Hi Rick,

Thanks again for your quick reply; you are right about having too many regressors, and we have done analyses with a fixed-shape response. Using the TENT function in conjunction with amplitude modulation was more of an experiment to see whether we could more accurately measure an anticipatory period before stimulus presentation. However, as you said, there is a significant trade-off between including more regressors and having each one explain less of the variance.

As a side note, where can I find the python libraries for xmat_tool.py? I tried installing them with fink, but received an error message saying they were not available for download (numpy, wx, and matplotlib).

Thank you!

-Andrew