Biology subjects

Fang, W.

Publications and source records attributed to Fang, W..

At least 37 records · Page 2Linked to original sources

bioRxiv2024

GageTracker: a tool for dating gene age by micro- and macro-synteny with high speed and accuracy

With the advent of the Earth Genome Project, an increasing number of species' genomes presents exciting opportunities for exploring genetic and phenotypic diversity in organisms. Determining the origin time of genes facilitates the elucidation of crucial genetic mechanisms underlying significant biological evolutionary questions such as the transition from aquatic to terrestrial life, the emergence of mammals, the origin of humans, as well as the development of species- or lineage-specific traits. However, accurately determining the origin time of these genes in species separated by long evolutionary distances remains a major challenge in bioinformatics as these genes often undergo significant changes in their genome sequences, making it difficult to trace them back to their origin. Here, we proposed a new approach for dating gene age based on the micro- and macro-synteny algorithms. This approach employs the parallel computation of orthologous genome alignments across multiple species. Our method was integrated into the GageTracker (Gene Age Tracker) software, providing a fast and accurate way to trace gene age with minimal user input, available at https://github.com/RiversDong/GageTracker. Benchmarked against the simMammals dataset (Alignathon), GageTracker achieved the same high-quality genome alignments as the optimized LastZ aligner, but improved operation speed by 1.4-7 times. In a separate analysis of 12 Drosophila genomes, GageTracker efficiently assessed the ages of 23,720 genes (including ~13,965 protein-coding genes) in just ~22 hours with default parameters. When comparing with the GenTree database (recognized as the most comprehensive and accurate tool for evaluating gene age), GageTracker achieved an impressive ~94.4% accuracy and ~99% macro consistency in assessing the age of protein-coding genes. Moreover, for the ~5.6% conflicting genes, GageTracker displayed slightly higher support rates than GenTree, as evidenced by data from OrthoDB, FlyBase, and Ensembl ortholog databases. Notably, younger genes identified by GageTracker exhibited a preferential expression pattern in the testis, further reinforcing the reliability of GageTracker in accurately tracing gene age.

bioinformatics↗

bioRxiv2024

Identifying a gene signature of metastatic potential by linking pre-metastatic state to ultimate metastatic fate

Identifying the key molecular pathways that enable metastasis by analyzing the eventual metastatic tumor is challenging because the state of the founder subclone likely changes following metastatic colonization. To address this challenge, we labeled primary mouse pancreatic ductal adenocarcinoma (PDAC) subclones with DNA barcodes to characterize their pre-metastatic state using ATAC-seq and RNA-seq and determine their relative in vivo metastatic potential prospectively. We identified a gene signature separating metastasis-high and metastasis-low subclones orthogonal to the normal-to-PDAC and classical-to-basal axes. The metastasis-high subclones feature activation of IL-1 pathway genes and high NF-{kappa}B and Zeb/Snail family activity and the metastasis-low subclones feature activation of neuroendocrine, motility, and Wnt pathway genes and high CDX2 and HOXA13 activity. In a functional screen, we validated novel mediators of PDAC metastasis in the IL-1 pathway, including the NF-{kappa}B targets Fos and Il23a, and beyond the IL-1 pathway including Myo1b and Tmem40. We scored human PDAC tumors for our signature of metastatic potential from mouse and found that metastases have higher scores than primary tumors. Moreover, primary tumors with higher scores are associated with worse prognosis. We also found that our metastatic potential signature is enriched in other human carcinomas, suggesting that it is conserved across epithelial malignancies. This work establishes a strategy for linking cancer cell state to future behavior, reveals novel functional regulators of PDAC metastasis, and establishes a method for scoring human carcinomas based on metastatic potential.

cancer biology↗

bioRxiv2024

The penetration ring is a novel infection structure formed by the penetration peg for invading plant cell membrane in rice blast fungus

