摘要：一项研究发现，大脑随着人衰老而缩小是一种人类独有的现象。尽管与衰老有关的神经变化已经在其它物种身上观察到，还没有直接对我们的最近亲黑猩猩进行过比较。由神经科学家、人类学家和灵长类动物学家组成的一个研究组合作研究了在人类大脑中观察到的总容量下降和区域缩小是否也会出现在逐渐衰老的黑猩猩身上。使用磁共振成像（MRI），Chet Sherwood及其同事比较了22岁到88岁的87名成年人的大脑5个区域的容量，以及从10岁到51岁的99只成年黑猩猩的大脑容量。这组作者测量了人和黑猩猩的新皮层灰质的总容量、新皮层白质的总容量、额叶灰质总容量、额叶白质总容量，以及海马区的容量。这组作者发现，对于人类，随着年龄的增长所有大脑结构的容量下降。相比之下，黑猩猩的脑容量没有显著变化。这组作者提出了一个假说，即这种差异可能反映了人类远远更长的寿命。这组作者提出，更大的大脑和更长的寿命的进化成本看上去表现为更容易出现与年龄有关的神经衰退，这种衰退可能对处理速度、情景记忆、空间技能以及神经退行性疾病风险的增加产生巨大影响。
大脑随着人衰老而缩小是一种人类独有的现象
生物探索推荐英文论文摘要：
Aging of the cerebral cortex differs between humans and chimpanzees
Abstract
Several biological changes characterize normal brain aging in humans. Although some of these age-associated neural alterations are also found in other species, overt volumetric decline of particular brain structures, such as the hippocampus and frontal lobe, has only been observed in humans. However, comparable data on the effects of aging on regional brain volumes have not previously been available from our closest living relatives, the chimpanzees. In this study, we used MRI to measure the volume of the whole brain, total neocortical gray matter, total neocortical white matter, frontal lobe gray matter, frontal lobe white matter, and the hippocampus in a cross-sectional sample of 99 chimpanzee brains encompassing the adult lifespan from 10 to 51 y of age. We compared these data to brain structure volumes measured in 87 adult humans from 22 to 88 y of age. In contrast to humans, who showed a decrease in the volume of all brain structures over the lifespan, chimpanzees did not display significant age-related changes. Using an iterative age-range reduction procedure, we found that the significant aging effects in humans were because of the leverage of individuals that were older than the maximum longevity of chimpanzees. Thus, we conclude that the increased magnitude of brain structure shrinkage in human aging is evolutionarily novel and the result of an extended lifespan.
