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Dear experts, We are struggling in interpreting what is the nature of the 'fitted responses' generated by SPM2 in the following experiments. Any input would be greatly appreciated. We have obtained serial fMRI scans with 1 condition (A) [and rest] over a period of 20 months. We then performed a Multiple regression analysis to investigate the effects of several clinical parameters on A response using 4 covariates including 1) each participant’s clinical rating at time of scan; 2) time in weeks since first scan (TIME). Individual participant’s f-maps were entered into this analysis. We identified significant increases and decreases with each co-variate. We later explored the Relationship between the response to condition A in the right insula and time since first scan in weeks. Figure (attached) represent the linear relationship of the parameter estimates of condition A-induced activations over time. This responses was extracted from the right insula. Question: What does this 'response' (y axis) truly represent? is it a parameter estimate (and thus what unit) ? Is it a relative signal change in BOLD from baseline? Thank you z