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Acoustic stimuli and visual stimuli

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  • Acoustic stimuli and visual stimuli

    Need help! I'm trying to create a startle paradigm with movie clips and pictures combined with startle probes. I want to combine acoustic probes with the pictures/movies and have figured out how to present visual and acoustic stimuli at the same time. However, I want to present the acoustic probe 3, 4 or 5 seconds after the onset of the visual stimuli, and not at the onset, but can't figure out how to! Anyone? Thanks!!

  • #2
    I have attached an example experiment to this post.

    There are three steps:
    - end your visual stimulus event immediately
    - present an inter-stimulus interval (ISI) after the visual stimulus
    - present your audio stimulus after the ISI

    Let me know if you need anything else.
    Attached Files

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    • #3
      Thank you for your reply! I manage to make it work. However, I'm using a stim tracker to send events from Superlab to Acq, and I ran into a couple of more issues. I want to present an ITI for 5 seconds in which the stimtracker will tell me in acq that the ITI is happening. This works fine. Then I want to present a picture, followed by a startle probe 3 seconds later. This is no longer a problem. But when the startle probe comes on, I want the stim tracker to send a pulse so I can detect this in Acq. This does not work. Why? The stimtracker works for telling me when the pictures and ITI's are running, but not the audio stimuli. This is driving me nuts!

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      • #4
        Next issue..

        Hi agin, please ignore my previous post - I'll try to be more specific below:

        I'm attaching an example of my experiment I want to create. In the attached file I have managed to present five pictures (10 second duration for all pictures), out of which tree are accompanied with a startle probe after 3, 4 and 5 seconds respectively. In between the pictures are ITI's which are 5 seconds each. All good so far.

        Here is my new issue: I am using stim tracker to send event markers to Acqknowledge. This is not working though. I want to add digital outputs when the ITI goes on. For example, raising the line when ITI starts and lower the line when the ITI ends. I also want to raise the line in another channel when the picture starts, and lower the line when the picture ends. I also want to send a pulse when the startle probe is presented. All in all, a lot of digital outputs. I have five categories of pictures, and want each category to be presented on a separate channel. I want the pulse for the startle probe to go on one channel, and the digital output for ITI on one channel. In total, seven channels serving different purpose. I want to be able to see what picture category is presented when analyzing my data in Acq.

        I tried to add a digital output pre and post ITI, and that worked, it sent a marker through stim tracker to Acq (raised the line at the onset, and lowered the line at the offset). It did not work however, to add digital outputs pre and post pictures, and at the onset of the startle probe. Why?

        I also wonder what the Superlab channels; E0, E1, E2, E3, E4, E5, E6 and E7 corresponds to in Acq.

        Thank you!!
        Attached Files

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        • #5
          I have modified your experiment to raise and lower a unique line for onsets and offsets of the first ITI and Picture events. I have also set a pulse upon the onset of the first Startle event.

          I cannot tell why you were having difficulties because the experiment you sent me had no digital output events; therefore, I could not see your past efforts.

          For future reference, please click File > Create an Experiment Package... so that your picture and audio files are included with your experiment. To run the experiment, I had to change all of your picture and audio events to text; that being said, I also tested the solution with actual picture and audio files.
          Attached Files

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          • #6
            Still having trouble

            Dear Arman,

            Thank you yet again for your help! Your solution works fine in Superlab as well as in acq - but not when I continue using the same solution throughout the block.

            What happens is that the channels don't register in Acq. EC0 is set for the ITI's - that works throughout the block. EC1 is set for the first picture - works fine. EC2 is set for startle - works fine throughout the block. However Picture 2 (want it on channel EC4), Picture 3 (want it on channel EC6), Picture 4 (want it on channel EC3) and Picture 5 (want it on channel EC 5) does not work in Acq. Nothing comes up even though I have used your solution in the same way during the whole block. Why is it that some channels don't want to register? What can I do? I need to use separate channels for all picture categories since they are different and I need to be able to tell them apart in Acq.

            I have created an experiment package - I'm so sorry about last time. It is only startle probes included and text files instead of pictures - but it works fine for me when I use pictures as well, so that shouldn't be a problem. Thank you for your patience!

            /Sofi
            Attached Files

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            • #7
              I have tested your experiment against a StimTracker and the digital outputs are working as you have described.

              As for why the lines aren't registering with Acq, you may want to contact their support team. In the meanwhile, I will forward your post to someone else at Cedrus that may be more helpful.

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              • #8
                You might also find these links helpful:

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