Far peripheral retina, each rod bipolar cell collects signals from about how many rods?

Far peripheral retina, each rod bipolar cell collects signals from about how many rods?

• A. 200
• B. 300
• C. 400
• D. 150

Answer: (B)

In the far peripheral retina, signals from many rods are pooled by each rod bipolar cell. This pooling, or convergence, is roughly on the order of a few hundred rods per rod bipolar cell—about three hundred. Summing inputs from so many rods increases sensitivity in very low light, because a faint signal from any one rod can reach a detectable level when combined with others. The trade-off is lower spatial resolution, since pooling across a large area blurs fine details. This high convergence is typical in the peripheral retina to maximize scotopic (rod-mediated) vision, whereas the central retina maintains lower convergence to preserve acuity with cones.

In the far peripheral retina, signals from many rods are pooled by each rod bipolar cell. This pooling, or convergence, is roughly on the order of a few hundred rods per rod bipolar cell—about three hundred. Summing inputs from so many rods increases sensitivity in very low light, because a faint signal from any one rod can reach a detectable level when combined with others. The trade-off is lower spatial resolution, since pooling across a large area blurs fine details. This high convergence is typical in the peripheral retina to maximize scotopic (rod-mediated) vision, whereas the central retina maintains lower convergence to preserve acuity with cones.