Biology subjects

Liu, W.

Publications and source records attributed to Liu, W..

At least 523 records · Page 29Linked to original sources

bioRxiv2019

Discovery of powdery mildew resistance gene candidates from Aegilops biuncialis chromosome 2Mb based on transcriptome sequencing

Powdery mildew is one of the most widespread diseases of wheat. Breeding resistant varieties by utilization of resistance genes is considered as the most economic and effective method of controlling this disease. Previous study showed that the gene(s) at 2Mb in Chinese Spring (CS)-Aegilops biuncialis 2Mb disomic addition line TA7733 conferred high resistance to powdery mildew. In this study, 15 Bgt isolates prevalent in different regions of China were used to further test the resistance spectrum of TA7733. As a result, TA7733 was high resistance to all tested isolates, indicating that the gene(s) on chromosome 2Mb was broad-spectrum powdery mildew resistance. In order to mine resistance gene candidates and develop 2Mb-specific molecular markers to assist the transfer resistance gene(s) at chromosome 2Mb, RNA-seq of TA7733 and CS was conducted before and after Bgt-infection, generating a total of 158,953 unigenes. Of which, 7,278 unigenes were TA7733-specific which were not expressed in CS, and 295 out of these 7,278 unigenes were annotated as R genes. Based on Blastn against with CS Ref Seq v1.0, 61 R genes were further mapped to homoeologous group 2. Analysis of R gene-specific molecular markers designed from R gene sequences verified 40 out of 61 R genes to be 2Mb specific. Annotation of these 40 R genes showed most genes encoded nucleotide binding leucine rich repeat (NLR) protein, being most likely resistance gene candidates. The broad-spectrum powdery mildew resistance gene(s), disease resistance gene candidates, and functional molecular markers of 2Mb-specific in present study will not only lay foundations for transferring disease resistance gene(s) from 2Mb to common wheat by inducing CS-Ae. biuncialis homoeologous recombination, but also provide useful candidates for isolating and cloning resistance gene(s) and dissecting molecular and genetic mechanisms of disease resistance from 2Mb.

genetics↗

bioRxiv2019

STING recruits NLRP3 to the ER and deubiquitinates NLRP3 to activate the inflammasome

One of the fundamental reactions of the innate immune responses to pathogen infection is the release of pro-inflammatory cytokines, including IL-1{beta}, processed by the NLRP3 inflammasome. STING is essential for innate immune responses and inflammasome activation. Here we reveal a distinct mechanism by which STING regulates the NLRP3 inflammasome activation, IL-1{beta} secretion, and inflammatory responses in human cell lines, mice primary cells, and mice. Interestingly, upon HSV-1 infection and cytosolic DNA stimulation, STING binds to NLRP3 and promotes the inflammasome activation through two approaches. First, STING recruits NLRP3 and promotes NLRP3 translocation to the endoplasmic reticulum, thereby facilitating the inflammasome formation. Second, STING interacts with NLRP3 and removes K48- and K63-linked polyubiquitination of NLRP3, thereby promoting the inflammasome activation. Collectively, we demonstrate that the cGAS-STING-NLRP3 signaling is essential for host defense against DNA virus infection.

immunology↗

bioRxiv2019

Differentiation of Urine-Derived Induced Pluripotent Stem Cells to Neuron, Astrocyte and Microvascular Endothelial Cells from a Diabetic Patient