Many fungal pathogens develop specialized infection structures such as appressoria to penetrate plant cells. However, it is not clear whether special structures are formed after cell wall penetration before invading host plasma membrane in hemibiotrophic pathogens. Here, we showed that a penetration ring consisting of Ppe1 secreted proteins is formed after appressorium-mediated cell wall penetration and remained at the base of penetration site after invading plant plasma membrane by the rice blast fungus Magnaporthe oryzae. The same persistent Ppe1 ring is formed after the penetration of neighboring cells by transpressoria. PPE1 is specifically expressed during plant infection and the {Delta}ppe1 mutant is defective in penetration and invasive growth. Blockage of penetration peg formation impedes the development of the Ppe1 ring. Close examinations showed that the penetration ring is formed at the collar of penetration pegs between the plant cell wall and plasma membrane and it is persistent as a fixed ring even after invasive hyphae invaded neighboring cells. Furthermore, Ppe1 is a member of an expanded family of secreted proteins that are unique to fungal pathogens using extreme appressorium turgor for plant penetration. Other members of the Ppe1 family also localize to the penetration ring for anchoring on plasma membrane during plant infection. Taken together, a penetration ring consisting of a family of secreted proteins is formed between plant cell wall and plasma membrane, which may function as a novel physical structure at the interface between the tip of penetration pegs and plant plasma membrane before the differentiation of invasive hyphae. Significance StatementLike many other plant pathogens, the rice blast fungus forms melanized appressoria (specialized infection structures) to penetrate plant cells. In this study, we showed that a penetration ring is formed by penetration pegs after appressorium-mediated penetration of plant cell wall. This ring of secreted proteins is persistent at the point of penetration pegs invading plant plasma membrane to form invasive hyphae. Therefore, after the penetration of plant cell wall, the rice blast fungus forms a penetration ring that consists of a family of secreted proteins unique to pathogens using extreme appressorium turgor for penetration and may function as a physical structure for anchoring onto plant plasma membrane and developing invasive hyphae in penetrated cells.

pathology↗

bioRxiv2024

TAK1-mediated phosphorylation of PLCE1 represses PIP2 hydrolysis to impede esophageal squamous cancer metastasis

TAK1 is a serine/threonine protein kinase that is a key regulator in a wide variety of cellular processes. However, the functions and mechanisms involved in cancer metastasis are still not well understood. Here, we found that TAK1 knockdown promoted esophageal squamous cancer cell (ESCC) migration and invasion, whereas TAK1 overexpression resulted in the opposite outcome. These in vitro findings were recapitulated in vivo in a xenograft metastatic mouse model. Mechanistically, co-immunoprecipitation and mass spectrometry demonstrated that TAK1 interacted with phospholipase C epsilon 1 (PLCE1), and phosphorylated PLCE1 at serine 1060 (S1060). Functional studies revealed that phosphorylation at S1060 in PLCE1 resulted in decreased enzyme activity, leading to the repression of PIP2 hydrolysis. As a result, the degradation products of PIP2 including diacylglycerol (DAG) and inositol IP3 were reduced, which thereby suppressed signal transduction in the axis of PKC/GSK-3{beta}/{beta}-Catenin. Consequently, expression of cancer metastasis-related genes was impeded by TAK1. Overall, our data indicate that TAK1 plays a negative role in ESCC metastasis, which depends on the TAK1 induced phosphorylation of PLCE1 at S1060.

cancer biology↗

bioRxiv2024

SHP2-triggered endothelium activation fuels estradiol-independent endometrial sterile inflammation

Endometrial hyperplasia (EH) is a common gynecological disease primarily driven by excess estrogen. How endometrial sterile inflammation regulates EH remains unclear. First, we found the upregulation of SHP2 in endometrial endothelial cells from patients with EH by scRNA-Seq. SHP2 promoted inflammatory activation of endothelial cells, which promoted macrophage transendothelial migration. Subsequently, IL1{beta} and TNF from macrophages gave a feedforward loop to enhance endothelial cell activation and result in more IGF1 secretion, thereby sustaining sterile endometrial inflammation and facilitating endometrial epithelial cell proliferation even after estradiol withdrawal. Mechanistically, results of bulk RNA-Seq and phosphoproteomic analyses showed that endothelial SHP2 dephosphorylated RIPK1Y380 after estradiol stimulation. This event promoted activator protein 1 (AP-1) activation, instigating inflammation and increased CXCL10, CXCL13, COX2 and IGF1 secretion. Furthermore, targeting SHP2 by SHP099 or endothelial-specific SHP2 deletion alleviated EH progression in mice. Collectively, our findings demonstrate that SHP2 mediates the transition of endothelial activation, from estradiol-driven short inflammation to macrophage-amplified continuous sterile inflammation. Targeting chronic sterile inflammation mediated by endothelial cell activation is a promising strategy for non-hormonal intervention in EH.

molecular biology↗

bioRxiv2023

Tip60-mediated Rheb acetylation links palmitic acid with mTORC1 activation and insulin resistance

