Nanoscopic 3D axon morphology in the normal and diseased human brain

The pathways of the brain control the speed of saltatory conduction by means of the micrometer-sized axons. The larger axons the faster the signal conduction along the axon. Holotomography imaging at ID16A showed that axons in the monkey brain visualized in 3D are not cylinder-like as assumed today but form a distribution of diameters along the axon. Human 3D axon morphology has not been explored. Selected pathways with different functions will give new insights into how 3D axon morphology adapts to the need for speed. It will provide validation data for in vivo 3D Magnetic Resonance Imaging (MRI) axon models to explain why a larger population of large axons is detected by MRI but not supported by 2D histology. Further, we will shed light on a novel hypothesis that neurodegenerative diseases may attack different axon diameter populations by quantifying the 3D morphology of known attacked pathways in a diseased brain to be compared with a healthy brain.