Perturbations of early visual experience imposed by either monocular deprivation (MD) or artificially induced strabismus (squint) affect the morphological development of cells in the lateral geniculate nucleus (LGN) of cats. These morphological anomalies are thought to arise from competitive mechanisms which control many features of LGN cell development. Competition between the axon terminals of LGN cells innervated by the right and left eyes for establishing and maintaining synaptic contacts with cells in the visual cortex (i.e., binocular competition) is known to be a very important mechanism for controlling the development of LGN cells. Much of our present understanding regarding the importance of binocular competition is based on the effects of MD and squint on LGN somata. The objective of the present study was to further explore the role of binocular competition in the somatic development of LGN cells and extend these observations to determine the role of binocular competition in the dendritic development of LGN cells. Binocular competition was eliminated in some of the animals reared with either MD or squint by concomitant sagittal transection of the optic chiasm (OX), performed on either postnatal day 27 or 28
