The functional significance of X and Y cells in normal and visually deprived cats

The so-called X cells in the retino-geniculostriate pathway have been suggested to be important in the analysis o f spatial patterns in the visual scene, whereas Y cells have been considered responsible for detecting temporal change. In this article Murray Sherman suggests that this is too simplistic a way o f differentiating these cells, and that a more appropriate differentiation can be drawn from their developmental history: he concludes that the development o f X cells is governed by a non-competitive mechanism, and Y cells by a mechanism involving binocular competition.