Hi!

I am starting to learn inquisit, and I would like to know how we can play a video file through Inquisit 3 by pressing the ENTER key on mouse. My video stimulus have duration of about 300ms and i need to repeat the video stimulus for about 150 times for evoked potential recording. I would also like to know how to send triggers (TTL pulses) from Inquisit to an external device.

Thank you 

You'll want to go for a setup along these lines:

<defaults>
/ inputdevice = mousekey
</defaults>

<trial mouseclick>
/ stimulusframes = [1=clickmessage]
/ validresponse = (lbuttondown)
</trial>

<text clickmessage>
/ items = ("Press left mouse button to start the video")
/ erase = false
</text>

<trial playvideo>
/ stimulusframes = [1=myvideo]
/ validresponse = (noresponse)
/ trialduration = 300
</trial>

<video myvideo>
/ items = myvideoitems
/ playthrough = true
</video>

<item myvideoitems>
/ 1 = "01.avi"
/ 2 = "02.avi"
/ 3 = "03.avi"
/ 4 = "04.avi"
/ 5 = "05.avi"
</item>

<block myblock>
/ trials = [1-5=sequence(mouseclick, playvideo)]
</block>

You'll want to study the documentation topics "How to Present TTL Signals Through the Parallel
Port", "How to Use the Parallel Port Monitor Tool" and the language reference for the <port> element. The "Auditory Oddball Task" available from the Task Library at millisecond.com may serve as a reference implementation. Searching the forum for terms such as "TTL", "Parallel Port", "trigger", etc. will bring a number of threads containing additional information and tips.

Regards,

~Dave

hi sir, 

Thank you, it worked out well. But iam not able to loop the stimulus (i.e continouously play the stimulus for about 150 times). Also i wanted to know  how to set interstimulus interval between video stimulus and to send trigger pulses only for the audio stimulus in the video.

Please be more specific about your design. I.e. do you want to repeat the video 150 times on a single <trial>? Or do you want to have 150 <trial>s, each displaying the same video? Also, are participants supposed to respond to the video stimulus or just watch it? Note that Inquisit collects only a single response per <trial> element.

Please study the "How to Control Trial Duration and Inter-Trial
Intervals" topic in the Inquisit documentation. Also, please complete the tutorials in the Inquisit helpfile to get an overview of the basic syntax features.

Hi Dave,

I am sure you will clarify  this for me. Now the video is playing well and i could loop it too, but triggering is the problem. How to go about with the parallel port LPT connections. Neuroscan equipment which we are planning to use have a 25 pin male connector. how to know which port to use (LPT 1 or LPT2) and is there anything to be set in the Inquisit software to enable this triggers to be sent. we need to send an 8 bit TTL pulse to Neuroscan equipment for it to recognise the triggers. i need to set only one trigger at the onset of the video.

Thanking You in advance. 

As I had mentioned previously, you need to properly set up a
<port> element to send triggers to external equipment such as NeuroScan. Thus:

You use the LPT port Neuroscan is connected to on the PC. Either

<port onsettrigger>
/ port = LPT1
[...]
</port>

or

<port onsettrigger>
/ port = LPT2
[...]
</port>

The 8-bit TTL signal to be sent is defined in the <port> element's /items attribute. For the specific signal NeuroScan expects as well as other NeuroScan-specific settings (e.g. the subport to use) refer to the NeuroScan documentation.

<port onsettrigger>
/ items = ("00000001")
[...]
</port>

Once this is set up properly, you need to send the trigger out at the desired time via your <trial> elements' /stimulustimes or /stimulusframes attributes. E.g.:

<trial mytrial>
/ stimulusframes = [1=myvideo,onsettrigger]
[...]
</trial>

You may test connectivity between Inquisit and NeuroScan by using the Parallel Port Monitor tool.

~Dave

Thank You Dave it worked...

But now when the command "onset trigger" is given, i am getting a trigger value of "1" only at the onset of the video stimulus.  But for my task, i have to the play the video 150 times and get a trigger for each trial (i.e. for each video). How to go about with this problem. The script i'am using presently is given below:

<defaults>

/ input device = mousekey

</defaults>

<text click message>

/ items = ( "Press left mouse button to start the video")

/ erase = false

</text>

<port onsettrigger>

/ port = LPT1

/ subport = data

/ items =  ("00000001")

</port>

<trial play video>

/ stimulusframes = [1=myvideo, onsettrigger]

response = timeout(500)

/ validresponse = (" ", noresponse)

/trialduration =10000

</trial>

<video myvideo>

/ items = myvideoitems

/ playthrough = true

/ loop = true

/ size = (90%, 90%)

</video>

<item myvideoitems>

/ 1 = "ba - ba.avi"

/ 2 = "ba - ba.avi"

/ 3 = "ba - ba.avi"

/ 4 = "ba - ba.avi"

/ 5 = "ba - ba.avi"

</item>

block myblock>

/ trials = [1-5=sequence(mouseclick, play video)]

</block>

There is some error with the trial no also. I am not able to play it 150 times.

