Neocortex Organization & Connectivity in Fetal Human Brains Revealed by Diffusion Tractography & Histology

Emi Takahashi¹, Rebecca D. Folkerth², P. Ellen Grant¹

During the fetal period, the most prominent transient layer is the subplate (SP) zone, located between the immature cortex (cortical plate; CP) and the immature white matter (intermediate zone; IZ), which contains numerous crossroads. Resolving accurate pathways running through the unmyelinated subcortical areas is critical to image the entire length of fiber pathways in the developing brain. Here, we applied high-angular resolution diffusion imaging (HARDI) tractography to intact whole postmortem fetal human brains. Our results show the usefulness of HARDI tractography, irrespective of the degree of myelination, for providing 3-dimensional information on developing cortical structure and connectivity.