HI All,
Please let me know if the below is not clear, I am trying to understand why I am losing so much variance between my encoding models.
I have 2 encoding analysis, one standard where for each subject I create a design matrix based on categories, (all durations of examples of category 1 and all durations of example of category 2). I then look at a level-2 contrast Category 1 - Category 2. This shows strong differences in several brain regions.
I then also have an encoding analysis where for each subject I use an LSS method to get a beta for each trial. I then concatenate based on category across subjects. In theory the two Level 2 contrasts should be similar since it is the same data albeit calculated in different ways. However my 2nd method ends up with effectively 0 signal.
Is this expected? Is there a way to improve this? Please let me know if it’s unclear what it is that I’m doing.