This image reveals a whole mouse brain from a transgenic line expressing GFP in Thy1-positive neurons, with fluorescent labeling tracing an intricate network of neuronal projections. Physical expansion of the tissue exposes fine structural details, transforming dense neural pathways into a glowing landscape that resembles a vascular system of connections.

Mapping the full extent of these projections has long been one of neuroscience’s greatest technical challenges, and here advanced imaging combined with machine learning–based analysis aims to automatically trace these circuits. This work supports efforts to understand how neurodegenerative diseases like Alzheimer’s disrupt long-range connectivity and to uncover new insights into brain network organization.

These samples were processed using SHIELD, eFLASH and mELAST technologies developed in the Chung Lab at MIT, which enable whole-organ molecular labeling and high-resolution imaging.