I am trying to help a colleague with fMRI project in which the responses from the scanner button box are behaving strangely. The task is fairly simple. It just plays some 10 sec video clips and collects a couple of responses to questions after each. The task runs fine even after changing settings in Styles and restricting response buttons.
The button box should return an R,B,G,Y response corresponding to the color of button pressed. Sometimes this works and is recorded in the log file, but most of the time the button-press value recorded in the log is one of the following...
...is apparently overwritten by the "T" value sent from the scanner at 2 second TRs (so all responses are Ts and their RT is the length of the response window).
...is not recognized at all and returns a "NULL" response value (happens when RT is restricted to specific button presses).
...is a "MOUSE-O" if RT to "any" response is allowed.
Can anyone suggest how best to set up DRT for an fMRI experiment or what to look into to prevent this presumably conflicting signal from the scanner from interfering with the button-box response? Many Thanks.