Biology subjects

Allen, M.

Publications and source records attributed to Allen, M..

At least 19 recordsLinked to original sources

bioRxiv2026

CSF1R-Mediated Microglial Engagement Is Required for Stress-Induced MMP-2/9 Activity

Stress is a major risk factor for numerous neuropsychiatric disorders and induces enduring synaptic plasticity within the nucleus accumbens core (NAcore), a key brain region involved in reward and stress-related behaviors. Previous studies from our laboratory demonstrated that stress-induced plasticity depends on matrix metalloproteinase (MMP)-2/9-mediated extracellular matrix (ECM) remodeling; however, the upstream cellular mechanisms regulating MMP activation remain unclear. Because microglia regulate neuroimmune signaling, ECM dynamics, and synaptic plasticity, we tested the hypothesis that microglial colony-stimulating factor 1 receptor (CSF1R) signaling contributes to stress-induced MMP-2/9 activation within the NAcore. Male rats received the CSF1R inhibitor PLX3397 prior to acute restraint stress. In vivo fluorescent zymography, immunohistochemistry, and quantitative PCR were used to assess MMP activity, microglial signaling, and inflammatory gene expression. Acute stress increased MMP-2/9 activity enhanced microglial CD68-associated phagocytic signaling, and elevated expression of Csf1r, Tnfa, Cnr2, and Mmp16 within the NAcore. Importantly, CSF1R inhibition attenuated stress-induced increases in MMP-2/9 activity and CD68 immunoreactivity. Combined, these findings identify microglial CSF1R signaling as an upstream regulator of stress-induced ECM remodeling within the NAcore and provide mechanistic insight into how acute stress recruits neuroimmune pathways to remodel reward circuitry.

neuroscience↗

bioRxiv2026

Galectin-1 Modulates Cell Adhesions, Caveolae, and Vascular Permeability in Kidney Endothelial Cells -- Insights from Proteomics, Phosphoproteomics, and Functional Studies

Microvascular inflammation and endothelial injury, triggered by interferon-gamma (IFN{gamma}), are hallmarks of antibody-mediated rejection (ABMR), the leading cause of premature kidney allograft loss. Glomerular extracellular matrix (ECM) remodeling and endothelial caveolae formation are important aspects of chronic ABMR. We found galectin-1, an immunomodulatory protein that interacts with the ECM, to be increased in the glomeruli of patients with ABMR, while its gene (LGALS1) expression was decreased by IFN{gamma} stimulation in glomerular endothelial cells. Mechanisms underlying endothelial dysfunction in ABMR, its links to ECM remodeling, and the role of immunomodulatory proteins such as galectin-1 remain incompletely understood. Here we studied the effects of galectin-1 modulation in glomerular microvascular endothelial cells (GMECs) in vitro. We demonstrated that galectin-1 was mainly expressed by glomerular endothelial cells in ABMR kidneys. To model key aspects of endothelial injury in ABMR, we knocked down LGALS1 in GMECs, followed by stimulation with IFN{gamma} and performed label-free quantitative proteomic and phosphoproteomic profiling of GMECs. Proteomic analysis identified 5446 proteins (FDR<0.01), of which 236, 827, and 267 were differentially expressed in response to LGALS1 knockdown, IFN{gamma} treatment, and their interaction, respectively (FDR<0.05). Both LGALS1 knockdown and the interaction between treatments significantly altered expression of adhesion proteins (FDR<0.01), particularly integrin subunit {beta}5, which was validated. Phosphoproteomic profiling identified 2727 phosphopeptides (FDR<0.01), with 28 that were differentially expressed across LGALS1 knockdown, IFN{gamma} treatment, and their interaction (P<0.01). Phosphorylation of CAVN1 and co-localization with its partner CAV1, critical for caveolar formation, were decreased in GMECs upon LGALS1 knockdown, IFN{gamma} stimulation, or both. In a microfluidic model of the glomerular microvasculature, addition of recombinant galectin-1 increased both endothelial permeability and secretion of proinflammatory cytokines, in LGALS1-silenced GMECs. Thus, endothelial signaling pathways regulated by inflammatory cues and galectin-1 contribute to endothelial injury and caveolae formation, highlighting galectin-1 as a potential therapeutic target in ABMR. SynopsisGalectin-1 is expressed by kidney glomerular endothelium. This study reveals that modifying galectin-1 in endothelial cells, in the presence of IFN{gamma} perturbs cytoskeletal, adhesion and caveolar proteins resulting in altered endothelial permeability. O_LILGALS1 knockdown increased ECM proteins and decreased interferon-induced proteins. C_LIO_LILGALS1 knockdown and IFN{gamma} treatment perturbed cell adhesion proteins such as ITGB5. C_LIO_LICAVN1 phosphorylation and colocalization with CAV1 decreased upon LGALS1 knockdown. C_LIO_LIExtracellular galectin-1 increased microvascular permeability in response to IFN{gamma}. C_LI

cell biology↗

bioRxiv2026

Dissociable Microstructural Correlates of Learning Rate and Learning Noise in Gamified Reward-Based Decision-Making

