Maintain fixation point throughout task? (case 20948)

Hi.
I would like to maintain a fixation point on the screen throughout my task and have images displayed over the fixation point periodically. That is, I don't want there to ever been a blank screen but always either a fixation point or an image. Also, I need the time in which the fixation is displayed before showing the image to be "jittered" (either 1500, 2000, or 2500 ms).

I have tried a few things including creating two row per trial-the first row for a fixation with a jittered duration and then the next row having both a display of the fixation cross (with a time of "0") and an image (with a loc of "0,0,0") but there is a gap on the screen between the display of the first row and the second row.

Any help would be greatly appreciated. I saw a similar thread created in 2007 but there was no response to the question.

Thank you!
Liz

Hi emartin8!

To achieve this effect, you will need to put all of your fixation points and images on a single line of your .csv input file. Whenever you have more than one row of stimuli in a .csv input file, DirectRT must show a blank screen because it needs time to compile all of the stimuli for the upcoming trial (see here in the DirectRT manual for more information: [url]http://www.empirisoft.com/directrt/help/directrt_trial_interval.htm[/url].

I've attached an example .csv file that should do what you want. Let me know if you have any other questions.

Thanks so much, Jason!

[QUOTE=jason_reed;21556]Hi emartin8!

To achieve this effect, you will need to put all of your fixation points and images on a single line of your .csv input file. Whenever you have more than one row of stimuli in a .csv input file, DirectRT must show a blank screen because it needs time to compile all of the stimuli for the upcoming trial (see here in the DirectRT manual for more information: [URL]http://www.empirisoft.com/directrt/help/directrt_trial_interval.htm[/URL].

I've attached an example .csv file that should do what you want. Let me know if you have any other questions.[/QUOTE]