Which layer is the location of synapses between photoreceptors and bipolar cells?

Which layer is the location of synapses between photoreceptors and bipolar cells?

• A. Outer Nuclear Layer (ONL)
• B. Inner Nuclear Layer (INL)
• C. Nerve Fiber Layer (NFL)
• D. Outer Plexiform Layer (OPL)

Answer: (D)

In the retina, the connections between photoreceptors and the next neurons occur in the outer plexiform layer. This layer houses the synapses where photoreceptor terminals communicate with bipolar cell dendrites (and with horizontal cells that provide lateral input). The other layers have different roles: the outer nuclear layer contains photoreceptor cell bodies, the inner nuclear layer contains the cell bodies of bipolar, horizontal, and amacrine cells, and the nerve fiber layer contains ganglion cell axons heading toward the optic nerve. The classic arrangement in the outer retina is an invaginating synapse in the outer plexiform layer, often described as a triad involving rod or cone terminals, a bipolar cell dendrite, and a horizontal cell process. Hence, the synaptic site between photoreceptors and bipolar cells is the outer plexiform layer.

In the retina, the connections between photoreceptors and the next neurons occur in the outer plexiform layer. This layer houses the synapses where photoreceptor terminals communicate with bipolar cell dendrites (and with horizontal cells that provide lateral input). The other layers have different roles: the outer nuclear layer contains photoreceptor cell bodies, the inner nuclear layer contains the cell bodies of bipolar, horizontal, and amacrine cells, and the nerve fiber layer contains ganglion cell axons heading toward the optic nerve. The classic arrangement in the outer retina is an invaginating synapse in the outer plexiform layer, often described as a triad involving rod or cone terminals, a bipolar cell dendrite, and a horizontal cell process. Hence, the synaptic site between photoreceptors and bipolar cells is the outer plexiform layer.