Fig. 9.

Fixel-based analysis results demonstrating a significant decrease (FWE-corrected p < 0.05) in apparent fibre density (AFD) in motor neurone disease (MND) patients compared to healthy controls. a) Significant fixels detected using various combinations of CFE parameters E and H. Fixels are coloured by direction, red: left–right, blue: inferior–superior, green: anterior–posterior. b) Fixels coloured by FWE-corrected p-value. c) Zoomed in region of the pons. As shown by the many crossing fibres in this region, the proposed CFE-based method enables fibre tract-specific analysis by attributing p-values to each fixel in voxels containing multiple fibre populations.