README file for retinotopic mapping stimulus program (retstim)

Tested and used under MAC OS 9.x with matlab 5.2.1

Required files:
 retstim.m           - main program file, run to show stimulus (apple-e)
 retstim_params.m    - file which defines experimental parameters
 make_retstim.m      - file that makes the stimulus
 showstuff_retstim.m - file that shows the stimulus

Run procedure:
 1. Run (apple-e retstim)
 2. When screen turns black press any button. 
    Stimulus is now ready and waiting...

Asks for;
 Which kind of scan? - needs answer!
 Which direction?    - needs answer!
 Stimulus size?      - [return]=ignore or proper answer 
                       if you want to move fixation dot
                       to account for off-center fixation.
 Fixation dot offset x? - [return]=ignore or proper answer.
 Fixation dot offset y? - [return]=ignore or proper answer.
 Stimulate with fixation dot? - answer [N]O, not tested yet.

Inputs:
 fMRI trigger, either as a buttonpress [default = a see parameter file]
 and/or a mouse press (the latter has not been tested in the scanner)
 takes subject responses to task - a buttonpress [see parameter file]

To run without syncing to triggers:
 run: retstim([],1);
 or set: runpsych = 1; in main file

Output 
 .mat file with stimulus parameters, important for information such
 as: which scan was done? direction? frequency?
 Unless you keep that information somewhere else.
 Percent correct and reaction time for the task.

Task
 (1) Detect regular pattern in the stimulus either 
 blue-yellow, red-green or black-white in the stimulus and 
 press button when detected. Time allowed 3 seconds. [default] 
 Make sure subjects can maintain fixation while doing this task!
 (2) Fixation dot changes into arrow at random points. 
 Detect and press corresponding button [left right]. 
 Set in parameter file.

Known bugs
 Bug in percent correct calculation which allows for cheating. 
 Not fixed yet since it is only to control for attention and there
 are ways to tell if that happened (well you can check the 
 reaction times)...
 but dont tell the subjects....

Good luck!
Serge Dumoulin
