Search bioRxiv⌕ Search

Biology subjects

Latham, A.

Publications and source records attributed to Latham, A..

8 recordsLinked to original sources

Infant Sensory Over-Responsivity: Relations to Early Life Adversity, Emerging Behavioral Problems, and Sensory Functional Connectivity

Background. Sensory over-responsivity (SOR) in mid- to late childhood is associated with early-life adversity (ELA) and psychopathology, yet the developmental origins and timing of these relationships remain unknown. This work leverages a longitudinal pediatric dataset enriched for ELA to characterize predictors and behavioral problems associated with infant/toddler SOR. Methods. Neonatal fMRI and longitudinal behavioral data were obtained from a sample (N=399) recruited during pregnancy and enriched for social disadvantage (SD). Negative binomial regression models were used to identify pre- and neonatal risk factors for and behavioral correlates of SOR at age two (Y2). Mediation analyses tested whether Y2 SOR mediates relationships between ELA and behavioral problems at age three (Y3). Relationships between neonatal functional connectivity (FC) measures and later SOR were also computed. Results. Two forms of prenatal ELA, SD and maternal psychosocial stress (PSS), positively predicted Y2 SOR, which in turn predicted Y2 and Y3 autism and anxiety problems, greater preschool internalizing symptoms, and greater preschool separation anxiety diagnoses. Positive relationships of prenatal PSS with Y3 autism, anxiety, and internalizing problems were partially mediated by Y2 SOR. Greater neonatal FC between the cortical somatomotor hand network and bilateral thalamus was also associated with SOR at one to two years later. Conclusions. The study results demonstrate the importance of infant/toddler SOR as an early predictor of autism and anxiety behaviors in early childhood and a mediating variable that links prenatal ELA with these behavioral outcomes. Results also implicate heightened neonatal signaling in sensory circuits as an early precursor of SOR.

neuroscience↗

Functional Organization of the Neonatal Basal Ganglia and Thalamus

The basal ganglia and thalamus are key nodes in subcortico-cortical loops involved in sensory, motor, and cognitive function. In adults, posterior regions of the subcortex link to cortical sensorimotor networks and anterior regions link to association networks. Alterations in the size, strength, and selectivity of these subcortical regional network representations are implicated in several neuropsychiatric disorders, many of which originate early in development. However, the organization of these network representations at birth remains incompletely understood, limiting our ability to devise normative and atypical developmental models of subcortico-cortical interactions. Using resting-state fMRI, we characterized the size, strength, and selectivity of cortical network representations in the basal ganglia and thalamus in a set of neonates (n=261) and compared results to children (age range 9-11 years, n=69) and adults (n=120). We found that the broad anterior-posterior organization of the subcortex is present at birth, yet representations of somatomotor networks were larger at birth compared to children and adults (p<0.001). The strength and selectivity of subcortico-cortical functional connectivity (FC) exhibited interactions between age group and network (all p<0.001), such that subcortical representations of sensorimotor networks exhibited stronger FC and higher selectivity in neonates, while subcortical representations of association networks exhibited stronger FC and higher selectivity in older cohorts. In parallel, data-driven clustering revealed areas with integration of multiple networks in the neonatal subcortex. These results suggest that subcortico-cortical FC evolves over development largely in a sensorimotor-association manner and provide a baseline for normative and disordered subcortical development. HIGHLIGHTSO_LIThe basic anterior-posterior layout of association to sensorimotor network representation in the basal ganglia and thalamus is present at term birth. C_LIO_LISensorimotor systems are overrepresented in neonates compared to children and adults. C_LIO_LISensorimotor representations exhibit greater functional connectivity strength and selectivity than association representations at birth, while association representations are stronger and more selective than sensorimotor representations in adults. C_LIO_LIThe neonatal subcortex exhibits substantial integration of multiple cortical networks. C_LI GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=150 SRC="FIGDIR/small/736181v1_ufig1.gif" ALT="Figure 1"> View larger version (48K): org.highwire.dtl.DTLVardef@1d3bfa3org.highwire.dtl.DTLVardef@ca904dorg.highwire.dtl.DTLVardef@c7c219org.highwire.dtl.DTLVardef@983020_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

Commonality and Variability in Functional Networks In Young Children Under 5 Years Old

Functional brain networks support human cognition, yet how individualized network architecture emerges in early childhood remains poorly understood. Averaging across participants can obscure age-specific organization and person-to-person differences, particularly in slowly developing association cortices. We developed an age-appropriate functional reference that captured common structure across toddlers without averaging away individual variability, enabling estimation of each childs networks from resting-state fMRI. Across cohorts of 8-60-month-old children, we found individualized network organization--including finer-scale subdivisions and emerging language lateralization--well before age five. Network layouts showed longitudinal stability, with greater consistency in sensory than association regions. Within-network connectivity was stronger and explained age-related variance when networks were defined using individualized rather than group-consensus topography. Left-lateralization of language networks tracked age-normalized verbal ability, linking early functional architecture to emerging cognition. These findings show that behaviorally relevant brain networks arise far earlier than previously recognized, providing a foundation for studying typical development and early biomarkers.