Thank you in advance......

Which is what you asked for.

Please use consistent terminology. Otherwise it's impossible to figure out what you're trying to do. You *don't* want a trigger for *each video*, but a trigger for *each repetition of the same video*. Right? Then the /loop attribute won't help. You'll have to repeat the *<trial>* displaying the video 150 times, with each trial showing the video only once. Then you'll have triggers for each repetition.

Regards,

~Dave

hi dave, 

Is there any way to delay the trigger in the video???

Just send the trigger out at a different time using the /stimulusframes or /stimulustimes attribute of your <trial> element.

Hi Dave, 

Is there any way to repeat the triggers in single trail (which contain 150 repetition of same video stimulus)? 

Suppose your video is 500ms long, then you could go for

/ stimulustimes = [0=myvideo,mytrigger; 500=myvideo,mytrigger; [...]; 75000=myvideo,mytrigger]

However this is wholly impractical. Repetitions won't bee seamless and a single trial may only collect a single response. Otherwise, there is no way.

Also note that you'd have to send additional erase triggers (i.e. set all bits to low) in between presentations in the above, single-trial scenario.

Hi Dave, 

Tried what you have given but i am getting only one trigger for the whole stimulus (or trial). My stimulus contain only one trial which contain a video  (duration of which is 1.5 minutes). This video contains 150 repetition of syllable /da/, the duration of which is about 450 ms.  So my task here is, i need to get one trigger each for one repetition of /da/. So totally now i need 150 triggers for each /da/ repetition in a single trail. Is it possible to get triggers for a stimulus like this, also i need not want to take any responses from the subject. Its only electrophysiological measure without any  behiavioral measure.

Thank you in advance........

See my previous reply. You need to additionally send another port stimulus between presentations, which resets all bits to zero.

/ stimulustimes = [0=myvideo,mytrigger; 20=bitstolow; 450=myvideo,mytrigger; 470=bitstolow; ... ]

with

<port bitstolow>
/ items = ("00000000")
[...]
</port>

Otherwise the signal will remain raised throughout the trial.

Hi Dave,

Thank you very much, it worked well...............

Hi Dave,

I am attaching the program which i use for an electrophysiological AV experiment. Now the triggers are coming well, my system hangs or the end frame of my video stays long and  i am not able to interrupt the experiment in between. And everytime  i have to restart my system for next presentation of experiment. can you please help me to get rid of this problem.

<port oddballsignal>

/ port = LPT1

/ subport = data

/ items = ("00000001")

</port>

<port bitstolow>

/ port = LPT1

/ subport = data

/ items = ("00000000")

</port>

<video oddball>

/ items = ("da- da (1000- 350).wmv")

/size = (100%, 100%)

/ volume =100

</video>

<trial oddball>

/ skip = [  if (values.lasttrial == trial.oddball.name) values.skipcount = values.skipcount + 1 else false ]

