Post-receptor cells connected with which photoreceptors have a larger summation area?

Post-receptor cells connected with which photoreceptors have a larger summation area?

• A. Cones
• B. Both
• C. Neither
• D. Rods

Answer: (D)

In the retina, how many photoreceptors feed into a single post-receptor cell determines the size of that cell’s summation area. Rods exhibit heavy convergence, with many rods funneling into the same post-receptor neuron, so the resulting receptive field is large. Cones, especially in the fovea, connect more one-to-one or with little pooling, giving smaller receptive fields and higher resolution. Because of this convergence pattern, the post-receptor cells connected with rods have the larger summation area, which makes them more sensitive to light but less able to resolve fine detail.

In the retina, how many photoreceptors feed into a single post-receptor cell determines the size of that cell’s summation area. Rods exhibit heavy convergence, with many rods funneling into the same post-receptor neuron, so the resulting receptive field is large. Cones, especially in the fovea, connect more one-to-one or with little pooling, giving smaller receptive fields and higher resolution. Because of this convergence pattern, the post-receptor cells connected with rods have the larger summation area, which makes them more sensitive to light but less able to resolve fine detail.