Gang, thanks for the help. I read the examples of 3dRegAna. I think we are after something different. What we are looking for is seeing if a subject's brain activity's response to stimuli matches what a subject reported.

For example, there are 3 stimuli: cold, warm, hot. Before we run the fmri experiment, we have each subject rate what they perceive as cold, warm, and hot in degrees fahrenheit. Thus each subject would have 3 temp ratings for cold, hot, and warm,respectively.

We then run each subject through an fmri scan, where they receive 3 stimuli at the same temperatures they reported before the scan.

Susquently, we normally run 3dDeconvolve on the time series for each subject incoporating the 3 factors of cold, hot, and warm, and look at the results to pinpoint what areas of the brain are activated at a particular p-value. However, in the last step with .1D files, 3dDeconvolve only knows when the 3 stimului/factors are applied, not the relationship amongst the 3 factors/stimuli. If using the gamma variate function, each stimuli .1D file has the same rise, peak,i.e., bascially the same shape. In theory, base on what each subjected reported as hot, warm, and cold, what you should find are activated areas that match what is reported as cold, warm, hot. Partial Fs values would indicate the hot stimuli having the highest partial F value, the warm stimuli having the middle F value, and the cold stimuli should having the lowest partial F value. However, a lot a times that isn't the case, sometimes all 3 levels have the same intensity, some times hot and warm response are around the same, with cold response being having the lowest instensity.

What we want to do is find out what areas of the brain, if any, are activated where the realtionship among the factors is indicated by weighting/scaling each factor. Thus, after running 3dDeconvolve, we will see activations where brain responds to the relationship indicated by the weighting of the 3 factors/stimuli: the hot stimuli having the highest intensity, the warm stimuli having the middle intensity, and the cold stimuli should having the lowest instensity. Is this possible in 3dDeconvolve? I'm not sure if 3dRegAna can help us with this? No?

Michael