Biology subjects

Slivka, M.

Publications and source records attributed to Slivka, M..

3 recordsLinked to original sources

bioRxiv2025

Cortical thickness changes precede high levels of amyloid by at least seven years

Alzheimers disease (AD) is now defined based on its underlying brain pathology1, with the presence of amyloid (A{beta}) plaques at high enough levels sufficient to warrant a diagnosis in the absence of cognitive symptoms. High levels of PET-detectable A{beta} are widely thought to be the first imaging marker, with structural brain changes detectable on MRI scans thought to occur later. We combined 4570 longitudinal MRIs and 1684 A{beta} PET scans from three cognitively healthy cohorts to test the difference in cortical thickness and its change between those that subsequently converted to be A{beta}-positive or stayed A{beta}-negative, using MRIs acquired exclusively in the years before conversion. We found those that subsequently developed elevated A{beta} levels show both thicker cortex and less cortical thinning, even when the last MRI used to estimate their thickness trajectories was acquired at least seven years before conversion. Many effects remained when accounting for quantitative A{beta} levels, suggesting some cortical thickness effects may be partly independent of A{beta}. Differences in cortical thickness and its change between converters and A{beta}-negative individuals showed moderate alignment with patterns of A{beta} deposition, and the timing of thickness changes tracked the temporal progression of A{beta} accumulation. Thus, if amyloid is AD1, we show that high levels of PET-detectable amyloid are not the first imaging marker of AD, as cortical thickness changes can be traced years before pathological amyloid. This has implications for understanding the sequence of events leading up to the earliest stages of AD.

neuroscience↗

bioRxiv2025

NEUROLINGUA: A Neuroimaging Database Tailored to Unravel the Complexity of Multilingual Comprehension

The neural mechanisms underlying language processing involve a well-defined brain network, including mainly left perisylvian areas. Yet, the extent of individual variability remains largely unexplored, particularly in bilingual and multilingual contexts. Differences in linguistic profiles (e.g., age of acquisition, exposure, proficiency) provide an opportunity to assess how network topology is shaped by sociolinguistic factors. To address this, we developed NEUROLINGUA, a comprehensive database of functional and structural MRI data, enriched with sociodemographic, sociolinguistic, and behavioral information. It includes 725 healthy individuals aged 18-82 immersed in a Basque-Spanish multilingual environment, ranging from near-monolinguals to highly proficient multilinguals. Participants completed a functional MRI language localizer with both auditory and visual comprehension tasks, enabling cross-modal comparisons, as well as sentences involving arithmetic problem-solving. Exploratory analyses confirmed associations between structural MRI, sociodemographic, and cognitive measures. We demonstrate that NEUROLINGUAs functional MRI data localize the language comprehension network and thus capture linguistic profile effects. This integrative dataset offers an unparalleled resource to investigate factors influencing language network adaptability and variability in diverse sociolinguistic contexts.

neuroscience↗

bioRxiv2025

How and when can environmental influences change cerebral cortex? An experimental training study of twins with birth weight differences

How environmental variation shapes the human cerebral cortex remains incompletely understood. We compared cortical brainprints based in 210 twins (71 MZ and 34 DZ pairs, age 16-78 years) to distinguish prenatal, adult naturalistic and experimentally induced environmental variation from genetic contributions. Genetic effects were reflected in higher brainprint similarity within monozygotic (MZ) than dizygotic (DZ) pairs. Early environmental contributions were evident in lower brainprint similarity in MZ twin pairs with larger birthweight discordances, driven by area across the cortical ribbon. Later within-pair environmental differences in adult weight and lifestyle had minimal influence. Still, a 10-week virtual-reality navigation intervention revealed training-induced changes in the gray-white interface, with curvature and area changes supported by microstructural reconfigurations. In support of gene-environment interactions, relative brainprint similarity increased in MZ but diverged in DZ pairs following training. The results demonstrate that in adulthood, early life environmental difference persistently contributes to make the cortical architecture of genetically identical twins deviate. Environmental influence in adulthood in the form of training can still affect similarity of twin brainprints at the grey-white-matter boundary. These findings show that distinct environmental influences at prenatal and adult stage are differentially expressed across cortical features within a genetically informed framework.

neuroscience↗