在newscientist看到的一则报导. 挺有趣的 (刚好本人也在研究脑) Brain scans have provided the most compelling evidence yet that being gay or straight is a biologically fixed trait. The scans reveal that in gay people, key structures of the brain governing emotion, mood, anxiety and aggressiveness resemble those in straight people of the opposite sex. First they used MRI scans to find out the overall volume and shapes of brains in a group of 90 volunteers consisting of 25 heterosexuals and 20 homosexuals of each gender. The results showed that straight men had asymmetric brains, with the right hemisphere slightly larger – and the gay women also had this asymmetry. Gay men, meanwhile, had symmetrical brains like those of straight women. ---------------------- 作者利用MRI去scan异性恋与同志的大脑. 结果发现: 异性恋男人的大脑左右不对称, 右大脑半球较大. 异性恋女人则对称 男同志的大脑左右对称 女同志则不对称 不仅如此, 也利用PET去侦测amygdala的血流速率 They found that the patterns of connectivity in gay men matched those of straight women, and vice versa (see image, above right). In straight women and gay men, the connections were mainly into regions of the brain that manifest fear as intense anxiety. "The regions involved in phobia, anxiety and depression overlap with the pattern we see from the amygdala," says Savic. This is significant, she says, and fits with data showing that women are three times as likely as men to suffer from mood disorders or depression. Gay men have higher rates of depression too, she says, but it's difficult to know whether this is down to biology, homophobia or simply feelings of being "different". In straight men and lesbians, the amygdala fed its signals mainly into the sensorimotor cortex and the striatum, regions of the brain that trigger the "fight or flight" response. "It's a more action-related response than in women," says Savic. http://0rz.tw/854LO ------------------------------------------------ 祝大家台风天平安 ^.^ --

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