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Androgenic Regulation of Sex Differences in Cortical Thickness of the Developing Mouse Brain
Author(s) -
Miyasaki Dillon,
Ramos Layla,
Tsai HoungWei
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.991.4
Subject(s) - somatosensory system , entorhinal cortex , cortex (anatomy) , cerebral cortex , medicine , biology , endocrinology , sexual dimorphism , testosterone (patch) , testicular feminization , sex characteristics , neuroscience , androgen receptor , hippocampus , prostate cancer , cancer
The cerebral cortex plays an important role in complex cognitive and social behaviors. Considerable evidence suggests that many of those are sexually dimorphic, but the neural mechanism underlying sex differences in cortical function still remains unclear. An earlier study showed greater cortical thickness in three areas of the parietal cortex of adult male mice compared with females, which seemed to be influenced by gonadal steroids, not sex chromosomal complement. Since activation of androgen receptor (AR) by perinatal testosterone secreted by the developing testes increases the in the number of calbindin‐positive neurons in the sexually dimorphic nucleus of the male preoptic area, a hypothalamic region that controls male copulatory behaviors, we thus hypothesized that AR might also be responsible for masculinization of the mouse cerebral cortex. To test our hypothesis, we collected the whole brains (n=4–6 per group) of wild‐type male and female mouse pups as well as their littermates with testicular feminization mutation (Tfm), lacking functional AR, on postnatal days 21–24. Their brains were post‐fixed in 4% paraformaldehyde, serially sectioned, and stained with crystal violet. After the slides were cover‐slipped, measurement of cortical thickness in the primary somatosensory cortex, secondary somatosensory cortex, secondary motor cortex, and entorhinal cortex was taken under a light microscope using ImageJ. Among these brain regions, our preliminary data showed a significant effect of experimental group on cortical thickness in the entorhinal cortex only (P = 0.01). While wild‐type male mice had a thicker entorhinal cortex than wild‐type females, the cortical thickness in Tfm mice was intermediate between the wild‐type males and females and did not differ significantly from either of those groups. Our preliminary data suggests an important role for the AR in sexual differentiation of brain structure in the mouse entorhinal cortex during development. Support or Funding Information This work was supported by National Institutes of Health Grant SC3‐GM102051.