Table 2.

Neuroanatomical regions affected in male and female IGD. Studies analyzed internet gaming disorder (IGD)-affected individuals, both males and females, and controls. For each study, analyzed neuroanatomical regions, size of the samples, male-to-female ratio, presence of sex-by-group analysis, race/geographical origins of the participants, mean (±standard deviation) of the participants, employed methods, and observed effects are reported. Internet-gaming-disorder-affected individuals (IGD), controls (Ctrl), gray matter (GM), white matter (WM), functional magnetic resonance imaging (fMRI), functional connectivity (FC), regional homogeneity (ReHo), voxel-based morphometry analysis (VBMA), tract-based spatial statistics (TBSS), fractional anisotropy (FA), diffusional kurtosis imaging (DKI), voxel-mirrored homotopic connectivity (VMHC), right (r), left (l), bilateral (b), inferior (i), superior (s), middle (M), median (m), cingulate gyrus (CG), para-hippocampus (pHIPP), frontal lobe (FL), frontal gyrus (FG), post-central gyrus (PCG), occipital gyrus (OG), temporal gyrus (TG), orbitofrontal cortex (OFC), supplementary motor area (SMA), external capsule (EC), parietal lobule (PL), parietal gyrus (PG), lateral lingual gyrus (LLG), paracentral lobule (PCL), cingulate cortex (CC), fusiform gyrus (FFG), posterior cingulate cortex (PCC), anterior cingulate cortex (ACC), dorsal lateral prefrontal cortex (DLPFC), rostral middle frontal gyrus (RMFG), supramarginal gyrus (SMG).

Neuro Anatomical Region	Sample (IGD/ Ctrl)	M/F	Sex-by-Group-Analysis	Race/ Geographical Regions	Age	Methods	Observed Effects	References
Cerebellum, brainstem, rCG, bpHIPP, rFL, lSFG, left pre-cuneus, fPCG, rMOG, rITG, lSTG, MTG	19/19	11/8 IGD 11/8 Ctrl	No	Chinese	n.c	fMRI to measure ReHo	↑ ReHo	[80]
rOFCR, bilateral insula, rSMA, right genu of corpus callosum, bFL, rEC	17/17	4/13 IGD 2/15 Ctrl	No	Chinese	16.25 ± 3.0 15.54 ± 3.2	MRI (VBMA and TBSS) to measure GM density and WM density changes	GM atrophy in the rOFC, bilateral insula, and rSMA ↓ FA in WM of right genu of corpus callosum, bFL rEC	[81]
Cerebellum, TG, iPL, iPG	17 /24	13/4 IGD 16/8 Ctrl	No	n.c.	16.94 ± 2.7 15.87 ± 2.7	fMRI to detect FC	↑ FC in the bilateral cerebellum posterior lobe and mTG ↓ FC in the biPL and riTG	[82]
Right anterolateral cerebellum, risTG, rSMA, MOG, right pre-cuneus, PCG, riFG, lLLG, lPCL, laCC, mCC, bFFG, insula, PCC, thalamus	18/21	15/3 IGD 18/3 Ctrl	No	n.c.	20.5 ± 3.5 21.95 ± 2.4	MRI followed by DKI in the detection of GM diffusion	↓ GM diffusion in all analyzed regions	[83]
Cerebellum, ACC, SMA, sPL, precuneus, insula, DLPFC, FG	28/28	18/10 IGD 20/8 Ctrl	No	n.c.	18.8 ± 1.3 19.3 ± 2.6	fMRI to measure GM volume, FC and VMHC method	↓ GM volume of the bilateral ACC, pre-cuneus, SMA, SPL, left DLPFC, left insula, and bilateral cerebellum ↓ VMHC between the left and right sFG (orbital part), iFG (orbital part), mFG and sFG	[84]
Striatal nuclei (caudate, putamen, and nucleus accumbens)	27/30	23/4 IGD 22/8 Ctrl	No	n.c.	17.9 ± 0.9 18.3 ± 1.6	fMRI to detect FC and to measure volumes	↑ volumes caudate and nucleus accumbens	[85]
ACC, DLPFC	28/25	17/11 IGD 16/9 Ctrl	No	n.c.	19.3 ± 2.1 19.7 ± 3.8	fMRI to detect FC	↓ FA in the salience network, right central executive network tracts, and between-network (the ACC-right DLPFC tracts)	[86]
sPL, precuneus, CG, sTG, brainstem	19/19	11/8 IGD 11/8 Ctrl	No	n.c.	21.4 ± 1.0 20.8 ± 1.1	Task-state in fMRI	↑ activation in the right SPL, right insular lobe, right precuneus, rCG, right STG, and left brainstem.	[87]
PCC, mPFC, iPL	64/63	36/28 IGD 41/22 Ctrl	No	n.c.	22.577 ± 2.2 23.085 ± 2.5	Resting-state fMRI to detect connectivity	↓ interactions between the left IPL-mPFC-PCC (↑inhibition)	[75]
rPCC, lMOG, rMTG, and rPCG	46/58	23/23 IGD 29/29 Ctrl	Yes	n.c	23.0 ± 1.1 22.7 ± 1.4	fMRI to measure ReHo	♂: ↓ ReHo in rPCC, ↑ ReHo in lMOG and MTG ♀: ↓ ReHo in lMOG and MTG	[88]
DLPFC, striatum, thalamus and insula	54/65	29/25 IGD 34/31 Ctrl	Yes	n.c	21.14 ± 2.4 21.17 ± 2.1	fMRI to evaluate FC	♂: ↓ FC between DLPFC and sFG ↑FC between striatum and thalamus/insula ♀: ↑FC between striatum and thalamus/insula	[76]
bRMFG, sFG, lSMG, rPCC, rsPL	62/71	29/33 IGD 37/34 Ctrl	Yes	n.c.	21.1 ± 1.4 20.7 ± 1.8	Structural MRI to evaluate cortical thickness	♂: ↑ bRMFG, sFG, lSMG ↓ rPCC ♀: ↓ bRMFG, sFG, lSMG ↑ rPCC	[89]