More Differences Between Brains of Men and Women
Scientists at Johns Hopkins have discovered “striking” differences between men and women in a part of the brain linked with ability to estimate time, judge speed, visualize things three-dimensionally and solve mathematical problems.
The differences, the rearchers say, may underlie well-known trends that vary by x, such as the fact that more men than women are architects, mathematicians and race-car drivers.
In a study reported this week in the journal Cerebral Cortex, the rearchers show that a brain region called the inferior parietal lobule (IPL) is significantly larger overall in men than in women. The area is part of the cerebral cortex and appears on both sides of the brain just above ear-level.
Also, there’s a symmetry difference, with men having a larger left IPL than right. in women in the study, it’s the right IPL that’s somewhat larger, though the difference between the two sides of the brain is less obvious than in men, says psychiatrist Godfrey Pearlson, M.D., who headed the project.
“This is the same part of Albert Einstein’s brain that was particularly large,” says Pearlson, “Scientists have noticed this region is also larger in the postmortem brains of other physicists and mathematicians.”
In the study, rearchers reviewed MRI-scans of the brains of 15 cloly matched men and women. They ud new computer software created by Hopkins psychiatrist Patrick Barta, M.D., Ph.D. to compare overall IRL volume by gender. The software lets scientists highlight the IRL by “painting” it in on computer images of each subject’s brain; it then calculates a highly accurate volume.
Rearchers also compared IRL volumes on the left and the right sides of the brain. After allowances for men’s larger overall head and brain size, men had roughly 6 percent more IRL tissue than women.
“The inferior parietal lobule is far more developed in people than in animals and has evolved relatively recently,” says Pearlson. It allows the brain to process information from ns such as vision and touch, and enables the sort of thinking involved in lective attention and perception.
Studies link the right IRL with a working memory of spatial relationships, the ability to n relationships between body parts and awareness of a person’s own affect or feelings. The left IPL, Pearlson says, is more involved in perception, such as judjing how fast something is moving, estimating time and having the ability to mentally rotate 3-D figures.
“To say this means mean are automatically better at some things than women is a simplification,” sa
ys Pearlson. “It’s easy to find women who are fantastic at math and physics and men who excel in language skills. Only when we look at very large populations and look for slight but significant trends do we e the generalizations. There are plenty of exceptions, but there’s also a grain of truth, revealed through the brain structure, that we think underlies some of the ways people characterize the xes.”
Earlier rearch by Pearlson showed that two crucial language areas in the frontal and temporal lobes of the brain were significantly larger in women, perhaps explaining their advantage in language-associated thought.
⼤脑结构，男⼥有别
约翰斯·霍普⾦斯⼤学的科学家们已经发现，在⼤脑中与估算时间、判断速度、想象三维事物和解数学题等能⼒有关的部位，男⼥之间有着“惊⼈的”差异。
研究⼈员说，这种差异可能形成众所周知的男⼥有别的现象，例如建筑师、教学家和赛车选⼿男性多于⼥性这⼀事实。
在本周的《⼤脑⽪层》杂志上报道的⼀项研究中，研究⼈员说明⼀个叫做下顶叶（IRL）的⼤脑部位，就总体来说，男性的⽐性的要⼤得多。该部位属⼤脑⽪层，正好位于⽿朵上⽅⼤脑两侧。
此外，还存在着⼀种对称的差异，男性的左下顶叶⼤于右下顶叶。领导这项研究的精神病学家、医学博⼠⼽弗雷·⽪尔逊说，研究表明，⼥性的右下顶叶略微⼤⼀些，尽管⼥性⼤脑两边的这种差异没有男性的那么明显。
⽪尔逊说：“这个部位与艾尔伯特·爱因斯坦⼤脑中那个特别⼤的部位是同⼀部位。科学家们已经注意到，⼫体解剖表明，其他物理学家和数学家的⼤脑也是这个部位⽐较⼤⼀些。”
研究⼈员在研究中观察了15个⼏乎不相上下的男⼥的⼤脑磁共振成像扫描图。他们使⽤的是霍普⾦斯⼤学精神病学家、医学博⼠兼哲学博⼠帕特⾥克·巴塔发明的新的电脑软件，以便⼤体上⽐较男性和⼥性的下顶叶的体积。这种软件能使科学家在每个受试者⼤脑的计算机图像上将下顶叶“涂上颜⾊”以使其凸现出来；然后它再⾼度精确地计算出其体积。
研究⼈员还⽐较了⼤脑左右两侧的下顶叶体积。在考虑到男性头部和⼤脑总体上较⼤的因素后，发现男性的下顶叶组织⽐⼥性的⼤约多6%。
⽪尔逊说：“⼈类的下顶叶⽐动物的要发达得多，⽽且是在相当晚的近期才进化⽽来的。”下顶叶使⼤脑能够处理从诸如视觉和触觉等感官传来的信息，并使涉及有选择性集中注意和知觉之类的思维活动得以进⾏。
研究报告表明，右下顶叶与对空间关系的实⽤记忆⼒、感知⼈体各部位相互关系的能⼒和对⾃我的⾃觉感情或感觉的意识有关。⽪尔逊说，左下顶叶则更多地涉及知觉，如判断某物移动的速度、估算时间以及拥有在⼤脑中旋转三维图形的能⼒。“如果说这意味着男性在某些事情上必然强于⼥性，那就把事情简单化了，”⽪尔逊说。“发现精通数学及物理的⼥性和擅长语⾔技能的男性是很容易的。只有在⼤量的⼈⼝中进⾏调查，并找出虽微不⾜道但有重要意义的趋势后，我们才能明⽩其中规律性的东西。当然有很多例外，但也不乏从⼤脑结构中显露出的真理的成分——我们认为，这构成了⼈们在性别⽅⾯的某些特征。”
⽪尔逊早些时候的研究表明，⼥性⼤脑额叶和颞叶中的两个关键的语⾔区域⽐男性的⼤得多，这也许解释了为什么⼥性在与语⾔有关的思维⽅⾯享有优势。