Humans learn which actions yield the highest rewards through trial and error, gradually forming expectations about outcomes. Yet, people differ substantially in how quickly and precisely they learn. Such individual variability may partly be explained by differences in the brains microstructural organisation. In this large-scale study, 248 participants completed a gamified reward-learning task and underwent quantitative MRI to assess whole-brain microstructural indices of myelination (R1) and cortical iron (R2*). Using computational modelling, we quantified participants learning rates and learning noise, reflecting variability in how reward information is updated over time. Whole-brain voxel-based quantification analyses revealed that increased myelination in the cerebellum was associated with a higher learning rate, whereas learning noise was linked to increased myelination and iron concentration in the precentral gyrus. Together, these findings show that reward learning is not a unitary process but is instead shaped by distinct neurobiological pathways that support learning precision and noise. This work highlights how microstructural variation in sensorimotor and associative cortices contributes to stable versus variable reward learning behaviour across individuals. Significance StatementThis study deepens our understanding of the neural microstructures involved in reward-related decision-making by employing advanced quantitative imaging and computational modelling to investigate brain microstructures associated with individual differences in noisy reward learning and decision-making, using a gamified task. Our results reveal distinct brain microstructures for learning rate and learning noise, which have not been reported before, thereby providing a new understanding of what may be involved in reward-based decision-making. These results provide new potential target pathways for future clinical research in psychiatric disorders where reward processing is implicated, such as ADHD and OCD.

neuroscience↗

bioRxiv2025

Functional memory of drought affects leaf chemical defenses and microbial interactions in aspen

Drought is an increasingly important driver of tree mortality, but its long-term impacts on trait expression remain poorly understood. Leaves are a key interface at which trees respond to abiotic stress, and foliar traits such as chemical defenses and microbial communities may play an important role in determining post-drought resilience. Here, we tested whether prior-year drought leaves a persistent imprint on leaf traits in Populus tremuloides. Using a three-year common garden experiment with controlled water limitation, we measured two major classes of defensive phenolics--salicinoid phenolic glycosides (SPGs) and condensed tannins (CTs)--alongside foliar fungal community composition. SPG concentrations increased and CTs declined in response to prior-year drought, with these effects persisting across growing seasons. While overall fungal community composition remained relatively stable, we detected shifts in the relative abundance of individual amplicon sequence variants (ASVs), particularly within potentially pathogenic lineages, associated with drought history. These findings provide evidence that drought leaves a legacy in leaf chemistry and microbial colonization, with potential consequences for how trees tolerate future abiotic and biotic stress. Our results highlight the importance of incorporating foliar trait legacies into models of forest resilience under climate change. Significance StatementTrees are known to exhibit long-term responses to drought, but whether such legacy effects extend to annually renewed tissues like leaves remains unclear. Our findings reveal that prior-year drought alters both chemical defenses and microbial associations in newly formed leaves, demonstrating a form of physiological memory. This work uncovers a novel mechanism by which trees integrate past environmental stress into future interactions, with implications for understanding forest resilience under climate change.

plant biology↗

bioRxiv2025

Hypoxia Imaging as a Radiomics Signature in Tumors Using Novel 19F-Eu-Based Contrast Agents for Magnetic Resonance Imaging

