Biology subjects

Bennett, I.

Publications and source records attributed to Bennett, I..

3 recordsLinked to original sources

bioRxiv2025

Connectome-based predictive modelling predicts frailty levels in older adults

Frailty is characterized by a persistent and progressive decline in physiological reserves, leading to increased vulnerability to stressors and a heightened risk of adverse health outcomes, both physically and mentally. Despite frailtys prevalence in older adults, there is limited research on its neural substrates, especially using task-based brain functional connectivity. In this study, we used connectome-based predictive modelling (CPM) to find a linear relationship between task-based connectomes -- taken from tasks that involved similar handgrip manipulations -- and a separate measure of frailty: the maximum grip strength in older adults. We observed that the task-based connectomes were able to explain individual differences in grip strength, with the Subcortical and Cerebellum network, particularly the caudate nucleus, functional connectivity being the strongest predictor. These findings demonstrate that task-based functional connectomes can serve as personalized markers that can predict individual behavioral measures, including handgrip strength, and point to involvement of the caudate nucleus in frailty. Key pointsO_LIWe used connectome-based predictive modeling on task-based fMRI to predict grip strength in older adults, a key marker of physical frailty. C_LIO_LIThe model significantly explained inter-individual differences in contraction strength using functional connectivity patterns. C_LIO_LISubcortical regions, especially the caudate nucleus, played a major role in prediction, highlighting their relevance in frailty assessment and potential interventions. C_LI

neuroscience↗

bioRxiv2022

Hippocampal microstructure, but not macrostructure, mediates age differences in episodic memory

Separate unimodal magnetic resonance imaging (MRI) literatures have shown that hippocampal gray matter macrostructure (volume) and microstructure (diffusion) decline in aging and relate to episodic memory performance, with multimodal MRI studies reporting that episodic memory may be better explained by a combination of these metrics. However, these effects are often assessed independent of age or only within older adults and therefore do not address whether these distinct modalities mediate the effect of age on episodic memory. Here, we simultaneously examined the unique and joint contribution of hippocampal volume and diffusion to age-related differences in episodic memory in 83 younger and 61 older adults who underwent a T1-and diffusion-weighted MRI and completed the Rey Auditory Verbal Learning Test. As expected, older age was significantly related to smaller volume and higher diffusion (intracellular, dispersion, and free) in bilateral hippocampus and to worse episodic memory performance (immediate and delayed free recall, recognition). Structural equation modelling revealed that the age-memory relationship was significantly mediated by hippocampal diffusion, but not volume. A non-significant influential indirect effect further revealed that the structural metrics did not jointly mediate the age-memory relationship. Together, these findings indicate that hippocampal microstructure uniquely contributes to age-related differences in episodic memory and suggest that volume and diffusion capture distinct neurobiological properties of hippocampal gray matter.

neuroscience↗

bioRxiv2019

Rapid antimicrobial sensitivity testing by single cell nanoscale optical interference

Growing antimicrobial resistance (AMR) is a serious global threat to human health. Current methods to detect resistance include phenotypic antibiotic sensitivity testing (AST) which measures bacterial growth and is therefore hampered by slow time to result (~12-24 hours). Therefore new rapid phenotypic methods for AST are urgently needed. Nanomechanical cantilever sensors have recently shown promise for rapid AST but challenges of bacterial immobilization can lead to variable results. Herein a novel cantilever-based method is described for detecting phenotypic antibiotic resistance within ~45 minutes, capable of detecting single bacteria. This method does not require complex, variable bacterial immobilization, and instead uses the laser and detector system to detect single bacterial cells in media as they pass through the laser focus. This provides a simple read out of bacterial antibiotic resistance by detecting growth (resistant) or death (sensitive), much faster than current methods. The potential of this technique demonstrated by determining resistance in both lab and clinical strains of E. coli, a key species for clinically burdensome urinary tract infections. This work provides the basis for a simple and fast diagnostic tool to detect antibiotic resistance in bacteria, reducing the health and economic burdens of AMR.

biophysics↗