We thank Fan and Hart (2010) for their comments on our article (Dekker et al., 2010). We agree that using the term 'brain abnormalities' could be seen as less appropriate. We twice use this term in the discussion when we state that 'cannabis naive schizophrenia patients showed brain abnormalities in the splenium of the corpus callosum, compared to early onset cannabis users', and later when we state that 'we identified congruent anatomical and diffusion abnormalities manifesting in the posterior corpus callosum, a brain area adjacent to the PCC, in cannabis naive schizophrenia patients.' As Fan and Hart (2010) suggest, the word 'abnormality' should only be used when there is a difference from the normal. Therefore, in future articles, we agree that it is better not to use the word 'abnormalities', but 'reduced fractional anisotropy (FA) values' or 'reduced white matter density' when we refer to comparisons within patient groups. However, we do not agree with their argument that the naive group's fractional anisotropy integrity appears to be within the normal range of healthy male adolescents, with reference to Ashtari et al. (2007). For the current study we used voxel-based morphometry (VBM) methods to discriminate between the FA voxel intensities on a voxel-by-voxel basis (Ashburner and Friston, 2000). We refrained from calculating the mean FA values or extracting a tensor since we were interested in the whole brain response of our study sample. Therefore, our data cannot necessarily be compared with those of Ashtari et al. (2007). Furthermore, voxel-based analysis (VBA) does not permit the generation of 'normal ranges' of FA values; it serves as a comparison of numerical values between 0 and 1 without a unit, with a higher FA value implying a higher degree of anisotropic motion of water molecules.
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机译：我们感谢Fan和Hart（2010）对本文的评论（Dekker等，2010）。我们同意，使用“大脑异常”一词可能被认为不太合适。当我们声明“与未使用大麻的早期发病者相比，大麻天真精神分裂症患者在call体脾脏中表现出大脑异常”时，我们在讨论中两次使用了该术语;后来，当我们声明“我们确定了一致的解剖学和扩散异常时，我们在讨论中使用了这个术语。在大麻天真的精神分裂症患者中表现在后体中，即邻近PCC的大脑区域。正如Fan and Hart（2010）所建议的那样，“异常”一词仅在与正常存在差异时才使用。因此，在以后的文章中，我们同意最好不要使用“异常”一词，而应使用“降低的各向异性分数（FA）值”或“降低的白质密度”，这是我们在患者组中进行的比较。但是，对于Ashtari等人的研究，我们不同意他们的观点，即幼稚组的分数各向异性完整性似乎在健康男性青少年的正常范围内。 （2007）。对于当前的研究，我们使用基于体素的形态学（VBM）方法在逐个体素的基础上区分FA体素强度（Ashburner和Friston，2000）。由于我们对研究样本的全脑反应感兴趣，因此我们避免计算平均FA值或提取张量。因此，我们的数据不一定能与Ashtari等人的数据进行比较。 （2007）。此外，基于体素的分析（VBA）不允许生成FA值的“正常范围”。它用作没有单位的0和1之间的数值比较，FA值越高，意味着水分子的各向异性运动程度越高。
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