/ stimulustimes = [350= oddball, oddballsignal; 370=bitstolow; 1350= oddball, oddballsignal; 1370=bitstolow; 2350=oddball, oddballsignal; 2370=bitstolow; 3350=oddball, oddballsignal; 3570=bitstolow; 4350=oddball, oddballsignal; 4370=bitstolow; 5350= oddball, oddballsignal; 5370=bitstolow; 6350= oddball, oddballsignal; 6370=bitstolow; 7350=oddball, oddballsignal; 7370=bitstolow; 8350=oddball, oddballsignal; 8370=bitstolow; 9350=oddball, oddballsignal; 9370=bitstolow; 10350= oddballsignal; 10370= bitstolow; 11350= oddball, oddballsignal; 11370=bitstolow; 12350=oddball, oddballsignal; 12370=bitstolow; 13350=oddball, oddballsignal; 13370=bitstolow; 14350=oddball, oddballsignal; 14370=bitstolow; 15350= oddball, oddballsignal; 15370=bitstolow; 16350= oddball, oddballsignal; 16370=bitstolow; 17350=oddball, oddballsignal; 17370=bitstolow; 18350=oddball, oddballsignal; 18370=bitstolow; 19350=oddball, oddballsignal; 19370=bitstolow; 20350= oddball, oddballsignal; 20370=bitstolow; 21350= oddball, oddballsignal; 21370=bitstolow; 22350=oddball, oddballsignal; 22370=bitstolow; 23350=oddball, oddballsignal; 23370=bitstolow; 24350=oddball, oddballsignal; 24370=bitstolow; 25350= oddball, oddballsignal; 25370=bitstolow; 26350= oddball, oddballsignal; 26370=bitstolow; 27350=oddball, oddballsignal; 27370=bitstolow; 28350=oddball, oddballsignal; 28370=bitstolow; 29350=oddball, oddballsignal; 29370=bitstolow; 30350= oddballsignal; 30370= bitstolow; 31350= oddball, oddballsignal; 31370=bitstolow; 32350=oddball, oddballsignal; 32370=bitstolow; 34350=oddball, oddballsignal; 34370=bitstolow; 35350=oddball, oddballsignal; 35370=bitstolow;36350= oddball, oddballsignal; 36370=bitstolow; 37350= oddball, oddballsignal; 37370=bitstolow; 38350=oddball, oddballsignal; 38370=bitstolow; 39350=oddball, oddballsignal; 39370=bitstolow; 40350=oddball, oddballsignal; 40370=bitstolow; 41350= oddball, oddballsignal; 41370=bitstolow; 42350= oddball, oddballsignal; 42370=bitstolow; 43350=oddball, oddballsignal; 43370=bitstolow; 44350=oddball, oddballsignal; 44370=bitstolow; 45350=oddball, oddballsignal; 45370=bitstolow; 46350= oddball, oddballsignal; 46370=bitstolow; 47350= oddball, oddballsignal; 473370=bitstolow; 48350=oddball, oddballsignal; 48370=bitstolow; 49350=oddball, oddballsignal; 49370=bitstolow; 50350=oddball, oddballsignal; 50370=bitstolow; 51350= oddballsignal; 51370= bitstolow; 52350= oddball, oddballsignal; 52370=bitstolow; 53350=oddball, oddballsignal; 53370=bitstolow; 54350=oddball, oddballsignal; 54370=bitstolow; 55350=oddball, oddballsignal; 55370=bitstolow; 56350= oddball, oddballsignal; 56370=bitstolow; 57350= oddball, oddballsignal; 57370=bitstolow; 58350=oddball, oddballsignal; 58370=bitstolow; 593350=oddball, oddballsignal; 59370=bitstolow; 60350=oddball, oddballsignal; 60370=bitstolow; 61350= oddball, oddballsignal; 61370=bitstolow; 62350= oddball, oddballsignal; 62370=bitstolow; 63350=oddball, oddballsignal; 63370=bitstolow; 64350=oddball, oddballsignal; 64370=bitstolow; 65350=oddball, oddballsignal; 65370=bitstolow; 66350= oddball, oddballsignal; 66370=bitstolow; 67350= oddball, oddballsignal; 67370=bitstolow; 68350=oddball, oddballsignal; 68370=bitstolow; 69350=oddball, oddballsignal; 69370=bitstolow; 70350=oddball, oddballsignal; 70370=bitstolow; 71350= oddballsignal; 71370= bitstolow;72350= oddball, oddballsignal; 72370=bitstolow; 73350=oddball, oddballsignal; 73370=bitstolow; 74350=oddball, oddballsignal; 74370=bitstolow; 75350=oddball, oddballsignal; 75370=bitstolow; 76350= oddball, oddballsignal; 75370=bitstolow; 76350= oddball, oddballsignal; 77370=bitstolow; 78350=oddball, oddballsignal; 78370=bitstolow; 79350=oddball, oddballsignal; 79370=bitstolow; 80350=oddball, oddballsignal; 80370=bitstolow]

/ validresponse = (" ")

/ correctresponse = (" ")

/ trialduration = 500

</trial>

<block oddball>

/ trials = [1 = replace(oddball)]

/ stop = [block.oddball.trialcount > 1]

</block>

<expt oddball>

/ blocks = [1=oddball]

</expt>

*************************************************************************************************

************* GLOBAL SETTINGS AND VARIABLES ******************************************

*************************************************************************************************

<values>

/ lasttrial = ""

/ skipcount = 0

</values>

/ trialduration = 500 doesn't make sense. You might also want to set /responsetime = 0, otherwise you may not be able to interrupt the experiment while the stimulus presentation sequence is running.