INAH 3

INAH 3 or Interstitial Nucleus of Anterior Hypothalamus 3 is a nucleus found in the anterior hypothalamus of the human brain. It is one of the four clusters of neurons in the hypothalamus that are sexually dimorphic, meaning they differ between males and females.

Anatomy

INAH 3 is located in the anterior hypothalamus, which is a region of the brain involved in the regulation of many physiological functions, including body temperature, hunger, thirst, fatigue, sleep, and circadian rhythms. The anterior hypothalamus also plays a role in sexual behavior and hormone secretion.

File:INAH 3 location.png

Location of INAH 3 in the human brain

Function

The exact function of INAH 3 is not fully understood. However, it is known to be larger in males than in females and has been implicated in sexual orientation. Some studies have suggested that the size of INAH 3 may be related to sexual orientation, with smaller INAH 3 volumes found in homosexual men compared to heterosexual men. However, these findings are controversial and further research is needed to confirm this relationship.

Research

Research on INAH 3 has primarily focused on its potential role in sexual orientation. The most well-known study was conducted by neuroscientist Simon LeVay, who found that INAH 3 was significantly smaller in homosexual men compared to heterosexual men. However, this study has been criticized for its small sample size and other methodological issues.

Other studies have also suggested a link between the size of INAH 3 and sexual orientation, but these findings are not consistent across all studies. Some researchers have suggested that other factors, such as hormone levels or genetic factors, may also influence the size of INAH 3.

See also

• Sexual differentiation of the brain
• Sexual orientation hypothesis
• Simon LeVay