Which layer contains the synapses between bipolar cell axons and ganglion cell dendrites?

Which layer contains the synapses between bipolar cell axons and ganglion cell dendrites?

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

Answer: (C)

The main idea is where the signaling between bipolar cells and ganglion cells happens. That connection is in the inner plexiform layer, the part of the retina where the axons of bipolar cells form synapses with the dendrites of ganglion cells (with amacrine cells providing lateral modulation in this same layer). The inner plexiform layer is also organized into sublayers that separate ON and OFF pathways, reflecting how signals that detect light increases (ON) or decreases (OFF) are routed to the appropriate ganglion cells. By contrast, the outer plexiform layer houses photoreceptor-to-bipolar and horizontal cell synapses, the inner nuclear layer contains the cell bodies of bipolar, amacrine, and horizontal cells, and the nerve fiber layer contains the axons of ganglion cells as they head toward the optic nerve.

The main idea is where the signaling between bipolar cells and ganglion cells happens. That connection is in the inner plexiform layer, the part of the retina where the axons of bipolar cells form synapses with the dendrites of ganglion cells (with amacrine cells providing lateral modulation in this same layer). The inner plexiform layer is also organized into sublayers that separate ON and OFF pathways, reflecting how signals that detect light increases (ON) or decreases (OFF) are routed to the appropriate ganglion cells. By contrast, the outer plexiform layer houses photoreceptor-to-bipolar and horizontal cell synapses, the inner nuclear layer contains the cell bodies of bipolar, amacrine, and horizontal cells, and the nerve fiber layer contains the axons of ganglion cells as they head toward the optic nerve.