Finally, another critical issue for neural prosthetics concerns the neural code for visual perception: How can the electrical activity of a neuron, or a neuronal population, encode and transmit visual information about an object? Here we will discuss how neurons of early visual areas may communicate information about the visible world to each other.

Abbreviations

2.1  Introduction

The process of “seeing” is complex and not well understood. But we do know that individual neurons in the early visual system are tuned to stimuli with specific attributes (such as color, shape, brightness, position on the retina, etc.). The receptive field of a visual neuron is the area of the visual field (or its corresponding region on the retina) that when stimulated (by light or electrical impulses) can influence the response of the neuron (Fig. 2.1). Visual stimuli outside a neuron’s receptive field

Fig. 2.1  Activation of retinal photoreceptors and their corresponding receptive fields during visual exploration. The eye focuses light that is reflected from the visual image onto the retina, upside down and backwards. Adjacent photoreceptors within the retina are activated by adjacent points of light from the painting. Figure by the Barrow Neurological Institute Illustrations Department