TABLE 2.

TFCE clusters within the locus coeruleus for regression models and group comparisons (FWE‐corrected P < 0.05)

	Coordinates of local maxima (mm)			Voxel	Volume (mm3)	t
	x	y	z
Regression
No covariates
MoCA	−3	−38.5	−22.5	95	11.875	4.02
	4.5	−39.5	−26.5	66	8.25	4.34
AS	−4.5	−39	−22.5	165	20.625	4.02
Age and LEDD covariates
MoCA	4.5	−39.5	−26.5	82	10.25	4.13
	−4.5	−40	−26.5	78	9.75	4.01
AS	−4.5	−39	−22.5	42	5.25	3.27
	−5	−39.5	−26	23	2.875	2.92
	−2.5	−37.5	−18	11	1.375	3.32
Group comparisons
HC > PSP	−5	−40	−27.5	124	15.5	3.88
	3	−38.5	−25	83	10.375	3.86
HC > PD	4.5	−38.5	−27	46	5.75	3.43

Models were tested using FSL's PALM and corrected across contrasts with 10,000 permutations. Standard coordinates in MNI space (mm³) are reported.

Abbreviations: TFCE, threshold free cluster enhancement; FWE, family‐wise error; MoCA, Montreal Cognitive Assessment; AS, Apathy Scale; LEDD, levodopa equivalent daily dose; HC, healthy control; PSP, progressive supranuclear palsy; PD, Parkinson's disease.