Differences in dietary fatty acid saturation impact glucose homeostasis and insulin sensitivity in vertebrates. Excess dietary intake of saturated fatty acids (SFAs) induces glucose intolerance and metabolic disorders. In contrast, unsaturated fatty acids (UFAs) elicit beneficial effects on insulin sensitivity. However, it remains elusive how SFAs and UFAs signal differentially toward insulin signaling to influence glucose homeostasis. Here, using a croaker model, we report that dietary palmitic acid (PA), but not oleic acid or linoleic acid, leads to dysregulation of mTORC1 signaling which provokes systemic insulin resistance and glucose intolerance. Mechanistically, using croaker primary myocytes, mouse C2C12 myotubes and HEK293T cells, we show that PA-induced mTORC1 activation is dependent on mitochondrial fatty acid {beta} oxidation. Notably, PA profoundly elevates acetyl-CoA derived from mitochondrial fatty acid {beta} oxidation which intensifies Tip60-mediated Rheb acetylation. Subsequently, the induction of Rheb acetylation facilitates hyperactivation of mTORC1 which enhances serine phosphorylation of IRS1 and simultaneously inhibits transcription of IRS1 through impeding TFEB nuclear translocation, leading to impairment of insulin signaling. Furthermore, targeted abrogation of acetyl-CoA produced from fatty acid {beta} oxidation or Tip60-mediated Rheb acetylation by pharmacological inhibition and genetic knockdown rescues PA-induced insulin resistance. Collectively, this study reveals a conserved acetylation-dependent mechanistic insight for understanding the link between fatty acids and insulin resistance, which may provide a potential therapeutic avenue to intervene in the development of T2D.

cell biology↗

bioRxiv2023

SPPUSM: An MS/MS spectra merging strategy for improved low-input and single-cell proteome identification

Single and rare cell analysis provides unique insights into the investigation of biological processes and disease progress by resolving the cellular heterogeneity that is masked by bulk measurements. Although many efforts have been made, the techniques used to measure the proteome in trace amounts of samples or in single cells still lag behind those for DNA and RNA due to the inherent non-amplifiable nature of proteins and the sensitivity limitation of current mass spectrometry. Here, we report an MS/MS spectra merging strategy termed SPPUSM (same precursor-produced unidentified spectra merging) for improved low-input and single-cell proteome data analysis. In this method, all the unidentified MS/MS spectra from multiple test files are first extracted. Then, the corresponding MS/MS spectra produced by the same precursor ion from different files are matched according to their precursor mass and retention time (RT) and are merged into one new spectrum. The newly merged spectra with more fragment ions are next searched against the database to increase the MS/MS spectra identification and proteome coverage. Further improvement can be achieved by increasing the number of test files and spectra to be merged. Up to 18.2% improvement in protein identification was achieved for 1 ng HeLa peptides by SPPUSM. Reliability evaluation by the "entrapment database" strategy using merged spectra from human and E. coli revealed a marginal error rate for the proposed method. For application in single cell proteome (SCP) study, identification enhancement of 28%-61% was achieved for proteins for different SCP data. Furthermore, a lower abundance was found for the SPPUSM-identified peptides, indicating its potential for more sensitive low sample input and SCP studies.

molecular biology↗

bioRxiv2023

A Novel Angiogenesis Role of GLP-1(32-36) to Rescue Diabetic Ischemic Lower Limbs via GLP-1R-Dependent Glycolysis

Glucagon-like peptide 1 (GLP-1) improves angiogenesis, but the mechanism remains unclear. To address this question, we conducted a metabolomics analysis in bone marrow-derived endothelial progenitor cells (EPCs) isolated from T1DM mice treated with or without GLP-1(32-36) amide, an end-product of GLP-1. GLP-1(32-36) treatment recovered glycolysis. In addition, GLP-1(32-36) treatment rescued diabetic ischemic lower limbs and EPCs dysfunction by regulating PFKFB3-driven glycolytic flux capacity and mitochondrial dynamics. The effects of GLP-1(32-36) were abolished in mice lacking a functional GLP-1 receptor (Glp1r-/-), which could be partially rescued in EPCs transiently expressing GLP-1R. GLP-1(32-36) treatment activated the eNOS/cGMP/PKG pathway, increased glycolysis, and enhanced EPCs angiogenesis. Taken together, these findings suggest that GLP-1(32-36) could be used as a monotherapy or add-on therapy with existing treatments for DPAD. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=117 SRC="FIGDIR/small/543344v1_ufig1.gif" ALT="Figure 1"> View larger version (50K): org.highwire.dtl.DTLVardef@2559eorg.highwire.dtl.DTLVardef@1430faborg.highwire.dtl.DTLVardef@1b9b188org.highwire.dtl.DTLVardef@36809c_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2023

