Prolonged myelination in human neocortical evolution
Prolonged myelination in human neocortical evolution
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DOI：
10.1073/pnas.1117943109
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发表时间：
2012-10-09
影响因子：
11.1
通讯作者：
Sherwood, Chet C.
中科院分区：
文献类型：
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作者：
Miller, Daniel J.;Duka, Tetyana;Sherwood, Chet C.
神经髓鞘形成促进跳跃动作电位传导，并在与行为和认知成熟相关的发育过程中表现出时空变化。虽然人类的认知发展是独特的，但尚不清楚人类新皮层中髓鞘形成的个体发育过程是否是进化上的例外。在这项研究中，我们量化了黑猩猩（N = 20）和人类（N = 33）的躯体感觉（3b/3a/1/2区）、运动（4区）、额极（前额叶区10）和视觉（17/18区）新皮层中有髓鞘轴突纤维长度密度和髓鞘相关蛋白的表达。我们的研究表明，与黑猩猩相比，人类的新皮层髓鞘形成在发育上是延长的。在黑猩猩中，有髓轴突的密度稳步增加，直到大约在性成熟时达到成人水平。相比之下，人类在儿童时期表现出较慢的髓鞘形成，其特征是成熟期延迟，延长到青春期后期。这项比较研究为理解人类认知和行为的进化提供了至关重要的证据，这些证据来自丰富的文化环境中神经系统发育的展开。正常发育过程的紊乱和髓鞘相关分子表达的减少与精神疾病如精神分裂症有关。因此，这些物种差异表明，人类特定的转变，在青春期皮质成熟的时间可能有影响的脆弱性，以某些精神疾病。
Nerve myelination facilitates saltatory action potential conduction and exhibits spatiotemporal variation during development associated with the acquisition of behavioral and cognitive maturity. Although human cognitive development is unique, it is not known whether the ontogenetic progression of myelination in the human neocortex is evolutionarily exceptional. In this study, we quantified myelinated axon fiber length density and the expression of myelin-related proteins throughout postnatal life in the somatosensory (areas 3b/3a/1/2), motor (area 4), frontopolar (prefrontal area 10), and visual (areas 17/18) neocortex of chimpanzees (N = 20) and humans (N = 33). Our examination revealed that neocortical myelination is developmentally protracted in humans compared with chimpanzees. In chimpanzees, the density of myelinated axons increased steadily until adult-like levels were achieved at approximately the time of sexual maturity. In contrast, humans displayed slower myelination during childhood, characterized by a delayed period of maturation that extended beyond late adolescence. This comparative research contributes evidence crucial to understanding the evolution of human cognition and behavior, which arises from the unfolding of nervous system development within the context of an enriched cultural environment. Perturbations of normal developmental processes and the decreased expression of myelin-related molecules have been related to psychiatric disorders such as schizophrenia. Thus, these species differences suggest that the human-specific shift in the timing of cortical maturation during adolescence may have implications for vulnerability to certain psychiatric disorders.