BackgroundComplications of central nervous system (CNS) in type 2 diabetes mellitus (T2DM) often lead to cognitive impairment and seriously affect the quality of life. However, there is no individualized disease model. Urinary epithelial cells (UECs) can be an ideal source for generating human induced pluripotent stem cells (hiPSCs) and progenitors, as they are easily accessible, non-invasive and universally available. Therefore, we intended to differentiate urine-derived hiPSCs into neuron (N), astrocyte (A) and microvascular endothelial cells (E) from a T2DM patient for future study its pathogenesis and precision medical treatment.\n\nMethods and ResultshiPSCs was successfully induced from UECs using integration free Sendai virus technology in a totally noninvasive manner. It had a normal karyotype (46, XY) and were proved to be pluripotent by immunofluorescence staining, alkaline phosphatase staining, karyotyping, teratoma experiments and methylated analysis. N, A and E were successfully induced and displayed typical morphological characteristics.\n\nConclusionsThis study indicates that N, A, E can be generated from urine-derived hiPSCs. Then we intend to create a new disease model in vitro to simulate the cerebral microenvironment of DM which will provide new methods for further investigate the disease-specific mechanisms.

cell biology↗

bioRxiv2019

Mendelian Randomization Analysis Dissects the Relationship between NAFLD, T2D, and Obesity and Provides Implications to Precision Medicine

BackgroundNon-alcoholic fatty liver disease (NAFLD) is epidemiologically correlated with both type 2 diabetes (T2D) and obesity. However, the causal inter-relationships among the three diseases have not been completely investigated.\n\nAimWe aim to explore the causal relationships among the three diseases.\n\nDesign and methodsWe performed a genome-wide association study (GWAS) on fatty liver disease in [~]400,000 UK BioBank samples. Using this data as well as the largest-to-date publicly available summary-level GWAS data, we performed a two-sample bidirectional Mendelian Randomization (MR) analysis. This analysis tested the causal inter-relationship between NAFLD, T2D, and obesity, as well as the association between genetically driven NAFLD (with two well-established SNPs at the PNPLA3 and TM6SF2 loci) and glycemic and lipidemic traits, respectively. Transgenic mice expressing the human PNPLA3 I148I (TghPNPLA3-I148I) and PNPLA3 I148M (TghPNPLA3-I148M) isoforms were used to further validate the causal effects.\n\nResultsWe found that genetically instrumented hepatic steatosis significantly increased the risk for T2D (OR=1.3, 95% CI: [1.2, 1.4], p=8.3e-14) but not the intermediate glycemic phenotypes at the Bonferroni-adjusted level of significance (p<0.002). There was a moderate, but significant causal association between genetically driven hepatic steatosis and decreased risk for BMI ({beta}=- 0.027 SD, 95%CI: [-0.043, -0.01], p=1.3e-4), but an increased risk for WHRadjBMI (Waist-Hip Ratio adjusted for BMI) ({beta}=0.039 SD, 95%CI: [0.023, 0.054], p=8.2e-7), as well as a decreased level for total cholesterol ({beta}=-0.084 SD, 95%CI [-0.13, -0.036], p=6.8e-4), but not triglycerides ({beta}=0.02 SD, 95%CI [-0.023, 0.062], p=0.36). The reverse MR analyses suggested that genetically driven T2D (OR=1.1, 95% CI: [1.0, 1.2], p=1.7e-3), BMI (OR=2.3, 95% CI: [2.0, 2.7], p=1.4e-25) and WHRadjBMI (OR=1.5, 95% CI: [1.3, 1.8], p=1.1e-6) causally increase the NAFLD risk. In the animal study, as compared to the TghPNPLA3-I148I controls, the TghPNPLA3-I148M mice developed higher fasting glucose level and reduced glucose clearance. Meanwhile, the TghPNPLA3-I148M mice demonstrated a reduced body weight, increased central to peripheral fat ratio, decreased circulating total cholesterol as compared to the TghPNPLA3-I148I controls.\n\nConclusionThis large-scale bidirectional MR study suggests that lifelong, genetically driven NAFLD is a causal risk factor for T2D (hence potentially a \"NAFLD-driven T2D\" subtype) and central obesity (or \"NAFLD-driven obesity\" subtype), but protects against overall obesity; while genetically driven T2D, obesity, and central obesity also causally increase the risk of NAFLD, hence a \"metabolic NAFLD\". This causal relationship revealed new insights into disease subtypes and provided novel hypotheses for precision treatment or prevention for the three diseases.

epidemiology↗

bioRxiv2019

Arabidopsis SWR1-associated protein methyl-CpG-binding domain 9 is required for histone H2A.Z deposition.

