PURPOSE The past work of our laboratory shows that the ON direction selective retina ganglion cells (ON DSGCs),with little or no dendrites into the OFF sublamina of the inner plexiform layer (IPL),receive an additional excitatory synaptic input when the light stimulus is removed.So here these questions are addressed:Do other RGCs with their dendrites restricted within the ON sublamina have this kind of input? Furthermore,do cells that have only the ON or OFF light response can have dendrites both in the ON and OFF sublaminae? And do cells that extend their dendrites into ON or OFF sublamina must receive direct excitatory synaptic inputs there? METHOD By intuition,for the resemblance of their light response to the ON direction selective ganglion cells,retina ganglion cells with sustained light response are selected based on their response to a 5-second light spot projected to the retinas.