Table 3. SPM clusters for observation of faces (compared with fixation).

Contrast	Region	Direction of effect	MNI coordinates of peak voxel (mm)			F-value	Cluster size (voxels)
			x	y	z
Main effect of genetic risk (low risk vs high risk)
	Right inferior frontal gyrus/ orbitofrontal cortexa	LR>HR	42	32	4	25.2	2096
			50	16	22	21.7
			60	18	12	20.1
	Left inferior frontal gyrus/ orbitofrontal cortexa	LR>HR	−60	18	30	19.3	613
			−44	22	4	17.4
			−46	32	−8	15.0
	Right lateral occipital cortexa	LR>HR	58	−72	0	18.7	37
	Right lateral occipital cortexa	LR>HR	34	−66	18	17.2	104
	Left lingual gyrus	HR>LR	−10	−80	−6	14.7	61
	Right fusiform gyrusa	LR>HR	44	−44	−18	14.1	175
	Right supramarginal gyrusa	LR>HR	52	−40	10	12.8	140
	Superior frontal/paracingulate gyrus	LR>HR	2	12	56	10.2	34
Main effect of MA abuse status (MA-dependent vs control)	Left occipital cortex	HC>MA	−26	−98	8	28.0	135
	Left occipital cortex	HC>MA	−2	−102	−8	17.2	34
	Left lingual gyrus	HC>MA	−2	−84	−2	13.6	78
	Right inferior frontal gyrus/ orbitofrontal cortex	HC>MA	48	46	−2	12.9	125
	Right middle frontal gyrusa	HC>MA	38	10	44	12.4	89
	Right precentral gyrus	HC>MA	−32	−14	66	12.0	38
	Left precentral gyrus	HC>MA	36	6	58	10.8	37
Overlap between effects	Right inferior frontal gyrus/ orbitofrontal cortex		44	40	−6	12.7	33

Abbreviations: HC, healthy control group; HR, high-risk group; LR, low-risk group; MA, methamphetamine-dependent group; MNI, Montreal Neurological Institute; SPM, statistical parametric mapping.

^aRegions that survived after entering age, sex and education as covariates.