Grouping individual independent BOLD effects - A new way to ICA group analysis

Jeng Ren Duann*, Tzyy Ping Jung, Terrence J. Sejnowski, Scott Makeig

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

A new group analysis method to summarize the task-related BOLD responses based on independent component analysis (ICA) was presented. As opposite to the previously proposed group ICA (gICA) method, which first combined multi-subject fMRI data in either temporal or spatial domain and applied ICA decomposition only once to the combined fMRI data to extract the task-related BOLD effects, the method presented here applied ICA decomposition to the individual subjects' fMRI data to first find the independent BOLD effects specifically for each individual subject. Then, the task-related independent BOLD component was selected among the resulting independent components from the single-subject ICA decomposition and hence grouped across subjects to derive the group inference. In this new ICA group analysis (ICAga) method, one does not need to assume that the task-related BOLD time courses are identical across brain areas and subjects as used in the grand ICA decomposition on the spatially concatenated fMRI data. Neither does one need to assume that after spatial normalization, the voxels at the same coordinates represent exactly the same functional or structural brain anatomies across different subjects. These two assumptions have been problematic given the recent BOLD activation evidences. Further, since the independent BOLD effects were obtained from each individual subject, the ICAga method can better account for the individual differences in the task-related BOLD effects. Unlike the gICA approach whereby the task-related BOLD effects could only be accounted for by a single unified BOLD model across multiple subjects. As a result, the newly proposed method, ICAga, was able to better fit the task-related BOLD effects at individual level and thus allow grouping more appropriate multisubject BOLD effects in the group analysis.

Original languageEnglish
Title of host publicationIndependent Component Analyses, Wavelets, Neural Networks, Biosystems, and Nanoengineering VII
DOIs
StatePublished - 2009
EventIndependent Component Analyses, Wavelets, Neural Networks, Biosystems, and Nanoengineering VII - Orlando, FL, United States
Duration: 13 Apr 200917 Apr 2009

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume7343
ISSN (Print)0277-786X

Conference

ConferenceIndependent Component Analyses, Wavelets, Neural Networks, Biosystems, and Nanoengineering VII
CountryUnited States
CityOrlando, FL
Period13/04/0917/04/09

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