INAH-3

INAH-3全稱前下視丘間質核-3（third interstitial nucleus of the anterior hypothalamus），是人類下視丘的一個核（英語：Nucleus (neuroanatomy)）。此神經核屬於性別二態核（英語：Sexually dimorphic nucleus），男性的INAH-3體積比女性的大許多^[1]，且同性戀男性的INAH-3大小比異性戀男性小，而與女性的大小接近^[2]。

相關研究

前下視丘間質核（INAH）的概念最早於1989年由加利福尼亞大學洛杉磯分校的研究人員提出，指人類視前區-下視丘前部（preoptic-anterior hypothalamic area，PO-AHA）^{[註 1]}新發現的4個神經核，即INAH-1、INAH-2、INAH-3與INAH-4，其中男性的INAH-3體積約為女性的2.8倍大^[3]。

1991年，美國神經生物學家西蒙·列維（英語：Simon LeVay）在《科學》期刊發表論文指出INAH-3可能為與性傾向有關的關鍵腦區，同性戀男性的INAH-3體積比異性戀男性的小，而與女性的大小相似^[2]^[4]。列維提出解釋此差異的三個假說，一為同性戀與異性戀男性的INAH-3大小在出生前或嬰兒時期即具差異，進而影響個體的性傾向；二為其體積差異為後天造成，即個體的性感受與行為塑造了INAH-3的大小差異；三為此差異與性傾向並不直接相關，而是特定干擾因素所致。其中他認為第一個假說最為可能，且基於大鼠實驗的結果而認為第二個假說為真的可能性不大^[5]^[6]。後續研究發現同性戀男性的INAH-3較小是神經纏繞較緊密造成，其INAH-3的神經元總截面積與神經元總數並不小於異性戀男性，且HIV病毒感染對INAH-3的大小沒有影響^[7]。

另外還有研究探討INAH-3與性別認同的關聯。荷蘭神經生物學家迪克·斯瓦普（英語：Dick Swaab）發現跨性別女性的INAH-3體積與生理女性相似，而跨性別男性的INAH-3體積則與生理男性相仿^[8]。

腳註

^ PO-AHA的功能包括調控促性腺激素的分泌、母性行為（英語：Maternal behavior in vertebrates）與性相關行為。

參考文獻

^ Allen LS; Hines M; Shryne JE; Gorski RA. Two sexually dimorphic cell groups in the human brain.. J Neurosci. 1989, 9 (2): 497–506. PMC 6569815 . PMID 2918374. doi:10.1523/JNEUROSCI.09-02-00497.1989 .
^ ^2.0 ^2.1 LeVay, S. A difference in hypothalamic structure between heterosexual and homosexual men.. Science. 1991, 253 (5023): 1034–7. Bibcode:1991Sci...253.1034L. PMID 1887219. S2CID 1674111. doi:10.1126/science.1887219.
^ Allen, L.S.; Hines, M.; Shryne, J.E.; Gorski, R.A. Two sexually dimorphic cell groups in the human brain.. The Journal of Neuroscience. 1989, 9 (2): 497–506. PMC 6569815 . PMID 2918374. doi:10.1523/JNEUROSCI.09-02-00497.1989 .
^ Dale Purves (編). Central Nervous System Dimorphisms Related to Reproductive Behaviors. Neuroscience 2:ed. Sinauer Associates, Inc. 2001.
^ LeVay, S.; Hamer, D.H. Evidence for a biological influence in male homosexuality.. Scientific American. 1994, 270 (5): 44–9. Bibcode:1994SciAm.270e..44L. PMID 8197444. doi:10.1038/scientificamerican0594-44.
^ Simon LeVay. Gay, Straight, and the Reason Why: The Science of Sexual Orientation. Oxford University Press. 2011: 195. ISBN 978-0-19-973767-3.
^ Byne, William; Tobet, Stuart; Mattiace, Linda A.; Lasco, Mitchell S.; Kemether, Eileen; Edgar, Mark A.; Morgello, Susan; Buchsbaum, Monte S.; Jones, Liesl B. The Interstitial Nuclei of the Human Anterior Hypothalamus: An Investigation of Variation with Sex, Sexual Orientation, and HIV Status. Hormones and Behavior. 2001-09-01, 40 (2): 86–92. PMID 11534967. S2CID 3175414. doi:10.1006/hbeh.2001.1680.
^ Garcia-Falgueras, A.; Swaab, D.F. A sex difference in the hypothalamic uncinate nucleus: relationship to gender identity.. Brain : A Journal of Neurology. 2008, 131 (Pt 12): 3132–46. PMID 18980961. doi:10.1093/brain/awn276 .

[3] PO-AHA的功能包括調控促性腺激素的分泌、母性行為（英語：Maternal behavior in vertebrates）與性相關行為。

[1] Allen LS; Hines M; Shryne JE; Gorski RA. Two sexually dimorphic cell groups in the human brain.. J Neurosci. 1989, 9 (2): 497–506. PMC 6569815 . PMID 2918374. doi:10.1523/JNEUROSCI.09-02-00497.1989 .

[LeVay_1991-2] 2.0 ^2.1 LeVay, S. A difference in hypothalamic structure between heterosexual and homosexual men.. Science. 1991, 253 (5023): 1034–7. Bibcode:1991Sci...253.1034L. PMID 1887219. S2CID 1674111. doi:10.1126/science.1887219.

[4] Allen, L.S.; Hines, M.; Shryne, J.E.; Gorski, R.A. Two sexually dimorphic cell groups in the human brain.. The Journal of Neuroscience. 1989, 9 (2): 497–506. PMC 6569815 . PMID 2918374. doi:10.1523/JNEUROSCI.09-02-00497.1989 .

[5] Dale Purves (編). Central Nervous System Dimorphisms Related to Reproductive Behaviors. Neuroscience 2:ed. Sinauer Associates, Inc. 2001.

[LeVay_1994-6] LeVay, S.; Hamer, D.H. Evidence for a biological influence in male homosexuality.. Scientific American. 1994, 270 (5): 44–9. Bibcode:1994SciAm.270e..44L. PMID 8197444. doi:10.1038/scientificamerican0594-44.

[7] Simon LeVay. Gay, Straight, and the Reason Why: The Science of Sexual Orientation. Oxford University Press. 2011: 195. ISBN 978-0-19-973767-3.

[ByneINAH3HIV-8] Byne, William; Tobet, Stuart; Mattiace, Linda A.; Lasco, Mitchell S.; Kemether, Eileen; Edgar, Mark A.; Morgello, Susan; Buchsbaum, Monte S.; Jones, Liesl B. The Interstitial Nuclei of the Human Anterior Hypothalamus: An Investigation of Variation with Sex, Sexual Orientation, and HIV Status. Hormones and Behavior. 2001-09-01, 40 (2): 86–92. PMID 11534967. S2CID 3175414. doi:10.1006/hbeh.2001.1680.

[Garcia-Falgueras_2008-9] Garcia-Falgueras, A.; Swaab, D.F. A sex difference in the hypothalamic uncinate nucleus: relationship to gender identity.. Brain : A Journal of Neurology. 2008, 131 (Pt 12): 3132–46. PMID 18980961. doi:10.1093/brain/awn276 .

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