Biology subjects

Korja, R.

Publications and source records attributed to Korja, R..

10 recordsLinked to original sources

bioRxiv2026

Cortical gray matter density at age five associated with preceding early longitudinal language profiles: A Voxel-based morphometry analysis of the FinnBrain Birth Cohort Study

Previous studies exploring the connection between early language development and brain anatomy have shown that cortical areas relating to individual differences in language skills are diverse and vary depending on the age of child. However, due to lack of large longitudinal samples, current literature is limited in answering the extent to which individual differences in language development prior to school age are reflected in areas of the cortex. To fill this gap, we compared gray matter density between participants that belonged to different longitudinally defined language profiles from 14 months to five years of age in a large population-based sample. Participants were 166 children from the FinnBrain Birth Cohort Study who had longitudinal language data from 14 months to five years of age and magnetic resonance imaging data at five years of age. Three groups of language development were used as per our prior study: persistent low, stable average, and stable high. Voxel-based morphometry metrics were calculated using SPM12 and the three language profile groups were compared to one another. Covariates included sex and age at brain scan. The statistics were thresholded at p < 0.01 and false discovery rate corrected at the cluster level. Of the three longitudinal language profiles, the stable high group had higher gray matter density than the persistent low group in the right superior frontal gyrus. No differences were found between the stable average and stable high groups, nor persistent low and stable average groups. The identified superior frontal cortical area belongs to executive functions neural network. This finding adds to the cumulating evidence that individual differences in language development are reflected in growth of gray matter supporting general processing ability rather than specialized language regions. The results suggest that cognitive development and early language development are linked through shared principles of neural growth, identifiable already at age five. Key pointsO_LIAn association between early language development from 14 months to five years of age and gray matter density differences of the right superior frontal gyrus was found at the age of five years. Children following the strongest language trajectory were more likely to exhibit higher gray matter density of the right superior frontal gyrus than children following the weakest trajectory. C_LIO_LIAs the superior frontal gyrus is part of executive functions network, we propose that individual differences in early language development are more defined by general learning mechanisms supported by those networks, rather than language specific pathways. C_LI

neuroscience↗

bioRxiv2026

Functional connectome harmonics and dynamic connectivity maps of the preadolescent brain

The maturation of large-scale functional brain networks during preadolescence underpins critical cognitive and behavioral development. However, the spatial and temporal organization of these networks in this age group remains incompletely characterized. Here we applied Functional Connectome Harmonics (FCH) and Leading Eigenvector Dynamics Analysis (LEiDA) to resting-state fMRI data from over 11,000 children aged 9-10 years in the ABCD Study. FCH revealed hierarchical spatial gradients spanning cortical and subcortical regions, while LEiDA identified recurrent dynamic brain states aligned with canonical intrinsic connectivity networks. Linking these spatial and temporal components, we established a low-dimensional harmonic scaffold constraining brain dynamics during this developmental window. These findings provide a large-scale spatiotemporal reference framework of preadolescent functional brain organization, offering a foundation for characterizing neurodevelopmental benchmarks and early neural markers relevant to adolescent mental health.

neuroscience↗

bioRxiv2025

skiftiTools: An R package for reading, writing, analysing, and visualising, tract-based spatial statistics (TBSS) derived diffusion MR images

skiftiTools processes three- and four-dimensional neuroimaging data, facilitating advanced statistical modelling with voxelwise data in any software of choice. Tract-Based Spatial Statistics (TBSS) is a conventionally used tool to make statistical calculations in voxel space for brain imaging data. While pre-existing software packages provide support for general linear model based statistics, there is a clear need for more sophisticated modeling. skiftiTools writes subject-per-volume NIfTI files as tab-separated value ASCII files, which are easily readable by most commonly used statistical tools such as R language (RStudio), SPSS, SAS, and GraphPad Prism. This facilitates a wide range of voxel-level statistical analyses from TBSS data, including estimation of standardised effect sizes, clustering, dimensionality reduction, non-linear and machine learning predictive modelling, which we showcase in this article using FinnBrain and developing Human Connectome Project diffusion MRI data. After statistical processing, the resulting ASCII data can then be read again for visualization. The package supports NIfTI image format, tab-separated ASCII format, and its own stand-alone format for efficient disk usage. It is open source (https://github.com/haanme/skiftiTools), built on R-language and has easy installation from Rs CRAN package repository. In addition, we provide basic functions available in Docker containers for further platform independence. HighlightsO_LIThe skiftiTools R package is an open-source, user-friendly interface for analysing voxelwise diffusion tensor imaging (DTI) data following tract-based spatial statistics (TBSS) processing C_LIO_LIIt supports reading, writing, visualization, mathematical operations, and data manipulation and thus allows comprehensive conventional and advanced statistics, including machine learning C_LIO_LIskiftiTools bridges a critical gap between statistical tools in R and voxelwise neuroimaging data - including comparable means to perform multiple comparison corrections and much needed possibility to use non-linear statistics C_LI

neuroscience↗

bioRxiv2025

Faecal transplantation from exuberant toddlers increases exploratory behaviour in rats

