sending EEG triggers in an combined fMRI/EEG experiment

[Stephen D. Benning]

On Mon, 2005-01-31 at 10:29 +0100, Boris Kleber wrote:
> Dear list members
>
> I'd like to use e-prime for an combined fMRI/EEG experiment. We'll use fMRI
> in a sparse-sampling design so that EEG is not affected by the scanning
> process. The presentation should be triggered by the MR pulse, which is no
> problem. However, I couldn't find detailed description on how to send a
> trigger to the EEG computer simultaneously with presentation onset.

You can use the OnsetSignal (and OffsetSignal) properties of each object
to send these triggers (and reset the trigger port to a "hold" value).
I'll assume that you have some object called OBJECT, a trigger port with
the address TRIGGER_PORT, and the trigger value you want to send as
TRIGGER_VALUE.  At the very beginning of your experiment, in a block of
Inline code, have the following lines:

OBJECT.OnsetSignalEnabled = True
OBJECT.OnsetSignalPort = TRIGGER_PORT
OBJECT.OnsetSignalData = TRIGGER_VALUE

If you want to reset the trigger port to a hold value (with the value
HOLD_VALUE) after the object has been presented, add these lines to the
same block of Inline code:

OBJECT.OffsetSignalEnabled = True
OBJECT.OffsetSignalPort = TRIGGER_PORT
OBJECT.OffsetSignalData = HOLD_VALUE

You'll want to repeat these lines of codes for all the objects you want
to have triggered, changing OBJECT to be the name of the appropriate
object in each case.

Now, if you'd like to assign a different value to TRIGGER_VALUE each
time OBJECT is presented (for example, if OBJECT is within a listbox,
and TRIGGER_ATTRIB is the column in the list box that gives the trigger
values that should be used for each presentation of OBJECT), add the
following in an Inline code block immediately before OBJECT:

OBJECT.OnsetSignalData = c.GetAttrib("TRIGGER_ATTRIB")

> I greatly appreciate any suggestion.
>
> Boris
>
>
--
Stephen D. Benning
Department of Psychology
University of Minnesota
Office: N631 Elliott Hall
75 East River Road
Minneapolis, MN  55455
E-mail: benn0224 at umn.edu