Oscillatory potentials originate from which retinal cells?

• A. Photoreceptors
• B. Bipolar cells
• C. Amacrine cells
• D. Ganglion cells

Answer: (C)

Oscillatory potentials come from the inner retina, driven by amacrine cell networks. Amacrine cells are inhibitory interneurons that link bipolar cells to ganglion cells and are interconnected in ways that create rapid, transient electrical activity. This inner-retina circuitry generates the high-frequency wavelets we see as oscillatory potentials on the electroretinogram, superimposed on the larger b-wave produced by the outer retina. Photoreceptors and bipolar cells mainly produce the a- and b-waves, while ganglion cells contribute later signals, so they aren’t the source of these oscillations.