Biology subjects

Cao, Y.

Publications and source records attributed to Cao, Y..

At least 199 records · Page 11Linked to original sources

bioRxiv2024

Plasticity in inhibitory networks improves pattern separation in early olfactory processing

Distinguishing between nectar and non-nectar odors is challenging for animals due to shared compounds and varying ratios in complex mixtures. Changes in nectar production throughout the day - and potentially many times within a foragers lifetime - add to the complexity. The honeybee olfactory system, containing fewer than 1,000 principal neurons in the early olfactory relay, the antennal lobe (AL), must learn to associate diverse volatile blends with rewards. Previous studies identified plasticity in the AL circuits, but its role in odor learning remains poorly understood. Using a biophysical computational network model, tuned by in vivo electrophysiological data, and live imaging of the honeybees AL, we explored the neural mechanisms and functions of plasticity in the early olfactory system. Our findings revealed that when trained with a set of rewarded and unrewarded odors, the AL inhibitory network suppresses shared chemical compounds while enhancing responses to distinct compounds. This results in improved pattern separation and a more concise neural code. Our calcium imaging data support these predictions. Analysis of a graph convolutional neural network performing an odor categorization task revealed a similar mechanism for contrast enhancement. Our study provides insights into how inhibitory plasticity in the early olfactory network reshapes the coding for efficient learning of complex odors. Significance StatementBy combining biophysical modeling, machine learning, electrophysiology and analysis of calcium imaging data, we demonstrate that associative and nonassociative plasticity in the honeybee antennal lobe (AL) the first relay of the insect olfactory system - work together to enhance the contrast between rewarded and unrewarded odors. Training the ALs inhibitory network within specific odor environments enables the suppression of neural responses to common odor components while amplifying responses to distinctive ones. This study sheds light on the olfactory systems ability to adapt and efficiently learn new odor-reward associations across varying environments, and it proposes innovative, energy-efficient principles applicable to artificial intelligence.

neuroscience↗

bioRxiv2024

Neutralizing gut-derived lipopolysaccharide as a novel therapeutic strategy for severe leptospirosis

Leptospirosis is an emerging infectious disease caused by pathogenic Leptospira spp. Humans and some mammals can develop severe forms of leptospirosis accompanied by a dysregulated inflammatory response, which often results in death. The gut microbiota has been increasingly recognized as a vital element in systemic health. However, the precise role of the gut microbiota in severe leptospirosis is still unknown. Here, we aimed to explore the function and potential mechanisms of the gut microbiota in a hamster model of severe leptospirosis. Our study showed that leptospires were able to multiply in the intestine, cause pathological injury, and induce intestinal and systemic inflammatory responses. 16S rRNA gene sequencing analysis revealed that Leptospira infection changed the composition of the gut microbiota of hamsters with an expansion of Proteobacteria. In addition, gut barrier permeability was increased after infection, as reflected by a decrease in the expression of tight junctions. Translocated Proteobacteria were found in the intestinal epithelium of moribund hamsters, as determined by fluorescence in situ hybridization, with elevated LPS levels in the serum. Moreover, gut microbiota depletion reduced the survival time, increased the leptospiral load, and promoted the expression of proinflammatory cytokines after Leptospira infection. Intriguingly, fecal filtration and serum from moribund hamsters both increased the transcription of TNF-, IL-1{beta}, IL-10, and TLR4 in macrophages compared with those from uninfected hamsters. These stimulating activities were inhibited by LPS neutralization using polymyxin B. Based on our findings, we identified an LPS neutralization therapy that significantly improved the survival rates in severe leptospirosis when used in combination with antibiotic therapy or polyclonal antibody therapy. In conclusion, our study not only uncovers the role of the gut microbiota in severe leptospirosis but also provides a therapeutic strategy for severe leptospirosis.

microbiology↗

bioRxiv2024

Blood immunophenotyping identifies distinct kidney histopathology and outcomes in patients with lupus nephritis

