Is first episode mania associated with grey matter abnormalities? We are not sure!

Abstract

With great interest, we have read the recent paper by Keramatian and colleagues entitled "Grey Matter Abnormalities in First Episode Mania: A Systematic Review and Meta-analysis of Voxel-Based Morphometry Studies" in Bipolar Disorders. 1 The authors systematically reviewed 15 voxel-based morphometry (VBM) studies and observed heterogeneous findings regarding the brain regions affected and the direction of grey matter (GM) alterations (decreases/increases) as well as statistically non-significant alterations in patients with first episode mania (FEM) relative to healthy controls. They further performed a quantitative coordinate-based meta-analysis (CBMA) of 12 whole-brain VBM studies and identified consistent GM alterations in the bilateral pregenual anterior cingulate cortex (ACC) in FEM. 1 The paper provided a thorough profile of GM volume alterations in FEM; however, we have some methodological concerns in the CBMA that compromised the validity of the metaanalytic results. Over the last two decades, CBMA has been a powerful metaanalytic technique to quantitatively integrate individual voxel-based neuroimaging studies to identify convergent findings for a particular research question. 2 The methods for CBMA are constantly evolving. The latest algorithm for CBMA is Seed-based d Mapping with

Do “Ten simple rules for neuroimaging meta-analysis” receive equal attention and accurate quotation? An examination on the quotations to an influential neuroimaging meta-analysis guideline

“…And: “ According to the recent best-practice guidelines for conducting neuroimaging meta -analyses, a study can only be included in the CBMA when it reports its results based on the whole-brain analysis without small volume corrections (SVC) ( Müller et al, 2018 ) . ” From ( Sheng et al, 2021 ). …”

Response to commentary on “Grey matter abnormalities in first episode mania: A systematic review and meta‐analysis of voxel‐based morphometry studies”

“…We appreciate the comments by Sheng et al 1 on our manuscript titled “Grey matter abnormalities in first‐episode mania: A systematic review and meta‐analysis of voxel‐based morphometry studies 2 ” and would like to take this opportunity to clarify our methodology and share the findings of additional analyses we have performed.…”

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We appreciate the comments by Sheng et al 1 on our manuscript titled "Grey matter abnormalities in first-episode mania: A systematic review and meta-analysis of voxel-based morphometry studies 2 " and would like to take this opportunity to clarify our methodology and share the findings of additional analyses we have performed.First, in the methods section of our published manuscript 2 we had stated that we used the latest version of Seed-based d Mapping (formerly known as "Signed Differential Mapping") software (SDM-PSI version 6.21), but erroneously provided the description for the previous version of this software. We would like to confirm that we did run our meta-analysis on SDM-PSI version 6.21, which offers new features such as threshold-free cluster enhancement (TFCE) statistics and the ability to use family-wise error (FWE) correction for multiple comparisons using common permutation tests.

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