Biology subjects

Linn, W.-J.

Publications and source records attributed to Linn, W.-J..

3 recordsLinked to original sources

bioRxiv2025

Cross-species brain circuitry from diffusion MRI tractography and mouse viral tracing

Understanding how brain networks support cognition requires knowing not only which regions are connected but the direction in which neuronal signals propagate. However, directed connectivity cannot be measured non-invasively in primates or humans, limiting systems-level inference. Here we integrate projection polarity from [~]1,200 mouse viral tracing experiments with species-specific diffusion MRI tractography to construct directed connectomes across mouse, marmoset, macaque, and human. Using a common cross-species atlas, we developed a path efficiency metric that balances projection strength against axonal length and applied shortest-path algorithms to quantify directional influence. This framework revealed conserved and divergent organization: the entorhinal-hippocampal projection was the most efficient in all species; humans showed strengthened anterior insula-superior temporal pathways; macaques exhibited peak inferior temporal outflows; and marmosets maintained disproportionately strong olfactory influence. These results provide a scalable and ethically feasible approach for modeling directed neuronal signaling across species.

neuroscience↗

bioRxiv2025

A common cross-species atlas of cortical gray matter

Translational neuroscience requires consistent anatomical frameworks to compare brain organization across species despite differences in size and specialization. Existing atlases are species-specific, limiting cross-species analyses. Here we developed a hierarchical common atlas delineating homologous cortical and subcortical gray matter regions across mouse, rat, marmoset, rhesus macaque, and human, built upon population-averaged minimal deformation templates and uniform tissue segmentation. The atlas was validated through cross-atlas Dice similarity against established human parcellations, cross-scale containment against species-specific atlases, cross-species geometric consistency of regional positioning, and comparison of independent mouse and marmoset invasive tracer connectivity, with a per-region homology confidence index quantifying the strength of each regional assignment. Cross-species tracer comparison revealed a structured gradient of correspondence, with sensorimotor connections showing strong conservation and association connections showing progressive divergence. This freely available atlas provides a unified coordinate system for comparative neuroscience, enabling quantitative evaluation of where cross-species correspondence holds and where species-specific divergence emerges.

neuroscience↗

bioRxiv2023

Probabilistic Coverage of the Frontal Aslant Tract in Young Adults: Insights into Individual Variability, Lateralization, and Language Functions

The frontal aslant tract (FAT) is a crucial neural pathway of language and speech, but little is known about its connectivity and segmentation differences across populations. In this study, we utilized diffusion MRI automatic tractography to investigate the probabilistic coverage of the FAT in a large sample of 1065 young adults. Our primary goal was to reveal individual variability and lateralization of FAT and its structure-function correlations in language processing. Our results showed that the left anterior FAT exhibited the most substantial individual differences, particularly in the superior and middle frontal gyrus, with greater variability in the superior than the inferior region. Furthermore, we found significant left lateralization in FAT, with a greater difference in innervation coverage in the inferior and posterior portions. Additionally, our analysis revealed a significant correlation between the size of left FAT inferior innervation areas and Picture Vocabulary function, highlighting the structural and functional importance of the left FAT in language processing. In comparison, the anisotropy of FAT did not show significant correlation. Overall, our study provides valuable insights into individual and population differences in FAT connectivity and segmentation and sheds light on its critical role in language functions.

neuroscience↗