Hi TDT team,
I have four beta.img (2 conditions) per subject across two runs that were used as the input for individual’s searchlight analysis. The res_accuracy_minus_chance.mat file generates discrete values (0, -25, 50, etc.), but when I open res_accuracy_minus_chance.nii file in SPM, the values (I’m looking at the intensity value) seem more continuous and do not match with the .mat output. So my questions are:
- how does TDT calculate the classification accuracy? Are the discrete values related to how many input files are included (so since I have 4 files, the accuracy ranges from 1/4 to 4/4)?
- What’s the relationship between res_accuracy_minus_chance.mat, and res_accuracy_minus_chance.nii? If I feed individual’s accuracy map into SPM for a 2nd-level analysis, are discrete values from the .mat file used as input?
- A side question: the second group analysis in SPM generates a beta_0001.img file, and I wonder if this can be used to interpret the result, rather than specifying a contrast vector (i.e., 1 if there’s one group) and using the spmT.img?