Dear all,
Recently I find there is a strange thing about eprime. I am engaged in an fMRI experiment. So there is a strict timing demand and I wrote several lines of codes to make it possible in the scanner that subjects use two keys to move the cursor in the screen to do rating from 1-9.
The very obvious problem is that when I run the codes, some presentation before the 1-9 ratings has got something like time ceiling. the rating time is always fixed as I assigned in the codes,but sometimes, the fixation time after the rating is shorten to 0, or sometimes the picture showing time after the fixation also flash more quickly than I expected while another fixation after the picture is still shown as I hoped. It's totally out of my mind. pictures didn't show up for the time I demand in the duration menu.
I think this may have something to do wt my rating part. So I'd better to write out how I realize this part:
Another guy give me this idea to make the rating 1-9 shown for 0s and afterwards every time I press the button I set up in the rating slide to left or right move the cursor, the eprime would catch the response and check which btton is pressed and make a decision whether the cursor move left or right and how long it would move. then after the axis is determined, I would draw the rating slide. and I have a cycle to control the time by datediff functon to check the start and the end of the cycle is about 5s apart.
I hope I make myself clear.
Any idea would be appreciated and hope someone can help me.
My best,
Sally