The ability to accurately identify and characterize regions of hypoxia has been an active area of study due to the biological ramifications of low oxygen tension in different pathological conditions, including inflammation, infections, wound healing, cardiovascular conditions, kidney and pulmonary diseases, hepatic and neurological toxicities, and cancer. Although hypoxia contributes a significant role in these conditions, the ability to accurately and instantaneously monitor the presence of hypoxia in vivo and correlate comprehensive analysis of hypoxia-dependent molecular signatures in response to treatments regimens is lacking. With the advent of hypoxia-responsive contrast agents for magnetic resonance imaging (MRI), including the recent development and characterization by our team of a novel probe that involves both 19F and EuII, the capability to integrate direct hypoxia imaging in real-time with new technologies that enable spatial transcriptomic profiling has become a possibility. To assess the capability of this agent for studying hypoxia, we used osteosarcoma as a model. In this preliminary study we demonstrate two major results: First, we show that convection-enhanced delivery (CED) is a reliable and robust methodology to distribute MRI contrast agents throughout a tumor. Second, we show that integration of direct hypoxia-detecting imaging modalities and spatial biology enables real-time in vivo insights into biology and identification of biomarkers directly applicable to disease development and response to therapy. The ability to identify and define hypoxia-mediated biology using direct rather than indirect MRI methods has extremely significant implications in the care of a wide-range of pathological conditions. Consequently, the framework outlined in these preliminary studies is applicable to other pathological conditions and provides the basis for direct in vivo hypoxia detection, monitoring, and biological analyses with translational applications to patient care and management.

cancer biology↗

bioRxiv2025

Arabidopsis arenosa influences its microbiome as a serpentine soil adaptation strategy

There is growing evidence that microbes can facilitate plant growth in metal-rich soils. However, our current understanding of how plants recruit their microbiomes under abiotic stress remains incomplete. Serpentine soils are elementally skewed, with high concentrations of magnesium and nickel, often accompanied by other heavy metals, which can limit calcium availability and present unique challenges to plant growth. These soils are also nutrient-poor, prone to erosion, and have low water-holding capacity. To date, the mechanisms by which plants adapt to serpentine soils remain poorly understood and the role of plant-associated microbiomes in this process has not been described. Here, we focus on Arabidopsis arenosa populations adapted to serpentine conditions and investigate their bacterial and fungal microbiomes to better understand the role of plant-associated microbes in serpentine adaptation. We show that serpentine soils harbour distinct plant-associated microbiomes across different plant niches and that the plant genetic background plays a key role in shaping microbial community composition. Finally, we identify serpentine-specific bacterial and fungal variants that may contribute to plant adaptation under these challenging soil conditions.

ecology↗

bioRxiv2025

Hierarchical Bayesian Modelling of Interoceptive Psychophysics

Interoception, the capacity to sense, perceive, and metacognitively appraise viscerosensory and homeostatic signals, is a growing focus in psychology and psychiatry. Adaptive psychophysical tasks now allow quantification of perceptual sensitivity, bias, and precision in cardiac and respiratory domains. However, accurately estimating these parameters often requires large numbers of trials or participants, posing practical challenges, especially in clinical research where participant availability and tolerance are limited. One approach to reduce participant burden while maintaining statistical rigour is to optimise data analysis. Here, we present hierarchical Bayesian models tailored for cardiac and respiratory interoceptive psychophysics that efficiently estimate sensitivity, bias, and precision at both individual and group levels. Using simulations and empirical data, we validate these models and demonstrate that they allow enhanced inference relative to conventional approaches. To support adoption, we provide openly-accessible resources, including a tutorial on how to implement and fit these models in R (written with researchers without modelling expertise in mind) and an app for sample-size justification. These tools facilitate robust, efficient, and generalisable modelling of interoceptive performance, enabling rigorous studies even with limited trials or participant availability.

neuroscience↗

bioRxiv2025

Internal DNA standards for Isopycnic Centrifugation of Environmental DNA in Quantitative Stable Isotope Probing

Element assimilation rates or the DNA replication rate of microbial taxa can be measured in environmental samples through quantitative DNA-stable isotope probing (DNA-qSIP). Here, we introduce a set of DNA standards that may be used to quantify the density of DNA extracted from environmental samples after isopycnic centrifugation. The standards are approximately 9 Kbp PCR products with either isotopically enriched (98 atom% 15N, 13C) nucleotides or natural abundance nucleotides and have densities that differ by 0.051 g/mL. The internal standards were tested in a DNA-qSIP analysis of bacterial populations in soil exposed to 63 atom% H218O, performed in two different laboratories with different equipment and protocols. While fractionation results, including number of fractions taken and differences in density between adjacent fractions, between the two laboratories were different, the internal standards allowed the two data sets to be compared, and both research groups found similar Excess Atom Fraction (EAF) of oxygen-18 in the DNA of bacterial taxa. These internal DNA standards allow direct comparison of DNA-qSIP results from different experiments regardless of operator, tracer enrichment levels, protocol or equipment used and can support the creation of a large global database that contains qSIP results from many different laboratories. ImportanceDNA-qSIP is an important technique in microbial ecology that allows the growth and nutrient assimilation rates of microbial taxa, including those that have not yet been cultured, to be measured. Growth and assimilation rates are extremely variable parameters in microbial ecology because most of the microbial community is dormant and inactive, which complicates linking microbial populations to ecosystem processes. DNA-qSIP is increasingly practiced in a range of laboratories, using different equipment, isotopes, substrates, and protocols, making comparison of results among different research groups challenging. Here we describe the development of internal standards, 2 pieces of DNA with different isotopic content and hence buoyant density, that can be added to environmental DNA before isopycnic centrifugation. Our results show the internal DNA standards allow DNA-qSIP results to be compared across laboratories and could contribute to the formation of a large DNA-qSIP database that contains growth or nutrient assimilation rates of microbial taxa from many different experiments.