Deposition of the histone variant H2A.Z by the SWI2/SNF2-Related 1 chromatin remodeling complex (SWR1-C) is important for gene regulation in eukaryotes, but the composition of the Arabidopsis SWR1-C has not been thoroughly characterized. Here identify interacting partners of a conserved Arabidopsis SWR1 subunit, ACTIN-RELATED PROTEIN 6 (ARP6). We isolated nine predicted components, and identified additional interactors implicated in histone acetylation and chromatin biology. One of the novel interacting partners, methyl-CpG-binding domain 9 (MBD9), also strongly interacted with the Imitation SWItch (ISWI) chromatin remodeling complex. MBD9 was required for deposition of H2A.Z at a distinct subset of ARP6-dependent loci. MBD9 was preferentially bound to nucleosome-depleted regions at the 5 ends of genes containing high levels of activating histone marks. These data suggest that MBD9 is a SWR1-C interacting protein required for H2A.Z deposition at a subset of actively transcribing genes.

molecular biology↗

bioRxiv2019

Fast, Accurate Polarization and Polarity Imaging withPolarized Structured Illumination

The orientation and wobbling behavior of the fluorescent dipoles are of great significance in revealing the structure and state of cells. Due to the poor optical sectioning capability of wide-field microscopy, the polarization modulation signals are susceptible to the neighboring fluorophores. The missing cone of wide field optical transfer function induces vast out-of-focus background, resulting in biased polarization orientation and decrease polarization factor. Here, we apply polarized structured illumination to achieve polarization modulation imaging with optical sectioning, and simultaneously measure the lipid polarity with two-color ratiometric imaging. Our results demonstrate a significant increase in measurement accuracy of not only the dipole orientations but also the wobbling behavior of the ensemble dipole. Compared to the conventional confocal polarization imaging, our method obtains an order-of-magnitude faster imaging speed, capturing the fast dynamics of subcellular structures in live cells.

biophysics↗

bioRxiv2019

Title: Risk factors for postoperative meningitis after microsurgery for vestibular schwannoma

OBJECTIVEMeningitis after microsurgery for vestibular schwannoma (VS) is a severe complication and result in high morbidity. But few studies have focused on meningitis after VS surgery alone. The purpose of this study was to identify the risk factors for meningitis after VS surgery.\n\nMETHODSWe undertook a retrospective analysis of all VS patients, who underwent microsurgery of VS and at least live for 7 days after surgery, between 1st June 2015 and 30st November 2018 at West China Hospital of Sichuan University. Univariate and multivariate analyses were performed to identify the risk factors for postoperative meningitis (POM).\n\nRESULTSWe collected 410 patients, 27 of whom had POM. Through univariate analysis, hydrocephalus (p=0. 018), Koos grade IV (p=0.04), The operative duration (> 3 hours p=0.03) and intraoperative bleeding volume ([≥] 400ml p=0. 02) were significantly correlated to POM. Multivariate analysis showed that Koos grade IV (p=0.04; OR=3.19; 95% CI 1.032-3.190), operation duration (> 3 hours p=0.03 OR= 7.927; 95% CI 1.043-60.265), and intraoperative bleeding volume ([≥] 400ml p=0.02; OR=2.551; 95% CI 1.112-5.850) are the independent influencing factors of POM.\n\nCONCLUSIONSKoos grade IV, the duration of operation, and the amount of bleeding were identified as independent risk factors for POM after microsurgery of VS. POM caused a prolonged hospital stay.

neuroscience↗

bioRxiv2019

The Vertebrate Codex Gene Breaking Protein Trap Library For Genomic Discovery and Disease Modeling Applications

