SPNs and A2A-SPNs), have distinct roles in regulating motor- and reward-related behaviors. Cre-selective CRISPR-dCas9 systems allow for cell-type specific, epigenomic-based manipulation of gene expression with gene-specific single guide RNAs (sgRNAs) and have potential to elucidate molecular mechanisms underlying striatal subtype mediated behaviors. Conditional transgenic Rosa26:LSL-dCas9-p300 mice were recently generated to allow for robust expression of dCas9-p300 expression with Cre-driven cell-type specificity. This system utilizes p300, a histone acetyltransferase which regulates gene expression by unwinding chromatin and making that region of the genome more accessible for transcription. Rosa26-LSL-dCas9-p300 mice were paired with Drd1-Cre and Ador2a-Cre mice to generate Drd1-Cre:dCas9-p300 and Ador2a-Cre:dCas9-p300 mouse lines and underwent behavioral phenotyping when sgRNAs were not p...

Autonomic imbalance—particularly reduced activity from brainstem parasympathetic cardiac vagal neurons (CVNs)—is a major characteristic of many cardiorespiratory diseases. Therapeutic approaches to selectively enhance CVN activity have been limited by the lack of defined, translationally relevant targets. Previous studies have identified an important excitatory synaptic pathway from oxytocin (OXT) neurons in the paraventricular nucleus of the hypothalamus to brainstem CVNs, suggesting that OXT could provide a key selective excitation of CVNs. In clinical studies, intranasal OXT has been shown to increase parasympathetic cardiac activity, improve autonomic balance, and reduce obstructive event durations and oxygen desaturations in obstructive sleep apnea patients. However, the mechanisms by which activation of hypothalamic OXT neurons, or intranasal OXT, enhance brainstem parasympathetic cardiac activity remain unclear. CVNs are located in two cholinergic brainstem nuclei: nucleus ambiguus (NA) and dorsal m...

Neurodevelopmental disorders disproportionately affect males compared with females. The biological mechanisms of this male susceptibility or female protection have not been identified. There is evidence that fetal/neonatal gonadal hormones, which play a pivotal role in many aspects of development, may contribute. Here, we investigate the effects of excess testosterone (T) during a critical period of sex-specific brain organization on social approach and fear learning behaviors in C57BL/6J wild-type mice. Male, but not female, mice treated with T on the day of birth (Postnatal Day 0; PN0) exhibited decreased social approach as juveniles and decreased contextual fear memory as adults, compared with vehicle (veh)-treated controls. These deficits were not driven by anxiety-like behavior or changes in locomotion or body weight. Mice treated with the same dose of T on PN18, which is outside of the critical period of brain masculinization, did not demonstrate impairments compared with the veh group. These finding...

The anterior cingulate cortex (ACC) plays a pivotal role in processing pain and emotion, communicating with both cortical and subcortical regions involved in these functions. The claustrum (CLA), a subcortical region with extensive connectivity to the ACC, also plays a critical role in pain perception and consciousness. Both ACC and CLA express Kappa (KOR), Mu (MOR), and Delta (DOR) opioid receptors, yet whether and how opioid receptors modulate this circuit are poorly understood. This study investigates the effects of opioid receptor activation on glutamatergic signaling in CLA→ACC circuitry using spatial transcriptomics, brain slice electrophysiology, optogenetics, and pharmacological approaches in mice of both sexes. Our results demonstrated that excitatory synaptic transmission generated by the CLA onto Layer 5 pyramidal (L5 PYR) cells in the ACC are reduced by KOR, MOR, and DOR agonists. However, only KOR agonists reduce monosynaptic transmission from the CLA onto L5 ACC PYR cells, highlighting the un...

Lipopolysaccharide (LPS) is a bacterial endotoxin that induces innate immune responses. The present study aimed to elucidate alterations in cerebral cortical surface morphology induced by neonatal exposure to LPS using gyrencephalic ferrets. Male ferret pups received a subcutaneous injection of LPS (500 µg/g of body weight) on Postnatal Day (P)6 and P7. Furthermore, EdU and BrdU were administered on P5 and P7, respectively, to label postproliferative and proliferating cells that were exposed to LPS in the late stage of cortical neurogenesis. On P20 when the primary sulci and gyri had formed, MRI-based morphometry revealed an anterior shift in sulcal infolding in the medial and dorsolateral cortices of LPS-exposed ferrets. Immunofluorescence analysis showed that LPS increased the density of BrdU-labeled cells and reduced their apoptosis, as indicated by cleaved caspase-3 (cCasp3) immunostaining, in the outer stratum of the lateral sulcus located on the parietal association cortex. Furthermore, cCasp3 immuno...

Every neuron contains the same genomic information, but its complement of proteins is the product of countless neuron-specific steps including pre-mRNA splicing. Despite advances in RNA sequencing techniques, pre-mRNA splicing biases that favor one isoform over another are largely inscrutable in live neurons in situ. Here, in Drosophila , we developed bichromatic fluorescent reporters to investigate alternative splicing of cacophony ( cac )—a gene that codes the pore-forming α1 subunit of the primary neuronal voltage-gated Ca2+ channel (VGCC). These reporters revealed a neuron-specific pattern of exon biases, highly consistent from one animal to the next, suggesting that each neuron splices a unique and consistent portfolio of VGCC isoforms. Stereotypical patterns were observed within motor neurons and multidendritic sensory neurons of female larvae and also within mushroom body Kenyon cells of female adults. In a validation step, we demonstrated that exon splice bias reporting was not dependent on the cho...