Lupus nephritis (LN) is a frequent manifestation of systemic lupus erythematosus, and fewer than half of patients achieve complete renal response with standard immunosuppressants. Identifying non-invasive, blood-based pathologic immune alterations associated with renal injury could aid therapeutic decisions. Here, we used mass cytometry immunophenotyping of peripheral blood mononuclear cells in 145 patients with biopsy-proven LN and 40 healthy controls to evaluate the heterogeneity of immune activation in patients with LN and to identify correlates of renal parameters and treatment response. Unbiased analysis identified 3 immunologically distinct groups of patients with LN that were associated with different patterns of histopathology, renal cell infiltrates, urine proteomic profiles, and treatment response at one year. Patients with enriched circulating granzyme B+ T cells at baseline showed more severe disease and increased numbers of activated CD8 T cells in the kidney, yet they had the highest likelihood of treatment response. A second group characterized primarily by a high type I interferon signature had a lower likelihood of response to therapy, while a third group appeared immunologically inactive by immunophenotyping at enrollment but with chronic renal injuries. Main immune profiles could be distilled down to 5 simple cytometric parameters that recapitulate several of the associations, highlighting the potential for blood immune profiling to translate to clinically useful non-invasive metrics to assess immune-mediated disease in LN.

immunology↗

bioRxiv2024

Comparison of urine proteome between obese people and normal weight people

ObjectiveTo explore whether urine proteome can reflect the difference between obese and normal weight people. MethodsUrine samples from obese and normal weight people were collected and identified by non-label quantitative proteomics using high performance liquid chromatography tandem mass spectrometry (LC-MS/MS). The difference proteins of urine proteome between obese and normal weight people were screened for protein function and biological pathway analysis. The urine proteome of obese individuals was compared with that of normal weight people, and the common differential proteins were counted to analyze the protein function and biological pathways. Reported biomarkers of obesity were searched in the urine proteome of obese individuals. Results38 different proteins can be identified in the urine proteome of obese people compared with normal weight people, some of which have been reported to be related to metabolism and obesity, and the biological processes of differential proteins are also related to metabolism and other processes. 8 common differential proteins in the urine proteome of obese individuals and normal weight people, among which some proteins have been reported to be related to metabolism and obesity, and the biological processes of differential proteins are also related to metabolism and other processes. Among the differential proteins in the urine proteome of obese individuals compared with the normal weight people, the reported obesity biomarkers can be matched. ConclusionsThe urine proteome can distinguish the obese people from the normal weight people, and the differential proteins in the urine proteome have key proteins that are known to be related to obesity and metabolism, and the biological processes of differential proteins also related biological processes such as nutrition and metabolism. Urine proteome has the potential to explore the pathogenesis of obesity and provide personalized treatment.

biochemistry↗

bioRxiv2023

Evolution of resistance to KRASG12C inhibitor in a non-small cell lung cancer responder

Despite initial therapeutic successes, most patients with non-small cell lung cancer (NSCLC) who carry the KRASG12C mutation ultimately exhibit resistance to targeted treatments. To improve our comprehension of how acquired resistance develops, we present an unprecedented longitudinal case study profiling the transcriptome of peripheral blood mononuclear cells (PBMCs) over 5 months from an NSCLC patient with the KRASG12C mutation and initial response to sotorasib followed by resistance and death. Single-cell RNA sequencing analysis uncovered notable fluctuations in immune cell populations throughout treatment with sotorasib. Specifically, we observed a decline in circulating CD8+CD161hi T cells correlating with periods of therapeutic response, followed by a resurgence during phases of nonresponse. This study established a high-resolution atlas detailing the evolutionary trajectory of resistance to sotorasib and characterizes a CD8+CD161hi T cells population in KRASG12C mutation patient.

cancer biology↗

bioRxiv2023

The current landscape and emerging challenges of benchmarking single-cell methods

With the rapid development of computational methods for single-cell sequencing data, benchmarking serves as a valuable resource. As the number of benchmarking studies surges, it is timely to assess the current state of the field. We conducted a systematic literature search and assessed 282 papers, including all 130 benchmark-only papers from the search and an additional 152 method development papers containing benchmarking. This collective effort provides the most comprehensive quantitative summary of the current landscape of single-cell benchmarking studies. We examine performances across nine broad categories, including often ignored aspects such as role of datasets, robustness of methods and downstream evaluation. Our analysis highlights challenges such as how to effectively combine knowledge across multiple benchmarking studies and in what ways can the community recognise the risk and prevent benchmarking fatigue. This paper highlights the importance of adopting a community-led research paradigm to tackle these challenges and establish best practice standards.

bioinformatics↗

bioRxiv2023

In vivo optimized three-photon imaging of intact mouse tibia links plasma cell motility to functional states in the bone marrow.

