Biology subjects

Stojanoski, B.

Publications and source records attributed to Stojanoski, B..

14 recordsLinked to original sources

bioRxiv2026

Divergence in neurodivergent brains: mapping the relationship between developmental trajectories in functional connectivity and clinical outcomes

Brain network development differs between neurodivergent (ND) and neurotypical (NT) youth, but its developmental trajectory, and relationship to clinical outcomes, remains unclear. We examined age-related changes in functional network connectivity and clinical symptoms in 861 participants (5-21 years) from the Healthy Brain Network, including NT youth and those with Neurodevelopmental Disorders (NDDs) and generalized anxiety disorder (GAD). Functional connectivity during movie-watching was modeled using generalized additive models across eight large-scale networks to characterize nonlinear developmental trajectories. Divergence in connectivity profiles between ND and NT groups first emerged during late childhood and were largest during adolescence. Importantly, divergence in connectivity patterns followed a similar trajectory path, but preceded, divergence in clinical outcomes. These findings identify adolescence as a sensitive period when differences in patterns of brain activity and clinical differences become increasingly pronounced, highlighting a potential window for targeted intervention.

neuroscience↗

bioRxiv2026

Differentiating neural mechanisms in response to emotional expressions on real and virtual faces

As avatars become more commonplace, understanding how the brain processes emotional expressions in virtual faces is critical. We compared behavioral and neural responses to real and virtual faces expressing seven emotions (anger, disgust, fear, joy, sadness, surprise, neutral). In Experiment 1 (n=61), participants rated the similarity between paired faces. Expressions conveying the same emotion were rated as highly similar across face types, whereas mismatched emotions yielded substantially lower similarity ratings, indicating perceived emotional meaning was preserved despite differences in face realism. In Experiment 2 (n=91), functional near-infrared spectroscopy was used to measure brain activity while participants viewed the same stimuli. General-linear-model analyses revealed greater activation limited to visual areas for 1) virtual faces and 2) surprise and neutral expressions. Functional connectivity analyses, however, revealed network level differences between face type and emotion across the brain. Real faces elicited stronger connectivity patterns across frontal, central-temporal, and parietal regions, whereas high-arousal emotions (fear, anger, and joy) were associated with broader network engagement than other expressions. Our results suggest face-type processing occur in early visual areas, and despite perceptual similarity, different emotions on real and virtual faces are associated with distinct patterns of network level connectivity across the brain.

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bioRxiv2025

Rate of functional network maturity and the role of environmental factors

The developmental period from childhood to adolescence is marked by significant changes to the functional properties of the brain that support various aspects of higher-level cognition. Environmental factors such as socioeconomic status and adversity can have an outsized influence on neurocognitive development. However, not all environmental factors have the same influence on cognitive and brain development. In the current study, we examined the differential influences of SES (i.e., parental education and neighbourhood safety) and adversity on the maturation rate of functional networks in children and adolescents. Using resting-state fMRI data, independent component analysis with dual regression was computed to identify six networks (Default Mode Network (DMN), Left Executive Control Network (ECN), Right ECN, Hippocampal (HPC), Salience, and Sensorimotor networks) of interest in children and adolescents aged 7 to 15 (N=216, acquired from the Healthy Brain Network). A neural maturity index was generated based on the degree of similarity between the spatial configuration of the six networks in each youth brain to that of an adult template (1243 total, with a mean age of 26; independently by sex). Regression analyses were used to determine the association between neural maturity, social-cognitive abilities and environmental factors such as parental education, neighbourhood safety and number of negative life events (adversity). We found one sensory (sensorimotor) and two association (default mode and executive control) networks matured faster than other networks. Only the rate of maturity of the DMN and HPC were associated with environmental factors. Maturity of the DMN was associated with less adversity and better social cognitive ability, whereas maturity of the HPC network was associated with younger participants with higher IQs. Moreover, these effects were stronger in females than males. Our results highlight the importance of examining the unique contributions of distinct dimensions of childhood environments on neurocognitive development.

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bioRxiv2025

Functional organization of multisensory integration network in children and youth with neurodevelopmental disorders predicts clinical sensory issues

