Uncovering the secrets of the fovea

Researchers have delved into how the highly specialised fovea functions on a cellular level

Researchers have examined the cellular underpinnings of the fovea in an attempt to explain the differences between its function and that of the peripheral retina.

Research published in Cell assessed how varying cellular and circuit mechanisms account for the different perceptual sensitivities of the fovea and peripheral retina.

Understanding how the fovea works is important in developing methods to correct central vision loss, including efforts to design visual prosthetics.

However, there are challenges to examining how the fovea works on a cellular circuit level because the fovea is absent in most mammals. 

The fovea provides more than half of the visual input from the eyes to the brain and is pivotal for detailed tasks like reading. However, compared to the peripheral vision, the fovea has less sensitivity to rapid variations in light input. 

The research suggests that these perceptual differences come from cone photoreceptors in the fovea. 

Researchers from the University of Washington School of Medicine and Howard Hughes Medical Center found that the responses of cone photoreceptors in the fovea are two-fold slower than those in the peripheral retina. While synaptic inhibition affects the response of midget ganglion cells in the periphery, it has little effect on these cells in the fovea. 

The study highlights that while the fovea and peripheral retina share similar core circuit architecture, they have profound functional differences.

Image credit: Petr Novák