Psychtoolbox and EEG

1
Hi,

I'm trying to put together an EEG experiment using Psychtoolbox on a
Mac for visual stimulus presentation. Currently the EEG is set up to
work with a PC; it may be possible to hook it up directly to the Mac
(still working on that).

In any case, I will need some way to have the Mac send out a trigger
signal for each stimulus presentation (exposure durations as short
as 13 or 20 ms, if that makes a difference). The signal would need
to go either to the EEG or to the PC, depending on what kind of
setup we can manage.

Is there a way to do this from within Matlab? I have looked through
the documentation on the Psychtoolbox web site but can't seem to
find anything. Any help would be greatly appreciated!

Thanks in advance!
Irit Rappley
2
Irit:

I use the ActiveWire digital IO card for sending & receiving trigger
pulses. The Psychtoolbox function ACTIVEWIRE is an easy-to-use way to
initialize, read from, and write to the card, which connects to the Mac
via standard USB cable. Each card is about $60US; see the psychtoolbox
archives and activewire's web site, http://www.activewireinc.com, for
more info.

If you're triggering your PC, you'll need some means of reading the
pulse there. It's possible to use the parallel port, but a digital IO
card (e.g., another activewire card) is probably a better way to go.

I understand there are some other USB/digital IO cards out there now,
and I think I've seen postings on psychtoolbox suggesting that people
have written Matlab mex files for controlling them. Check the archives.

Best,
Tom Fikes
Westmont College

On Wednesday, Jul 9, 2003, at 01:40 US/Pacific, rappley123 wrote:

> Hi,
>
> I'm trying to put together an EEG experiment using Psychtoolbox on a
> Mac for visual stimulus presentation. Currently the EEG is set up to
> work with a PC; it may be possible to hook it up directly to the Mac
> (still working on that).
>
> In any case, I will need some way to have the Mac send out a trigger
> signal for each stimulus presentation (exposure durations as short
> as 13 or 20 ms, if that makes a difference). The signal would need
> to go either to the EEG or to the PC, depending on what kind of
> setup we can manage.
>
> Is there a way to do this from within Matlab? I have looked through
> the documentation on the Psychtoolbox web site but can't seem to
> find anything. Any help would be greatly appreciated!
>
> Thanks in advance!
> Irit Rappley
>
>
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----------------------------------------------------------
Thomas G. Fikes
Dept. of Psychology, Westmont College
Santa Barbara, CA 93108
805.565.6115 (voice); 805.565.6116 (fax)
web: http://homepage.westmont.edu/~fikes