Table 2.

Sex differences in cortical and subcortical structures of the adult brain

Brain region/aspect	Sample size and age (M ± SD or range)	Sample source	Brain-relevant sample characteristics	Brain imaging methods and measurements		Statistically controlled confounding variables	Selected findings and Conclusions	Pattern	Authors
Cortex	30 M; 30 F M: 25.45 ± 4.72 F: 24.32 ± 4.35	Images from Center for Scientific Innovation and Technology, Magdeburg, Germany	Healthy young M and F	1.5 T General Electric Loni software Measurements CTh		ICV Age	Without ICV correction, F > M in the four lobes With ICV correction, still F > M, except for a small region in the temporal lobe Conclusions F have thicker cortex than M	F > M	Luders et al. (2006)
Cortex	90 M; 94 F Age range: M: 18–67 F: 18–70	Normal Ss from TongRen Hospital, Beijing, China	Healthy adult M and F, population from Asia	1.5 General Electric Signa scanner CTh measured using an automated surface method + graph theoretical approaches Measurements CTh		ICV Age	F > M: Frontal, parietal and occipital lobes. M > F: Small portions of temporal lobes Conclusions F thicker cortex than M. In small regions M > F	F > M M > F (small regions)	Lv et al. (2010)
Cortex	31 M; 21 F Age range: M: 18–42 F: 19–36	Seoul Normal Ss from National University Hospital, Seoul, Korea	Healthy adult M and F Population from Asia	1.5 T General Electric Signa scanner Measurements: CTh		ICV Age	F > M: frontal, parietal and occipital lobes Temporal lobes show relatively less significant thickening in F Conclusions F thicker cortex than M	F > M	Im et al. (2006)
Cortex	90 M; 86 F M: 31 ± 21.3 F: 33.9 ± 22.3 Age range whole sample: 7–87	Normal Ss community sample, Department of Psychiatry, Columbia University, New York, USA	A large age range population	1.5 T General Electric Signa GM thickness calculated using Eikonal fire equation Measurements CTh		Age ICV body size	The thicker cortices in F than M: right inferior parietal and posterior temporal independent of differences in body size and ICV Conclusions F thicker cortex than M	F > M	Sowell et al. (2007)
Cortex, amygdala and hypothalamus	27 M; 21 F M: 39.13 ± 12 F:36.3 ± 10.5	Normal, 93% Caucasian Ss. Department of Psychiatry, Harvard Medical School, Boston, USA	Healthy adults, M and F same ethnicity, education	1.5 T General Electric Signa Semiautomatic delimitations Measurements Volume		Age ICV	Volume: M > F amygdala and hypothalamus F > M: cortex Conclusions M greater volumes in amygdala & hypothalamus	M > F F > M	Goldstein et al. (2001)
Amygdala and hippocampus	313 M; 306 F Age range for the whole sample 40–90	Mental Health Institute of Beijing Medical University, China	Large population of normal adults from Asia	1.5 T MR unit Volume of structures Manually outlined using as a brain atlas slices from 2 postmortem specimens Measurements Volume			Volume of amygdale and hippocampus declines with age No sex differences Conclusions No SD in large sample no caucasian	M = F	Mu et al. (1999)
Amygdala and hippocampus	57 M; 59 F M:27.0 ± 5.7 F:25.0 ± 5.3	Volunteers Department of Psychiatry, University Medical Center, Philadelphia, USA	Healthy adult population	1.5 T General Electric Signa Brain volumes extracted automatically ‘ROIS manually outlined for subcortical structures Measurements Volume		ICV	M and F have similar volume in amygdale and hippocampus Conclusions No SD	M = F	Gur et al. (2002)
Basal ganglia	463 M; 541 F Age range whole sample: 18–36	Ss enrolled in the Brain Imaging Genetic project at Medical Center, Radboud University, Nijmegen, Netherlands	Large healthy population	1.5 and 3 T scanners Automatic volumetry on MRI images Measurements volume		Age Separate cohorts for the two type of scanners Control for total GM and WM	M > F putamen and globus pallidus No SD for caudate nucleus and nucleus accumbens Conclusions some basal ganglia show SD	M > F	Rijpkema et al. (2012)
Cortex and subcortical structures	40 M; 51 F Age range whole sample: 18–33	Healthy young adults. Department of Psychiatry and clinical Psychobiology, University of Barcelona, Spain	Healthy adult population	1.5 T General Electric scanner VBM ROIs analyses of olfactory system structures Uncorrected Measurements concentration		Age	M > F: BA 28, pallidum. F > M: BA10, 11, 25, hippocampus, amygdala Conclusions subcortical regions show both M > F and F > M patterns of SD	M > F F > M	García-Falgueras et al. (2006)
Temporal lobe Superior temporal gyrus Amygdala Hippocampus	53 M, 46 F Age range all Ss: 4.7–17.8	Recruited from the community, Child Psychiatric Branch, National Institute of Mental Health, Bethesda, USA	Healthy young population	1.5 T Signa Advance scanner Manual tracing Measurements volume		Age Handedness Tanner stage ICV	R Amygdala increases only in M, while R Hippocampus increases only in F Conclusions SD in maturational changes	M > F F > M	Giedd et al. (1996)

ICV intracraneal volume, GM gray matter, WM white matter, CTh cortical thickness, BA Brodmann’s area, VBM voxel-based morphometry, SD sex differences, F female, M male, Ss subjects