Biology subjects

Dickerson, B.

Publications and source records attributed to Dickerson, B..

4 recordsLinked to original sources

bioRxiv2026

Characterisation of Posterior Predominant Amyloid PET Binding Across Multiple Cohorts

The standard approach to quantify amyloid (A{beta}) PET averages uptake within a single cortical mask that assumes no clinically relevant spatial heterogeneity in uptake patterns. Here, in a sample of 12,379 clinically impaired participants taken from four phenotypically diverse cohorts we use data-driven approaches to discover heterogeneous patterns of A{beta}-PET binding, uncovering a reproducible and clinically relevant pattern of posterior predominant A{beta}-PET binding. In particular, A{beta}-PET positive participants who have posterior predominant binding are less likely to be APOE-{varepsilon}4 carriers, more severely impaired, have thinner cortex in posterior regions, and greater posterior tau PET burden. Furthermore, in a subsample of participants with neuropathological assessment, participants with posterior predominant A{beta} binding have a higher likelihood of having cerebral amyloid angiopathy at autopsy. These findings suggest that A{beta}-PET accumulates along two orthogonal axes with biological and clinical relevance, indicating that the standard approach to assess A{beta}-PET is insufficient to capture meaningful signal from A{beta}-PET imaging. This work has implications for the diagnosis and treatment of Alzheimers disease and extends our understanding of the mechanisms governing variable A{beta}-PET distribution and its downstream effects.

neuroscience↗

bioRxiv2025

Noncoding and Coding Mechanisms of Aging Heart Failure with Preserved Ejection Fraction with Thyroid Dysfunction

Heart Failure with preserved Ejection Fraction (HFpEF) is a heterogeneous geriatric syndrome with complex pathophysiology and comorbidities. Long noncoding RNAs (lncRNAs) account for a large majority of the functional mammalian transcriptome and act as key regulators in complex physiological and pathological processes. However, the role of lncRNAs and the development of thyroid dysfunction in aging HFpEF is not clear. We investigated the ZSF1 model in both early and more severe stages of HFpEF (5-, 13- and 20-months old [mo]). We assessed molecular, biochemical, and pathophysiological roles involving lncRNAs, mRNAs, and inflammatory markers. Thyroid hormone (TH) immuno-sorbent assays showed significant decreases in serum T3 levels in 5-mo and serum T4 levels in 5-mo and 13-mo obese HFpEF groups compared to lean controls. Morphometric analyses showed significant increases in heart and LV weights in obese HFpEF rats indicating cardiac hypertrophy. LncRNA microarray and RT-qPCR revealed that three key lncRNAs were significantly increased in 13-mo obese HFpEF but not in 5-mo obese HFpEF left ventricles compared to the ZSF1 lean controls. Microarray analyses showed that Sik1 mRNA was significantly upregulated and Anxa13 was downregulated in early obese HFpEF hearts compared to the lean controls. Additionally, we also uncovered previously unreported tissue and serum inflammatory cytokine profiles in early and late HFpEF. This study has identified key novel lncRNA and inflammatory markers in early and late hypothyroid HFpEF. Further studies may help in better understanding and development of diagnostic and therapeutic targets for HFpEF that presents with severe morbidity and mortality.

genomics↗

bioRxiv2018

Recent demographic histories and genetic diversity across pinnipeds are shaped by anthropogenic interactions and mediated by ecology and life-history

A central paradigm in conservation biology is that population bottlenecks reduce genetic diversity and negatively impact population viability and adaptive potential. In an era of unprecedented biodiversity loss and climate change, understanding both the determinants and consequences of bottlenecks in wild populations is therefore an increasingly important challenge. However, as most studies have focused on single species, the multitude of potential drivers and the consequences of bottlenecks remain elusive. Here, we used a comparative approach by integrating genetic data from over 11,000 individuals of 30 pinniped species with demographic, ecological and life history data to elucidate the consequences of large-scale commercial exploitation by 18th and 19th century sealers. We show that around one third of these species exhibit strong genetic signatures of recent population declines, with estimated bottleneck effective population sizes reflecting just a few tens of surviving individuals in the most extreme cases. Bottleneck strength was strongly associated with both breeding habitat and mating system variation, and together with global abundance explained a large proportion of the variation in genetic diversity across species. Overall, there was no relationship between bottleneck intensity and IUCN status, although three of the four most heavily bottlenecked species are currently endangered. Our study reveals an unforeseen interplay between anthropogenic exploitation, ecology, life history and demographic declines, sheds new light on the determinants of genetic diversity, and is consistent with the notion that both genetic and demographic factors influence population viability.

evolutionary biology↗

bioRxiv2017

Evidence for a Large-Scale Brain System Supporting Allostasis and Interoception in Humans

AbstractLarge-scale intrinsic brain systems have been identified for exteroceptive senses (e.g., sight, hearing, touch). We introduce an analogous system for representing sensations from within the body, called interoception, and demonstrate its relation to regulating peripheral systems in the body, called allostasis. Employing the recently introduced Embodied Predictive Interoception Coding (EPIC) model, we used tract-tracing studies of macaque monkeys, followed by two intrinsic functional magnetic resonance imaging samples (N = 280 and N = 270) to evaluate the existence of an intrinsic allostatic/interoceptive system in the human brain. Another sample (N = 41) allowed us to evaluate the convergent validity of the hypothesized allostatic/interoceptive system by showing that individuals with stronger connectivity between system hubs performed better on an implicit index of interoceptive ability related to autonomic fluctuations. Implications include novel insights for the brains functional architecture, dissolving the artificial boundary between mind and body, and unifying mental and physical illness.

neuroscience↗