We calculated the membrane potential of the pre-synaptic terminals (psT) of the bipolar cells in the bipolar cell layer in response to stimulation with rectangular pulses. We find out, that both depolarisation and hyperpolarisation occur in a temporal shift. To analyse the effect of depolarisation and hyperpolarisation separately we have developed the TriState Stimulation. From subretinal stimulation experiments with TriState we find out that a depolarisation of the psT gives with significant lower threshold an retinal response then a hyperpolarisation. Further we compared TriState to rectangular subretinal stimulation. From that experiments we conclude that the rising edge of rectangular pulses make the
significant stimulation effect.