Hi Jidan,

          There are multiple ways to approach thresholding the components.  We have recently been using a mixture model to select a T-threshold.  See Allen et al, 2011, Frontiers in Systems Neuroscience, Appendix B for details.  BTW, I’d suggest you move future ICA-related questions to the icatb listserv as it’s a little off topic for the SPM listserv (https://lists.sourceforge.net/lists/listinfo/icatb-discuss)

Regards,

VDC

From: Jidan Zhong [mailto:[log in to unmask]]
Sent: Monday, March 12, 2012 7:25 PM
To: Vince D. Calhoun
Cc: [log in to unmask]
Subject: Re: [SPM] t-test on ICA results

Dear Sir,

I have a similar question to this. I wonder after I do the one-sample or two samples t-test, what do you usually use for the threshold? I read some papers and found they always use z value as the threshold. I wonder if this is necessary for group analysis.

I met a problem for thresholding. If I do not convert t-statistical result to z-map and do the threshoding, say, FDR correction with p<0.05, the results are like covering a lot of  white matter. Another way is to convert t-statistical maps to z-map and then do threholding. Are these two ways both OK?

Thank you.

Jidan

On Tue, Mar 13, 2012 at 1:12 AM, Vince D. Calhoun <[log in to unmask]> wrote:

Hi mojdeh,
 Yes, it's fine to do this.

Regards,

Vince

------Original Message------
From: Mojdeh Z
Sender: SPM List
To: SPM List
ReplyTo: Mojdeh Z
Subject: [SPM] t-test on ICA results
Sent: Mar 12, 2012 10:35 AM

Dear SPMers,

I was wondering if I can use SPM to do one and two sample t-test on the results of GIFT ICA. More specifically, I have two groups of controls and patients and I have identified the DMN component of each subject using GIFT, now I want to perform a voxel-wise one and two sampel t-test on the subject component maps.

Thanks for your help in advance,

Mojdeh Zamyadi, MSc
Clinical Research Project Assistant
The Hospital for Sick Children
555 University Avenue
Toronto ON M5G 1X8

_____________________________________

Vince D. Calhoun, Ph.D.
Chief Executive Officer and
Director Image Analysis & MR Research
The Mind Research Network

Professor Depts. of Electrical and Computer Engineering (primary),
Neurosciences, Psychiatry, and Computer Science
University of New Mexico

--
Regards,

Jidan