Real-time monitoring of eye movements using infrared video-oculography during functional magnetic resonance imaging of the frontal eye fields

Monitoring eye movements is a critical aspect of experimental design for st udies of spatial attention and visual perception. However, obtaining online eye-movement recordings has been technologically difficult during function al magnetic resonance (MR) imaging studies. Previous approaches to monitori ng eye movements either have distorted the MR images or have shown MR-relat ed interference in the recordings. We report a technique using long-range i nfrared video-oculography to record eye movements without causing artifacts in the MR images. Analysis of the MR signal from a phantom obtained with t he eye-movement equipment turned on or off confirmed the absence of signifi cant additional noise in the MR time series. Eye movements of three subject s were monitored while they performed tasks of covert and overt shifts of s patial attention. Activation of the frontal eye fields during the covert ta sk was seen even when the eye-movement recordings demonstrated no significa nt difference in saccadic eye movements between the baseline and the active conditions. (C) 2000 Academic Press.