Fixed Duration Trials with TTL signals on response mid-trial

Back

Home
»
Millisecond Forums
»
Inquisit 4
»
Fixed Duration Trials with TTL signals on response mid-trial

Fixed Duration Trials with TTL signals on response mid-trial

Author	Message
xiller09	xiller09 posted 12 Years Ago HOT Topic Details Share Topic
Group: Forum Members Posts: 21, Visits: 10	I have a trial like this at the moment. <trial sometrial> / stimulustimes = [0=cue, TTLmarker_cueon;500=mask] / validresponse = (" ") / trialduration = 2000 </trial> I need a way of sending out a parallel port signal (TTLmarker_responsemade) when the participant makes a response. However, I need a way of doing this that preserves a 2 second duration between onsets. I had thought about something like this, but it doesn't work: <trial sometrial> / stimulustimes = [0=cue, TTLmarker_cueon;500=mask] / validresponse = (" ") / ontrialend = [values.iti = trial.sometrial.latency] </trial> <trial ititrial> /stimulustimes = [0=TTLmarker_responsemade] /trialduration = values.iti </trial> Any thoughts?
	Reply Like 16
Dave	Dave posted 12 Years Ago ANSWER Post Details Share Post
Group: Administrators Posts: 13K, Visits: 108K	Why don't you use /pre- or /posttrialpause for that?
	Reply Like 15
xiller09	xiller09 posted 12 Years Ago ANSWER Post Details Share Post
Group: Forum Members Posts: 21, Visits: 10	Because that would get me equal distances between responses rather than between trial starts? Or am I missing another use for it like: / posttrialpause = 2000-trial.sometrial.latency
	Reply Like 16
Dave	Dave posted 12 Years Ago ANSWER Post Details Share Post
Group: Administrators Posts: 13K, Visits: 108K	Not necessarily, as /pre- and /posttrialpause accept variables which you can compute at runtime as needed. However, what's wrong with /trialduration, which will indeed fix every trial's duration to 2000ms, thus guaranteeing your onset distance.
	Reply Like 15
xiller09	xiller09 posted 12 Years Ago ANSWER Post Details Share Post
Group: Forum Members Posts: 21, Visits: 10	Hi Dave, The issue with setting trialduration to 2000 is that I need to present two port stimuli: <port cueon> / port = lpt1 / subport = data / items = ("10000010") </port> <port cueresp> / port = lpt1 / subport = data / items = ("10000011") </port> port.cueon needs to be sent when the cue stimulus appears. I have no problems with this one. port.cueresp needs to be sent when the participant makes a response. I can't work out how to send this signal while preserving a 2000ms trial duration.
	Reply Like 14
Dave	Dave posted 12 Years Ago ANSWER Post Details Share Post
Group: Administrators Posts: 13K, Visits: 108K	You use /responsemessage. For details see http://www.millisecond.com/forums/Topic1739.aspx#1739.
	Reply Like 15
xiller09	xiller09 posted 12 Years Ago ANSWER Post Details Share Post
Group: Forum Members Posts: 21, Visits: 10	Brilliant, that is exactly it. Thanks Dave. - Tim
	Reply Like 16