Connectional specificity in the cat's retinogeniculate system.

The establishment of normal patterns of retinogeniculate projections in cats is the end-product of the operation of at least three guidance/recognition mechanisms. First, topographic order must be retained in the central maps of visual space. Second, inputs from the two eyes must segregate from each other and target their appropriate layers in the lateral geniculate nucleus. Finally, specific cell classes in the retina must stabilize contacts with functionally matched geniculate neurons. These processes are ordered temporally, and may permit the specification of accurate retinogeniculate connections using a minimum of molecular gradients and markers.