BACKGROUND Sleep plays an important role in vulnerability to mood disorders. However, despite the existence of sex differences in vulnerability to mood disorders, no study has yet investigated the sex effect on sleep network organization and its potential involvement in vulnerability to mood disorders. The aim of our study was to empirically investigate the sex effect on network organization during REM and slow-wave sleep using the effective connectivity measured by Granger causality. METHODS Polysomnographic data from 44 healthy individuals (28 men and 16 women) recruited prospectively were analysed. To obtain the 19 × 19 connectivity matrix of all possible pairwise combinations of electrodes by Granger causality method from our EEG data, we used the Toolbox MVGC multivariate Granger causality. The computation of the network measures was realized by importing these connectivity matrices into EEGNET Toolbox. RESULTS In men and women, all small-world coefficients obtained are compatible with a small-world network organization during REM and slow-wave sleep. However, compared to men, women present greater small-world coefficients during REM sleep as well as for all EEG bands during this sleep stage, which indicates the presence of a small-world network organization less marked during REM sleep as well as for all EEG bands during this sleep stage in women. In addition, in women, these small-world coefficients during REM sleep as well as for all EEG bands during this sleep stage are positively correlated with the presence of subclinical symptoms of depression. CONCLUSIONS Thus, the highlighting of these sex differences in network organization during REM sleep indicates the presence of differences in the global and local processing of information during sleep between women and men. In addition, this small-world network organization less marked during REM sleep appears to be a marker of vulnerability to mood disorders specific to women, which opens up new perspectives in understanding sex differences in the occurrence of mood disorders.

中文翻译：

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妇女快速眼动睡眠过程中神经网络组织的变化：对易患情绪障碍的性别差异有影响。

背景技术睡眠在对情绪障碍的脆弱性中起重要作用。然而，尽管在情绪障碍易感性方面存在性别差异，但尚无研究调查性别对睡眠网络组织的影响及其可能参与情绪障碍易感性。我们研究的目的是使用格兰杰因果关系度量的有效连通性，以实证研究REM和慢波睡眠期间性别对网络组织的影响。方法对前瞻性征募的44名健康人（28名男性和16名女性）的多导睡眠监测数据进行分析。为了通过格兰杰因果关系方法从我们的EEG数据中获得所有可能的成对电极组合的19×19连接矩阵，我们使用了Toolbox MVGC多元格兰杰因果关系。通过将这些连通性矩阵导入EEGNET Toolbox，可以实现网络度量的计算。结果在男性和女性中，在快速眼动和慢波睡眠期间，获得的所有小世界系数都与小世界网络组织兼容。但是，与男性相比，女性在REM睡眠期间以及在此睡眠阶段的所有EEG频段呈现出更大的小世界系数，这表明存在一个在REM睡眠以及所有EEG中标记较少的小世界网络组织女性在这个睡眠阶段的乐队。此外，在女性中，REM睡眠期间以及这些睡眠阶段所有EEG频段的这些小世界系数与亚临床症状的抑郁呈正相关。结论因此，REM睡眠期间网络组织中的这些性别差异的突出表明，男女在睡眠期间在全局和局部信息处理方面存在差异。此外，这个在REM睡眠中较少受到关注的小世界网络组织似乎是易患女性特有的情绪障碍的标志，这为了解情绪障碍发生中的性别差异开辟了新的视角。