Which photoreceptors exhibit neural convergence?

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

Answer: (B)

Neural convergence in the retina refers to many photoreceptors funneling their signals into fewer downstream neurons, which increases sensitivity at the cost of spatial detail. Rods show strong convergence: in much of the retina, many rods feed into a smaller number of bipolar and then ganglion cells. This pooling makes rod vision highly sensitive in dim light, because even faint signals from many rods can wake up the output neurons, but it reduces spatial resolution, leading to lower acuity.

Cones, especially in the fovea, have much less convergence or can be nearly one-to-one with ganglion cells, which preserves fine detail and color information at higher light levels. Because of this reduced convergence, cones do not exemplify neural convergence as clearly as rods do.

So, rods exhibit neural convergence.