Intravital multi-photon imaging of the bone marrow is crucial to the study of cellular dynamics, communication with the microenvironment and functions, however, imaging of deep tissue areas is challenging and minimally invasive methods for deep-marrow imaging in intact long bones are needed. We developed a high pulse energy 1650 nm laser prototype, which permits to surpass >100 {micro}m thick cortical bone and to perform three-photon microscopy (3PM) in more than 400 {micro}m depth in the marrow cavity of intact mouse tibia in vivo. Its unique 3 and 4 MHz laser repetition rates allowed us to analyze motility patterns of rare cells over large fields of view deep within the unperturbed marrow. In this way, we found a bi-modal migratory behavior of marrow plasma cells. Besides, the analysis of third harmonics generation (THG) in the tibia identified this signal to be a label-free indicator of the abundance of cellular organelles, in particular the endoplasmic reticulum, reflecting protein biosynthesis capacity. We found that only one third of the plasma cells in the tibia marrow of adult mice have a strong THG signal and, thus, a high protein synthesis capacity, while the other two thirds of plasma cells display a low THG signal. Finally, we identified an inverse link between migratory behavior and THG signal strength in marrow plasma cells. As in these cells, the protein biosynthesis capacity indicated by a strong THG signal is mainly associated with antibody secretion, we could relate motility to functional states of plasma cells in vivo. Our 3PM method retains the ability to connect cellular dynamics to protein biosynthesis capacity in various marrow cell types beyond plasma cells, as THG is a ubiquitous signal, opening new perspectives on understanding how tissue microenvironment impacts on cellular functions in the bone marrow.

biophysics↗

bioRxiv2023

Rhythmic sampling of multiple decision alternatives in the human brain

Humans and other animals navigate decisions by sequentially attending to (sampling) subsets of the available information. The internal dynamics of the selective sampling of decision-relevant information remain unknown. Here we use magnetoencephalography recordings and neural decoding to track the spontaneous dynamics of the locus and strength of covert attention as human participants performed a three-alternative perceptual choice task. The strength of covert attention fluctuated rhythmically around 11 Hz. A shift of attention from one alternative to another tends to occur at the trough of this oscillation, presumably enabling comparisons. These shifts further reset the attentional oscillation. By contrast, at the peak of the oscillation, attention tends to increase the focus on the currently sampled alternative, presumably deepening processing of that alternative. We propose intrinsic attentional oscillations as a core mechanism governing the flexible sampling of decision alternatives.

neuroscience↗

bioRxiv2023

In vivo proximity proteomics uncovers palmdelphin (PALMD) as a Z-line-associated mitigator of isoproterenol-induced cardiac injury

Z-lines are core ultrastructural organizers of cardiomyocytes that modulate many facets of cardiac pathogenesis. Yet a comprehensive proteomic atlas of Z-line-associated components remain incomplete. Here, we established an adeno-associated virus (AAV)-delivered, cardiomyocyte-specific, proximity-labeling approach to characterize the Z-line proteome in vivo. We found palmdelphin (PALMD) as a novel Z-line-associated protein in both adult murine cardiomyocytes and human pluripotent stem cell-derived cardiomyocytes. Germline and cardiomyocyte-specific palmd knockout mice were grossly normal at baseline but exhibited compromised cardiac hypertrophy and aggravated cardiac injury upon long-term isoproterenol treatment. By contrast, cardiomyocyte-specific PALMD overexpression was sufficient to mitigate isoproterenol-induced cardiac injury. PALMD ablation perturbed transverse tubules (T-tubules) and their association with sarcoplasmic reticulum, which formed the Z-line-associated junctional membrane complex (JMC) essential for calcium handling and cardiac function. These phenotypes were associated with disrupted localization of T-tubule markers caveolin-3 (CAV3) and junctophilin-2 (JPH2) and the reduction of nexilin (NEXN) protein, a crucial Z-line-associated protein that is essential for both Z-line and JMC structures and functions. PALMD was found to interact with NEXN and enhance its protein stability while the Nexn mRNA level was not affected. Together, this study discovered PALMD as a potential target for myocardial protection and highlighted in vivo proximity proteomics as a powerful approach to nominate novel players regulating cardiac pathogenesis. HighlightsO_LIIn vivo proximity proteomics uncover novel Z-line components that are undetected in in vitro proximity proteomics in cardiomyocytes. C_LIO_LIPALMD is a novel Z-line-associated protein that is dispensable for baseline cardiomyocyte function in vivo. C_LIO_LIPALMD mitigates cardiac dysfunction and myocardial injury after repeated isoproterenol insults. C_LIO_LIPALMD stabilizes NEXN, an essential Z-line-associated regulator of the junctional membrane complex and cardiac systolic function. C_LI

molecular biology↗

bioRxiv2023

Temporal genomic analysis of melanoma rejection identifies regulators of tumor immune evasion

