What role do horizontal cells play in the retina?

• A. They connect photoreceptors to ganglion cells directly
• B. They are the primary light-detecting cells
• C. They distribute photoreceptor output to multiple bipolar cells for signal amplification
• D. They secrete neurotransmitters to the optic nerve

Answer: (C)

Horizontal cells act as lateral communication hubs in the outer retina, shaping how photoreceptor signals are processed before they reach bipolar cells. They connect to neighboring photoreceptors and to bipolar cells, providing inhibitory feedback and feedforward influence that creates center-surround receptive fields. This means a photoreceptor’s output can influence multiple bipolar cells, spreading and modulating the signal across a local network. The result is enhanced contrast and edge detection as signals from illuminated areas are dampened in the surrounding region. They are not the primary light detectors, nor do they directly connect photoreceptors to ganglion cells or send signals straight to the optic nerve.