This work is carried out by analysing the retrograde and transneuronal retrograde degenerations appeared following a total or partial unilateral removal of the optical lobe, in Coturnix coturnix japonica newborn and adult specimens. By means of this technique we are able to contribute new information on the so far unknown nervous relationships between several mesencephalic (IO, SP+IPS, TP, PT and SpL) and diencephalic (SPC, DSOD, Rt, GLv, DLAmc and LA) nuclei and the optical tectum; we also give information, when it is possible, about the preferential target field on the optical tectum, and about the significance of the different degenerational behaviours of the thalamic GLv and DLAmc nuclei in newborn and adult subjects.