See-through Brains and Diffusion Tensor MRI Clarified Fiber Connections: A Preliminary Microstructural Study in a Mouse with Callosal Agenesis

Clearing methods that render the brain optically transparent allow high-resolution threedimensional (3D) imaging of neural networks. We used diffusion tensor imaging (DTI) and two-photon imaging of cleared brains to analyze white matter in BTBR mice. We confirmed corpus callosum agenesis and identified an abnormal commissure close to the third ventricle. DTI and cleared-brain two-photon imaging revealed that these commissural fibers constituted a frontal clustering of the ventral hippocampal commissure and provided a detailed assessment of white matter structure in mice.