Cerebral Cortex Advance Access published online on June 11, 2008
Cerebral Cortex, doi:10.1093/cercor/bhn100
Sex Differences and the Impact of Steroid Hormones on the Developing Human Brain
1 Institute of Neuroscience and Biophysics, Research Center Juelich, D-52425 Juelich, Germany, 2 Brain Imaging Centre West, Research Center Juelich, D-52425 Juelich, Germany, 3 Child Neuropsychology Section, Department of Child and Adolescent Psychiatry, University Hospital Aachen, D-52074 Aachen, Germany, 4 Parmenides Center for the Study of Thinking, D-80333 Munich, Germany, 5 Department of Biological and Medical Psychology, University of Bergen, 5009 Bergen, Norway, 6 Department of Psychology, Durham University, Durham DH1 3LE, United Kingdom, 7 Biopsychology, Faculty of Psychology, Ruhr-University Bochum, D-44780 Bochum, Germany, 8 Department of Child and Adolescent Psychiatry, University Hospital Aachen, D-52074 Aachen, Germany, 9 Department of Neurology, University Hospital, D-50931 Cologne, Germany
Address correspondence to Kerstin Konrad, Child Neuropsychology Section, Department of Child and Adolescent Psychiatry, Neuenhofer Weg 21, D-52074 Aachen, Germany. Email: kkonrad{at}ukaachen.de.
Little is known about the hormonal effects of puberty on the anatomy of the developing human brain. In a voxel-based morphometry study, sex-related differences in gray matter (GM) volume were examined in 46 subjects aged 8–15 years. Males had larger GM volumes in the left amygdala, whereas females had larger right striatal and bilateral hippocampal GM volumes than males. Sexually dimorphic areas were related to Tanner stages (TS) of pubertal development and to circulating level of steroid hormones in a subsample of 30 subjects. Regardless of sex, amygdala and hippocampal volumes varied as a function of TS and were associated with circulating testosterone (TEST) levels. By contrast, striatal GM volumes were unrelated to pubertal development and circulating steroid hormones. Whole-brain regression analyses revealed positive associations between circulating estrogen levels and parahippocampal GM volumes as well as between TEST levels and diencephalic brain structures. In addition, a negative association was found between circulating TEST and left parietal GM volumes. These data suggest that GM development in certain brain regions is associated with sexual maturation and that pubertal hormones might have organizational effects on the developing human brain.
Key Words: brain morphometry • sex differences • sexual maturation • steroid hormones