Development of identical orientation maps for two eyes without common visual experience.

In the mammalian visual cortex, many neurons are driven binocularly and response properties such as orientation preference or spatial frequency tuning are virtually identical for the two eyes. A precise match of orientation is essential in order to detect disparity and is therefore a prerequisite for stereoscopic vision. It is not clear whether this match is accomplished by activity-dependent mechanisms together with the common visual experience normally received by the eyes, or whether the visual system relies on other, perhaps even innate, cues to achieve this task. Here we test whether visual experience is responsible for the match in a reverse-suturing experiment in which kittens were raised so that both eyes were never able to see at the same time. A comparison of the layout of the two maps formed under these conditions showed them to be virtually identical. Considering that the two eyes never had common visual experience, this indicates that correlated visual input is not required for the alignment of orientation preference maps.