Which cells make up the three cellular types within the inner nuclear layer?

Which cells make up the three cellular types within the inner nuclear layer?

• A. Photoreceptors, bipolar cells, and ganglion cells
• B. Bipolar cells, horizontal cells, and amacrine cells
• C. Rods, cones, and horizontal cells
• D. Müller glia, astrocytes, and microglia

Answer: (B)

In the retina, the inner nuclear layer houses the cell bodies of three interneuron types that process visual signals between the photoreceptors and the ganglion cells. These are bipolar cells, horizontal cells, and amacrine cells. Bipolar cells carry signals vertically from photoreceptors to ganglion cells; horizontal cells provide lateral modulation at the outer retina to help with contrast; amacrine cells provide further modulation between bipolar cells and ganglion cells in the inner retina, influencing timing and integration before the signal reaches the brain. Photoreceptors reside in the outer nuclear layer, and ganglion cells are in the ganglion cell layer, so a trio of bipolar, horizontal, and amacrine cells correctly identifies the neuronal population whose somas sit in the inner nuclear layer. Glial cells are present in the retina as support cells, but they are not the defining trio for this layer.

In the retina, the inner nuclear layer houses the cell bodies of three interneuron types that process visual signals between the photoreceptors and the ganglion cells. These are bipolar cells, horizontal cells, and amacrine cells. Bipolar cells carry signals vertically from photoreceptors to ganglion cells; horizontal cells provide lateral modulation at the outer retina to help with contrast; amacrine cells provide further modulation between bipolar cells and ganglion cells in the inner retina, influencing timing and integration before the signal reaches the brain. Photoreceptors reside in the outer nuclear layer, and ganglion cells are in the ganglion cell layer, so a trio of bipolar, horizontal, and amacrine cells correctly identifies the neuronal population whose somas sit in the inner nuclear layer. Glial cells are present in the retina as support cells, but they are not the defining trio for this layer.