Tuesday, June 5, 2012

MVPA significance with the binomial test: update 1

A clarification is in order: in the previous post I imply that Francisco advocates using the binomial to test for significance across subjects as I illustrated in the R code. He doesn't. The code showing how to calculate the binomial for each person separately is the way he describes, though.

Francisco gives a few ideas in the "Group level analysis" section of his "Information Mapping" paper (citation below), mostly advocating descriptions or count-based techniques. This can work fairly well for searchlight analyses (e.g. map the proportion of subjects with each voxel significant), but not as well for ROI-based analyses like the toy example in the previous post. He'll be sharing some thoughts in a future post.

 ResearchBlogging.orgPereira F, & Botvinick M (2011). Information mapping with pattern classifiers: a comparative study. NeuroImage, 56 (2), 476-96 PMID: 20488249

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