Cross-species standardised cortico-subcortical tractography.

Area of Science:

• Neuroimaging
• Neuroanatomy
• Diffusion Magnetic Resonance Imaging

Background:

• Cortico-subcortical white matter tracts are crucial for brain function but are under-represented in diffusion magnetic resonance imaging (dMRI) tractography.
• Non-invasive mapping of these tracts is challenging and less explored than cortico-cortical bundles.

Purpose of the Study:

• To introduce standardized dMRI tractography protocols for delineating tracts between the cortex and deep subcortical structures (caudate, putamen, amygdala, thalamus, hippocampus).
• To enable comparative neuroanatomy studies by designing protocols applicable to both human and macaque brains.

Main Methods:

• Development of standardized tractography protocols for human and macaque brains.
• Validation of tractography reconstructions against topographical principles from macaque tracer studies.
• Assessment of protocol robustness against data quality and individual variability.

Main Results:

• Demonstrated that tractography reconstructions align with established topographical principles from macaque tracer data and translate to humans.
• Showcased the robustness of the proposed protocols against variations in data quality.
• Confirmed that the protocols preserve individual variability, including familial structure in humans.

Conclusions:

• The developed standardized protocols provide a reliable method for mapping cortico-subcortical white matter tracts in humans and macaques.
• These species-matched protocols are valuable for comparative neuroanatomy, facilitating the mapping of homologous grey matter regions across species.