Biology subjects

Connor, T.

Publications and source records attributed to Connor, T..

9 recordsLinked to original sources

bioRxiv2026

Hemodynamic Signals Reshape Biological Inference in Widefield Calcium Imaging

Widefield calcium imaging is widely used to study cortex-wide neural dynamics, yet fluorescence signals are strongly influenced by hemodynamic fluctuations arising from blood volume and oxygenation changes. Although hemodynamic correction is frequently applied, it remains unclear whether vascular contributions represent a modest preprocessing concern or systematically bias biological interpretations of cortical activity. Here, we used dual-wavelength imaging to determine how hemodynamic correction reshapes inference of cortical dynamics across mouse lines expressing GCaMP6s, GCaMP6f, and jGCaMP8m, across multiple analytical domains, and under healthy and glioblastoma conditions. We systematically compared uncorrected and corrected signals using analyses spanning functional parcellation, connectivity, spectral structure, brain-behavior coupling, and low-dimensional network-state dynamics. Hemodynamic correction consistently reduced global functional connectivity, increased network modularity, redistributed spectral power away from slow-frequency dominance, and reorganized multivariate representations of cortical state space. These findings demonstrate that vascular signals do not behave as unstructured measurement noise but instead introduce organized variance that propagates across analytical pipelines and influences inference of cortical dynamics. The consequences of this bias were particularly relevant in glioblastoma, where tumor-associated vascular remodeling amplifies the mismatch between fluorescence signals and underlying neuronal activity. In this disease setting, correction revealed hemispheric asymmetries, reduced network-state entropy, and constrained trajectories within cortical state space that were obscured in uncorrected recordings, demonstrating that vascular remodeling can fundamentally alter interpretation of tumor-associated brain dynamics. More broadly, vascular signals systematically biased estimates of functional organization, network architecture, brain-behavior relationships, and disease-associated phenotypes. Together, these findings establish hemodynamic correction as a critical determinant of biological interpretation in mesoscale calcium imaging rather than a simple preprocessing refinement.

neuroscience↗

bioRxiv2026

A Deterministically Synchronized Widefield Imaging and Virtual Reality Platform for Multimodal Brain Behavior Recording

ObjectiveSimultaneous recording of brain activity, behaviour, and virtual environments is essential for understanding large-scale neural dynamics during behaviour. However, existing systems often rely on software-based synchronization or post hoc alignment, introducing latency, jitter, and drift that obscure fast brain-behavior interactions. ApproachHere, we present a deterministically synchronized widefield calcium imaging platform that unifies neural imaging, high-speed behavioural monitoring, and closed-loop virtual reality (VR) under a shared hardware-defined clock. This system enables millisecond-precision temporal alignment across modalities, including dual-wavelength hemodynamic correction, pupil and orofacial tracking, locomotion sensing, and VR rendering. Main resultsThe platform achieves stable hardware-level synchronization across neural imaging, behavioural recordings, and VR rendering without reliance on software timestamps. It supports widefield imaging rates up to 100 Hz and integrates seamlessly with both ViRMEn and Blender VR engines, exhibiting a mean locomotion-to-VR update latency of [~]1.5 ms. Multimodal recordings during VR navigation demonstrate robust temporal alignment between cortical activity, facial dynamics, pupil signals, and locomotion. SignificanceThis system provides a deterministic multimodal framework for studying brain-behaviour relationships during active behaviour. By enabling millisecond-precision synchronization across neural imaging, behaviour, and virtual environments, this platform enables causal investigation of brain-behaviour interactions at millisecond precision and provides a foundation for next-generation closed-loop neuroengineering experiments.

neuroscience↗

bioRxiv2026

NeuroPupil: A generalization-first framework for scalable and biologically informative cross-species pupillometry

Quantitative pupillometry provides a noninvasive window into brain state and neurological function, but its broader use across experimental and clinical settings is limited by challenges in achieving accurate, scalable, and generalizable measurements. Here, we present NeuroPupil, a deep learning framework for high-throughput, cross-species pupillometry that emphasizes robust generalization across subjects, behavioral contexts, and imaging conditions. Through systematic benchmarking of training strategies and network architectures, we identify pooled multi-subject training combined with an optimized U-Net architecture as a key determinant of reliable and transferable pupil tracking performance. Across diverse mouse and human datasets, NeuroPupil achieves improved accuracy and substantial gains in computational efficiency compared to existing approaches, enabling practical analysis of large-scale datasets. We further demonstrate that improved pupil tracking fidelity enhances downstream biological inference: NeuroPupil-derived pupil features significantly improve prediction of distributed cortical activity in behaving mice and preserve diagnostically relevant temporal structure in human clinical recordings. These findings highlight the importance of precise and scalable measurement for linking pupil dynamics to brain activity and clinical phenotypes. By integrating benchmarking, scalability, and accessible software tools, NeuroPupil provides a reproducible framework for large-scale pupillometry and facilitates its application in systems and translational neuroscience.

