Those contrasts have 22 columns, but you have 3 sessions. Did you just leave off some trailing zeros?
Also, there is a '1' in the 22nd column of both contrasts, yet they are for different conditions. Is this a typo perhaps?
How many columns should there be in total?
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From: Maria Dauvermann [[log in to unmask]]
Sent: Sunday, August 01, 2010 12:22 AM
To: [log in to unmask]; Watson, Christopher
Subject: Re: Error in defining t-contrast
I want to define the t-contrast of "targets" and "hits".
The t-contrast for targets looks like this: 0 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1. SPM tells me that this t-contrast is invalid, but I don't understand why. Other t-contrasts that look very similar are okay.
The contrast for hits looks like this: 0 0 0 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1.
The design matrix consists of three sessions. When I defined the GLM I add the onsets of each session. Maybe the matrices don't have the same length and that is the problem? If yes, I don't know how to change the onsets. What do I need to do then?
Thank you, Maria
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