Biology subjects

Suo, C.

Publications and source records attributed to Suo, C..

3 recordsLinked to original sources

bioRxiv2020

The effects of regular aerobic exercise on hippocampal structure and function

Regular exercise has numerous benefits for brain health, including the structure and function of the hippocampus. The hippocampus plays a critical role in memory function, and is altered in a number of psychiatric disorders associated with memory impairments (e.g. depression and schizophrenia), as well as healthy ageing. While many studies have focussed on how regular exercise may improve hippocampal integrity in older individuals, less is known about these effects in young to middle-aged adults. Therefore, we assessed the associations of regular exercise and cardiorespiratory fitness with hippocampal structure and function in these age groups. We recruited 40 healthy young to middle-aged adults, comprised of two groups (n = 20) who self-reported either high or low levels of exercise, according to World Health Organisation guidelines. We assessed cardiorespiratory fitness using a graded exercise test (VO2max) and hippocampal structure via manual tracing of T1-weighted magnetic resonance images. We also assessed hippocampal function using magnetic resonance spectroscopy to derive estimates of NAA concentration and hippocampal-dependent associative memory and pattern separation tasks. We observed evidence of increased N-acetyl-aspartate concentration and associative memory performance in individuals engaging in high levels of exercise. However, no differences in hippocampal volume or pattern separation capacity were observed between groups. Cardiorespiratory fitness was positively associated with hippocampal volume (left, right, and bilateral), N-acetyl-aspartate concentration, and pattern separation. However, no association was observed between cardiorespiratory fitness and associative memory. Therefore, we provide evidence that higher levels of exercise and cardiorespiratory fitness are associated with improved hippocampal structure and function. Exercise may provide a low-risk, effective method of improving hippocampal integrity in an early-to-mid-life stage.

neuroscience↗

bioRxiv2020

INSIGHT: a scalable isothermal NASBA-based platform for COVID-19 diagnosis

We present INSIGHT (Isothermal NASBA-Sequencing-based hIGH-througput Test): a two-stage COVID-19 testing strategy, using a barcoded isothermal NASBA reaction that combines point-of-care diagnosis with next generation sequencing, aiming to achieve population-scale COVID-19 testing. INSIGHT combines the advantages of near-patient with centralised testing. Stage 1 allows a quick decentralised readout for early isolation of pre-symptomatic or asymptomatic patients. The same reaction products can then be used in a highly multiplexed sequencing-based assay in Stage 2, confirming the near-patient testing results and facilitating centralised data collection. Based on experiments using commercially acquired human saliva with spiked-in viral RNA as input, the INSIGHT platform gives Stage 1 results within one to two hours, using either fluorescence detection or a lateral flow (dipstick) readout, whilst simultaneously incorporating sample-specific barcodes into the amplification product. INSIGHT Stage 2 can be performed by directly pooling and sequencing all post-amplification barcoded Stage 1 products from hundreds of thousands of samples with minimal sample preparation steps. The 95% limit of detection (LoD-95) for INSIGHT is estimated to be below 50 copies of viral RNA per 20 l of reaction. Our two-stage testing strategy is suitable for further development into a rapid home-based and point-of-care assay, and is potentially scalable to the population level.

molecular biology↗

bioRxiv2020

Multi-day rTMS exerts site-specific effects on functional connectivity but does not influence associative memory performance

Transcranial magnetic stimulation (TMS) is a non-invasive brain stimulation technique with the capacity to modulate brain network connectivity and cognitive function. Recent studies have demonstrated long-lasting improvements in associative memory and resting-state connectivity following multi-day repetitive TMS (rTMS) to individualised parietal-hippocampal networks. We aimed to assess the reproducibility and network- and cognitive-specificity of these effects following multi-day rTMS. Participants received four days of 20 Hz rTMS to a subject-specific region of left lateral parietal cortex exhibiting peak functional connectivity to the left hippocampus. In a separate week, the same stimulation protocol was applied to a subject-specific region of pre-supplementary motor area (pre-SMA) exhibiting peak functional connectivity to the left putamen. We assessed changes to associative memory before and after each week of stimulation (N = 39), and changes to resting-state functional connectivity before and after stimulation in week one (N = 36). We found no evidence of long-lasting enhancement of associative memory or increased parieto-hippocampal connectivity following multi-day rTMS to the parietal cortex, nor increased pre-SMA-putamen connectivity following multi-day rTMS to pre-SMA. Instead, we observed some evidence of site-specific modulations of functional connectivity lasting [~]24 hours, with reduced connectivity within targeted networks and increased connectivity across distinct non-targeted networks. Our findings suggest a complex interplay between multi-day rTMS and network connectivity. Further work is required to develop reliable rTMS paradigms for driving changes in functional connectivity between cortical and subcortical regions.

neuroscience↗