Abstract

Saccades made toward and away from a flashed visual stimulus (prosaccades and antisaccades, respectively) are known to engage different cognitive processes. Brain regions important for such controlled execution include both anterior and posterior heteromodal cortices, the dorsolateral prefrontal cortex (DLPFC) and intraparietal sulcus (IPS). Despite task-dependent differences in activity, however, the functional interactions of DLPFC and IPS with the oculomotor network are largely unknown. We used event-related fMRI to image human brain activity during performance of an interleaved pro/anti saccade task. Since traditional univariate statistics cannot address the issue of functional connectivity, a bi- or multivariate technique is necessary. Coherence between the fMRI time series of all brain voxels with each of a small number of seed regions, including DLPFC and IPS, was used to measure functional interactions. The DLPFC, but not IPS, showed greater differential coherence with the supplementary motor area (SMA) between pro- and antisaccade trials. Alternately, the IPS, but not DLPFC, showed greater differential coherence with the frontal eye fields (FEF). These results, which are independent of standard task-correlated activations, suggest that the functional influence of anterior and posterior heteromodal areas on the oculomotor system depends on current task goals in a region-specific manner. Namely, interactions of IPS with FEF and of DLPFC with SMA are sensitive to visually guided versus internally generated or competing saccade goal acquisition.

From: Miller, L. M., F. T. Sun, et al. (2002). Prefrontal and parietal interactions with oculomotor control centers differ during pro- and antisaccades. Society for Neuroscience, Orlando.