ATR and atrial fibrillation: The ILF, initially spared in Pre-HD, becomes impaired in HD (increased AD on the left side; increased RD bilaterally; increased iron on the right side); the AF and Cing, initially with a spared microstructure in Pre-HD, show bilateral microstructural changes in HD; the IFO, damaged unilaterally in Pre-HD, becomes impaired bilaterally in HD; the UF remains stable and relatively spared in both Pre-HD and HD; the SLF and the ATR, already damaged in the Pre-HD phase, become increasingly impaired.