Differences in sensory processing in neurodevelopmental conditions, including Autism Spectrum Disorder (ASD) and Attention-deficit/Hyperactivity Disorder (ADHD), cascade into downstream clinical symptomatology. This includes differences in combining sensory information from multiple modalities into a unified percept, known as multisensory integration. Little is known about the functional organization of multisensory network (MSN) in these groups, its relation to clinical sensory issues, or its interaction with other higher-order cortical networks. We examined resting-state fMRI data from 417 participants in the Province of Ontario Neurodevelopmental Network (ASD=174, ADHD=130, Typical Development=113; Mean age=11.96{+/-}4.10). Timeseries data were extracted from the MSN and seven additional resting-state cortical networks (RSNs). Undirected and directed functional connectivity (FC) metrics were computed within the MSN and between the MSN and other RSNs. FC was compared across diagnoses and related to clinical sensory characteristics. The thalamus emerged as a hub region in both undirected and directed FC within the MSN and between the MSN-RSNs. Some diagnosis-related differences were observed, with increased MSN-RSN FC particularly in ADHD; however, associations with sensory characteristics were stronger in both undirected and directed FC within the MSN and between the MSN-RSNs, regardless of diagnosis. Converging evidence was seen in data-driven clusters based on FC metrics, which did not align with diagnosis, but instead mapped on to the overall level of sensory issues reported. That the data-driven clusters sorted not by diagnosis but by sensory characteristics suggests that these sensory characteristics and their underlying neurobiology are transdiagnostic in nature as opposed to specific to ASD or ADHD.

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bioRxiv2025

The Developmental Trajectory of the Social Brain: A Movie-Based Exploration from childhood to adolescence

In childhood and adolescence, functional brain networks go through different stages of development, and the levels of connectivity within and between these networks change with age. The developmental trajectory of these large-scale networks of the brain have been extensively investigated; however, many aspects of our social brain and its developmental patterns remain unclear. This study employed a cross-sectional design to investigate the brains of 753 children and adolescents (ages 5-15) while they watched a movie. This research investigates the functional distinctness and developmental synchronicity of brain areas implicated in social cognition, such as empathy and affective and cognitive theory of mind, across childhood and adolescence using generalized additive models and inter-region group analysis. Our findings suggest that social cognition components networks such as cognitive and affective theory of mind and empathy exhibit distinct developmental trajectories throughout childhood and adolescence. The findings support the theory that social cognitive networks are developmentally distinct from each other, even in the absence of task-specific paradigms.

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bioRxiv2025

Decoding the neural basis of sensory phenotypes in Autism

BackgroundDifferences in sensory processing are a defining characteristic of autism, affecting up to 87% of autistic individuals. These differences cause widespread perceptual changes that can negatively impact cognition, development, and daily functioning. Recent research identified five sensory processing phenotypes with varied behavioural presentations; however, their neural basis remains unclear. This study aims to ground these sensory phenotypes in unique patterns of functional connectivity. MethodsWe analyzed data from 146 autistic participants in the Province of Ontario Neurodevelopmental Network. We classified participants into sensory phenotypes using k-means clustering of scores from the Short Sensory Profile. We then computed a connectivity matrix from 200 cortical and 32 subcortical regions and calculated graph-theoretic measures (betweenness centrality, strength, local efficiency, clustering coefficient) to assess information exchange between these regions. We then trained machine learning models to use these measures to classify between all pairs of sensory phenotypes. ResultsWe replicated that our sample of autistic participants was best categorized into five sensory phenotypes. The machine learning models distinguished 7/10 phenotype pairs using graph-theoretic measures (p < 0.005). Information exchange within and between the somatomotor network, orbitofrontal cortex, posterior parietal cortex, prefrontal cortex and subcortical areas were highly predictive of sensory phenotype. ConclusionsThis study shows that distinct sensory phenotypes in autism correspond with unique patterns of functional connectivity. Cortical, subcortical, and network-level connectivity all play a role in shaping distinct sensory processing styles in autism. These findings lay the groundwork for understanding these phenotypes and highlight opportunities to develop interventions in cases of maladaptive sensory processing.

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bioRxiv2024

On the same wavelength: The relationship between neural synchrony and cognitive ability during movie watching in late childhood and early adolescence

Cognitive development in late childhood and adolescence occurs alongside increasingly complex environments. To examine how cognitive abilities relate to neural processing of naturalistic experiences, we analyzed fMRI data from 309 children and adolescents (ages 7-15; majority White) in the Healthy Brain Biobank. Participants watched a 10-minute clip of Despicable Me during scanning and completed the WISC. Intersubject correlation (ISC) was used to measure brain synchrony during viewing. Adolescents (11-15) with higher cognitive scores showed greater ISC in default mode and frontoparietal networks. In contrast, younger children (7-11) with high scores showed increased synchrony only in somatosensory regions. These findings suggest age- and cognition-related differences in how children and adolescents process complex, real-world stimuli.

