Dear FreeSurfer experts,

In my experiment, some subjects missed some trials and some not. I wish set the missed trials as an external regressor, however, mkanalysis-sess seems applying the same parameters for all subjects. In my understanding, -taskreg extreg N, the N is same for all subjects. Is my understanding right?  If it is right, how can I sove my problem that not all subjects have the  external regressor because some subjects have no missing trials?

Best,

Zhiwei