[Eeglablist] Interpreting LORETA t-test results

Bethel Osuagwu b.osuagwu.1 at research.gla.ac.uk
Mon Feb 2 14:12:45 PST 2015

Hi Rohit,

After running the stats package, you need to open the file '-Thresholds&ExtremePs.txt' which looks thus:

                                    t(0.01)    t(0.05)    t(0.10)   ExtremeP
One-Tailed  (A>B):      0.641      0.575      0.536    0.87240
One-Tailed  (A<B):      -0.641     -0.574     -0.534    0.00000
Two-Tailed (A<>B):     0.661      0.606      0.574    0.00020

In this case, for any voxel to be significant at 0.05 level in your sLORETA image/s the voxel must have a value thus: 
a)   >=0.575 (condition A is more positive than condition B which can mean that A is more active)
b)   <=-0.574 (condition A is more negative than condition B which can mean that A is more active if you think in terms of a very negative ERP for A)
c)    >0.606 (there is a difference between condition A and B) 

>From the 'Slice Viewer' click on 'Find Max/Min' button and enter 0.575 to list the voxels satisfying a) above.

By the way could you remove the stuff about domains at the bottom of your email, else your email is classified as SPAM

From: eeglablist-bounces at sccn.ucsd.edu [eeglablist-bounces at sccn.ucsd.edu] On Behalf Of Dr.Rohit Tyagi [rohittyagi_2k at rediffmail.com]
Sent: 31 January 2015 09:34
To: eeglablist
Subject: [SPAM?] [Eeglablist] Interpreting LORETA t-test results

Dear Researchers,

Pardon me for asking this, since its not directly about EEGLab.
I usually use EEGLab or some MATLAB script to save ERPs as text files and the then want to use those to process for source localization in LORETA or the newer LORETA-Conn.

I follow the LORETA tutorial to do the processing, but am stuck at understanding the t-test results that are generated by that software. Since there are no details given about the interpretation of those results in their tutorial, I would like to ask anyone who has experience with that software to give some information about this.
Or any other forum where i can try to learn about this ?

Thanks and Regards,

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