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bioRxiv2023

Using Machine Learning to Identify Neural Mechanisms Underlying the Development of Cognition in Children and Adolescents with ADHD

Children and adolescents diagnosed with Attention Deficit Hyperactivity Disorder (ADHD) often show deficits in various measures of higher-level cognition, such as, memory and executive functioning. Poorer high-level cognitive functioning in children with ADDH has been associated with differences in functional connectivity across the brain, including the frontoparietal network. However, little is known about the developmental changes to cortical functional connectivity profiles associated with higher-order cognitive abilities in this cohort. To characterize changes in the functional brain connectivity profiles related to higher-order cognitive functioning, we analyzed a large dataset(n=479) from the publicly available Healthy Brain Network which included fMRI data collected while children and adolescents between the ages of 6 and 16 watched a short movie-clip. The cohort was divided into two groups, neurotypical youth (n=106), and children and adolescents with ADHD (n=373). We applied machine learning models to functional connectivity profiles generated from the fMRI data to identify patterns of network connectivity that differentially predict cognitive abilities in our cohort of interest. We found, using out-of-sample cross validation, models using functional connectivity profiles in response to movie-watching successfully predicted IQ, visual spatial, verbal comprehension, and fluid reasoning in children ages 6 to 11, but not in adolescents with ADHD. The models identified connections with the default mode, memory retrieval, and dorsal attention networks as driving prediction during early and middle childhood, but connections with the somatomotor, cingulo-opercular, and frontoparietal networks were more important in middle childhood. This work demonstrated that computational models applied to neuroimaging data in response to naturalistic stimuli can identify distinct neural mechanisms associated with cognitive abilities at different developmental stages in children and adolescents with ADHD.

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bioRxiv2023

Differential effects of prolonged aerobic and resistance exercise on cognitive functioning in sedentary young adults

ObjectivesInconsistencies in the literature make it difficult to outline the relationship between exercise and cognition in young adults. Our aim is to better understand the relationship between prolonged aerobic and resistance exercise and cognitive abilities in sedentary young adults, and how this relationship is mediated by changes in cardiovascular fitness. MethodsTwenty-three volunteers were recruited and assigned to two groups to complete one hour of continuous daily workout sessions of aerobic (SPIN) and anaerobic (SCSW) exercises over a 30 day period. Each subject was provided with a Polar-10 wearable to record the heart rate (HR) activity during the workout sessions. The workout sessions were completed during five consecutive days over four consecutive weeks. Each week, HR data were collected from the last workout session. Volunteers also completed a neurocognitive test battery (Cambridge Brain Sciences, CBS) each exercise session, including an additional baseline measure before exercise regime began. ResultsWe found that memory, reasoning and verbal abilities improved throughout the aerobic, but not the resistance exercise program. We found a positive correlation between heart rate index (HRI) and memory and reasoning test scores. We also found a negative correlation between reasoning ability and HRM (heart rate mean), and heart rate skewness (SKW). The results of a regression model to predict memory and reasoning abiltiies revealed that memory was best predicted by HRI and HRM, while the reasoning ability was best predicted by only HRI. ConclusionRegular aerobic exercises improved specific cognitive performance and it was possible to predict the performance by employing the HR parameters HRI and HRM.

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bioRxiv2020

Longitudinal white matter changes associated with cognitive training

Improvements in behaviour are known to be accompanied by both structural and functional changes in the brain. However whether those changes lead to more general improvements, beyond the behaviour being trained, remains a contentious issue. We investigated whether training on one of two cognitive tasks would lead to either near transfer (that is, improvements on a quantifiably similar task) or far transfer (that is, improvements on a quantifiably different task), and furthermore, if such changes did occur, what the underlying neural mechanisms might be. Participants trained on either a verbal inhibitory control task or a visuospatial working memory task for four weeks, over the course of which they received five diffusion tensor imaging scans. Two additional tasks, a test of verbal reasoning and a test of spatial span, served as measures of near transfer for the inhibitory control task and spatial working memory task, respectively. These two tasks also served as measures of far transfer for the alternate training task. Behaviourally, participants improved on the task that they trained on, but did not improve on cognitively similar tests (near transfer), nor cognitively dissimilar tests (far transfer). Extensive changes to white matter microstructure were observed, with verbal inhibitory control training leading to changes in a left-lateralized network of fronto-temporal and occipito-frontal tracts, and visuospatial working memory training leading to changes in right-lateralized fronto-parietal tracts. Very little overlap was observed in changes between the two training groups. On the basis of these results, we suggest that near and far transfer were not observed because the changes in white matter tracts associated with training on each task are almost entirely non-overlapping with, and therefore afford no advantages for, the untrained tasks.

