Brain Imaging & Analysis Center

Stimulus timing is controlled by simple text files with two parts. The lines at the top specify parameters to use during the paradigm. These can be any CIGAL commands, but typically just involve setting global variable values. In this example, most of the parameter section (“fslscheds”) is devoted to specifying how to convert stimulus events into timing files suitable for FSL image analysis. The text below the blank line is the stimulus timing list, organized as a table. Each line specifies a separate stimulus event. The columns specify stimulus file (or text string or command), a user-defined ID value, a control flag, the onset and duration in milliseconds, and screen location for visual stimuli. Stimuli can overlap in time and do not need to be listed in chronological order.

The following is an example of a simple input file that mixes graphics, pictures, text, movies, and sound stimuli. (Text following a ';' is ignored by CIGAL.)

showplay 0			; initialize new showplay task
sbackcolor = "black"		; screen background color
stextcolor = 'white'
return			; end of parameters (must be followed by blank line)

;Stimulus    		       ID  Flg  Onset(ms) Duration  LocationXY
"Press for faces"		99   0        0      4000    -1  -1  ; show text
fix		 		 1   0     4000         0    -1  -1  ; central '+'
tones1.wav	 		12   0     6000      4000
face1.jpg			13   1    10000      1000   200 100
dots1.avi			14   0    12000      4000    -1  -1
fix		 		 1   0    16000         0    -1  -1
tones3.wav	  		22   0    18000      4000
face2.pcx    			23   1    22000      1000   400 200
dots2.avi			24   0    24000      4000    -1  -1
quit				 0   0    30000