Biology subjects

Drew, A.

Publications and source records attributed to Drew, A..

5 recordsLinked to original sources

bioRxiv2025

Corticolimbic structure-function coupling is sensitive to childhood adversity and buffers adversity-related symptoms during development

Childhood adversity is a potent predictor of mental health problems across the lifespan, and a rich cross-species literature implicates stress-sensitive corticolimbic circuits in adversity-related psychopathology. Structure-function coupling (SFC) is a promising multimodal marker that is sensitive to developmental plasticity. While emerging evidence suggests cortical SFC is sensitive to adversity exposure during early childhood, it is unknown how SFC in stress-sensitive corticolimbic circuits links adversity exposure with mental health across development. We examined associations between adversity exposure, transdiagnostic symptomatology, and both amygdala-cortical and hippocampal-cortical SFC across development in a large sample of youth (N = 607, 39% F). Results revealed that adversity exposure moderated age-related change in amygdala-vmPFC SFC (p = .007), such that youth exposed to higher, but not lower, levels of adversity showed an age-related increase in amygdala-vmPFC SFC. Further, amygdala-vmPFC SFC buffered the effect of adversity on internalizing symptoms (p = .012), such that those youth with higher adversity exposure who had stronger amygdala-vmPFC SFC also displayed lower internalizing symptoms. Separately, higher adversity exposure was associated with lower hippocampal-limbic network SFC (p = .037), which moderated the effect of adversity on internalizing symptoms (p = .010). These findings highlight that structural and functional neurodevelopment of amygdala-vmPFC and hippocampal-limbic network connections may adapt in distinct ways to support mental health following adversity, with implications for risk and resilience against internalizing psychopathology. Significance StatementDelineating how childhood adversity alters neurodevelopment is critical to understanding the origins of adversity-related risk for mental health disorders. Here, we leverage a multimodal marker of the correspondence between brain structure and function to test how corticolimbic circuits are jointly shaped by adversity exposure. Results reveal that the structure-function coupling of amygdala-vmPFC and hippocampal-limbic networks is associated with adversity exposure and differentially moderate risk for internalizing psychopathology. These findings suggest key roles for neural stress regulation and memory circuits in adapting to support optimal functioning following adversity exposure, and highlight the concordance of neural structure and function as an important indicator of individual-level risk and resilience.

neuroscience↗

bioRxiv2023

A laboratory framework for ongoing optimisation of amplification based genomic surveillance programs

Constantly evolving viral populations affect the specificity of primers and quality of genomic surveillance. This study presents a framework for continuous optimisation of sequencing efficiency for public health surveillance based on the ongoing evolution of the COVID-19 pandemic. SARS-CoV-2 genomic clustering capacity based on three amplification based whole genome sequencing schemes was assessed using decreasing thresholds of genome coverage and measured against epidemiologically linked cases. Overall genome coverage depth and individual amplicon depth were used to calculate an amplification efficiency metric. Significant loss of genome coverage over time was documented which was recovered by optimisation of primer pooling or implementation of new primer sets. A minimum of 95% genome coverage was required to cluster 94% of epidemiologically defined SARS-CoV-2 transmission events. Clustering resolution fell to 70% when only 85% of genome coverage was achieved. The framework presented in this study can provide public health genomic surveillance programs a systematic process to ensure an agile and effective laboratory response during rapidly evolving viral outbreaks.

genomics↗

bioRxiv2020

Alpha fluctuations regulate the accrual of visual information to awareness

Endogenous brain processes play a paramount role in shaping up perceptual phenomenology. This is illustrated by the alternations experienced by humans (and other animals) when watching perceptually ambiguous, static images. We hypothesised that endogenous alpha fluctuations in the visual cortex pace the accumulation of sensory information leading to perceptual outcomes. Here, we addressed this hypothesis using binocular rivalry combined with visual entrainment and electroencephalography in humans (64 female, 53 male). The results revealed a correlation between the individual frequency of alpha oscillations in the occipital cortex and perceptual alternation rates experienced during binocular rivalry. In subsequent experiments we show that regulating endogenous brain activity via rhythmic entrainment produced corresponding changes in perceptual alternation rate. These changes were observed only in the alpha range but not at lower entrainment frequencies, and were much reduced when using arrhythmic stimulation. Additionally, entraining at frequencies above the alpha range did not result in speeding up perceptual alternation rates. Overall, these findings support the notion that visual information is accumulated via alpha cycles to promote the emergence of conscious perceptual representations. We suggest that models of binocular rivalry incorporating posterior alpha as a pacemaker can provide an important advance in the comprehension of the dynamics of visual awareness.

neuroscience↗

bioRxiv2019

Neural evidence of cognitive conflict during binocular rivalry

To make sense of ambiguous and, at times, incomplete sensory input, the brain relies on a process of active interpretation. At any given moment, only one of several possible perceptual outcomes prevails in our conscious experience. Our hypothesis is that the competition between alternative representations induces cognitive conflict, eventually leading to fluctuations between different perceptual interpretations. We used binocular rivalry, a popular protocol to probe changes in perceptual awareness [1-3] and drew on the conflict monitoring theory, which holds that cognitive control is invoked by the detection of conflict during information processing. We looked for an increase in power of fronto-medial theta oscillations (5-7 Hz), an established EEG marker of conflict detection [4-7]. Our results show that fm-theta power increases right before perceptual alternations and decreases thereafter, suggesting that conflict monitoring is related to perceptual competition. Furthermore, to investigate conflict resolution via attentional engagement, as held by the conflict monitoring theory [8], we also looked for changes in parieto-occipital alpha oscillations (8-12 Hz) associated to perceptual switches. These oscillations have been associated to attention allocation via functional inhibition in sensory cortices [9-12]. The power of parieto-occipital alpha was inversely related to that of fm-theta, reflecting periods of high inter-ocular inhibition during stable perception, and low inhibition around moments of perceptual change. Our findings validate a prediction made 20 years ago in the seminal paper formulating the conflict monitoring theory, and establish a previously unknown link between conflict mechanisms and the processes leading to perceptual awareness. HighlightsO_LIBinocular rivalry induces conflict between competing perceptual representations C_LIO_LIMid-frontal theta power increases around the resolution of perceptual conflict C_LIO_LIPosterior alpha decreases reflect neural excitability around perceptual switches C_LIO_LIThe results link cognitive conflict theory with perceptual inference C_LI

neuroscience↗

bioRxiv2019

Assessing the viability of biochemical networks across planets

The concept of the origin of life implies that initially, life emerged from a non-living medium. If this medium was Earths geochemistry, then that would make life, by definition, a geochemical process. The extent to which life on Earth today could subsist outside of the geochemistry from which it is embedded is poorly quantified. By leveraging large biochemical datasets in conjunction with planetary observations and computational tools, this research provides a methodological foundation for the quantitative assessment of our biologys viability in the context of other geospheres. Investigating a case study of alkaline prokaryotes in the context of Enceladus, we find that the chemical compounds observed on Enceladus thus far would be insufficient to allow even these extremophiles to produce the compounds necessary to sustain a viable metabolism. The environmental precursors required by these organisms provides a map for the compounds which should be prioritized for detection in future planetary exploration missions. The results of this framework have further consequences in the context of planetary protection, and hint that forward contamination may prove infeasible without meticulous intent.

systems biology↗