The zebrafish is a powerful model to explore the molecular genetics and expression of the vertebrate genome. The gene break transposon (GBT) is a unique insertional mutagen that reports the expression of the tagged member of the proteome while generating Cre-revertible genetic alleles. This 1000+ locus collection represents novel codex expression data from the illuminated mRFP protein trap, with 36% and 87% of the cloned lines showcasing to our knowledge the first described expression of these genes at day 2 and day 4 of development, respectively. Analyses of 183 molecularly characterized loci indicate a rich mix of genes involved in diverse cellular processes from cell signaling to DNA repair. The mutagenicity of the GBT cassette is very high as assessed using both forward and reverse genetic approaches. Sampling over 150 lines for visible phenotypes after 5dpf shows a similar rate of discovery of embryonic phenotypes as ENU and retroviral mutagenesis. Furthermore, five cloned insertions were in loci with previously described phenotypes; embryos homozygous for each of the corresponding GBT alleles displayed strong loss of function phenotypes comparable to published mutants using other mutagenesis strategies (ryr1b, fras1, tnnt2a, edar and hmcn1). Using molecular assessment after positional cloning, to date nearly all alleles cause at least a 99+% knockdown of the tagged gene. Interestingly, over 35% of the cloned loci represent 68 mutants in zebrafish orthologs of human disease loci, including nervous, cardiovascular, endocrine, digestive, musculoskeletal, immune and integument systems. The GBT protein trapping system enabled the construction of a comprehensive protein codex including novel expression annotation, identifying new functional roles of the vertebrate genome and generating a diverse collection of potential models of human disease.

genomics↗

bioRxiv2019

Integrated analysis of the miRNA-mRNA network associated with LMP1 gene in nasopharyngeal carcinoma

Epstein-Barr virus oncogenic latent membrane protein 1 (LMP1) has been known to play important roles in nasopharyngeal carcinoma (NPC). LMP1 gene also induced a variety of microRNAs (miRNAs) which bear pivotal roles in regulation of mRNAs expression. However, little was known about the global change of mRNAs and miRNAs induced by LMP1 gene in NPC. In our study, one NPC tissue microarray profile and two LMP1-associated microarray expression profiles data were downloaded from the Gene Expression Omnibus database. A protein-protein interaction network was constructed by using bioinformatics platform Gene-Cloud of Biotechnology Information (GCBI). 78 differentially expressed miRNAs and 3322 differentially expressed genes were identified in order to generate a macroscopic network between miRNAs and mRNAs associated with LMP1 gene. In addition, two significant models were generated to illustrate the expression tendency. Our study provided a way to reveal the interaction between miRNAs and mRNAs in LMP1 axis, bringing insights into the pathogenesis of NPC.

microbiology↗

bioRxiv2019

GIGANTEA recruits deubiquitylases, UBP12 and UBP13, to regulate accumulation of the ZTL photoreceptor complex

To remain synchronous with the environment, plants constantly survey daily light conditions using an array of photoreceptors and adjust their circadian rhythms accordingly. ZEITLUPE (ZTL), a blue light photoreceptor with E3 ubiquitin ligase activity, communicates end-of-day light conditions to the circadian clock. To function properly, ZTL protein must accumulate but not destabilize target clock transcription factors before dusk, while in the dark ZTL mediates degradation of target proteins. It is not clear how ZTL can accumulate to high levels in the light while its targets remain stable. Two deubiquitylating enzymes, UBIQUITIN-SPECIFIC PROTEASE 12 and UBIQUITIN-SPECIFIC PROTEASE 13 (UBP12 and UBP13), which have opposite genetic and biochemical functions to ZTL, were shown to associate with the ZTL protein complex. Here we demonstrate that the ZTL light-dependent interacting partner, GIGANTEA (GI), recruits UBP12 and UBP13 to the ZTL photoreceptor complex. We show that loss of UBP12 and UBP13 reduces ZTL and GI protein levels through a post-transcriptional mechanism. Furthermore, the ZTL target protein TOC1 is unable to accumulate to normal levels in ubp mutants, indicating that UBP12 and UBP13 are necessary to stabilize clock transcription factors during the day. Our results demonstrate that the ZTL photoreceptor complex contains both ubiquitin-conjugating and -deconjugating enzymes, and that these two opposing enzyme types are necessary for the complex to properly regulate the circadian clock. This work also shows that deubiquitylating enzymes are a core design element of circadian clocks that is conserved from plants to animals.