neuroscience↗

bioRxiv2025

DeepFace: A High-Precision and Scalable Deep Learning Pipeline for Predicting Large-Scale Brain Activity from Facial Dynamics in Mice

We present DeepFace, a next-generation facial analysis pipeline that enhances orofacial tracking and cortical activity prediction in mice. Rather than replacing existing tools, DeepFace builds upon DeepLabCut and Facemap to address scalability bottlenecks and improve behavioral quantification. It offers high precision, keypoint customization, and robust performance across GCaMP6s, GCaMP6f, and jGCaMP8m lines. With scalable batch processing and high-performance computing compatibility, DeepFace enables high-throughput brain-behavior analysis in large-scale preclinical neuroscience.

neuroscience↗

bioRxiv2024

Transcutaneous Vagus Nerve Stimulation Reduces Pain and OA Progression in Mouse Models of Post-Traumatic Osteoarthritis

Currently, there are no disease-modifying osteoarthritis (OA) drugs (DMOAD) to prevent OA progression and there are limitations on pain relieving therapeutics. Vagus nerve stimulation (VNS) delivered by an implantable device is FDA-approved for refractory epilepsy and severe depression. Here, we investigated the efficacy of transcutaneous VNS (tVNS) for preventing OA progression and providing pain relief in two mouse models of post-traumatic OA (PTOA): the surgical destabilized medial meniscus (DMM) and the non-surgical forced tibial compression anterior cruciate ligament rupture (ACLR). Here, we show that 2 weeks of tVNS significantly reduced histological OA scores in male and female mice after ACLR compared to sham stimulation. In female, but not male, mice, tVNS reduced hyperalgesia and mechanical allodynia. In the slower DMM model, 8 weeks of tVNS improved weight bearing in male and female mice, but only female mice had improved hyperalgesia. Male mice had lower OA histological scores. Serum proinflammatory cytokines were significantly reduced by tVNS in both models but differed by gender and model. Overall, these results provide strong pre-clinical evidence that tVNS reduces OA progression, improves pain, and suppresses pro-inflammatory cytokines, making it a promising DMOAD.

physiology↗

bioRxiv2024

Adipose tissue protein kinase D (PKD): regulation of signalling networks and its sex-dependent effects on metabolism

The protein kinase D (PKD) family of three highly homologous isoforms (PKD1, PKD2, and PKD3) are implicated as nutrient sensing signalling kinases that regulate the response of adipose and other tissues to the nutrient environment. However, the physiological role of adipose tissue PKD and its downstream cellular signalling targets are not well characterised. Phosphoproteomics was performed to elucidate signalling events downstream of PKD activation in differentiated 3T3L1 adipocytes using a triple isoform siRNA knockdown model. This revealed PKD-regulated pathways including insulin and cAMP signalling, which control metabolic responses in adipose tissue. An adipose tissue-specific and inducible dominant negative PKD (atDNPKD) mouse model that achieves functional inhibition of all three PKD isoforms was generated to assess the function of adipose PKD on whole-body metabolism in vivo in both male and female mice. Insulin-stimulated suppression of lipolysis was blunted in male, but not female, atDNPKD mice compared to control mice. Female, but not male, atDNPKD mice had higher fasting insulin but normal insulin action. Male atDNPKD mice showed greater sensitivity to the {beta}3-adrenergic receptor agonist CL316,243 on measures of lipolysis and energy expenditure, and displayed greater fat oxidation during fasting. During refeeding, male atDNPKD mice consumed less food and took longer to regain body weight lost during fasting. These effects were not observed in female mice. These findings indicate that PKD provides sex-dependent fine-tuning control of cAMP signalling in adipose tissue that is important for the coordination of energy balance during fasting and refeeding. NEW & NOTEWORTHYThe protein kinase D (PKD) family is a target for the treatment of obesity-related disorders. However, the physiological role of PKD in adipose tissue remains to be resolved. Using phosphoproteomics and an adipose tissue PKD loss-of-function mouse model, results demonstrate that PKD provides fine tuning of metabolic signalling in adipose tissue and metabolic responses to fasting and refeeding challenges, via coordination of feeding behaviour and regulation of body weight.

