Lamprey ganglion cells contact photoreceptor cells

Lamprey retinal ganglion cells are localized in two separate layers: those close to the vitreous and those at the junction between the inner nuclear and inner plexiform layers, including some others in the inner nuclear layer, close to the photoreceptor cell layer. Whereas most ganglion cell dendrites arborize in the inner plexiform layer and contact amacrine, bipolar and retinopetal cell profiles, some of them, located in the inner nuclear layer, ascend radially through the outer plexiform layer and establish contacts with photoreceptor cells. This ganglion cell type might correspond to the biplexiform ganglion cells already described in gnathostome vertebrate species and could provide a fastforward signal from photoreceptors to ganglion cells, bypassing the usual bipolar cell interneuron.