before optic nerve outgrowth in xenopus laevis embryos , a change of state occurs in the differentiating retinal cell population which renders the cells refractory to information about subsequent changes in their positions , and commits individual ganglion cells to develop specific position-dependent properties ( locus specificities ) which subserve the formation of orderly retinotopic connections in the optic tectum .
C0007634
cells
C1708726
locus