Biology subjects

Rokos, L.

Publications and source records attributed to Rokos, L..

3 recordsLinked to original sources

bioRxiv2025

Corticothalamic circuit mechanisms underlying brain region and ageing variations in resting-state alpha activity

Understanding the neural mechanisms underlying oscillations in resting-state brain activity, which exhibit substantial spatial and age-related variations, remains a significant challenge. This study aims to characterize the contributions of neural circuits to the mechanisms governing resting-state alpha oscillations, which are crucial for various neurocognitive processes and pathologies. Using the Cam-CAN dataset, source-space MEG analyses revealed a pronounced posterior-anterior gradient in alpha frequency, alpha power, and aperiodic components, alongside notable age-related changes. Through neurophysiological modelling, we uncover strong corticothalamic interactions in occipital regions, contrasting with predominantly corticocortical interactions in frontal areas. Ageing is associated with reduced intrathalamic activity and increased corticothalamic delay in occipital regions, while fronto-central regions exhibit increased intrathalamic activity. These findings establish how different circuits shape alpha oscillations across posterior-anterior axis and age, providing a mechanistic foundation for targeted clinical interventions and offering benchmarks for future studies in patient populations.

neuroscience↗

bioRxiv2025

Young and old adult brains experience opposite effects of acute sleep restriction on the functional connectivity network

Chronic, long-term sleep loss is detrimental to brain health and cognitive ability. However, older adults are affected differently by acute, short-term loss of sleep than young and middle-aged adults. Older adults are more resilient to the effects of acute sleep loss and, depending on the cognitive domain, may be completely unaffected while younger adults suffer. To elucidate the brain network responses to sleep loss underlying these cognitive differences between age groups, we investigated the static and dynamic functional connectivity effects of sleep restriction (sleep limited to 3 hours) and how these effects differ between younger adults (20-30 years) and older adults (65-75 years). We found a functional connectivity subnetwork that was primarily strengthened in younger adults after sleep restriction but weakened in older adults after sleep restriction. Similar crossover interactions were consistently observed in further analyses of functional connectivity degree, modularity, and dynamic functional connectivity state fractional occupancy. Our findings demonstrate that the effect of sleep restriction on older adults is fundamentally different from younger adults. These results most strongly support the compensation theory of aging, which predicts a fundamental shift in the effects of sleep loss, rather than a mere dampening of the sleep benefits experienced by younger adults.

neuroscience↗

bioRxiv2024

Examining Relationships between Functional and Structural Brain Network Architecture, Age, and Attention Skills in Early Childhood

Early childhood is a critical period showing experience-dependent changes in brain structure and function. The complex link between the structural connectivity (SC) and functional connectivity (FC) of the brain is of particular interest, however, its relationship with both age and attention in early childhood is not well understood. In this study, children between the ages of 4 and 7, and at a one-year follow-up visit, underwent neuroimaging (diffusion-weighted and passive-viewing functional magnetic resonance imaging) and assessments for selective, sustained, and executive attention. We examined regional graph theory metrics and SC-FC coupling of the structural and functional networks. Partial least squares (PLS) was used to investigate longitudinal brain measure changes and cross-sectional associations with age and attention. We observed longitudinal changes in functional graph theory metrics and age-related decreases in SC modularity. Region-wise graph theory analyses revealed variable brain-behaviour relationships across the brain, highlighting regions where structural topology is linked to age and attentional performance. Furthermore, we identified SC as a dominant predictor of age when compared to FC and SC-FC coupling. The findings emphasise how early childhood is a dynamic period where cognitive functioning is intricately and predominantly linked to structural network features. Significance StatementThis study investigates early childhood brain development, particularly the changes in structural and functional connectivity of the brain and the relationship between them. We examined children aged 4 to 7 over a year, and used graph theory analyses to characterise variable developmental changes and brain-behaviour relationships across the brain. Our findings emphasise the nuanced and regionally specific relationship between brain network structure and behaviour in early childhood, highlighting regions where structural topology correlates with attentional performance. This research underscores the dynamic nature of childhood brain development and the predominant role of SC in cognitive maturation, providing valuable insights into typical developmental trajectories and potential targets for early intervention strategies.

neuroscience↗