Decreased intra-tumor heterogeneity (ITH) correlates with increased patient survival and immunotherapy response. However, even highly homogenous tumors may display variability in their aggressiveness, and how immunologic-factors impinge on their aggressiveness remains understudied. Here we studied the mechanisms responsible for the immune-escape of murine tumors with low ITH. We compared the temporal growth of homogeneous, genetically-similar single-cell clones that are rejected vs. those that are not- rejected after transplantation in-vivo using single-cell RNA sequencing and immunophenotyping. Non- rejected clones showed high infiltration of tumor-associated-macrophages (TAMs), lower T-cell infiltration, and increased T-cell exhaustion compared to rejected clones. Comparative analysis of rejection- associated gene expression programs, combined with in-vivo CRISPR knockout screens of candidate mediators, identified Mif (macrophage migration inhibitory factor) as a regulator of immune rejection. Mif knockout led to smaller tumors and reversed non-rejection-associated immune composition, particularly, leading to the reduction of immunosuppressive macrophage infiltration. Finally, we validated these results in melanoma patient data. Statement of significanceHere, we uncover the association of Mif expression with tumor growth and aggressiveness, specifically in low ITH tumors. These findings could facilitate the development of new strategies to treat patients with homogeneous, high-MIF expressing tumors that are unresponsive to immune checkpoint therapy.

cancer biology↗

bioRxiv2023

Fast evolution of SARS-CoV-2 BA.2.86 to JN.1 under heavy immune pressure

While the BA.2.86 variant demonstrated significant antigenic drift and enhanced ACE2 binding affinity, its ability to evade humoral immunity was relatively moderate compared to dominant strains like EG.5 and HK.3. However, the emergence of a new subvariant, JN.1 (BA.2.86.1.1), which possesses an additional spike mutation, L455S, compared to BA.2.86, showed a markedly increased prevalence in Europe and North America, especially in France. Here, we found that L455S of JN.1 significantly enhances immune evasion capabilities at the expense of reduced ACE2 binding affinity. This mutation enables JN.1 to effectively evade Class 1 neutralizing antibodies, offsetting BA.2.86s susceptibility and thus allowing it to outcompete both its precursor BA.2.86 and the prevailing variants HV.1 (XBB.1.5+L452R+F456L) and JD.1.1 (XBB.1.5+L455F+F456L+A475V) in terms of humoral immune evasion. The rapid evolution from BA.2.86 to JN.1, similar to the earlier transition from BA.2.75 to CH.1.1, highlights the importance of closely monitoring strains with high ACE2 binding affinity and distinct antigenicity, despite their temporarily unremarkable immune evasion capabilities. Such strains could survive and transmit at low levels, since their large antigenic distance to dominant strains allow them to target distinct populations and accumulate immune-evasive mutations rapidly, often at the cost of receptor binding affinity.

immunology↗

bioRxiv2023

UDP-glucosyltransferase 71C4 regulates seed development by redistributing phenylpropanoid metabolism in cotton

Seeds are important for plant reproduction, and hence it is important to identify genes regulating seed development. Here, we focused on a member of the glycosyltransferase (GT) family, UDP-glucosyltransferase 71C4 (UGT71C4), which influences the seed width, seed length, and yield traits (lint percentage and seed index) by regulating the lignin and flavonoid pathways of phenylpropane metabolism, affects the oil and protein contents of mature seeds, and controls the seed size by regulating cell proliferation. Overexpression of UGT71C4 leads to seed enlargement by activating expression of peroxiredoxins and the flavonoid metabolism pathway; induces accumulation of ROS, which promotes cell proliferation; and significantly improves yield traits, with the seed index increasing from 10.66 to 11.91 and protein increasing by 5.34%, but oil content decreasing 8.98%. Conversely, knockout of UGT71C4 causes seeds to become smaller; the lignin metabolism pathway to be activated, especially enzymes relating to lignin synthesis leading to increased ectopic deposition of lignin in the ovule and constrained ovule growth and development; and significant improvement of yield traits, with lint percentage increasing from 39.62% to 41.94%, seed index decreasing from 10.66 to 8.60, protein content decreasing 4.28%, and no significant change in oil content. Our research provides new insights into seed size regulation through UDP-glucosyltransferase, providing potential methods for improving plant yield.

