Magnetic resonance imaging can study both the strength of communication between brain regions (functional connectivity) and the properties of the pathways that connect them (white matter microstructure). Animal studies suggest that these things are related, but there is little literature on this in humans.
Jeroen Mollink, Karla Miller and Saad Jbabdi used 11,000 subjects from UK Biobank to ask whether features related to white matter microstructure (diffusion MRI) can predict the synchrony of functional MRI activity in the regions a given pathway connects.
They constructed models of diffusion MRI derived features to predict functional connectivity. 'One exciting finding is that that microstructure-function relationships are a general property of the brain', said lead author Jeroen Mollink, 'Our microstructure models were able to identify statistically significant variation in function in the vast majority - 90% - of brain regions we considered.'
The research revealed that these relationships are specific, in that you almost always get a better prediction if you use the correct white matter pathway for a given region, compared to predictions using a different white matter pathway.
In addition, these relationships are reproducible. The researchers trained the models on an initial cohort of 7500 subjects, and then used them to predict functional connectivity in 3800 un-seen subjects.
Finally, the team discovered a unique genetic profile for these relatoinships, via a genome-wide association study of the function-microstructure prediction for each region
The identification of these small but reproducible effects can be a first step toward aggregate measures with greater explanatory power.