In support of the topographic-gradient hypothesis,it has been shown that
A) axons do not grow out from the retinas until the retinas are fully grown, which is why babies have disproportionately large eyes.
B) axons do not grow out from the retinas until their target structures (e.g., optic tectums) are fully grown.
C) retinas and optic tectums always grow in precise proportion to one another.
D) the synaptic connections originally formed by retinal ganglion cells on the optic tectums gradually shift as both the eyes and optic tectums grow at different rates during development.
E) both A and B

Question

Quizplus · Accepted Answer

The statement "the synaptic connections originally formed by retinal ganglion cells on the optic tectums gradually shift as both the eyes and optic tectums grow at different rates during development" supports the topographic-gradient hypothesis, which postulates that visual information is mapped onto the visual system based on the spatial arrangement of the retinal ganglion cells. As the retina and optic tectum grow at different rates during development, the synaptic connections initially formed by the retinal ganglion cells need to shift to maintain precise mapping. Choices A and B are incorrect as they are not related to the topographic-gradient hypothesis. Choice C is incorrect as the proportion between retinas and optic tectums can be altered due to various factors.

In Support of the Topographic-Gradient Hypothesis,it Has Been Shown That