Biology subjects

Washington, C.

Publications and source records attributed to Washington, C..

5 recordsLinked to original sources

bioRxiv2025

Mapping the projectional architecture of the mouse midbrain dopaminergic system using cell type-specific barcoding

Brain-wide neural circuits are formed by the diverse axonal branching patterns of neurons of different cell types. Here we introduce POINTseq (projections of interest by sequencing), a cell type-specific barcoded connectomics method that uses selective barcoding and sequencing to rapidly map single-cell projections of a cell type of interest for thousands of neurons per animal. POINTseq leverages pseudotyping of Sindbis virus and a specific alphavirus-cellular receptor pair to make Sindbis infections cell type specific. It thus integrates MAPseq-style high-throughput barcoded projection mapping with the established viral-genetic neural circuit analysis toolbox. We validated POINTseq by mapping genetically and projection-defined cell populations in the mouse motor cortex. We then applied POINTseq to midbrain dopaminergic neurons and reconstructed the brain-wide single-cell projections of 5,902 dopaminergic neurons in ventral tegmental area (VTA) and substantia nigra pars compacta (SNc). These neurons cluster into over 25 connectomic cell types, vastly exceeding the known diversity of dopaminergic cells, and form stereotyped projection motifs that may mediate parallel dopamine signaling. This data constitutes the anatomical substrate on which the diverse functions of dopamine in the brain are built. HIGHLIGHTSO_LIWe develop POINTseq, which uses pseudotyped Sindbis virus and cell type-specific expression of a viral receptor for cell type-specific barcoding. C_LIO_LIPOINTseq enables massively multiplexed single-cell projection mapping of cell types of interest. C_LIO_LIWe map the brain-wide projections of 5,902 individual VTA and SNc dopaminergic neurons. C_LIO_LIVTA and SNc dopaminergic neurons form over 25 connectomic cell types. C_LIO_LIProjections are organized into stereotyped motifs that may mediate the distinct functions of dopamine. C_LI

neuroscience↗

bioRxiv2025

MAPseq2: a sensitive and cost-effective barcoded connectomics method

The barcoded connectomics tool MAPseq enables highly multiplexed projection mapping of individual neurons by translating neuroanatomy into a format solvable by DNA sequencing. Here we present MAPseq2, a user-friendly protocol with up to [~]10-fold increased sensitivity compared to the current state of the art and [~]10-fold decreased cost. As MAPseq workflows are used across a range of barcoded connectomics methods, including BARseq, BRICseq, and ConnectID, all improvements in MAPseq2 directly transfer to these technologies.

neuroscience↗

bioRxiv2024

Few-shot Algorithms for Consistent Neural Decoding (FALCON) Benchmark

Intracortical brain-computer interfaces (iBCIs) can restore movement and communication abilities to individuals with paralysis by decoding their intended behavior from neural activity recorded with an implanted device. While this activity yields high-performance decoding over short timescales, neural data are often nonstationary, which can lead to decoder failure if not accounted for. To maintain performance, users must frequently recalibrate decoders, which requires the arduous collection of new neural and behavioral data. Aiming to reduce this burden, several approaches have been developed that either limit recalibration data requirements (few-shot approaches) or eliminate explicit recalibration entirely (zero-shot approaches). However, progress is limited by a lack of standardized datasets and comparison metrics, causing methods to be compared in an ad hoc manner. Here we introduce the FALCON benchmark suite (Few-shot Algorithms for COnsistent Neural decoding) to standardize evaluation of iBCI robustness. FALCON curates five datasets of neural and behavioral data that span movement and communication tasks to focus on behaviors of interest to modern-day iBCIs. Each dataset includes calibration data, optional few-shot recalibration data, and private evaluation data. We implement a flexible evaluation platform which only requires user-submitted code to return behavioral predictions on unseen data. We also seed the benchmark by applying baseline methods spanning several classes of possible approaches. FALCON aims to provide rigorous selection criteria for robust iBCI decoders, easing their translation to real-world devices. https://snel-repo.github.io/falcon/

neuroscience↗

bioRxiv2023

Vasopressin regulates social play behavior in sex-specific ways through glutamate modulation in the lateral septum

Social play is a highly rewarding behavior that is essential for the development of social skills. Social play is impaired in children diagnosed with autism, a disorder with a strong sex bias in prevalence. We recently showed that the arginine vasopressin (AVP) system in the lateral septum (LS) regulates social play behavior sex-specifically in juvenile rats: Administration of a AVP 1a receptor (V1aR) antagonist increased social play behavior in males and decreased it in females. Here, we demonstrate that glutamate, but not GABA, is involved in the sex-specific regulation of social play by the LS-AVP system. First, males show higher extracellular glutamate concentrations in the LS than females while they show similar extracellular GABA concentrations. This resulted in a baseline sex difference in excitatory/inhibitory balance, which was eliminated by V1aR antagonist administration into the LS: V1aR antagonist increased extracellular glutamate release in females but not in males. Second, administration of the glutamate receptor agonist L-glutamic acid into the LS prevented the V1aR antagonist-induced increase in social play behavior in males while mimicking the V1aR antagonist-induced decrease in social play behavior in females. Third, administration of the glutamate receptor antagonists AP-5 and CNQX into the LS prevented the V1aR antagonist-induced decrease in social play behavior in females. Last, both sexes showed increases in extracellular LS-GABA release upon V1aR antagonist administration into the LS and decreases in social play behavior upon administration of the GABA-A receptor agonist muscimol into the LS, suggesting that GABA is not involved in the sex-specific regulation of social play by the LS-AVP system. Finally, to start identifying the cellular mechanism mediating the sex-specific effects of the LS-AVP system on LS-glutamate, we determined the presence of potential sex differences in the type of LS cells expressing V1aR. However, no sex differences were found in the percentage of Avpr1a+ LS cells expressing markers for either GABAergic neurons, somatostatin-expressing neurons, calbindin 1-expressing neurons, or astrocytes. In conclusion, these findings demonstrate that the LS-AVP system regulates social play sex-specifically via differential local glutamatergic neurotransmission in male and female juvenile rats. Further research is required to uncover the underlying cellular mechanism.

neuroscience↗

bioRxiv2020

De novo coding variants in the AGO1 gene cause a neurodevelopmental disorder with intellectual disability

High-impact pathogenic variants in more than 1,000 protein-coding genes cause Mendelian forms of neurodevelopmental disorders (NDD), including the newly reported AGO2 gene. This study describes the molecular and clinical characterization of 28 probands with NDD harboring heterozygous AGO1 coding variants. De novo status was always confirmed when parents were available (26/28). A total of 15 unique variants leading to amino acid changes or deletions were identified: 12 missense variants, two in-frame deletions of one codon, and one canonical splice variant leading to a deletion of two amino acid residues. Some variants were recurrently identified in several unrelated individuals: p.(Phe180del), p.(Leu190Pro), p.(Leu190Arg), p.(Gly199Ser), p.(Val254Ile) and p.(Glu376del). AGO1 encodes the Argonaute 1 protein, which functions in gene-silencing pathways mediated by small non-coding RNAs. Three-dimensional protein structure predictions suggest that these variants might alter the flexibility of the AGO1 linkers domains, which likely would impair its function in mRNA processing. Affected individuals present with intellectual disability of varying severity, as well as speech and motor delay, autistic behavior and additional behavioral manifestations. Our study establishes that de novo coding variants in AGO1 are involved in a novel monogenic form of NDD, highly similar to AGO2 phenotype.

genetics↗