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bioRxiv2020

Examining the relationship between social cognition and neural synchrony during movies in children with and without autism

Children who have been diagnosed with autism spectrum disorder (ASD) often show a marked deficit in measures of social cognition. In autistic adults, measures of social cognition have been shown to relate to differences in brain synchronization (as measured by fMRI) when individuals are processing naturalistic stimuli, such as movies. However, whether children with social impairments, with or without a diagnosis of ASD, differ in their neural responses to movies has not yet been investigated. In the current study, neural synchrony, measured using fMRI, was examined in three groups of children aged 7 to 12, who differed with respect to scores on a measure of autistic traits associated with social impairment and whether or not they had been diagnosed with ASD. While watching the movie Despicable Me, those diagnosed with ASD had significantly less neural synchrony in areas that have been previously shown to be associated with social cognition (e.g. areas related to theory of mind), and plot following (e.g. the lateral prefrontal cortex), than those who did not have an ASD diagnosis. In contrast, two groups who differed in their degree of social impairment, but did not have a diagnosis of ASD, showed no significant differences in neural synchrony across the whole brain. These results shed some light on how autistic traits may contribute to an individuals conscious experience of the world, and how, for children with ASD, that experience may differ markedly from that of those without ASD.

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bioRxiv2019

Representation of semantic information in ventral areas during encoding is associated with improved visual short-term memory

We rely upon visual short-term memory (VSTM) for continued access to perceptual information that is no longer available. Despite the complexity of our visual environments, the majority of research on VSTM has focused on memory for lower-level perceptual features. Using more naturalistic stimuli, it has been found that recognizable objects are remembered better than unrecognizable objects. What remains unclear, however, is how semantic information changes brain representations in order to facilitate this improvement in VSTM for real-world objects. To address this question, we used a continuous report paradigm to assess VSTM (precision and guessing rate) while participants underwent functional magnetic resonance imaging (fMRI) to measure the underlying neural representation of 96 objects from 4 animate and 4 inanimate categories. To isolate semantic content, we used a novel image generation method that parametrically warps images until they are no longer recognizable while preserving basic visual properties. We found that intact objects were remembered with greater precision and a lower guessing rate than unrecognizable objects (this also emerged when objects were grouped by category and animacy). Representational similarity analysis of the ventral visual stream found evidence of category and animacy information in anterior visual areas during encoding only, but not during maintenance. These results suggest that the effect of semantic information during encoding in ventral visual areas boosts visual short-term memory for real-world objects.

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bioRxiv2018

Animacy and real world size shape object representations in the human medial temporal lobes

Identifying what an object is, and whether an object has been encountered before, is a crucial aspect of human behavior. Despite this importance, we do not have a complete understanding of the neural basis of these abilities. Investigations into the neural organization of human object representations have revealed category specific organization in the ventral visual stream in perceptual tasks. Interestingly, these categories fall within broader domains of organization, with distinctions between animate, inanimate large, and inanimate small objects. While there is some evidence for category specific effects in the medial temporal lobe (MTL), it is currently unclear whether domain level organization is also present across these structures. To this end, we used fMRI with a continuous recognition memory task. Stimuli were images of objects from several different categories, which were either animate or inanimate, or large or small within the inanimate domain. We employed representational similarity analysis (RSA) to test the hypothesis that object-evoked responses in MTL structures during recognition-memory judgments also show evidence for domain-level organization along both dimensions. Our data support this hypothesis. Specifically, object representations were shaped by either animacy, real-world size, or both, in perirhinal and parahippocampal cortex, as well as the hippocampus. While sensitivity to these dimensions differed when structures when probed individually, hinting at interesting links to functional differentiation, similarities in organization across MTL structures were more prominent overall. These results argue for continuity in the organization of object representations in the ventral visual stream and the MTL.

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bioRxiv2017

Differences in the spatial and temporal patterns of head motion during MRI of adults and infants

AimHead motion has a profound effect on MRI, and will contaminate comparisons of function or structure between groups that move differently. This work compares adults and infants. Infants might move differently for physical, physiological and cognitive reasons, but so far these differences have not been quantified.\n\nMethodsThe spatial modes and total magnitude of motion in the MRI scanner were measured (N=211). The effects of group (infant vs. adult) and stimulation paradigm (auditory vs. visual) were evaluated.\n\nResultsSpatial modes of motion were found to be distinct between infant and adult groups. Infants had less anterior-posterior translational motion, but greater motion in other dimensions, often with complex multi-axis patterns. In magnitude distribution, sleeping infants often remained more still than adults, but when movement did occur it was more extreme and abrupt. Two groups of adults presented with different stimulation showed similar shapes of motion.\n\nConclusionThe spatial modes and magnitude distribution of motion differed substantially between groups, and must be considered carefully as a confound in comparisons of structure or function. The abruptness and magnitude of movement suggests that for infants relative to adults post-processing strategies such as de-noising are likely to be more effective than prospective motion correction.\n\nKey notesO_LIQuantified the spatial and temporal distribution of motion during MRI in 211 adults and neonates\nC_LIO_LIThe different spatial modes in adults and infants were visualized and statistically contrasted\nC_LIO_LIThe magnitude of motion had \"heavier tails\" in infants, with more still periods, and more large movements, than adults.\nC_LI

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