Hello,
I m programming an EEG-Experiment which consists of different visual stimuli. Therefore I need trigger to the EEG-Computer that indicate the onset of the visual stimuli. But it is not functioning. I would be thankful for any advice. My code I wrote is:
<port sig_tn>/ port = lpt1/ subport = data/ items = ("00001011") </port><trial tn>/ trialcode = "11"/ inputdevice=mouse/ validresponse = (rbuttondown, noresponse)/ correctresponse = (rbuttondown) / responseframe = 0/ responseinterrupt = trial/ responsemessage = (rbuttondown, resp_t, 0)/ stimulustimes = [0=negativ, sig_tn; 500=blank]/ trialduration = rand (1300, 1700)</trial>
Kind regards...
Rainer.
A few things to help troubleshooting:
(1) Verify that you've indeed directed Inquisit to use the correct port by checking your system's settings via the Windows Device Manager (control panel).
(2) Check if you are able to send data to your EEG machine via Inquisit's parallel port monitor tool (Tools -> Parallel Port Monitor..).
(3) Various threads here have information on sending / receiving TTL signals as well as some specific troubleshooting hints. Useful search terms include 'TTL', 'EEG' and '<port'.
(4) The software review article by Stahl (2006) has a rather extensive section on setting up TTL signals in Inquisit (note that the paper deals with Inquisit 2.0, however I don't think that things have change around much between versions).
(5) In case you only get sporadic triggers, consider erasing your port signal each time it's been sent.
Let us know what you find. Best wishes from a fellow Inquisit user,
~Dave
"To understand recursion, you must first understand recursion." - Unknown Zen Master