Complex synaptic activation of bipolar, amacrine and ganglion cells is elicited with biphasic electrical stimulation

Summary form only given. Correlation of excitatory and inhibitory input currents with ganglion cell spiking responses suggest that excitatory and inhibitory presynaptic neurons (likely bipolar and amacrine cells respectively) are activated by biphasic stimulus pulses. Inhibitory input, likely arising from direct or indirect (via bipolar) activation of amacrine cells, suppresses the ganglion cell spiking response and therefore increases the stimulus current threshold for ganglion cell activation. This suggests that electrical stimulation drives a complex interactive range of presynaptic activity. Stimulus parameters that minimize direct or indirect activation of amacrine cells may result in generating higher response/stimulus efficiency.