Table 2.

Results of voxel-wise analyses of FA and MD maps.

Modality	Contrast	Anatomical region	Cluster size	Exact cluster p-value	Peak T-value	Peak MNI coordinates
WM FA	Baseline: PD > HC	Midbrain, cortico-spinal, pontine WM and cerebellum	4118	0.012	4.61	9,-39,-35
		Anterior corpus callosum and right anterior corona radiata	2523	0.030	4.33	20,34,19
		Left inferior longitudinal and inferior-occipital fasciculus	2277	0.037	3.96	-42,-39,-8
		Left anterior corona radiata	2009	0.043	3.77	-20,17,3
GM MD	Baseline: PD > HC	Bilateral primary sensorimotor and supplementary motor areas	5486	0.047	4.3	4,-9,52
FA GM	Interaction: stronger decrease in PD	Bilateral parietal, occipital, posterior temporal, posterior thalamus, vermis	24383	0.006	5.54	-36,-81,1
FA WM	Interaction: stronger decrease in PD	Left optic radiation, anterior and middle corpus callosum	5094	0.017	5.45	4,-25,18
MD GM	Interaction: stronger increase in PD	Bilateral medial and lateral prefrontal, right insula and posterior thalamus	30012	0.038	5.02	51,10,-5
MD WM	Interaction: stronger increase in PD	Mid-brain, left optic radiation, anterior and middle corpus callosum	9260	0.015	5.11	4,-27,16

PD, Parkinson’s disease; FA, fractional anisotropy; GM, gray matter; HC, healthy controls; MD, mean diffusivity; MNI, Montreal Neurological Institute space; WM, white matter.