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

Abstract

Studying the human subcortical auditory system non-invasively is challenging due to its small, densely packed structures deep within the brain. Additionally, the system's elaborate 3-D structure can be difficult to understand with available 2-D schematics and animal models. We addressed these issues using histology, post mortem MRI, and in vivo 7-Tesla MRI. We created anatomical atlases with state-of-the-art human histology and post mortem MRI (50μm). We measured functional MRI responses to natural sounds and demonstrate that functional localization of subcortical structures is reliable within individuals across different experiments. Further, the derived group functional atlas locates these structures within 2mm. Using diffusion MRI tractography, we revealed subcortical auditory structural connectivity maps in vivo (1050μm isotropic resolution) and post mortem (200μm). This work captures current MRI capabilities for investigating the human subcortical auditory system, describes challenges that remain, and contributes novel, public data, atlases, and tools for researching the human auditory system.

Footnotes

* Added second in vivo functional experiment; revised figures; revised text; included supplementary videos