Retinal lateral inhibition: an important mechanism for sharp-vision and color discrimination with high contrast sensitivity

of the neighboring neuron.4−10 LI prevents the spread of action potentials from the stimulated neurons to the lateral neighboring neurons. Cells using LI have existed mainly in the cerebral cortex and thalamus. LI has been observed in the retina and lateral geniculate nuclei of the animals in experimental studies. Although LI has been identified primarily in the processings in visual sensation, it also occurs during sensory procedures such as touch, hearing, and smell. 4−10 Retinal lateral inhibition (RLI) is also known as contrast encoder. RLI creates a stimulation contrast allowing increased sensory perception and enhances the contrast between the center and the periphery in a stimulated region. If activated at the same time, neighboring photoreceptors react less, although they are activated alone. Thus, when fewer neighboring neurons are stimulated, a neuron reacts more strongly. RLI is that the rod and cone photoreceptors in the perception zone interfere with each other to be active, inhibiting the response to central illumination by an increase in environmental illumination.1-10 When a certain type of cone is stimulated at a point, the same cone sends an inhibitory signal to the adjacent cone carrying the same photosensitive pigment to it with the help of horizontal cells (HCs). RLI is the main mechanism for achieving high visual acuity, sharpening the sensory location and color discrimination, which is involved in the transmission of contrasting edges in the visual image and increasing the contrasting sharpness.3,7−10