PSYC 370 Lecture Notes - Lecture 18: Sexually Dimorphic Nucleus, Optic Chiasm, Fornication
8 Jul 2019
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Document Summary
When scientists starte looking at the brain to see where sexual responses may be mediated- the hypothalamus was the first place they looked bc diff nuclei in the hypothalamus guided survival behaviours. In the hypothalamus, in adult rat tissue they discovered one particular nucleus that is consistently larger in male rats than females. This is known as a sexually dimorphic nucleus bc it differs b/w the nucleus. This nucles is below a band of fibers called the anterior commissure and dorsal to the optic chiasm. They also found in male rats the size of the sexually dimorphic nucleus correlates positively with testosterone levels. If you lesion the sdn w/o touching surrounding tissue, it doesn"t change the sexual behaviour. Further research showed that the differentiation occurs in the very early prenatal period and it involves exposure to androgen levels. It is not testosterone tht is creating this effect. The testosterone crosses the bbb and becomes estradiol.
