Just in case someone looks for the same problem :
I needed to list only .mat files that contains a specific string (here my variable "InputFileName") and begins with 'res_" :
dotMatFiles = struct2cell(dir(fullfile(path2MatRes,['res_*',InputFileName,'*.mat'])))';
This line of code get the list of all matlab files and stock the information into a cell array so I can loop through it later to get the full path of the files.
I hope this would help someone.