Inter-individual differences can inform treatment procedures and - if accounted for - have the potential to significantly improve patient outcomes. However, when studying brain anatomy, these inter-individual variations are commonly unaccounted for, despite reports of differences in gross anatomical features, cross-sectional and connectional anatomy. Brain connections are essential to facilitate functional organisation and, when severed, cause impairments or complete loss of function. Hence the study of cerebral white matter may be an ideal compromise to capture inter-individual variability in structure and function. We reviewed the wealth of studies that associate functions and clinical symptoms with individual tracts using diffusion tractography. Our systematic review indicates that tractography has proven to be a sensitive method in neurology, psychiatry, and healthy populations to identify variability and its functional correlates. However, the literature may be biased, as we determined that the most commonly studied tracts are not necessarily those with the highest sensitivity to cognitive functions and pathologies. Additionally, the hemisphere of the studied tract is often unreported, thus neglecting functional laterality and asymmetries. Finally, we demonstrate that tracts, as we define them, are not usually correlated with only one, but rather multiple cognitive domains or pathologies. While our systematic review identified some methodological caveats, it also suggests that tract-function correlations might be a promising biomarker for precision medicine. It characterises variations in brain anatomy, differences in functional organisation, and predicts resilience and recovery in patients.

中文翻译：

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白质变异性、认知和障碍：系统评价

个体差异可以为治疗程序提供信息，并且——如果考虑到——有可能显着改善患者的治疗效果。然而，在研究脑解剖学时，这些个体间差异通常无法解释，尽管有报道称在大体解剖特征、横截面和连接解剖学方面存在差异。大脑连接对于促进功能组织至关重要，并且在切断时会导致功能障碍或完全丧失。因此，对大脑白质的研究可能是捕捉结构和功能的个体间差异的理想折衷方案。我们回顾了大量使用扩散纤维束成像将功能和临床症状与单个纤维束相关联的研究。我们的系统评价表明，牵引成像已被证明是神经病学中的一种敏感方法，精神病学和健康人群，以确定变异性及其功能相关性。然而，文献可能有偏见，因为我们确定最常研究的领域不一定是那些对认知功能和病理最敏感的领域。此外，研究区域的半球通常未被报告，因此忽略了功能侧向性和不对称性。最后，我们证明了我们定义的区域通常不仅与一个相关，而是与多个认知领域或病理相关。虽然我们的系统评价确定了一些方法论上的警告，但它也表明，道功能相关性可能是精准医学的一个有前途的生物标志物。它表征了大脑解剖结构的变化、功能组织的差异、