microbiology↗

bioRxiv2025

Peripheral Beta-Blockade Differentially Enhances Cardiac and Respiratory Interoception

Interoception, the perception of internal visceral states, arises from complex brain-body interactions across the central and peripheral nervous systems. Despite noradrenalines key role in these interactions, its specific contribution to interoceptive processes remains unclear. In a placebo-controlled, randomised, within-subject study, we employed computational modelling of interoceptive psychophysics to determine how pharmacological beta-adrenoceptor antagonism controls interoception across cardiac and respiratory domains. Both cardio-selective bisoprolol and non-selective propranolol improved cardiac perceptual sensitivity, with bisoprolol exerting an enhanced effect on cardiac metacognition. In contrast, both beta-blockers increased respiratory perceptual precision, with no corresponding changes in sensitivity or metacognition. These findings reveal a novel dissociation between central and peripheral beta-adrenergic mechanisms in interoception, highlighting the pivotal role of peripheral noradrenaline in regulating multi-organ brain-body interactions. Our results suggest that beta-blockers may provide promising routes for modulating distinct facets of interoception, potentially opening new avenues for intervention in conditions characterised by disrupted bodily self-awareness.

neuroscience↗

bioRxiv2025

Integrative Epigenomic Landscape of Alzheimer's Disease Brains Reveals Oligodendrocyte Molecular Perturbations Associated with Tau

Alzheimers disease (AD) brains are characterized by neuropathologic and biochemical changes that are highly variable across individuals. Capturing epigenetic factors that associate with this variability can reveal novel biological insights into AD pathophysiology. We conducted an epigenome-wide association study of DNA methylation (DNAm) in 472 AD brains with neuropathologic measures (Braak stage, Thal phase, and cerebral amyloid angiopathy score) and brain biochemical levels of five proteins (APOE, amyloid-{beta} (A{beta})40, A{beta}42, tau, and p-tau) core to AD pathogenesis. Using a novel regional methylation (rCpGm) approach, we identified 5,478 significant associations, 99.7% of which were with brain tau biochemical measures. Of the tau-associated rCpGms, 93 had concordant associations in external datasets comprising 1,337 brain samples. Integrative transcriptome-methylome analyses uncovered 535 significant gene expression associations for these 93 rCpGms. Genes with concurrent transcriptome-methylome perturbations were enriched in oligodendrocyte marker genes, including known AD risk genes such as BIN1, myelination genes MYRF, MBP and MAG previously implicated in AD, as well as novel genes like LDB3. We further annotated the top oligodendrocyte genes in an additional 6 brain single cell and 2 bulk transcriptome datasets from AD and two other tauopathies, Picks disease and progressive supranuclear palsy (PSP). Our findings support consistent rCpGm and gene expression associations with these tauopathies and tau-related phenotypes in both bulk brain tissue and oligodendrocyte clusters. In summary, we uncover the integrative epigenomic landscape of AD and demonstrate tau-related oligodendrocyte gene perturbations as a common potential pathomechanism across different tauopathies.

genomics↗

bioRxiv2024

ggrain - a ggplot2 extension for raincloud plots

Clear data visualization is essential to effectively communicate empirical findings across various research fields. Raincloud plots fill this need by offering a transparent and statistically robust approach to data visualization. This is achieved by combining three plots in an aesthetically pleasing fashion. First, a dot plot displays raw data with minimal distortion, allowing a fast glance at the sample size and outlier identification. Next, a box plot displays key distributional summary statistics such as the median and interquartile range. Lastly, a violin plot transparently displays the underlying distribution of the data. Despite the widespread use of raincloud plots, an R-package in alignment with the grammar of graphics was lacking. `ggrain` fills this need by offering one easy-to-use function (`geom_rain`) allowing the quick and seamless plotting of rainclouds in the R ecosystem. Further, it enables more complex plotting features such as factorial grouping, mapping with a secondary (continuous) covariate, and connecting observations longitudinally across multiple waves.

