Finally, a striking difference was observed between the responses of retinal ganglion cells innervating the different circuits and the responses of neurons in the target nuclei to full-field stimuli. The 'chirp' stimulus produces robust responses in most retinal ganglion cells but fails to illicit responses in either the posterior pulvinar, or the parabigeminal nucleus ([Figure 0---figure supplement 0](#fig0s0){ref-type="fig"}), which might be due to non-linear integration of retinal inputs or summation of opposite signed weights.