Mapping the human subcortical auditory system using histology, post mortem MRI and in vivo MRI at 7T

Studying the human subcortical auditory system non-invasively is challenging due to its small structures deep within the brain. Additionally, the elaborate three-dimensional (3-D) structure of the system can be diZcult to understand based on currently available 2-D schematics and animal models. To address these issues, we measured functional magnetic resonance imaging (fMRI) responses from the human subcortical auditory system at 7 Tesla and validated the results by creating an atlas based on state of the art human histology (BigBrain) and post mortem MRI. Furthermore, using diffusion MRI tractography, we revealed structural connectivity maps of the human subcortical auditory pathway both in vivo (1050 μm isotropic resolution) and post mortem (200 μm isotropic resolution). This work contributes novel tools for researching the human auditory system to understand its structural organization as well as facilitates dissemination of this knowledge by making the created atlases openly available.