Which two cell types are the main contributors to the ERG signal?

Which two cell types are the main contributors to the ERG signal?

• A. Ganglion cells and Amacrine cells
• B. Müller cells and RPE
• C. Photoreceptors and bipolar cells
• D. Photoreceptors and Ganglion cells

Answer: (C)

The ERG reflects the summed electrical activity of the retina in response to light. The initial negative-going deflection, the a-wave, comes from photoreceptors as they hyperpolarize when stimulated. The following large positive deflection, the b-wave, mainly arises from bipolar cells—especially ON-type bipolar cells—with Müller glia shaping the extracellular signal. Other cells contribute to additional waveforms (for example, RPE-related components under some conditions or later activity from ganglion/amacrine cells), but the principal generators of the standard ERG signal are photoreceptors and bipolar cells.

The ERG reflects the summed electrical activity of the retina in response to light. The initial negative-going deflection, the a-wave, comes from photoreceptors as they hyperpolarize when stimulated. The following large positive deflection, the b-wave, mainly arises from bipolar cells—especially ON-type bipolar cells—with Müller glia shaping the extracellular signal. Other cells contribute to additional waveforms (for example, RPE-related components under some conditions or later activity from ganglion/amacrine cells), but the principal generators of the standard ERG signal are photoreceptors and bipolar cells.