plant biology↗

bioRxiv2023

High-content fluorescence bioassay to investigate pore formation, ion channel modulation and cell membrane lysis induced by venoms

Venoms comprise highly evolved bioactive molecules modulating ion channels, receptors, coagulation factors, and the cellular membrane. This array of targets and bioactivity requires high-content bioassays to aid the development of novel envenomation treatments and biotechnological and pharmacological agents. To address this gap in venoms research, we developed a fluorescence-based high-throughput and high-content cellular assay to simultaneously identify common cellular activities produced by venoms: membrane lysis, pore-formation, and ion channel modulation. By combining intracellular calcium with extracellular nucleic acid measurements, we distinguished these venom mechanisms using one cellular assay. We applied our high-content bioassay in three cell types exposed to venom components representing lytic, ion pore-forming or ion channel modulator toxins. Beyond the distinct profiles produced by these three types of action mechanisms, we found that the pore-forming latrotoxin -Lt1a prefers human neuroblastoma to kidney cells and cardiomyocytes, while the lytic bee peptide melittin is not selective. Furthermore, evaluation of snake venoms showed that Elapid species induced rapid membrane lysis, while Viper species showed variable to no activity on neuroblastoma cells. These findings demonstrate that our high-content bioassay distinguish clades and interspecific traits and capture the clinical observations at venom level and is capable of differentiate ion pore-forming from membrane lysis and ion channel modulation. We hope our research will accelerate the understanding of venom biology and the diversity of toxins inducing cytotoxic, cardiotoxic and neurotoxic effects and assist in identifying venom components whose properties could benefit humankind.

pharmacology and toxicology↗

bioRxiv2023

Single-cell bisulfite-free 5mC and 5hmC sequencing with high sensitivity and scalability

Existing single cell bisulfite-based DNA methylation analysis is limited by low DNA recovery, and the measurement of 5hmC at single-base resolution remains challenging. Here we present a bisulfite-free single-cell whole-genome 5mC and 5hmC profiling technique, named Cabernet, which can characterize 5mC and 5hmC at single-base resolution with high genomic coverage. Cabernet utilizes Tn5 transposome for DNA fragmentation, which enables the discrimination between different alleles for measuring hemi-methylation status. Using Cabernet, we revealed the 5mC, hemi-5mC and 5hmC dynamics during early mouse embryo development, uncovering genomic regions exclusively governed by active or passive demethylation. We show that hemi-methylation status can be used to distinguish between pre- and post-replication cells, enabling more efficient cell grouping when integrated with 5mC profile. The property of Tn5 naturally enables Cabernet to achieve high-throughput single-cell methylome profiling, where we probed mouse cortical neurons and embryonic day 7.5 (E7.5) embryos, and constructed the library for thousands of single cells at high efficiency, demonstrating its potential for analyzing complex tissues at substantially low cost. Together, we present a new way of high-throughput methylome and hydroxymethylome detection at single-cell resolution, enabling efficient analysis of epigenetic status of biological systems with complicated nature such as neurons and cancer cells. Significance StatementMost of current methylation profiling techniques rely on bisulfite treatment, which suffers low DNA recovery. The technique proposed in this study, named Cabernet, can be used to measure 5mC and 5hmC at single-base resolution with high genomic coverage. By using Tn5 transposome, hemi-methylation status can be measured and high-throughput methylome profiling can be achieved. Together, it provides an efficient way to analyze the epigenetic landscape of complicated biological systems.

genomics↗

bioRxiv2023

Adaptive Functions of Structural Variants in Human Brain Development

Quantifying the structural variants (SVs) in nonhuman primates could provide a niche to clarify the genetic backgrounds underlying human-specific traits, but such resource is largely lacking. Here, we report an accurate SV atlas in a population of 562 rhesus macaques, verified by two public SV benchmarks, an inhouse benchmark of eight macaque genomes with long-read sequencing and another inhouse benchmark of one macaque genome with whole-genome assembly. This accurate, quantitative SV map indicates stronger purifying selection on inversions, one type of poorly-clarified SVs to date, especially for those located on regulatory regions, suggesting a strategy for prioritizing inversions with the most important functions. Based on the distribution and the evolutionary features of these inversions in macaque population, we then identified 75 human-specific inversions, clarified their functional effects and prioritized them. Notably, the top-ranked inversions have substantially shaped the human transcriptome, through their dual-effects of reconfiguring the ancestral genomic architecture and introducing regional mutation hotspots at the inverted regions. As a proof-of-concept, we linked APCDD1, located on one of these inversions with the highest rank score and downregulated in human brains, to neuronal maturation. The accumulation of human-specific mutations on its promoter region, accelerated by the formation of the inversion, contributed to the decreased expression in humans. Notably, the overexpression of APCDD1 could accelerate the neuronal maturation, while its depletion in mice delays the neuronal maturation. This study thus highlights the contribution of SVs, especially the inversions, to the distinct features in human brain development.

