Other pre-stimulus methods. Auditory. In addition to the use of the TG/WN sound generator, PSYLAB software allows computer generated sounds to be used for pre-stimulus. Wave files are placed in the C:\CPI\STIMULUS folder, with their names entered into fields in the Media Names panel. Sounds are then loaded by number under control of the PCC script file, and are played immediately. Visual. PSYLAB software allows pictures to be loaded into the C:\CPI\STIMULUS folder. Picture file names are entered into the Media Names panel, which assigns a number to each picture which may be opened using the Load instruction in the stimulus script file. The picture is shown using the Show instruction, which allows immediate picture presentation, not hampered by disk access speed. Two VDUs may be attached to the computer on separate video cards, allowing pictures to be shown on the subject monitor while the operator sees physiology graphs and control panels on the main VDU. AVI video may also be shown in a similar manner. Alternative methods of visual stimulation that have been used include use of a digitally controlled power bar outlet allowing up to 5 lamps or other devices to be switched under . Side projectors and high speed shutters may also be used under PSYLAB control. |
