The Potential Binocular Field and Its Tectal Representation in Rana Pipiens

We have studied binocularity in Rana pipiens using optical, behavioral, and electrophysiological assays. The first two assays yielded a consistent picture of the size and shape of the area of uniocular visual field overlap, the potential binocular field. Potential binocular field has an extent of about 90 degrees on the horizontal in front of the frog, narrows to about 60 degrees above the frog's head, and continues to a point well behind the frog. This differs somewhat from a previous report (Fite, '73). Uniocular visual field extent on the horizontal is in excess of 225 degrees, permitting both a large binocular field and panoramic vision. The electrophysiological assay confirms the large uniocular visual field extent. It further shows that physiological binocularity closely reflects uniocular visual field overlap, in the sense that tectal loci representing positions in the potential binocular field, including those behind the frog's head, display convergent inputs from the two eyes.