Table 3.

Locations of clusters with significant differences in white matter density

		Significant clusters*	MNI coordinates			Maximuma
Users vs controls
Lower signal intensity	R	Superior longitudinal fasciculus	16	54	0	5.17
	R	Middle frontal gyrus (BA 6, 8)	34	42	−6	4.11
	R	Medial frontal gyrus	16	48	18	3.91
	R	Uncinate fasciculus	14	−4	−12	4.14
Higher signal intensity	–	No significant clusters	–	–	–	–
Abstainers vs controls
Lower signal intensity	–	No significant clusters	–	–	–	–
Higher signal intensity	–	No significant clusters	–	–	–	–
Users vs abstainers
Lower signal intensity	L	Insula	−38	12	12	6.39
	L	Middle frontal gyrus	−34	44	−4	5.60
	R	Middle frontal gyrus	36	42	−6	5.51
	L	Medial frontal gyrus	−16	52	14	5.23
	R	Medial frontal gyrus	10	42	36	5.15
Higher signal intensity	–	No significant clusters	–	–	–	–

If a cluster is within the corona radiata, the nearest gray matter is listed as the cluster label

^*p<0.01 corrected cluster level, 200 voxels minimum

^at value at the voxel level