Meng Jie, Hao Lei, Wei Dongtao, Sun Jiangzhou, Li Yu, Qiu Jiang
Key Laboratory of Cognition and Personality (SWU), Ministry of Education, Chongqing 400715, China; Department of Psychology, Southwest University, Chongqing 400715, China.
State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China; Department of Psychology, Beijing Normal University, Beijing 100875, China.
Biol Psychol. 2017 Dec;130:41-49. doi: 10.1016/j.biopsycho.2017.10.002. Epub 2017 Oct 5.
Loneliness is a common experience. Susceptibility to loneliness is a stable trait and is heritable. Previous studies have suggested that loneliness may impact regional gray matter density and brain activation to social stimuli, but its relation to white matter structure and how it may interact with genetic factors remains unclear. In this study, we investigated whether and how a common polymorphism (Val66Met) in the brain-derived neurotrophic factor gene modulated the association between loneliness and white matter microstructure in 162 young adults. The tract-based spatial statistics analyses revealed that the relationships between loneliness and white matter microstructures were significantly different between Val/Met heterozygotes and Val/Val homozygotes. Specifically, loneliness was significantly correlated with reduced fractional anisotropy and increased radial diffusivity in widespread white matter fibers within Val/Met heterozygotes. It was also significantly correlated with increased radial diffusivity in Met/Met genotypes but showed no significant association with white matter measures in Val/Val genotypes. Furthermore, the associations between loneliness and fractional anisotropy (or radial diffusivity) in Val/Met heterozygotes turned out to be global effects. These results provide evidence that loneliness may interact with the BDNF Val66Met polymorphism to shape the microstructures of white matter, and the Val/Met heterozygotes may be more susceptible to social environment.
孤独是一种常见的体验。易感性是一种稳定的特质且具有遗传性。以往的研究表明，孤独可能会影响区域灰质密度以及大脑对社交刺激的激活，但孤独与白质结构的关系以及它如何与遗传因素相互作用仍不明确。在本研究中，我们调查了脑源性神经营养因子基因中的一种常见多态性（Val66Met）是否以及如何调节162名年轻人孤独感与白质微观结构之间的关联。基于纤维束的空间统计学分析显示，Val/Met杂合子和Val/Val纯合子中孤独感与白质微观结构之间的关系存在显著差异。具体而言，在Val/Met杂合子中，孤独感与广泛白质纤维中分数各向异性降低和径向扩散率增加显著相关。在Met/Met基因型中，孤独感也与径向扩散率增加显著相关，但在Val/Val基因型中与白质测量指标无显著关联。此外，Val/Met杂合子中孤独感与分数各向异性（或径向扩散率）之间的关联是全局性的。这些结果提供了证据，表明孤独可能与BDNF Val66Met多态性相互作用以塑造白质微观结构，并且Val/Met杂合子可能对社会环境更敏感。
