Could Sex Differences in White Matter be Explained by g ratio?
Could Sex Differences in White Matter be Explained by g ratio?
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DOI：
10.3389/neuro.05.014.2009
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发表时间：
2009
影响因子：
2.9
通讯作者：
Toro R
中科院分区：
文献类型：
--
作者：
Paus T;Toro R
最近的磁共振成像研究表明，男性青春期白质的年龄相关变化可能表明g比的增加，其中轴突的径向生长超过了髓鞘厚度的相应增加。我们回顾了最初的Rushton模型，其中g比为~ 0.6代表轴突和纤维直径与-à-vis传导速度之间的最佳关系，并指出证据表明大直径纤维的g比略高。我们估计直径大于9.6 μm的纤维具有相对较薄的髓鞘，并且这种大直径纤维比例越来越大的大脑中髓鞘浓度逐渐降低。最后，我们指出了“次优”g比率对青春期后期出现“断开”障碍（如精神分裂症）的可能影响。
Recent studies with magnetic resonance imaging suggest that age-related changes in white matter during male adolescence may indicate an increase in g ratio wherein the radial growth of an axon outpaces a corresponding increase in myelin thickness. We review the original Rushton model where a g ratio of ∼0.6 represents an optimal relationship between the axon and fibre diameters vis-à-vis conduction velocity, and point out evidence indicating slightly higher g ratio in large-diameter fibres. We estimate that fibres with a diameter larger than 9.6 μm will have a relatively thinner myelin sheath, and brains with increasingly larger proportions of such large-diameter fibres will have progressively lower concentration of myelin. We conclude by pointing out possible implications of “suboptimal” g ratio for the emergence of “disconnection” disorders, such as schizophrenia, in late adolescence.
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影响因子：
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作者：
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通讯作者：
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