Dear Pravesh,

unfortunately I can't provide you with an answer to your question but as I am dealing with the problems of GSR in Conn as well, I would like to ask you what is the difference between "Global Signal" and "mean Global Signal"?

As far as I am informed the Global Signal is the mean signal of all the involved voxels, so what exactly do you mean by mean global signal?

Cheers,
Sascha

EDIT: nevermind, mean Global Signal is the mean of the global signal (obvious from your code). Sorry, at first glance I thought it's another "type" of global signal...