The con_ files contain both positive and negative values.
Best Regards, Donald McLaren
=================
D.G. McLaren, Ph.D.
Research Fellow, Department of Neurology, Massachusetts General Hospital and
Harvard Medical School
Postdoctoral Research Fellow, GRECC, Bedford VA
Website: http://www.martinos.org/~mclaren
Office: (773) 406-2464
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On Mon, Oct 29, 2012 at 5:23 PM, Thomas Kraynak <[log in to unmask]> wrote:
> Hi Dr. McLaren & all,
>
> I have a similar yet much simpler question regarding reversibility in interpreting these effects. I understand that reversibility of seed->target direction in the same psychological context is not legitimate. But is positive PPI X->Y within taskA-taskB the same as the negative PPI X->Y within B-A? That is, if I wanted to include the negative PPI files of B-A in a higher order regression model but only have access to positive PPI con files of B-A, can't I just use imcalc [*(-1)] to invert them? Or do I need to re-model the entire PPI within the context of A-B so that I have what is considered to be the negPPI of B-A.
>
> Thank you!
>
> Thomas
>
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