Navigation Links
Gay Men, Straight Women Have Similar Brains
Date:6/16/2008

Scans also showed similarities between lesbians, straight men

MONDAY, June 16 (HealthDay News) - MRI and PET scan studies are showing remarkable similarities between the brains of gay men and straight women, and between those of lesbians and straight men.

For example, the brains of straight men and of gay women share certain common features: both are slightly asymmetric, with the right hemisphere larger than the left, say the Swedish researchers.

On the other hand, the brains of gay men and straight women are both symmetrical.

Similar trends emerged when scientists tracked connectivity in the amygdala, the region of the brain involved in emotional learning and in activating the fight-or-flight response. They noted strong similarities between gay men and straight women, and lesbians and straight men.

The findings are published in the current issue of the Proceedings of the National Academy of Sciences.

"This is a very interesting study demonstrating a possible neurobiological relationship in brain size between gay men and straight women," said Paul Sanberg, distinguished professor of neurosurgery and director of the University of South Florida Center for Aging and Brain Repair in Tampa.

The neurobiology of sexual orientation is a controversial topic. Some research suggests that the brain activity of homosexual individuals in areas unrelated to sex mirror brain activity in straight individuals of the opposite sex. And certain psychological studies have revealed differences in how men and women use the brain's different hemispheres for verbal tasks, for example.

For this study, researchers from the Karolinska Institute in Stockholm first performed magnetic resonance imaging (MRI) on 90 participants -- 25 heterosexual men and an equal number of heterosexual women, plus 20 homosexual men and 20 homosexual women.

The right hemispheres of straight men and gay women were found to be bigger than the left, while the respective volume of these two cerebral hemispheres were about the same in gay men and straight women.

Fifty of the original participants also underwent positron emission tomography (PET) measurements of blood flow to the brain, designed to analyze connections between the right and left amygdalas. PET scans were performed both while the participants were resting and while they were smelling unscented air.

Here again, lesbians appeared to react more like straight men, while gay men were more like straight women.

According to the authors, fight-or-flight reactions -- controlled in part by the amygdala -- are more common in men than in women.

The differences, which were not related to sexual attraction, could be due to environmental effects, genetics or the influence of sex hormones, the study authors stated.

Although some sex differences in brain size are visible at birth, the brain continues to develop as the child matures, meaning that environmental factors could also play a role.

The current wisdom regarding genetics and sexual orientation posits that genes may play a role in male homosexuality but not in female homosexuality, the researchers said.

Experts have also speculated that exposure to sex hormones prenatally influence sexual preference. Male rhesus monkeys have more androgen (a male sex hormone) receptors in the right side of the brain, while females have an equal distribution of receptors for the hormone.

And brain asymmetry in male rats is established by early exposure to androgens. Symmetry in female brain hemispheres can be reversed by removing the ovaries soon after birth.

This study does little to clarify the reasons behind the differences, the researchers added, although it certainly does add to the debate.

More information

There's more on how the brain works at The Franklin Institute.



SOURCES: Paul Sanberg, Ph.D., D.Sc., distinguished professor of neurosurgery and director, University of South Florida Center for Aging and Brain Repair, Tampa; Proceedings of the National Academy of Sciences, June 16-20, 2008


'/>"/>
Copyright©2008 ScoutNews,LLC.
All rights reserved  

Related medicine news :

1. PartsSource Given 2008 Leading Edge Award for Second Straight Year
2. OPEN LETTER: Medical Journal Calls Upon Barack Obama to Set the Record Straight on AIDS Virus
3. The pitter patter of little feet... climbing straight up a wall
4. Homeless Vets - VA Sets the Record Straight
5. HIV/AIDS Cases Among State and Federal Prison Inmates Fell for the Sixth Straight Year During 2005
6. Different HIV rates among gay men and straight people not fully explained by sexual behavior
7. Health Insurance Premium Growth Slows for Fourth Straight Year
8. Less Intensive Treatment Given Diabetic Women With Heart Disease
9. Women Get Lung Cancer From Smoking at Same Rates as Men
10. Trust for Americas Health Releases Report on Connection between Womens Health and Stalled Infant Mortality Rates
11. Ovarian function and fertility preserved in women with severe systemic lupus erythematosus
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Gay Men, Straight Women Have Similar Brains
(Date:6/25/2016)... ... June 25, 2016 , ... ... non-athletes recover from injury. Recently, he has implemented orthobiologic procedures as a method ... —Johnson is one of the first doctors to perform the treatment. Orthobiologics are ...
(Date:6/24/2016)... Los Angeles, CA (PRWEB) , ... June 24, 2016 , ... ... plastic surgery procedures that most people are unfamiliar with. The article goes on to ... known procedures, but also many of these less common operations such as calf and ...
(Date:6/24/2016)... ... , ... Marcy was in a crisis. Her son James, eight, was out of control. Prone ... physically. , “When something upset him, he couldn’t control his emotions,” remembers Marcy. “If ... at my other children and say he was going to kill them. If we ...
(Date:6/24/2016)... ... June 24, 2016 , ... Dr. ... accelerated orthodontic treatment. Dr. Cheng has extensive experience with all areas of orthodontics, ... and accelerated osteogenic orthodontics. , Micro-osteoperforation is a revolutionary adjunct to orthodontic ...
(Date:6/24/2016)... Plano, TX (PRWEB) , ... June 24, 2016 , ... ... taking part in Genome magazine’s Code Talker Award, an essay contest in which patients ... for an award to be presented at the 2016 National Society of Genetic Counselors ...
Breaking Medicine News(10 mins):
(Date:6/24/2016)... Tenn. , June 24, 2016  Arkis ... providing less invasive and more durable cerebrospinal fluid ... in funding.  The Series-A funding is led by ... Lighthouse Fund, and other private investors.  Arkis, new ... neurosurgical instrumentation and the market release of its ...
(Date:6/23/2016)... , June 23, 2016 Any dentist who has ... of the current process. Many of them do not even ... technical difficulties and high laboratory costs involved. And those who ... it at such a high cost that the majority of ... Dr. Parsa Zadeh , founder of Dental Evolutions ...
(Date:6/23/2016)... Roche (SIX: RO, ROG; OTCQX: RHHBY) announced ... BRAHMS PCT (procalcitonin) assay as a dedicated testing solution ... this clearance, Roche is the first IVD company in ... sepsis risk assessment and management. PCT is ... levels in blood can aid clinicians in assessing the ...
Breaking Medicine Technology: