Collective Response of ON and OFF Bipolar Cells to Light Contributes to Improved Visual Acuity

In the visual signal relay, retinal bipolar cells transduce neurotransmitter signals from photoreceptor cells into electrical signals for onward transmission to the brain. The electrical activity of bipolar cells is reflected in the b-wave of the electroretinogram which is majorly contributed by ON bipolar cells leading to the currently accepted belief that light-induced signals travel through these cells only. Here, we probe the role of ON and OFF pathways to generate visual percept under the hypothesis that the ON Bipolar Cell fine image (central illumination) is superimposed onto a coarser image formed due to OFF Bipolar Cell (surround illumination). This improves image sharpness through edge detection by unsharp masking, thereby contributing to improved visual acuity. This new finding could be useful in stimulating the retina through sub-retinal implants to restore vision.