Regional Gene Expression in the Retina, Optic Nerve Head, and Optic Nerve of Mice with Experimental Glaucoma and Optic Nerve Crush

A major risk factor for glaucomatous optic neuropathy is the level of intraocular pressure (IOP), which can lead to retinal ganglion cell axon injury and cell death. The optic nerve has a rostral unmyelinated portion at the optic nerve head followed by a caudal myelinated region. The unmyelinated region is differentially susceptible to IOP-induced damage in rodent models and in human glaucoma. While several studies have analyzed gene expression changes in the mouse optic nerve following optic nerve injury, few were designed to consider the regional gene expression differences that exist between these distinct areas. We performed bulk RNA-sequencing on the retina and on separately micro-dissected unmyelinated and myelinated optic nerve regions from naive C57BL/6 mice, mice after optic nerve crush, and mice with microbead-induced experimental glaucoma (total = 36). Gene expression patterns in the naive unmyelinated optic nerve showed significant enrichment of the Wnt, Hippo, PI3K-Akt, and transforming growth factor {beta} pathways, as well as extracellular matrix-receptor and cell membrane signaling pathways, compared to the myelinated optic nerve and retina. Gene expression changes induced by both injuries were more extensive in the myelinated optic nerve than the unmyelinated region, and greater after nerve crush than glaucoma. Changes three and fourteen days after injury largely subsided by six weeks. Gene markers of reactive astrocytes did not consistently differ between injury states. Overall, the transcriptomic phenotype of the mouse unmyelinated optic nerve was significantly different from immediately adjacent tissues, likely dominated by expression in astrocytes, whose junctional complexes are inherently important in responding to IOP elevation.

molecular biology↗

bioRxiv2022

Comprehensive integration of single-cell transcriptomic data illuminates the regulatory network architecture of plant cell fate specification

Plant morphogenesis relies on precise gene expression programs at the proper time and position which is orchestrated by transcription factors (TFs) in intricate regulatory networks at a cell-type specific manner. Here we presented a reference single-cell transcriptomic atlas of Arabidopsis seedlings by integration of 40 published scRNA-seq datasets from representative tissues as well as the entire under- and above-ground parts. We identified 34 distinct cell types or states, largely expanding our current view of plant cell compositions. We then mapped the developmental trajectory of root-shoot lineage separation and identified differential gene expression programs that may regulate the cell fate determination of under- and above-ground organs. Lastly, we systematically constructed cell-type specific gene regulatory networks and uncovered key regulators that act in a coordination manner to control cell-type specific gene expression. Taken together, our study not only offers a valuable resource plant cell atlas exploration but also provides molecular insights into gene-regulatory programs that determines organ specify, particularly the differentiation between root and shoot.

bioinformatics↗

bioRxiv2022

DNA methylation of the endothelin receptor B makes blue fish yellow

Natural selection shapes traits during evolution including animal coloration known to be important for concealment and communication and color has been particularly salient in the explosive radiation of cichlid fish species in the rift valley lakes of East Africa. Though selection can produce variation in color via genetic substrates during early development, plasticity in coloration can occur through endocrine, neural and transcriptional cues in response to various environmental stimuli. It is well known that some animals often change color to match their visual ecology. Adult male cichlid fish (Astatotilapia burtoni, Lake Tanganyika) can switch between blue and yellow body colors. Different colors result from the expression of pigment-bearing cells, which differ in density and function between these two color morphs. We show that A. burtoni switches from yellow to blue depending on their visual environment by downregulating endothelin receptor B (EdnRB) mRNA via DNA hypermethylation at a single cytosine residue within its promoter. EdnRB functions in yellow chromatophores to signal the aggregation of yellow pigments, making yellow less visible. Taken together, the regulation of EdnRB through DNA methylation in yellow chromatophores, in part, contributes to pigmentation changes from blue to yellow, depending on visual environment.

genetics↗

bioRxiv2022

The wheat head blight pathogen Fusarium graminearum recruits facultative endohyphal bacteria from the soil, making the fungal-bacterial holobiont nitrogen-fixing and increasing the fungal pathogenicity

