即使是一些陳詞濫調也提示了一些真理性的東西,。眾所周知男人生氣時比較容易大喊大叫或者捶打墻壁，而女人生氣時則比較容易會靜坐著生悶氣,，不易向外發(fā)泄,。這些又給我們提示了什么？最近一項研究顯示,，大腦杏仁核存在的內在差異決定影響男人與女人處事方式（包括情感反應）,。研究顯示不但杏仁核的結構及功能存在性別差異，而且在杏仁核的活性與大腦其它區(qū)的協(xié)調作用方面男性與女性存在差別,。
杏仁核跨大腦左右半球，其功能在于幫助人們控制情感反應如恐懼等如何進行及被記憶,。多項研究發(fā)現杏仁核被激活時存在性差異,。在一項研究中,，叫志愿者回憶恐怖電影，在男性志愿者中,，右杏仁核變得更活躍,。而在女生則表現為左杏仁核更活躍。加州大學神經生物學家Larry Cahill想知道杏仁核表現的上述性別差異是否為硬線性的,，即想弄清楚甚至在沒有什么事情激活它的時候,，杏仁核是否保持這種性別特異性傾向。如果答案是肯定的,，那么這將提示男性與女性杏仁核存在固有的差異,。Cahill及其同事研究了36名男性和36名女性（男性與女性志愿者皆為右利手的）的PET掃描資料。PET掃描時要求志愿者閉上雙眼處于放松休息狀態(tài),。他們發(fā)現,，即使在休息狀態(tài)，男性與女性杏仁核工作存在差異,。在女生,，左杏仁核血流量伴隨大腦其它區(qū)血流量衰減及充盈，而右杏仁核極小有如此現象,。而在男性,，則表現為右杏仁核血流量改變伴隨大腦其它區(qū)血流量變化。
更有有趣的發(fā)現在于與杏仁核協(xié)調作用的區(qū)域的差異,。在女生,，這些區(qū)域似乎是下丘腦及有關的皮質下區(qū)，而下丘腦的作用在于調控人體的應激反應及情感反應,。而在男性,，杏仁核協(xié)調作用于大腦的有關運動及視覺區(qū)，運運區(qū)及視覺區(qū)被認為是在與外部世界反應發(fā)揮重要作用,。研究者在2006年4月7日NeuroImage報道了他們的發(fā)現,。對于此項發(fā)現，神經科學家John Gabrieli認為,，對于男性來說,，似乎存在更強的協(xié)調性以便處理處界事物。但目前人們還不能確切理解這些確實存在的差異內在意義,。
原文出處：Jennifer Couzin ScienceNOW Daily News 7 April 2006
原始文獻:
A "His" or "Hers" Brain Structure?
By Jennifer Couzin
ScienceNOW Daily News
7 April 2006
Even oft-repeated gender stereotypes harbor some truth: Angry men are more likely to yell or punch a wall, whereas angry women sit silently stewing. Now, a new study is tracing these distinctions in how men and women process emotion to an almond-shaped structure deep in the brain. Not only does the structure, the amygdala, function differently by gender, but its activity in men is also coupled with very different brain regions than it is in women.
The amygdala straddles both sides of the brain and helps control how emotions such as fear are processed and remembered. Several studies have found gender differences when the amygdala is stimulated--by having volunteers recall scary movies, for example. In men, the right side of the amygdala, known simply as the right amygdala, appears more likely to become active, whereas in women it's the left. Neurobiologist Larry Cahill of the University of California, Irvine, wondered whether this difference was hardwired--whether, in other words, the amygdala retained its gender-specific tendencies even when nothing was activating it. If so, this would suggest that the structure was inherently different in men than in women.
Cahill and his colleagues studied PET scans of 36 men and 36 women, all of whom were right-handed. The scans had been collected for various brain studies where volunteers were asked to close their eyes and relax while the pictures were taken. The team found that, even at rest, the amygdala worked differently in men and women. In women, blood flow to the left amygdala ebbed and flowed along with other brain structures while the right amygdala did little. In men, it was blood flow to the right amygdala that varied along with blood flow elsewhere in the brain, the researchers report 1 April NeuroImage.
Especially intriguing, says Cahill, were the regions with which the amygdala was acting in concert. In women, those tended to be the hypothalamus, which directs the body's stress response and affects feelings, and the related subgenual cortex. In men, the amygdala acted with motor and visual brain areas, which are "believed important for interacting with the external world," says Cahill. He admits he doesn't know what the volunteers were thinking while being scanned or whether that affected the results.
Still, the study suggests that "this might be a default state," says John Gabrieli, a neuroscientist at the Massachusetts Institute of Technology in Cambridge. For men, he says, "it seems that there's a stronger coupling ... [for] dealing with stuff out there in the world," while this wasn't shown for women. No one knows quite what it all means, Gabrieli admits, but the findings are "food for thought."
