Hi all,

I am interested in pulling out a global connectivity measure for a given network mask. I'm using some resting state network templates from Stanford (available at Stanford resting state network maps.

I've tried doing it two ways:

1) I took preprocessed resting state data and used the 3dTCorrMap and then extracted out the value form that map:
e.g., 3dTcorrMap -mask <DMN_template.nii.gz> -input <preprocessed 4D time series> -Mean <DMN>_GBC.nii.gz
followed by an extaction of the mean of the resulting GBC image.

2)
@compute_gcor -input <preprocessed 4D time series> -mask <DMN_template.nii.gz

However, I notice that I get very slightly different numbers using the two methods. What am I doing wrong or failing to understand?

Thanks,
Matt