physiology↗

bioRxiv2023

Afanc: a Metagenomics Tool for Variant Level Disambiguation of NGS Datasets

Genomics is amongst the most powerful tools available for mounting a clinical response to infectious disease. The accurate and precise taxonomic evaluation of pathogens is essential when building a picture of pathogenicity, virulence, transmission, and drug resistance. Carrying out such profiling in a high throughput manner necessitates the development of reliable bioinformatic tools. Here we present Afanc, a novel metagenomic profiler which is sensitive down to species and strain level taxa, and capable of elucidating the complex pathogen profile of compound datasets. We compared Afanc against currently available cutting edge profilers using 3 datasets: single species read sets simulated from the full Mycobacteriaceae taxonomic landscape; compound read sets containing multiple Mycobacteriaceae species and variants; and real data covering the majority of the M. tuberculosis lineage taxonomic space. Afanc outperformed all profilers, both generic and Mycobacteriaceae specific, across all tested fields. As a species agnostic profiler, we predict that Afanc will be of great utility when carrying out highly specific and sensitive pathogen profiling of clinical datasets. Such analyses are essential in advising both the clinical response to an individual disease case, and in forming the foundation of epidemiological surveys.

bioinformatics↗

bioRxiv2022

Class IIa HDACs reprogram mitochondrial metabolism to inhibit apoptosis and ferroptosis in response to lipotoxicity

Lipotoxicity, the accumulation of lipids in non-adipose tissues, alters the metabolic transcriptome and mitochondrial metabolism in skeletal muscle. The mechanisms involved remain poorly understood. Here we show that lipotoxicity increased histone deacetylase 4 (HDAC4) and histone deacetylase 5 (HDAC5), which reduced the expression of metabolic genes and oxidative metabolism in skeletal muscle, resulting in increased non-oxidative glucose metabolism. This metabolic reprogramming was also associated with impaired apoptosis and ferroptosis responses, and preserved muscle cell viability in response to lipotoxicity. Mechanistically, increased HDAC4 and 5 decreased acetylation of p53 at K120, a modification required for transcriptional activation of apoptosis. Redox drivers of ferroptosis derived from oxidative metabolism were also reduced. The relevance of this pathway was demonstrated by overexpression of loss-of-function HDAC4 and HDAC5 mutants in skeletal muscle of obese db/db mice, which enhanced oxidative metabolic capacity, increased apoptosis and ferroptosis and reduced muscle mass. This study identifies HDAC4 and HDAC5 as repressors of skeletal muscle oxidative metabolism, which is linked to inhibition of cell death pathways and preservation of muscle integrity in response to lipotoxicity.

cell biology↗

bioRxiv2022

Amyloid beta 42 alters cardiac metabolism and impairs cardiac function in obesity

There are epidemiological associations between obesity and type 2 diabetes, cardiovascular disease and Alzheimers disease. While some common aetiological mechanisms are known, the role of amyloid beta 42 (A{beta}42) in these diverse chronic diseases is obscure. Here we show that adipose tissue releases A{beta}42, which is increased from adipose tissue of obese mice and is associated with higher plasma A{beta}42. Increasing circulating A{beta}42 levels in non-obese mice had no effect on systemic glucose homeostasis but had obesity-like effects on the heart, including reduced cardiac glucose clearance and impaired cardiac function. These effects on cardiac function were not observed when circulating levels of the closely related A{beta}40 isoform were increased. Administration of an A{beta} neutralising antibody prevented obesity-induced cardiac dysfunction and hypertrophy. Furthermore, A{beta} neutralising antibody administration in established obesity prevented further deterioration of cardiac function. Multi-contrast transcriptomic analyses revealed that A{beta}42 impacted pathways of mitochondrial metabolism and exposure of cardiomyocytes to A{beta}42 inhibited mitochondrial function. These data reveal a role for systemic A{beta}42 in the development of cardiac disease in obesity and suggest that therapeutics designed for Alzheimers disease could be effective in combating obesity-induced heart failure.

physiology↗