scientific communication and education↗

bioRxiv2024

Putative neofunctionalization of a Poales-specific EXO70 clade

EXO70s are uniquely expanded in land plants compared to all other eukaryotic lineages. The functional implications of this expansion and diversification on the conserved role of EXO70 as a subunit of the octameric exocyst complex have remained unresolved. We previously demonstrated barley (Hordeum vulgare) EXO70FX12, a member of the monocot-specific EXO70FX clade, is required for resistance to wheat stripe rust in conjunction with the leucine-rich repeat receptor kinase (LRR-RK) HvPUR1. Through phylogenetic analysis, we identified unique features of the EXO70FX clade, leading us to hypothesize that this clade experienced neofunctionalization. Using structural predictions and protein-protein interaction assays, we demonstrate that HvEXO70FX12 lost the ability to serve as a subunit within the exocyst complex. We predict that the EXO70FX clade has largely lost exocyst association and represents a novel acquisition that emerged during Poales diversification for immunity.

plant biology↗

bioRxiv2024

deadtrees.earth - An Open-Access and Interactive Database for Centimeter-Scale Aerial Imagery to Uncover Global Tree Mortality Dynamics

Excessive tree mortality is a global concern and remains poorly understood as it is a complex phenomenon. We lack global and temporally continuous coverage on tree mortality data. Ground-based observations on tree mortality, e.g., derived from national inventories, are very sparse, not standardized and not spatially explicit. Earth observation data, combined with supervised machine learning, offer a promising approach to map tree mortality over time. However, global-scale machine learning requires broad training data covering a wide range of environmental settings and forest types. Drones provide a cost-effective source of training data by capturing high-resolution orthophotos of tree mortality events at sub-centimeter resolution. Here, we introduce deadtrees.earth, an open-access platform hosting more than a thousand centimeter-resolution orthophotos, covering already more than 300,000 ha, of which more than 58,000 ha are fully annotated. This community-sourced and rigorously curated dataset shall serve as a foundation for a global initiative to gather comprehensive reference data. In concert with Earth observation data and machine learning it will serve to uncover tree mortality patterns from local to global scales. This will provide the foundation to attribute tree mortality patterns to environmental changes or project tree mortality dynamics to the future. Thus, the open and interactive nature of deadtrees.earth together with the collective effort of the community is meant to continuously increase our capacity to uncover and understand tree mortality patterns.

ecology↗

bioRxiv2024

Increased stomach-brain coupling indexes a dimensional signature of negative mental health symptoms.

Visceral rhythms orchestrate the physiological states underlying human emotion. Chronic aberrations in these brain-body interactions are implicated in a broad spectrum of mental health disorders. However, the relationship of gastric-brain coupling to affective symptoms remains poorly understood. We investigated the relationship between this novel interoceptive axis and mental health in 243 participants, using a cross validated machine learning approach. We find that increased fronto-parietal brain coupling to the gastric rhythm indexes a dimensional signature of worse mental health, spanning anxiety, depression, stress, and well-being. Control analyses confirm the specificity of these interactions to the gastric-brain axis. Our study proposes coupling between the stomach and brain as a factor in mental health and offers potential new targets for interventions remediating aberrant brain-body coupling.

neuroscience↗

bioRxiv2024

Large- Scale Deep Proteomic Analysis in Alzheimer's Disease Brain Regions Across Race and Ethnicity