BackgroundBehavioural phenotypes have previously been transferred via faecal microbiota transplantation (FMT) from patients with psychiatric disorders to rodents. Studies indicate that the gut microbiota composition may be linked to certain temperament traits, defined as biologically-based differences in emotional reactivity and self-regulation. Here, we aimed to determine if the gut microbiota plays a role in temperament using an FMT approach. We focused on the temperament traits of exuberance, defined as positive reactivity, decreased behavioural inhibition, and high behavioural approach tendencies. MethodsFaeces from 2.5-year-old toddlers from FinnBrain Birth Cohort Study with high exuberance/approach or high behavioural inhibition in the LabTAB bubbles-episode was transferred to juvenile male Sprague Dawley rats (age 22/23 days). Behaviour of the rat recipients (n=53) was assessed using the novel non-social arena, novel social arena, hole board test for exploratory behaviour, social approach-avoidance test, and forced swim test. The faecal pellets collected from the rodents were analyzed with 16s rRNA sequencing and faecal samples from the sample of toddlers (which included the donors, n=176) were analysed using short-read metagenomic sequencing. The striatum and prefrontal cortex from the rodents brains were analysed post-mortem using RNAseq. ResultsMicrobiome from toddlers with high exuberance traits induced increased exploratory behaviour compared to vehicle-controls and rats receiving faeces from inhibited toddlers. Locomotor activity, social, and depressive-like behaviour remained unaffected. We noted a downregulation of the dopamine synapse pathway within the striatum of the rats that received faeces from the inhibited trait donors compared with vehicle-controls. Faecal microbiota of rats receiving faeces from the same donor resembled more each other than rats from a different cage. Clostridium species AM29 11AC in toddler microbiome was positively related to exuberance, but there were no cross-sectional associations between faecal metabolites in the human sample. ConclusionsFMT from exuberant toddlers lead to altered exploratory-related behaviour in rats.

microbiology↗

bioRxiv2025

Neonatal White Matter Microstructure Predicts Infant Attention Disengagement from Fearful Faces

Infants develop an attentional bias towards faces already at birth, with further specification towards fearful faces emerging at 6 months and diminishing around 11 months of age. However, the neurobiological origins of attentional bias to fear are still poorly understood. To understand the neural structures underlying perception of facial expressions, the current study utilized newborn diffusion magnetic resonance images (N = 86; 41 females; = 27.15 days) and eye tracking from the same infants at 8-months ( = 8.75 months) as a behavioural measure. An overlap paradigm was used to measure attention disengagement from fearful, happy, and neutral faces. Tract-based spatial statistics revealed that higher white matter (WM) mean diffusivity in widespread regions across the brain was associated with lower attention disengagement from fearful faces. The same association was found with happy faces but was limited to only the splenium of the corpus callosum and sensorimotor pathways. Variance in neonatal WM microstructure may reflect individual differences in growth that is related to attentional bias development later in infancy.

neuroscience↗

bioRxiv2024

Effortful control and cortical brain structure in 5-year-old children: findings from the FinnBrain birth cohort study

The aim of this study was to explore the associations between an aspect of self-regulation (SR), effortful control (EC), and cortical brain structure in 5-year-old children. Efficient EC is a predictor of many attributes and important outcomes in life, such as social-emotional functioning, psychiatric and somatic health, finance, and criminal activity. The early brain correlates of EC are not widely studied, while a better understanding of them would aid in recognizing individuals at risk for maladaptive outcomes. Participants (N = 155) were a part of the FinnBrain Birth Cohort Study in Finland. T1-weighted brain magnetic resonance images were processed using FreeSurfer. The data was statistically analysed with a vertex-wise general linear model. At the age of 5 years, EC and its subscales, Attentional focusing, Inhibitory control (INH), Low intensity pleasure (LIP) and perceptual sensitivity, were assessed via parental report using The Childrens Behaviour Questionnaire. We found positive associations between overall EC and cortical volume in the left superior parietal region and in the right inferior temporal region. We also found positive associations between EC and surface area on the left hemisphere in the superior parietal region. The findings were driven by the EC subscales of INH and LIP with INH linking positively with left surface area and volume, and LIP linking with left cortical volume. We extended the previous literature by shedding light on early structural brain correlates of EC in a large sample of typically developing 5-year-olds. The results differed significantly from previous findings in older children, highlighting the need for longitudinal studies to better understand the neural underpinnings of SR throughout development.

neuroscience↗

bioRxiv2024

Neonatal Amygdala Mean Diffusivity: A Potential Predictor of Emotional Face Perception

