Question

The receptive field size increases at successive progressing stages in the visual pathway. What evidence is there for this? Does this make sense?

Answer 1

For each visual neuron a receptive field is a discrete area within visual space where a luminous stimulus could alter the neuron’s activity and drive electrical responses in a retinal ganglion cell. Retinal ganglion cells which are located at the center of vision have the smallest receptive fields while those located in the visual periphery have the largest receptive fields. Therefore, as we move away from the point of fixation (eccentricity) in the visual pathway, we successively stimulate neurons at the periphery and in turn increase the size of receptive field. Hence at each processing stage (movement away from point of fixation), the receptive field size increases with the distance from the point of fixation. Here it is important to note that small receptive field size results in sharp resolution.

The evidence of the increase in size of recptive field as we successively progress in visual pathway is the poor spatial resolution of our vision as we move away from (farther) the point of fixation.

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