自然：凶大无脑可能有一定道理。。。

夏娜的灼眼555

Nature：脂肪组织越多，大脑会越小吗？
作者：Natureasia 来源：Natureasia 2011-12-1 21:55:39


日前，nature杂志在线发表了瑞士研究人员的研究成果。他们通过研究发现脑子大小与脂肪组织之间存在着一定的关系。

从能量供应角度来说，脑是一个维持成本很高的器官，而人类的脑子要比具有可比性的灵长类脑子大得多，那么人类是怎样维持这样的大脑而又没有任何明显的难度呢？一个被广泛接受的解释是“昂贵组织假说”，该假说提出，在脑的大小与其他从能量角度来说昂贵的器官（尤其是消化道）的质量之间有一个平衡。

研究人员对100个哺乳动物物种所做的一项调查显示没有这样一个平衡，从而驳斥了昂贵组织竞争能量的观点。不过，在脑子的大小与以脂肪组织的形式所存储的能量多少之间有一个负相关。研究者提出，人脑大小的增加受能量输入的稳定化和来自运动、生长及生殖的能量的转向的综合影响。(生物谷Bioon.com)



doi:10.1038/nature10629
PMC:
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Energetics and the evolution of human brain size

Ana Navarrete,1 Carel P. van Schaik1 & Karin Isler1

The human brain stands out among mammals by being unusually large. The expensive-tissue hypothesis1 explains its evolution by proposing a trade-off between the size of the brain and that of the digestive tract, which is smaller than expected for a primate of our body size. Although this hypothesis is widely accepted, empirical support so far has been equivocal. Here we test it in a sample of 100 mammalian species, including 23 primates, by analysing brain size and organ mass data. We found that, controlling for fat-free body mass, brain size is not negatively correlated with the mass of the digestive tract or any other expensive organ, thus refuting the expensive-tissue hypothesis. Nonetheless, consistent with the existence of energy trade-offs with brain size, we find that the size of brains and adipose depots are negatively correlated in mammals, indicating that encephalization and fat storage are compensatory strategies to buffer against starvation. However, these two strategies can be combined if fat storage does not unduly hamper locomotor efficiency. We propose that human encephalization was made possible by a combination of stabilization of energy inputs and a redirection of energy from locomotion, growth and reproduction.

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