Question

Detail the structure and function of individual components in the retina and describe the neural mechanisms for Lateral Inhibition. Also describe the mechanism of a related optical illusion and how the illusion works at cell level.

Answer 1

The retina is the light-sensitive area where the image is formed. It is made up of ten distinct layers.

1. Inner limiting membrane – basement membrane.
2. Nerve fibre layer – axons of the ganglion cell bodies.
3. Ganglion cell layer –
4. Inner plexiform layer –
5. Inner nuclear layer –
6. Outer plexiform layer –
7. Outer nuclear layer –
8. External limiting membrane –
9. Inner segment / outer segment layer –
10. Retinal pigment epithelium –

Thus the retina layer is made up of a basement membrane made up of Muller cells, amacrine cells, ganglions, bipolar cells, etc.

lateral inhibition is the capacity of an excited neuron to reduce the activity of its neighbours to strengthen the perception of vision. It is produced in the retina by interneurons that spread signals over a neighbourhood of presynaptic cells i.e photoreceptors and bipolar cells and send inhibitory signals back to them. Thus lateral inhibition accentuates the edges of the stimulus.

Optical illusion can create images that are actually not present and thus misleads the brian by using colour, light and patterns.