Check stimulus & system before testing
Hardware
Reset the triggers at the end of the program
In correcting some of the data from the trigger box short, we came upon a couple of instances of E-Prime coding, which can under several circumstances cause problems for data processing. In order to help both your own data processing and your fellow MEG users, please send a "0" trigger at the very beginning and very end of your e-prime script. This will prevent any problems from subsequent user's (and your own previous) scripts affecting your own data and from you affecting other user's data.
E-prime - suggested inline code to add at beginning of Session Procedure:
Instructions.OnsetSignalEnabled = True Instructions.OnsetSignalPort = &H378 Instructions.OnsetSignalData = 0
Trigger test
As an additional safety precaution, Martin Vestergaard has kindly offered to write an e-prime script and put it on the desktop of the pc for all users called "trigger_test" in a couple of days. The script will perform two functions one is to test all of the triggers. When you run the script, watch the trigger box and make sure you see all of the lights light up and turn off. This will perform two functions: allow you to check the trigger connections are all working, and reset the triggers to 0 so your data will not be affected.
Check the timing
I would like to take this (unfortunately lengthy) opportunity, to remind you that you should always test the timing of your specific script. In addition, it is recommended that you consult an E-Prime expert (of which several qualified people exist at the CBU) with your script and have it checked. Martin Vestergaard has kindly agreed to help you with your E-Prime scripts.
You should make sure you understand exactly what stimulus presentation systems we have and what their limitations are (see StimulusDetails).