In nature, fungal endophytes often have facultative endohyphal bacteria. Can a fungal pathogen such as Fusarium graminearum, pathogenic on wheat, get facultative endohyphal bacteria from soil (FEB) and how does the FEB affect the fungal phenotype? We constructed a growth system/microcosm that allowed a molecularly well-studied F. graminearum isolate, PH-1, to grow through natural soil and then be re-isolated on a gentamicin-containing medium, allowing endohyphal growth of the bacteria while killing eventual bacteria growing on the agar medium. We had labelled the F. graminearum PH-1 with a His1mCherry gene staining the fungal nuclei fluorescent red to confirm re-isolation of the same isolate we sent through the soil. Through qPCR of the 16SrRNA gene in the bacteria using universal primers combined with qPCR of the mCherry gene of DNA from the re-isolated cultures of the Fg-FEB holobionts growing on gentamicin-containing media, it was found that most of the holobiont isolates contained about 10 16SrRNA genes per fungal mCherry gene. The Fg-FEB holobiont isolates were sub-cultured several times, and the FEB content on lab media was stable. Sequencing the 16SrRNA gene from several Fg-FEB holobiont isolates revealed known endophytic bacteria capable of nitrogen fixation. We compared the pathogenicity of one of the Fg-FEB holobionts Fg-S.maltophilia, with the background without FEB and found that it was more pathogenic than without FEB. We could also show that the bacterial 16SrRNA load per fungal His1mCherry gene inside the wheat stayed the same as in culture. Finally, we tested if the Fg-S.maltophilia was capable of nitrogen fixation and could show that it, on a nitrogen-free medium, formed a dense mycelium containing proteins at similar levels as on regular nitrogen-containing media. Our results could indicate that naturally occurring fungal pathogens outside lab conditions might contain facultative endohyphal bacteria, positively affecting their pathogenicity and ecological fitness.

ecology↗

bioRxiv2022

Rab7/Retromer-based endolysosomal trafficking facilitates effector secretion and host invasion in rice blast

Secretion is a fundamental process in all living organisms. Using conventional secretion pathways, many plant pathogens release effectors into the host plants to downregulate immunity and promote infection. However, this does not always constitute the only way that effectors are sorted and tracked to their final destination such as the biotrophic interfacial complex-associated effectors produced by the blast fungus Magnaporthe oryzae. Here, we uncover a novel unconventional route originating from fungal vacuolar membrane to the host interface and plasma membrane. We found that a GFP-MoRab7 labeled vacuole is closely associated with the interface structure throughout M. oryzae invasive growth. Conditional inactivation of MoRab7 impaired the establishment of the biotrophy interface and secretion of Pwl2 effector. To perform the vacuolar trafficking pathway, MoRab7 first recruits the retromer complex to the vacuole membrane, enabling it recognizes a batch of SNARE proteins, including the v-SNARE MoSnc1. Live-cell imaging supports both retromer complex component and MoSnc1 protein labeled vesicles showing the trafficking dynamics toward the interface or plasma membrane, and then fusion with target membranes. Lastly, disruption of the MoRab7/Retromer/MoSnc1-based endolysosomal cascade affects effector secretion and fungal pathogenicity. Taken together, we discovered an unconventional protein and membrane trafficking route starting from the fungal endolysosomes to the M. oryzae-rice interaction interface, and dissect the role of MoRab7/Retromer/MoSnc1 constituent sorting machinery in effector secretion during invasive growth in M. oryzae.

plant biology↗

bioRxiv2022

Quantitative fate mapping: Reconstructing progenitor field dynamics via retrospective lineage barcoding

Natural and induced somatic mutations that accumulate in the genome during development record the phylogenetic relationships of cells; however, whether these lineage barcodes can capture the dynamics of complex progenitor fields remains unclear. Here, we introduce quantitative fate mapping, an approach to simultaneously map the fate and quantify the commitment time, commitment bias, and population size of multiple progenitor groups during development based on a time-scaled phylogeny of their descendants. To reconstruct time-scaled phylogenies from lineage barcodes, we introduce Phylotime, a scalable maximum likelihood clustering approach based on a generalizable barcoding mutagenesis model. We validate these approaches using realistically-simulated barcoding results as well as experimental results from a barcoding stem cell line. We further establish criteria for the minimum number of cells that must be analyzed for robust quantitative fate mapping. Overall, this work demonstrates how lineage barcodes, natural or synthetic, can be used to obtain quantitative fate maps, thus enabling analysis of progenitor dynamics long after embryonic development in any organism.

