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Trigger Extension for Psyscope
Functional MRI studies of speech are problematic for several reasons. In speech production experiments, movement
of the mouth and jaw causes susceptibility artifacts in images obtained during movement. In both perception and production studies,
the subject must deal with the very loud noises that accompany echo planar imaging. This noise may affect the
perceptual system's response and may alter the strategies used for speech production.
In order to overcome these problems, we have used an event-related technique in which we trigger the scanner to
begin image acquisition just following jaw movement in production studies
or auditory stimulus presentation in
speech perception studies. Because of the delay in the hemodynamic response, we can actually collect data about
the areas that were active during production or during the presentation of the auditory stimulus.
In order to trigger the scanner at appropriate times, we developed an extension to the Psyscope program for stimulus presentation. This
extension allows the experimenter to specify 'trigger events' within the experiment scripts that send a TTL pulse
from the serial port of a Macintosh computer. This TTL pulse can be used to signal the start of image
acquisition.
Please contact Jay Bohland for information about obtaining the extension.
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