Genetic code hidden in the brain's white matter can now reveal which regions are sending messages and which are just listening.
Gene co-expression gradients provide a new way to determine the direction of signal flow between brain areas. Standard MRI scans only show that two regions are physically connected, leaving the direction of information a mystery. This framework uses the underlying genetic signatures of neurons to identify the senders and the receivers in living humans. Knowing the direction of these signals is vital for understanding how the brain processes everything from sight to memory. This tool allows for the creation of a functional atlas of the human mind that includes a clear flow of traffic. It effectively turns a static map of brain wires into a live diagram of communication.
Gene Gradients Reveal Directed Structural Connectivity Across Species
bioRxiv · 10.64898/2026.05.05.723068
Diffusion MRI (dMRI) tractography is widely used to estimate structural connectivity (SC) between brain regions in vivo, but it lacks directional information about white matter pathways. Here, we introduce a computational framework to infer directionality by first combining dMRI-derived SC with gene co-expression gradients, then fitting a structure-function model based on the Lyapunov equation. We found that our model successfully predicts ground-truth neuron-to-neuron synaptic connectivity in t