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Information about Sexually Dimorphic Nucleus

The sexually dimorphic nucleus (SDN) is a cluster of cells in the preoptic area of the hypothalamus, an area of the human brain and that of other mammals, which is controversially considered by some studies to play a key role in the sexual differentiation of the brain. This cluster of cells contains about twice as many cells in adult men compared to adult women.[1]

Role in sexual development

At birth, the sexually dimorphic nucleus contains around 20% of the cells found at 24-48 months of age; after that age, a decrease in cell count occurs in females, but not males, causing the physical sexual differentiation of the brain.[1] Initially some studies considered this area of the brain a likely candidate for neurological changes leading to homosexuality, but studies such as Swaab et al found no statistically significant difference in cell count between test groups of heterosexual and homosexual male adults. However, studies by neuroscientist Simon LeVay have shown a statistically significant difference in other areas of the brain, such as in the third interstitial nucleus of the anterior hypothalamus (INAH-3), which was found to have a lower cell count in homosexual male adults compared to heterosexuals.[3]

References

1. ^ Swaab D, Gooren L, Hofman M (1995). "Brain research, gender and sexual orientation". Journal of Homosexuality 28 (3-4): 283-301. PMID 7560933. 
2. ^
3. ^ Zachs, R. LeVay Shares Thoughts On 'Gay Gene' Research. The Tech. 1996, 116:27, pp. 17. Massachusetts Institute of Technology.

External links

The preoptic area is a region of the hypothalamus. According to the MeSH classification, it is considered part of the anterior hypothalamus.

Functions

The preoptic area is responsible for thermoregulation and receives nervous stimulation from thermoreceptors in the skin,
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The hypothalamus links the nervous system to the endocrine system via the pituitary gland (hypophysis). The hypothalamus, (from Greek ὑποθαλαμος = under the thalamus) is located below the thalamus, just above the brain stem.
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The human brain controls the central nervous system (CNS), by way of the cranial nerves and spinal cord, the peripheral nervous system (PNS) and regulates virtually all human activity.
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Mammalia
Linnaeus, 1758

Subclasses & Infraclasses
  • Subclass †Allotheria*
  • Subclass Prototheria
  • Subclass Theria

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Sexual differentiation is the process of development of the differences between males and females from an undifferentiated zygote (fertilized egg). As male and female individuals develop from zygotes into fetuses, into infants, children, adolescents, and eventually into adults, sex
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Neurology is a branch of medicine dealing with disorders of the nervous system. Medical professionals (such as Biomedical Doctors and Physicians) specializing in the field of neurology are called neurologists
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Heterosexuality is sexual or romantic attraction between opposite sexes, and is the most common sexual orientation among humans. The current use of the term has its roots in the broader 19th century tradition of personality taxonomy.
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Simon LeVay (born 28 August 1943 in Oxford, England) is a neuroscientist and author known for his studies about brain structures and sexual orientation. He is also the co-author of a textbook on human sexuality and has coauthored books on diverse topics such as earthquakes,
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Anterior can refer to:
  • Anterior and posterior, both Anatomical terms of location
  • Anterior (band), A Welsh Metal band

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Journal of Homosexuality (ISSN 0091-8369) is a long-standing peer-reviewed academic journal (founding editor Charles Silverstein) published by The Haworth Press, Inc., in New York.
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The Tech, first published in 1881, is the oldest and largest campus newspaper at the Massachusetts Institute of Technology in Cambridge, Massachusetts. Editions are published on Tuesday and Friday throughout the academic year, daily during freshman orientation period, once a
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Massachusetts Institute of Technology (MIT) is a private, coeducational research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing 32 academic departments,[3]
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NeuroNames is a system of nomenclature for the human and/or macaque brain.

It is maintained by the University of Washington and is a part of a tool called "BrainInfo". BrainInfo helps one identify structures in the brain.
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