neuroscience↗

Early Life Neuroimaging: The Generalizability of Cortical Area Parcellations Across Development

The cerebral cortex consists of distinct areas that develop through intrinsic embryonic patterning and postnatal experiences. Accurate parcellation of these areas in neuroimaging studies improves statistical power and cross-study comparability. Given significant brain changes in volume, microstructure, and connectivity during early life, we hypothesized that cortical areas in 1- to 3-year-olds would differ markedly from neonates and increasingly resemble adult patterns as development progresses. Here, we parcellated the cerebral cortex into putative areas using local functional connectivity gradients in 92 toddlers at 2 years old. We demonstrate high reproducibility of these cortical regions across 1- to 3-year-olds in two independent datasets. The area boundaries in 1- to 3-year-olds were more similar to those in adults than those in neonates. While the age-specific group area parcellation better fit the underlying functional connectivity in individuals during the first 3 years, adult area parcellations might still have some utility in developmental studies, especially in children older than 6 years. Additionally, we provide connectivity-based community assignments of the parcels, showing fragmented anterior and posterior components based on the strongest connectivity, yet alignment with adult systems when weaker connectivity was included.

neuroscience↗

Prenatal environment is associated with the pace of cortical network development over the first three years of life

Environmental influences on brain structure and function during early development have been well-characterized. In pre-registered analyses, we test the theory that socioeconomic status (SES) is associated with differences in trajectories of intrinsic brain network development from birth to three years (n = 261). Prenatal SES is associated with developmental increases in cortical network segregation, with neonates and toddlers from lower-SES backgrounds showing a steeper increase in cortical network segregation with age, consistent with accelerated network development. Associations between SES and cortical network segregation occur at the local scale and conform to a sensorimotor-association hierarchy of cortical organization. SES-associated differences in cortical network segregation are associated with language abilities at two years, such that lower segregation is associated with improved language abilities. These results yield key insight into the timing and directionality of associations between the early environment and trajectories of cortical development.

neuroscience↗

OpenABC Enables Flexible, Simplified, and Efficient GPU Accelerated Simulations of Biomolecular Condensates

Biomolecular condensates are important structures in various cellular processes but are challenging to study using traditional experimental techniques. In silico simulations with residue-level coarse-grained models strike a balance between computational efficiency and chemical accuracy. They could offer valuable insights by connecting the emergent properties of these complex systems with molecular sequences. However, existing coarse-grained models often lack easy-to-follow tutorials and are implemented in software that is not optimal for condensate simulations. To address these issues, we introduce OpenABC, a software package that greatly simplifies the setup and execution of coarse-grained condensate simulations with multiple force fields using Python scripting. OpenABC seamlessly integrates with the OpenMM molecular dynamics engine, enabling efficient simulations with performances on a single GPU that rival the speed achieved by hundreds of CPUs. We also provide tools that convert coarse-grained configurations to all-atom structures for atomistic simulations. We anticipate that Open-ABC will significantly facilitate the adoption of in silico simulations by a broader community to investigate the structural and dynamical properties of condensates. Open-ABC is available at https://github.com/ZhangGroup-MITChemistry/OpenABC

biophysics↗

Micropolarity governs the structural organization of biomolecular condensates

Microenvironment is critical to the function of cells and organisms. One example is provided by biomolecular condensates, whose microenvironment can be vastly different from the surrounding cellular environments to engage unique biological functions. How microenvironments of biomolecular condensates affect their structure and function remains unknown. Here, we show that the arrangements and partitioning of biomolecules are dictated by the differences between the micropolarity of each subcompartment. Sufficient difference in micropolarity results in layered structures with the exterior shell presenting a more polar microenvironment than the interior core. Accordingly, micropolarity inversion is accompanied by conversions of the layered structures. These findings demonstrated the central role of the previously overlooked microenvironment in regulating the structural organization and function of membraneless organelles.

biochemistry↗

Single-stranded nucleic acid sensing and coacervation by linker histone H1

The linker histone H1 is the most abundant group of eukaryotic chromatin-binding proteins. The mechanism underlying the diverse physiological functions of H1 remains unclear. Here we used single-molecule fluorescence and force microscopy to observe the behavior of H1 on DNA under different tensions. Unexpectedly, we found that H1 coalesces around nascent ssDNA. Molecular dynamics simulations revealed that multivalent and transient interactions between H1 and ssDNA mediate their phase separation. We further showed that longer and unpaired nucleic acids result in more viscous, gel-like H1 droplets. Finally, we imaged H1 puncta in cells under normal and stressed conditions and observed that RPA and H1 occupy separate nuclear regions. Overall, our results provide a new perspective to understanding the role of H1 in genome organization and maintenance.

biophysics↗