Biology subjects

Burrows, M.

Publications and source records attributed to Burrows, M..

4 recordsLinked to original sources

bioRxiv2026

Multimodal imaging suggests potential immune-vascular contributions to altered regional brain perfusion and oxygen metabolism in Post-COVID-19 Syndrome

Post-COVID-19 Syndrome (PCS) frequently presents with persistent fatigue, cognitive impairment, and emotional symptoms. Although structural brain changes remain subtle, growing evidence implicates functional and metabolic disruptions in ongoing symptomatology. We used multimodal MRI to investigate cerebral perfusion and oxygen metabolism in PCS and examined their associations with cognitive function and peripheral biomarkers. We enrolled 40 individuals with prior mild SARS-CoV-2 infection, including 20 with persistent fatigue and 20 recovered controls matched for age, sex, BMI, and acute COVID-19 severity. Participants underwent structural MRI, arterial spin labelling (ASL) to quantify regional cerebral blood flow (CBF), and asymmetric spin echo imaging to estimate oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen consumption (CMRO{square}). We assessed cognition using an online battery and measured serum levels of TNF-, IL-6, IL-8, IL-13, IFN-{gamma}, GFAP, and S100{beta}, alongside blood routine tests. We performed ANCOVAs on predefined regions of interest (hippocampus, anterior cingulate cortex [ACC], insula, amygdala, striatum), followed by Bayesian inference and exploratory whole-brain analyses. PCS participants showed increased CMRO{square} in the hippocampus and decreased CMRO{square} in the ACC. Subfield analysis revealed elevated OEF and CMRO{square} across most hippocampal regions, excluding the entorhinal cortex. Whole-brain analyses identified increased perfusion in salience-related regions (insula, ACC, thalamus) and decreased perfusion in posterior cortical and cerebellar areas, in the absence of grey matter volume differences. Higher hippocampal metabolism positively correlated with cognitive performance, suggesting compensatory adaptation to sustain function. In contrast, lower ACC CMRO{square} correlated with depressive symptoms, reduced motivation, and elevated TNF- and GFAP, consistent with neurovascular uncoupling possibly driven by immune-glial activation. These findings reveal distinct physiological disruptions in PCS, with potential implications for stratified, metabolism-focused interventions.

neuroscience↗

bioRxiv2025

Inhibiting Glycan Degradation Prevents HIV-Induced Inflammaging and Cognitive Impairment

Cognitive impairment is a frequent outcome of chronic viral infections linked to premature aging, including HIV. The mechanisms underlying this decline remain poorly understood. Here, we identify pro-inflammatory glycan degradation, characterized by loss of sialic acid and galactose, alterations that are hallmarks of premature aging, as key contributors to HIV-associated cognitive impairment (HIV-CI). In two independent cohorts of people living with HIV, these degradative changes were enriched in individuals with cognitive impairment, particularly females, and correlated with worse cognitive performance. In both a humanized mouse model of HIV and Eco-HIV, a complementary model that allows behavioral testing, pharmacological inhibition of glycan degradation with sialidase inhibitors prevented virally induced inflammation, immune activation, accelerated aging, and memory deficits. These findings implicate glycan degradation as a contributor to inflammation and cognitive impairment in HIV and highlight glycan-preserving therapies as a promising strategy to mitigate inflammation, premature aging, and cognitive decline during viral infections.

microbiology↗

bioRxiv2020

Elucidating the complex organization of neural micro-domains in the locust Schistocerca gregaria using dMRI

To understand brain function it is necessary to characterize both the underlying structural connectivity between neurons and the physiological integrity of these connections. Previous research exploring insect brain connectivity has used microscopy techniques, but this methodology is time consuming and cannot be applied to living animals and so cannot be used to understand dynamic physiological processes. The relatively large brain of the desert locust, Schistercera gregaria (Forks[a]l) is ideal for exploring a novel methodology; diffusion magnetic resonance imaging (dMRI) for the characterization of neuronal connectivity in an insect brain. The diffusion-weighted imaging (DWI) data were acquired on a preclinical system using a customised multi-shell diffusion MRI scheme. Endogenous imaging contrasts from the averaged DWIs and Diffusion Kurtosis Imaging (DKI) scheme were applied to classify various anatomical features and diffusion patterns in neuropils, respectively. The application of micro-MRI and dMRI modelling to the locust brain provides a novel means of identifying anatomical regions and connectivity in an insect brain. Furthermore, quantitative imaging indices derived from the kurtosis model that include fractional anisotropy (FA), mean diffusivity (MD) and kurtosis anisotropy (KA) could, in future, be used to quantify longitudinal structural changes in neuronal connectivity due to environmental stressors or ageing.

neuroscience↗

bioRxiv2018

The BRadykinesia Akinesia INcoordination (BRAIN) tap test: capturing the sequence effect

BackgroundThe BRAIN tap test is an online keyboard tapping task that has been previously validated to assess upper limb motor function in Parkinsons disease (PD).\n\nObjectivesTo develop a new parameter which detects a sequence effect and to reliably distinguish between PD patients on and off medication. Alongside, we sought to validate a mobile version of the test for use on smartphones and tablet devices.\n\nMethodsBRAIN test scores in 61 patients with PD and 93 healthy controls were compared. A range of established parameters captured speed and accuracy of alternate taps. The new VS (Velocity Score) recorded the inter-tap speed. Decrement in the VS was used as a marker for the sequence effect. In the validation phase, 19 PD patients and 19 controls were tested using multiple types of hardware platforms including smart devices.\n\nResultsQuantified slopes from the VS demonstrated bradykinesia (sequence effect) in PD patients (slope cut-off -0.002) with sensitivity of 58% and specificity of 81% (discovery phase of the study) and sensitivity of 65% and specificity of 88% (validation phase). All BRAIN test parameters differentiated between on medication and off medication states in PD. Most BRAIN tap test parameters had high test-retest reliability values (ICC>0.75). Differentiation between PD patients and controls was possible on all hardware versions of the test.\n\nConclusionThe BRAIN tap test is a simple, user-friendly and free-to-use tool for assessment of upper limb motor dysfunction in PD, which now includes a measure of bradykinesia.

neuroscience↗