Anticorrelations

Submitted by alex on Sat, 05/23/2009 - 21:22

 Hi again,
I am interested in using REST to examine anticorrelations. I just wanted to check the following:
1 - If I include a global signal timeseries as a covariable, then the analysis will produce maps showing voxels significantly correlated with the seed timecourse after controlling for global signal fluctuations. That is, it is essentially like performing a global signal regression. Is this correct?
2 - Anticorrelations will be revealed by negative values in the resulting connectivity and z-maps. Is this correct?

thanks for your help,

Forums: 
Resting-state fMRI topics

Maximum variable size

Submitted by alex on Wed, 05/20/2009 - 20:02

 Hi,
I tried to start a seed-based connectivity analysis, but it stopped at the first, detrending stage with the error: "Maximum variable size allowed by the program is exceeded".

Is there a limit on the number of volumes or subjects that can be analysed? I have 840 volumes. I was trying a pilot analysis in 5 subjects.

Thanks for your help,
Alex

Forums: 
Resting-state fMRI topics