plant biology↗

bioRxiv2019

Extension of the in vivo haploid induction system from diploid maize to hexaploid wheat

Doubled haploid breeding technology has been one of the most important techniques for accelerating crop breeding. In compare to in vivo haploid induction in maize, which is efficient and background independent, wheat haploid production by interspecific hybridization pollinated with maize is influenced by genetic background and requires rescue of young embryos. Here, we analyzed the homologues of maize haploid induction gene MTL/ZmPLA1/NLD in several crop species systematically, the homologues are highly conserved in sorghum, millet and wheat etc. Since wheat is a very important polyploidy crop, as a proof of concept, we demonstrated that the in vivo haploid induction method could be extended from diploid maize to hexaploid wheat by knocking out the wheat homologues (TaPLAs). Result showed that double knock-out mutation could trigger wheat haploid induction at ~ 2%-3%, accompanied by 30% - 60% seed setting rate. The performance of haploid wheat individual showed shorter plant, narrower leaves and male sterile. Our results also revealed that knockout of TaPLA-A and TaPLA-D do not affect pollen viability. This study not only confirmed the function of the induction gene and explored a new approach for haploid production in wheat, but also provided an example that the in vivo haploid induction could be applied in more crop species with different ploidy levels. Furthermore, by combining with gene editing, it would be a fast and powerful platform for traits improvement in polyploidy crops breeding.

plant biology↗

bioRxiv2019

A Pandas complex adapted for piRNA-guided transposon silencing

The repression of transposons by the Piwi-interacting RNA (piRNA) pathway is essential to protect animal germ cells. In Drosophila ovaries, Panoramix (Panx) enforces transcriptional silencing by binding to the target-engaged Piwi-piRNA complex, although the precise mechanisms by which this occurs remain elusive. Here, we show that Panx functions together with a germline specific paralogue of a nuclear export factor, dNxf2, and its cofactor dNxt1 (p15), as a ternary complex to suppress transposon expression. Structural and functional analyses demonstrate that dNxf2 binds Panx via its UBA domain, which plays an important role in transposon silencing. Unexpectedly, dNxf2 interacts directly with dNxf1 (TAP), a general nuclear export factor. As a result, dNxf2 prevents dNxf1 from binding to the FG repeats of the nuclear pore complex, a process required for proper RNA export. Transient tethering of dNxf2 to nascent transcripts leads to their nuclear retention. Therefore, we propose that dNxf2 may function as a Pandas (Panoramix-dNxf2 dependent TAP/p15 silencing) complex, which counteracts the canonical RNA exporting machinery and restricts transposons to the nuclear peripheries. Our findings may have broader implications for understanding how RNA metabolism modulates epigenetic gene silencing and heterochromatin formation.

molecular biology↗

bioRxiv2019

More than efficacy revealed by single-cell analysis of antiviral therapeutics

Development of antiviral therapeutics emphasizes minimization of the effective dose and maximization of the toxic dose, first in cell culture and later in animal models. Long-term success of an antiviral therapeutic is determined not only by its efficacy but also by the duration of time required for drug-resistance to evolve. We have developed a microfluidic device comprised of ~6000 wells, with each well containing a microstructure to capture single cells. We have used this device to characterize enterovirus inhibitors with distinct mechanisms of action. In contrast to population methods, single-cell analysis reveals that each class of inhibitor interferes with the viral infection cycle in a manner that can be distinguished by principal component analysis. Single-cell analysis of antiviral candidates reveals not only efficacy but also properties of the members of the viral population most sensitive to the drug, the stage of the lifecycle most affected by the drug, and perhaps even if the drug targets an interaction of the virus with its host.

