Recent evidence suggests that,in addition to the glutamatergic bipolar cells,amacrine cells(ACs)which are normally thought to be retinal inhibitory interneurons,also provide excitatory inputs to ganglion cells(GCs)through various non-glutamate neurotransmitters.However,with regular methodologies,it is hard to isolate such excitatory signals by blocking glutamatergic synapses,in that excitation of ACs themselves depends on glutamatergic signaling.