Hi,

I'm doing a little experiment for PPI analysis that involves playing with t-contrast weights. I designed a little experiment that involved the person looking at famous faces vs. non-famous faces and a control group.

If I wanted to see famous faces the t-contrast weight vector would be: 1 -1 0

non-famous would have t-contrast weight vector would be: -1 1 0

I'm having a super hard time trying to explain what these +1 and -1 mean when looking at the glass brain on SPM...

When looking at the famous faces, if the +1 activates voxels in the occipital lobe while also activating voxels in other regions of the brain, how would you explain? Could I say that while viewing the famous faces, the occipital lobe modulates brain region X, Y, Z? My PI wants me to use the word "modulate."

I have a similar picture that he drew me that he wanted me to explain. The blue spots are suppose to be activated clusters.

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