microbiology↗

bioRxiv2019

FcγRIIB I232T polymorphic change allosterically suppresses ligand binding

Fc{gamma}RIIB bindings to its ligand suppress immune cell activation. A single-nucleotide polymorphic (SNP) change, I232T, in the transmembrane (TM) domain of Fc{gamma}RIIB loses its suppression function, which clinically associates with systemic lupus erythematosus (SLE). Previously, we reported that I232T tilts Fc{gamma}RIIBs TM domain. In this study, combining with molecular dynamics simulations and single-cell FRET assay, we further revealed that such tilting by I232T unexpectedly bends the Fc{gamma}RIIBs ectodomain towards plasma membrane to allosterically impede Fc{gamma}RIIBs ligand association. We then used single-cell biomechanical assay to further find out that I232T also reduces two-dimensional in-situ binding affinities and association rates of Fc{gamma}RIIB interacting with its ligands by three-folds. This allosteric regulation by a SNP provides an intrinsic molecular mechanism for functional loss of Fc{gamma}RIIB-I232T in SLE patients.

immunology↗

bioRxiv2019

Complete genome sequence and evolution analysis of Psychrobacter sp. YP14 from Gammaridea Gastrointestinal Microbiota of Yap Trench

Psychrobacter sp. YP14, a moderately psychrophilic bacterium belonging to the class Gammaproteobacteria, was isolated from Gammaridea Gastrointestinal Microbiota of Yap Trench. The strain has one circular chromosome of 2,895,311 bp with a 44.66% GC content, consisting of 2333 protein-coding genes, 53 tRNA genes and 9 rRNA genes. Four plasmids were completely assembled and their sizes were 13,712 bp, 19711 bp, 36270 bp, 8194 bp, respectively. In particular, a putative open reading frame (ORF) for dienelactone hydrolase (DLH) related to degradation of chlorinated aromatic hydrocarbons. To get an better understanding of the evolution of Psychrobacter sp. YP14 in this genus, six Psychrobacter strains (G, PRwf-1, DAB_AL43B, AntiMn-1,P11G5, P2G3), with publicly available complete genome, were selected and comparative genomics analysis were performed among them. The closest phylogenetic relationship was identified between strains G and K5 based on 16s gene and ANI (average nucleotide identity) values. Analysis of the pan-genome structure found that YP14 has fewer COG clusters associated with transposons and prophage which indicates fewer sequence rearrangements compared with PRwf-1. Besides, stress response-related genes of strain YP14 demonstrates that it has less strategies to cope with extreme environment, which is consistent with its intestinal habitat. The difference of metabolism and strategies coped with stress response of YP14 are more conducive to the study of microbial survival and metabolic mechanisms in deep sea environment.

genomics↗

bioRxiv2019

The gut microbiota regulates mouse biliary regenerative responses

Injury to the biliary epithelium triggers cholangiopathies. However, factors involved in regulating the pathogenesis remains incompletely understood. Here, we report that the gut microbiota is important in regulating hepatobiliary fibroproliferative regenerative process. In helminth Clonorchis sinensis-induced bile duct injury model, wild-type mice showed more extensive peribiliary fibroproliferative responses than non-littermate IL-33-deficient mice. However, these reactions could be attenuated by co-housing of the animals together. In the meantime, the relatively fibroproliferative-resistant IL-33-deficient mice could become fibroproliferative-responsive especially in large intrahepatic bile duct by antibiotics treatment. Furthermore, microbiota-derived metabolite butyrate was able to inhibit biliary organoid expansion in vitro and temper 3,5-diethoxycarbonyl-1,4-dihydrocollidine-induced biliary fibrosis in vivo. Together, our data implies a potential way of management of hepatobiliary diseases by modulating gut microbiota.

