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首页> 外文期刊>Royal Society Open Science >Fossil skulls reveal that blood flow rate to the brain increased faster than brain volume during human evolution
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Fossil skulls reveal that blood flow rate to the brain increased faster than brain volume during human evolution

机译：化石头骨揭示出人类进化过程中流向大脑的血液流速快于脑体积

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The evolution of human cognition has been inferred from anthropological discoveries and estimates of brain size from fossil skulls. A more direct measure of cognition would be cerebral metabolic rate, which is proportional to cerebral blood flow rate (perfusion). The hominin cerebrum is supplied almost exclusively by the internal carotid arteries. The sizes of the foramina that transmitted these vessels in life can be measured in hominin fossil skulls and used to calculate cerebral perfusion rate. Perfusion in 11 species of hominin ancestors, from Australopithecus to archaic Homo sapiens, increases disproportionately when scaled against brain volume (the allometric exponent is 1.41). The high exponent indicates an increase in the metabolic intensity of cerebral tissue in later Homo species, rather than remaining constant (1.0) as expected by a linear increase in neuron number, or decreasing according to Kleiber's Law (0.75). During 3 Myr of hominin evolution, cerebral tissue perfusion increased 1.7-fold, which, when multiplied by a 3.5-fold increase in brain size, indicates a 6.0-fold increase in total cerebral blood flow rate. This is probably associated with increased interneuron connectivity, synaptic activity and cognitive function, which all ultimately depend on cerebral metabolic rate.
机译：人类认知的进化是从人类学发现和化石头骨的脑大小估计中推断出来的。认知的更直接量度是脑代谢率，它与脑血流速度（灌注）成正比。人源性大脑几乎完全由颈内动脉供应。可以在人化石化石头骨中测量在生活中传递这些血管的孔的大小，并用于计算脑灌注率。当按大脑体积缩放时，从古猿到古老的智人的11种人种祖先的灌注按比例增加（异速指数为1.41）。高指数表明以后的人类物种中脑组织的代谢强度增加，而不是如神经元数量线性增加或根据克莱伯定律（0.75）所期望的那样保持恒定（1.0）。在人类素的3 Myr进化过程中，脑组织灌注增加了1.7倍，乘以脑大小的3.5倍时，表明总脑血流量增加了6.0倍。这可能与神经元间连接性，突触活动和认知功能增强有关，而这些最终都取决于脑代谢率。

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