Superior performance for visually guided pointing in the lower visual field

The superior hemiretina in primates and humans has a greater density of gan glion cells than the inferior hemiretina, suggesting a bias towards process ing information in the lower visual field (loVF). In primates, this over-re presentation of the loVF is also evident at the level of striate and extras triate cortex. This is particularly true in some of the visual areas consti tuting the dorsal "action" pathway, such as area V6A. Here we show that vis ually guided pointing movements with the hand are both faster and more accu rate when performed in the loVF when compared to the same movements made in the upper visual field (upVF). This was true despite the fact that the bio mechanics of the movements made did not differ across conditions. The loVF advantage for the control of visually guided pointing movements is unlikely to be due to retinal factors and may instead reflect a functional bias for controlling skilled movements in this region of space. Possible neural cor relates for this loVF advantage for visually guided pointing are discussed.