How does lateral inhibition create opposite responses in the centre and surround of a receptive field?

Lateral inhibition is the physiological mechanism responsible for the centre-surround antagonism observed in sensory receptive fields, such as those in the retina. This organization creates opposite responses by ensuring that stimuli in the centre and the surrounding regions of a receptive field exert opposing influences on the activity of a single sensory neuron.312

In the visual system, this process functions as follows:

• Antagonistic Inputs: The receptive field is organized so that photoreceptors in the centre and those in the periphery connect to the same ganglion cell but produce different effects. For an on-centre cell, stimulation of the centre excites the cell, while stimulation of the surround inhibits it.32
• Role of Interneurons: This inhibition is mediated by specialized cells, such as amacrine cells or horizontal cells, which connect to bipolar cells over a wide area. These interneurons exert an inhibitory influence on the central pathway, effectively canceling out excitatory signals when the entire field is illuminated uniformly.32
• Functional Significance: By causing the excitatory and inhibitory effects to cancel each other out during uniform stimulation, lateral inhibition prevents the brain from being overwhelmed by redundant information. Instead, the system becomes highly sensitive to contrast, movement, and contours, where differences in illumination between the centre and surround trigger a prominent response.32