Our group is working on obtaining beta values from GLM analysis of the functional data (E.g., motor task).
In the example of HCP data loader, the subtraction analysis was just subtracting mean bold signal of the right foot from the left foot.
However, as far as I know, the usual approach is convolving the boxcar function with the haemodynamic response function and then build a design matrix, then performing glm and obtaining beta values with respect to each contrast.
But one problem here is that our data is preprocessed and parcellated, so I am not sure how can we apply the usual approach here. Would it be just sufficient to use the values from subtraction analysis?
Thanks in advance,