Human precentral cortical activation patterns during saccade tasks: an fMRI comparison with activation during intentional eyeblink tasks.

Some fMRI studies in humans have located the frontal eye field (FEF) in two distinct regions along the precentral sulcus (PCS): one localized more medically, in the superior precentral sulcus (supPCR) at the junction with the superior frontal sulcus, and the other localized more laterally, along the medial part of the inferior precentral sulcus (infPCR). However, there has been no evidence of any different task activations between the regions. In the present study using fMRI, we have compared activation patterns in the regions near the PCS during saccade, fixation, and eyeblink tasks. We found that only the supPCR was activated specifically by the saccade task, while the infPCR was activated by both the saccade and eyeblink tasks. This result provides evidence that the supPCR is the human FEF homologous to the monkey FEF and that the infPCR may be homologous to the monkey premotor area.