The ability to differentiate between different facial expressions is an important part of human social and emotional development that begins in infancy. Studies have shown that within the first year of life, infants develop a distinctive attentional bias towards fearful facial expressions. Investigations into the neural basis for this bias have highlighted the significance of the amygdala. The amygdalas role in directing attention towards fearful facial expressions underscores its importance in early emotional development, significantly influencing how infants interpret and react to facial expressions. To date, no studies have been conducted to investigate the associations between the amygdala microstructure and infants perception of emotional faces. This study aimed to elucidate this relationship while also investigating whether this association is sex specific. We measured the amygdala microstructural properties using diffusion tensor imaging mean diffusivity (MD) measurements in 40 healthy infants aged 2 to 5 weeks. Eye tracking was used to assess attention disengagement from fearful vs. non-fearful (happy and neutral) facial expressions as well as scrambled non-face control picture at 8 months. Generally, infants were age-typically less likely to disengage from fearful faces than from non-fearful faces towards salient distractors. A significant negative association was observed between the right amygdala MD measures and disengagement probability from fearful faces in the overall sample. Moreover, there was a positive association between the bilateral amygdala MD measures and the disengagement probability from scrambled non-face control picture in girls. These results indicate that the amygdala MD is associated with attention disengagement processes already in infancy, both in fear processing and in non-emotional conditions. Specifically, these findings highlight the role of the amygdala microstructure in modulating attentional processes, which may have implications for emotional regulation and susceptibility to emotional dysregulation later in life.

neuroscience↗

bioRxiv2023

Attentional bias toward fearful faces is associated with maternal postnatal distress and alterations in white matter microstructure in 5-year-old females

The development of face processing system is paramount for social interaction and communication skills. Eye-tracking provides a viable means to investigate face processing even in very young children and can be used to derive indices of affective processing biases that are adaptive in supporting preparedness for emotional encoding. The neural correlates of early-emerging attentional biases have not been explored. In the current study, we gathered diffusion tensor imaging (DTI) and eye-tracking data (attention disengagement from neutral, happy, fearful faces, and control pictures towards distractor stimuli) to investigate the association of white matter (WM) microstructural alterations and attentional biases in 117 (55 female) typically developing 5-year-old children. We estimated fractional anisotropy (FA) and used tract-based spatial statistics (TBSS) before conducting voxel-wise analyses testing associations between attentional biases and brain diffusivity. We found that reduced WM integrity (indexed as decrease in FA) in widespread WM regions, including the splenium of corpus callosum, left anterior limb of internal capsule (ALIC), left posterior limb of internal capsule (PLIC), left posterior thalamic radiation and optic tract, predicted higher attentional bias toward fearful expressions in females (adjusted for potential confounders). Further, maternal postnatal anxiety and depressive symptoms were detected to associate positively with attentional bias toward fearful expression, but only in females. Based on these findings and prior results on association between maternal distress and reduced WM integrity in female offspring, it is possible that alterations in WM microstructure may transmit the long-term effects of maternal mental distress during early life to increased vigilance towards negative emotional expressions. These hypotheses and sexual dimorphism in the observed associations require replication and are potential focus areas for future studies.

neuroscience↗

bioRxiv2023

Structural brain correlates of non-verbal cognitive ability in 5-year-old children: findings from the FinnBrain Birth Cohort study

Non-verbal cognitive ability predicts multiple important life outcomes, e.g., school and job performance. It has been associated with parieto-frontal cortical anatomy in prior studies in adult and adolescent populations, while young children have received relatively little attention. We explored the associations between cortical anatomy and non-verbal cognitive ability in 165 5-year-old participants (mean scan age 5.40 years, SD 0.13; 90 males) from the FinnBrain Birth Cohort study. T1-weighted brain magnetic resonance images were processed using FreeSurfer. Non-verbal cognitive ability was measured using the Performance Intelligence Quotient (PIQ) estimated from the Block Design and Matrix Reasoning subtests from the Wechsler Preschool And Primary Scale Of Intelligence (WPPSI-III). In vertex-wise general linear models, PIQ scores associated positively with volumes in left caudal middle frontal and right pericalcarine regions, as well as surface area in left caudal middle frontal, left inferior temporal, and right lingual regions. There were no associations between PIQ and cortical thickness. To the best of our knowledge, this is the first study to examine structural correlates of non-verbal cognitive ability in a large sample of typically developing 5-year-olds. The findings are generally in line with prior findings from older age groups.

neuroscience↗

bioRxiv2021

Feasibility of FreeSurfer processing for T1-weighted brain images of 5-year-olds: semiautomated protocol of FinnBrain Neuroimaging Lab

Pediatric neuroimaging is a quickly developing field that still faces important methodological challenges. One key challenge is the use of many different atlases, automated segmentation tools, manual edits in semiautomated protocols, and quality control protocols, which complicates comparisons between studies. In this article, we present our semiautomated segmentation protocol using FreeSurfer v6.0, ENIGMA consortium software, and the quality control protocol that was used in FinnBrain Birth Cohort Study. We used a dichotomous quality rating scale for inclusion and exclusion of images, and then explored the quality on a region of interest level to exclude all regions with major segmentation errors. The effects of manual edits on cortical thickness values were minor: less than 2% in all regions. Supplementary materials cover registration and additional edit options in FreeSurfer and comparison to the computational anatomy toolbox (CAT12). Overall, we conclude that despite minor imperfections FreeSurfer can be reliably used to segment cortical metrics from T1-weighted images of 5-year-old children with appropriate quality assessment in place. However, custom templates may be needed to optimize the results for the subcortical areas. Our semiautomated segmentation protocol provides high quality pediatric neuroimaging data and could help investigators working with similar data sets.

neuroscience↗