Intertectal connections are not modified by visual experience in developing Hyla moorei

Abstract One eye was rotated in a series of premetamorphic Hyla moorei. After metamorphosis the visuotectal projections were mapped electrophysiologically. In every case both the contralateral and intertectal projections from the rotated eye were themselves rotated and those through the unrotated eye were normal. This shows that the intertectal connections were prefunctionally specified and had not been modified by visual experience. Using the same electrophysiological recording system, a modification of intertectal connections had previously been demonstrated in Xenopus laevis. Other workers found no environmental modification using Rana pipiens but it was unclear whether this represented a species difference between Xenopus and Rana or a difference in recording techniques. The present finding suggests that species differences do exist in terms of the plasticity of intertectal connections between those frogs in which the eyes undergo a considerable change in interocular alignment and those in which this does not occur.