Using the stim_times function, two of my files look like this:
1)
233.75 *
*
*
2)
221 *
374 *
*
Could these two be causing the problem (i.e., no responses in run 3)?
In my X matrix I am getting more than 9 columns: 8 lines for each stim type (I have 8 regressors). Because of the two above stimuli, some are VERY close to zero (for example, the first line of first stimulus above has no 'bumps' on it).
I think this must be the problem since there are no two stimulus classes with identical timings.
Thanks so much for your help on this,
Erin