Creating an Accurate 3D Map of the Human Brain
New method for reconstructing histological sections copes well with deformed tissue parts, unlike many previous methods.
One major goal of neuroscientists is to create a comprehensive high-resolution map of neural pathways in the human brain. This is a feat that spans multiple spatial scales, from a few micrometers for the diameter of a nerve fiber to several centimeters for long-range connections. 3D polarized light imaging (3D-PLI) is a multiscale neuroimaging technique that can close the spatial gap, enabling scientists to use different resolutions to visualize nerve fibers and their pathways in brain sections. However, the 3D reconstruction of histological sections can be challenging, in part due to large deformations caused by tissue splits inevitably introduced during the sectioning procedure.
To overcome this hurdle, researchers recently proposed a complete pipeline for the accurate, robust 3D reconstruction of multiscale, spatially misaligned 3D-PLI data. As reported in a study published July 6 in the journal NeuroImage, the researchers applied their registration method to 126 consecutive unstained histological sections of the temporal lobe of the human brain. High-resolution (64 microns) 3D-PLI data covered the whole temporal lobe, while ultra-high resolution (1.3 microns) images represented the hippocampus region.
The researchers demonstrated that their proposed method copes well with both large and small deformations, handles complex deformations better than previous approaches, and yields more accurate registration results than state-of-the-art methods. In contrast to many existing registration methods, the proposed approach can deal with missing tissue parts and tissue ruptures. Visual assessment of the registered images revealed coherent alignment of key anatomical features such as sulci (grooves), gyri (ridges) and white matter (nerve fiber bundles).
According to the authors, this is the first time that 3D reconstruction has been performed using a large stack of unstained histological sections of the human temporal lobe and the hippocampus based on high-resolution and ultra-high-resolution 3D-PLI data. In the future, fiber tracking based on the reconstructed 3D volumes could allow scientists to uncover the human brain connectome.