evolutionary biology↗

bioRxiv2023

MUSTANG: MUlti-sample Spatial Transcriptomics data ANalysis with cross-sample transcriptional similarity Guidance

AO_SCPLOWBSTRACTC_SCPLOWSpatially resolved transcriptomics has revolutionized genome-scale transcriptomic profiling by providing high-resolution characterization of transcriptional patterns. We here present our spatial transcriptomics analysis framework, MUSTANG (MUlti-sample Spatial Transcriptomics data ANalysis with cross-sample transcriptional similarity Guidance), which is capable of performing multi-sample spatial transcriptomics spot cellular deconvolution by allowing both cross-sample expression based similarity information sharing as well as spatial correlation in gene expression patterns within samples. Experiments on two real-world spatial transcriptomics datasets demonstrate the effectiveness of MUSTANG in revealing biological insights inherent in cellular characterization of tissue samples under the study. MUSTANG is publicly available at at https://github.com/namini94/MUSTANG

bioinformatics↗

bioRxiv2023

Bayesian optimization of separation gradients to maximize the performance of untargeted LC-MS

Liquid chromatography (LC) with gradient elution is a routine practice for separating complex chemical mixtures in mass spectrometry (MS)-based untargeted analysis. Despite its prevalence, systematic optimization of LC gradients has remained challenging. Here we develop a Bayesian optimization method, BAGO, for autonomous and efficient LC gradient optimization. BAGO is an active learning strategy that discovers the optimal gradient using limited experimental data. From over 100,000 plausible gradients, BAGO locates the optimal LC gradient within ten sample analyses. We validated BAGO on six biological studies of different sample matrices and LC columns, showing that BAGO can significantly improve quantitative performance, tandem MS spectral coverage, and spectral purity. For instance, the optimized gradient increases the count of annotated compounds meeting quantification criteria by up to 48.5%. Furthermore, applying BAGO in a Drosophila metabolomics study, an additional 57 metabolites and 126 lipids were annotated. The BAGO algorithms were implemented into user-friendly software for everyday laboratory practice and a Python package for its flexible extension.

bioinformatics↗

bioRxiv2023

Decision bias and sampling asymmetry in reward-guided learning

Human economic decisions are highly sensitive to contexts. Deciding between two competing alternatives can be notoriously biased by their overall value ( magnitude effect) or by a third decoy option ( distractor effect). Some prominent explanations appeal to diminishing value sensitivity and divisive normalization in value representations, i.e., representational bias, that feed into the choice stage. However, these explanations have recently come under scrutiny due to empirical inconsistencies and mounting alternative theories. Here, we posit that context-sensitive choices may not stem from representational biases but rather emerge as by-products of asymmetric sampling during value learning. In a reward-guided choice task, participants aimed to maximize cumulative rewards through trial and error. The task introduced alternating blocks with either a colored distractor or a neutral notional distractor. We observed decreased choice accuracy when higher-value distractors were present, a pattern that persisted even in the notional distractor blocks. Using computational modeling, we show that this phenomenon falls out naturally from a simple learning rule without relying on any additional mechanism such as divisive normalization or nonlinear utility. Furthermore, we found that, contrary to divisive normalization, choice accuracy was not influenced by distractor value but strongly depended on the magnitude of the targets values per se. This magnitude sensitivity was also found in the notional distractor conditions and could lawfully be reproduced by the learning model. Importantly, when counterfactual feedback eliminated sampling asymmetry, the observed decision bias vanished. Our results suggest that the genesis of context-sensitive choices may lie in the learning dynamics themselves, specifically sampling asymmetry, rather than in pre-decisional representational biases. This finding reframes the discourse on irrational decision-making, attributing it to acquired biases during the learning process, not necessarily computational intricacies at the choice stage.

neuroscience↗