Talk:Endocrine - Gonad Development
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Cite this page: Hill, M.A. (2024, June 17) Embryology Endocrine - Gonad Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Endocrine_-_Gonad_Development |
2012
Fetal Testosterone Influences Sexually Dimorphic Gray Matter in the Human Brain
J Neurosci. 2012 Jan 11;32(2):674-680.
Lombardo MV, Ashwin E, Auyeung B, Chakrabarti B, Taylor K, Hackett G, Bullmore ET, Baron-Cohen S. Source Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge CB2 8AH, United Kingdom, Department of Psychology, University of Bath, Bath BA2 7AY, United Kingdom, Centre for Integrative Neuroscience and Neurodynamics, School of Psychology and Clinical Language Sciences, University of Reading, Reading RG6 6AH, United Kingdom, Department of Clinical Biochemistry, Addenbrooke's Hospital, Cambridge CB2 0QQ, United Kingdom, Department of Fetal Medicine, Rosie Maternity Hospital, Cambridge CB2 0SW, United Kingdom, and Brain Mapping Unit, Department of Psychiatry, University of Cambridge, Cambridge CB2 0SZ, United Kingdom. Abstract In nonhuman species, testosterone is known to have permanent organizing effects early in life that predict later expression of sex differences in brain and behavior. However, in humans, it is still unknown whether such mechanisms have organizing effects on neural sexual dimorphism. In human males, we show that variation in fetal testosterone (FT) predicts later local gray matter volume of specific brain regions in a direction that is congruent with sexual dimorphism observed in a large independent sample of age-matched males and females from the NIH Pediatric MRI Data Repository. Right temporoparietal junction/posterior superior temporal sulcus (RTPJ/pSTS), planum temporale/parietal operculum (PT/PO), and posterior lateral orbitofrontal cortex (plOFC) had local gray matter volume that was both sexually dimorphic and predicted in a congruent direction by FT. That is, gray matter volume in RTPJ/pSTS was greater for males compared to females and was positively predicted by FT. Conversely, gray matter volume in PT/PO and plOFC was greater in females compared to males and was negatively predicted by FT. Subregions of both amygdala and hypothalamus were also sexually dimorphic in the direction of Male > Female, but were not predicted by FT. However, FT positively predicted gray matter volume of a non-sexually dimorphic subregion of the amygdala. These results bridge a long-standing gap between human and nonhuman species by showing that FT acts as an organizing mechanism for the development of regional sexual dimorphism in the human brain.
PMID 22238103
2010
Organizational effects of fetal testosterone on human corpus callosum size and asymmetry
Psychoneuroendocrinology. 2010 Jan;35(1):122-32.
Chura LR, Lombardo MV, Ashwin E, Auyeung B, Chakrabarti B, Bullmore ET, Baron-Cohen S. Source Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK. lrc36@cam.ac.uk Abstract Previous theory and research in animals has identified the critical role that fetal testosterone (FT) plays in organizing sexually dimorphic brain development. However, to date there are no studies in humans directly testing the organizational effects of FT on structural brain development. In the current study we investigated the effects of FT on corpus callosum size and asymmetry. High-resolution structural magnetic resonance images (MRI) of the brain were obtained on 28 8-11-year-old boys whose exposure to FT had been previously measured in utero via amniocentesis conducted during the second trimester. Although there was no relationship between FT and midsaggital corpus callosum size, increasing FT was significantly related to increasing rightward asymmetry (e.g., Right>Left) of a posterior subsection of the callosum, the isthmus, that projects mainly to parietal and superior temporal areas. This potential organizational effect of FT on rightward callosal asymmetry may be working through enhancing the neuroprotective effects of FT and result in an asymmetric distribution of callosal axons. We suggest that this possible organizational effect of FT on callosal asymmetry may also play a role in shaping sexual dimorphism in functional and structural brain development, cognition, and behavior. PMID 19833443
