Millisecond Forums

OK - thanks for prompt response. We'll have to work it out with Biopac, then.

Best,
Robert

No. Ideally, you would have AcqKnowledge conduct the necessary real-time analysis and then send a simple TTL signal to Inquisit based on the analysis' result. I.e., a very similar scenario to what is demonstrated here: https://www.biopac.com/video/?video_category=hardware-tutorials&v=ttl-output-trigger-external-devices

Thanks. Now, is it in principle possible that Inquisit registers not only TTL signals but also raw data from Acknowledge, analyses it and based on the analysis triggers trials?

Robert

This should be possible. You would send a TTL signal to Inquisit either before the (predicted) signal peak or after. Inquisit can then initiate a <trial> presenting Stim2 in response.

Dave,

Thanks for the tips.

What we want to do is to condition stimulus presentation on the signal from skin-conductance measurement. The latter is registered with Biopack and Acknowledge.

Now, on any given trial Stim1 is presented first, and then we need to present Stim2. Assuming that Stim1 invokes stress response (SCR response) we want to present Stim2 either before, after or exactly in the peak of SCR response.

Do you think its possible with Inquisit? We'll have to analyse the SCR signal on-line, and ocassionally even predict if it would still raise or not.

Best, Robert

The basic pipeline to do this would be to have AcqKnowledge send TTL signals to the computer running Inquisit via that machine's parallel port. On the hardware side, you would need a STP100C-C, I think, for the parallel port interfacing: https://www.biopac.com/product/isolated-digital-interfaces/

You should then be able to have AcqKnowledge send TTL signals to the presentation computer running Inquisit:
https://www.biopac.com/video/?video_category=hardware-tutorials&v=ttl-output-trigger-external-devices

In Inquisit, the <trial> element can accept TTL signals as input by setting its /inputdevice to lpt (status register) or lptdata (data register):

https://www.millisecond.com/support/docs/v4/html/language/attributes/inputdevice.htm

Based on the input received you could then adjust the stimulus selection.

Hope this gives you a general idea / starting point.