microbiology↗

bioRxiv2019

Comparison of different orders of Legendre polynomials in random regression model for estimation of genetic parameters and breeding values of milk yield in the Chinese Holstein population

Random regression test-day model has become the most commonly adopted model for routine genetic evaluations for different dairy populations, which allows accurately accounting for genetic and environmental effects at different periods during lactation. The objective of this study was to explore appropriate random regression test-day model for genetic evaluation of milk yield in Chinese Holstein population. Data included 419,567 test-day records from 54,417 cows in the first lactation. Variance components and breeding values were estimated using random regression test-day model with different order (first order to fifth order) of Legendre polynomials, and accounted for homogeneous or heterogeneous residual variance across the lactation. The goodness of fit of the models was evaluated by total residual variance (TRV) and - 2logL. Further, the predictive ability of the models was assessed by Spearmans rank correlation between estimated breeding values for 305d milk yield (EBV305) from the full data set and reduced data set in which the records from the last calving year were masked. The results showed that random regression models using third order Legendre polynomials (LP3) with heterogeneous residual variance achieved the lower TRV and - 2logL value and the highest correlation for EBV305 between full data and reduced data. Heritability estimated by this model was 0.250 for 305d milk yield and ranged from 0.163 to 0.304 for test-day milk yield. We suggest random regression model with Legendre polynomial of order 3 and accounting for heterogeneous residual variances could be an appropriate model to be used for genetic evaluation of milk yield for Chinese Holstein population.

genetics↗

bioRxiv2019

Adaptive efficient coding of correlated acoustic properties

Natural sounds such as vocalizations often have co-varying acoustic attributes where one acoustic feature can be predicted from another, resulting in redundancy in neural coding. It has been proposed that sensory systems are able to detect such covariation and adapt to reduce redundancy, leading to more efficient neural coding. Results of recent psychoacoustic studies suggest that, following passive exposure to sounds in which temporal and spectral attributes covaried in a correlated fashion, the auditory system adapts to efficiently encode the two co-varying dimensions as a single dimension, at the cost of lost sensitivity to the orthogonal dimension. Here we explore the neural basis of this psychophysical phenomenon by recording single-unit responses from primary auditory cortex (A1) in awake ferrets exposed passively to stimuli with two correlated attributes in the temporal and spectral domain similar to that utilized in the psychoacoustic experiments. We found that: (1) the signal-to-noise (SNR) ratio of spike rate coding of cortical responses driven by sounds with correlated attributes was reduced along the orthogonal dimension; while the SNR ratio remained intact along the exposure dimension; (2) Mutual information of spike temporal coding increased only along the exposure dimension; (3) correlation between neurons tuned to the two covarying attributes decreased after exposure; (4) these exposure effects still occurred if sounds were correlated along two acoustic dimensions, but varied randomly along a third dimension. These neurophysiological results are consistent with the Efficient Learning Hypothesis and may deepen our understanding of how the auditory system represents acoustic regularities and covariance. SignificanceIn the Efficient Coding (EC) hypothesis, proposed by Barlow in 1961, the neural code in sensory systems efficiently encodes natural stimuli by minimizing the number of spikes to transmit a sensory signal. Results of recent psychoacoustic studies are consistent with the EC hypothesis, showing that following passive exposure to stimuli with correlated attributes, the auditory system adapts so as to more efficiently encode the two co-varying dimensions as a single dimension. In the current neurophysiological experiments, using a similar stimulus design and experimental paradigm to the psychoacoustic studies of Stilp and colleagues (2010, 2011, 2012, 2016), we recorded responses from single neurons in the auditory cortex of the awake ferret, showing adaptive efficient neural coding of correlated acoustic properties.

neuroscience↗