Editor letter and review the way I got it.
Your manuscript had been reviewed by the editorial board of BRAIN RESEARCH REVIEWS.
In view of the large number of papers reviewed, it has been necessary to accept for publication only those reports considered to be of high priority. I regret that the referee editors recommended rejection of your report on the basis of priority.
I am returning your manuscript along with comments by the referee editors.
Dominik P. Purpura
Papers are judged for suitability and priority for publication on the basis of their relevance for understanding brain mechanisms, originality, soundness pf methods, clariy of presentation, adaquacy of illustration and/or tables, and general format. The referee's comments on these matters of specific criticism and suggesstions is noted below.
MS # 53951 by Dr. Yehouda Harpaz
Reproducibility of cognitive imaging of the cerebral cortex: a survey of the recent literature.
The paper addresses the question of reproducibility in brain imaging through published results. It relies on the work published during most of the year 1997. The review (section 2) is divided in the comparisons of results across studies ("reproducibility across studies"), within studies ("comparison between individuals in the same study") and the relevant reviews.
I believe the topic of this paper to important and intesresting. However, it lacks a scientific methodology and doesn't discuss some essential statistical points related to imaging experiment reproducibility, especially the use of random versus fixed effect models in the papers reviwed by the author. I realize that at the time of the writing, the notion of fixed versus random effects models (leading to the generalisability or not of the experimental results to the parent population in which the subjecte were drawn) was not common knowledge but has become so during the past two years. One may simply conclude from the paper that fixed effect models do not show too good reproducibility across study, and this is now widely admited and does not address the reproducibility of functional imaging itself but only of the methods used in the field to analyse the data. Two other points are worth mentioning : the relation between reproducibility and sensitivity (scanner, number of subjects in the study, statistical method employed) and the question of the statistical threshold related to the multiple comparison problem, a point that may not have been fully understood by the author (cf the introduction). Presentation of the data (eg the maximum intensisty projection) may also have led the author to some misunderstanding.
The paper as it stands may therefore mislead the general reader in forming an opinion on the brain functional imaging reproducibility.
Again, I do think that the point of reproducibility is a very important one, and that more information is needed on this topic in the cognitive functional imaging, but it should be treated with more mathematical rigor than what is done in the present manuscript. It seems that so far, the manuscript presents the (not always fully informed) opinion of the author rather than actual results.
Nevertheless, the opinion presented here is not widespread and as such deserved special attention. I suggest that it could be be communicated through a letter to the editor or a short communication, pointing out the statistical problems involved.