What's the format of the entries in your trial list, and what does "execute the stimuli" mean in this context? Does it mean to pass the entries of that list into some other function, does it mean to run the functions with the names stored in the entries in the list, or does it mean something else?
If the entries in the trial list are script or function names and executing them means to call the scripts or functions, the easiest approach probably would be to change your .txt file into a .m file (just change the extension, assuming there's no extra text in the file) and run it.