AbstractO_ST_ABSIntroductionC_ST_ABSAlzheimers disease (AD) is the most prevalent neurodegenerative disease, yet our comprehension predominantly relies on studies within the non-Hispanic White (NHW) population. Here we aimed to provide comprehensive insights into the proteomic landscape of AD across diverse racial and ethnic groups. MethodsDorsolateral prefrontal cortex (DLPFC) and superior temporal gyrus (STG) brain tissues were donated from multiple centers (Mayo Clinic, Emory University, Rush University, Mt. Sinai School of Medicine) and were harmonized through neuropathological evaluation, specifically adhering to the Braak staging and CERAD criteria. Among 1105 DLPFC tissue samples (998 unique individuals), 333 were from African American donors, 223 from Latino Americans, 529 from NHW donors, and the rest were from a mixed or unknown racial background. Among 280 STG tissue samples (244 unique individuals), 86 were African American, 76 Latino American, 116 NHW and the rest were mixed or unknown ethnicity. All tissues were uniformly homogenized and analyzed by tandem mass tag mass spectrometry (TMT-MS). ResultsAs a Quality control (QC) measure, proteins with more than 50% missing values were removed and iterative principal component analysis was conducted to remove outliers within brain regions. After QC, 9,180 and 9,734 proteins remained in the DLPC and STG proteome, respectively, of which approximately 9,000 proteins were shared between regions. Protein levels of microtubule-associated protein tau (MAPT) and amyloid-precursor protein (APP) demonstrated AD-related elevations in DLPFC tissues with a strong association with CERAD and Braak across racial groups. APOE4 protein levels in brain were highly concordant with APOE genotype of the individuals. DiscussionThis comprehensive region resolved large-scale proteomic dataset provides a resource for the understanding of ethnoracial-specific protein differences in AD brain.

neuroscience↗

bioRxiv2024

Bridging the Gap: Multi-Omics Profiling of Brain Tissue in Alzheimer's Disease and Older Controls in Multi-Ethnic Populations

INTRODUCTIONMulti-omics studies in Alzheimers disease (AD) revealed many potential disease pathways and therapeutic targets. Despite their promise of precision medicine, these studies lacked African Americans (AA) and Latin Americans (LA), who are disproportionately affected by AD. METHODSTo bridge this gap, Accelerating Medicines Partnership in AD (AMP-AD) expanded brain multi-omics profiling to multi-ethnic donors. RESULTSWe generated multi-omics data and curated and harmonized phenotypic data from AA (n=306), LA (n=326), or AA and LA (n=4) brain donors plus Non-Hispanic White (n=252) and other (n=20) ethnic groups, to establish a foundational dataset enriched for AA and LA participants. This study describes the data available to the research community, including transcriptome from three brain regions, whole genome sequence, and proteome measures. DISCUSSIONInclusion of traditionally underrepresented groups in multi-omics studies is essential to discover the full spectrum of precision medicine targets that will be pertinent to all populations affected with AD.

neuroscience↗

bioRxiv2024

Microstructural Brain Correlates of Inter-individual Differences in Respiratory Interoception

Interoception, the perception and integration of physiological signals, is a fundamental aspect of self-awareness and homeostasis. While previous work has explored interoceptive processing in relation to the cardiac system, research in the respiratory domain, particularly in relation to brain structure and function, is limited. To address this gap, we utilised a Bayesian psychophysical model to quantify perceptual, metacognitive, and affective dimensions of respiratory interoception in a sample of 207 healthy participants. We also measured individual whole-brain microstructural indices of myelination, myeloarchitecture, and cortical iron using quantitative brain imaging. Voxel-based quantification analyses revealed distinct patterns of cortical microstructure in the insular, cingulate, and primary sensory cortices, which underpin interoceptive perceptual sensitivity and precision. In addition, metacognitive bias was associated with increased myelination of the cingulate cortex and periaqueductal grey, while metacognitive sensitivity correlated with myelination of the midline prefrontal cortex. At an affective level, sensitivity to respiratory resistance was related to the myelination of the primary somatosensory cortex. By revealing specific histological brain patterns tied to individual differences in respiratory interoception, our results uncover the neural pathways that govern perceptual, metacognitive, and emotional facets of interoceptive processing.

neuroscience↗

bioRxiv2024

The respiratory cycle modulates distinct dynamics of affective and perceptual decision-making

Respiratory rhythms play a critical role not only in homeostatic survival, but also in modulating other non-interoceptive perceptual and affective processes. Recent evidence from both human and rodent models indicates that neural and behavioural oscillations are influenced by respiratory state as breathing cycles from inspiration to expiration. To explore the mechanisms behind these effects, we carried out a psychophysical experiment where 41 participants categorised dot motion and facial emotion stimuli in a standardised discrimination task. When comparing behaviour across respiratory states, we found that inspiration accelerated responses in both domains. We applied a hierarchical evidence accumulation model to determine which aspects of the latent decision process best explained this acceleration. Computational modelling showed that inspiration reduced evidential decision boundaries, such that participants prioritised speed over accuracy in the motion task. In contrast, inspiration shifted the starting point of affective evidence accumulation, inducing a bias towards categorising facial expressions as more positive. These findings provide a novel computational account of how respiratory rhythms modulate distinct aspects of perceptual and affective decision-dynamics.

neuroscience↗