In the retina's inner-to-outer sequence, which layer lies immediately after the Ganglion Cell Layer?

• A. Inner Nuclear Layer
• B. Outer Plexiform Layer
• C. Inner Plexiform Layer
• D. Nerve Fiber Layer

Answer: (C)

Think of the retina in an inner-to-outer sequence: nerve fiber layer, then ganglion cell layer, then inner plexiform layer, followed by the inner nuclear layer, and so on. The ganglion cell layer contains the bodies of ganglion cells, and just beyond this layer the signals are handed off and processed in the inner plexiform layer, where bipolar cell dendrites and ganglion (and amacrine) cell processes form synapses. This crossing and integration of signals in the inner plexiform layer is why it lies immediately after the ganglion cell layer. The nerve fiber layer is actually closer to the vitreous and contains the ganglion cell axons that head toward the optic nerve, while the inner nuclear and outer plexiform layers lie further outward.