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February 17, 2009 10:23AM
Hi Iris,

I don't have much experience with pre-processing for ICA. You may want to try de-trending (using 3dDetrend) before running principal component analysis (with 3dpc) and see if that makes any difference.

After you run 3dICA, you should have two output files: One is the time series components (10 in your case), whose plots should automatically pops out when 3dICA.R finishes up, and the other one is mixing coefficients (10 sub-bricks) associated with those time series components. When you use AFNI graphic viewer, each sub-brick shows the weighting at a voxel associated with the corresponding time series component. In other words, the mixing coefficient at a voxel indicates how much role the corresponding time series component plays in the original data. You many want to familiarize yourself with the ICA principle a little bit:

[sccn.ucsd.edu]

HTH,
Gang
Subject Author Posted

ICA question

Iris Yang February 16, 2009 04:08PM

Re: ICA question

Gang Chen February 17, 2009 10:23AM

Re: ICA question

Iris Yang February 17, 2009 01:00PM

Re: ICA question

Irist Yang February 18, 2009 11:03AM

Re: ICA question

Gang Chen February 18, 2009 01:54PM

Re: ICA question

Iris Yang February 18, 2009 02:11PM

Re: ICA question

Gang Chen February 18, 2009 03:56PM

Re: ICA question

Iris Yang February 19, 2009 10:59AM