developmental biology↗

bioRxiv2022

A reference single-cell regulomic and transcriptomic map of cynomolgus monkeys

Non-human primates (NHP) are attractive laboratory animal models that accurately reflect both developmental and pathological features of humans. Here we present a compendium of cell types from the cynomolgus monkey Macaca fascicularis (denoted as Monkey Atlas) using both single-cell chromatin accessibility (scATAC-seq) and RNA sequencing (scRNA-seq) data at the organism-wide level. The integrated cell map enables in-depth dissection and comparison of molecular dynamics, cell-type composition and cellular heterogeneity across multiple tissues and organs. Using single-cell transcriptomic data, we inferred pseudotime cell trajectories and cell-cell communications to uncover key molecular signatures underlying their cellular processes. Furthermore, we identified various cell-specific cis-regulatory elements and constructed organ-specific gene regulatory networks at the single-cell level. Finally, we performed a comparative analysis of single-cell landscapes among mouse, cynomolgus monkey and human, and we showed that cynomolgus monkey has significantly higher degree of cell-type similarity to human than mouse. Taken together, our study provides a valuable resource for NHP cell biology.

bioinformatics↗

bioRxiv2022

High-Throughput Screening for Myelination Promoting Compounds Using Human Stem Cell-derived Oligodendrocyte Progenitor Cells Identifies Novel Targets

Promoting myelination capacity of endogenous oligodendrocyte precursor cells (OPCs) is a promising therapeutic approach for central nervous system demyelinating disorders such as Multiple Sclerosis (MS). To aid in the discovery of myelination promoting compounds, we generated an advanced, genome engineered, human pluripotent stem cell (hPSC) line that consist of three reporters (identification-and-purification tag, GFP, and secreted NanoLuc) driven by the endogenous PDGFR, PLP1 and MBP genes, respectively. Based upon this line, we established a high-throughput drug screening platform and performed a small molecule screen with 2500 bioactive molecules. In addition to a number of previously known pathways, our screening effort identified new pathways whose inhibition enhance oligodendrocyte maturation and myelination. Although further genetic and molecular validation is required, the identified inhibitors could potentially be repurposed to develop remyelination therapy for MS and other demyelinating disorders.

neuroscience↗

bioRxiv2021

The first sheep graph pan-genome reveals the spectrum of structural variations and their effects on different tail phenotypes

Structural variations (SVs) are a major contributor to genetic diversity and phenotypic variations, but their prevalence and functions in domestic animals are largely unexplored. Here, we assembled 26 haplotype-resolved genome assemblies from 13 genetically diverse sheep using PacBio HiFi sequencing. We constructed a graph-based ovine pan-genome and discovered 142,422 biallelic insertions and deletions, 7,028 divergent alleles and 13,419 multiallelic variations. We then used a graph-based approach to genotype the biallelic SVs in 684 individuals from 45 domestic breeds and two wild species. Integration with RNA-seq data allows to identify candidate expression-associated SVs. We demonstrate a direct link of SVs and phenotypes by localizing the putative causative insertion in HOXB13 gene responsible for the long-tail trait and identifying multiple large SVs associated with the fat-tail. Beyond generating a benchmark resource for ovine structural variants, our study highlights that animal genetic research will greatly benefit from using a pan-genome graph rather than a single reference genome.

genomics↗

bioRxiv2021

Neural dynamics of causal inference in the macaque frontoparietal circuit

Natural perception relies inherently on inferring causal structure in the environment. However, the neural mechanisms and functional circuits that are essential for representing and updating the hidden causal structure and corresponding sensory representations during multisensory processing are unknown. To address this, monkeys were trained to infer the probability of a potential common source from visual and proprioceptive signals on the basis of their spatial disparity in a virtual reality system. The proprioceptive drift reported by monkeys demonstrated that they combined historical information and current multisensory signals to estimate the hidden common source and subsequently updated both the causal structure and sensory representation. Single-unit recordings in premotor and parietal cortices revealed that neural activity in premotor cortex represents the core computation of causal inference, characterizing the estimation and update of the likelihood of integrating multiple sensory inputs at a trial-by-trial level. In response to signals from premotor cortex, neural activity in parietal cortex also represents the causal structure and further dynamically updates the sensory representation to maintain consistency with the causal inference structure. Thus, our results indicate how premotor cortex integrates historical information and sensory inputs to infer hidden variables and selectively updates sensory representations in parietal cortex to support behavior. This dynamic loop of frontal-parietal interactions in the causal inference framework may provide the neural mechanism to answer long-standing questions regarding how neural circuits represent hidden structures for body-awareness and agency.

neuroscience↗