Reason for studying the control of gaze

Little in visual neuroscience is of greater concern than a human being's ability to control the direction of gaze (the direction of the line of sight in spatial coordinates). Why? What could possibly make the human's control of gaze so important? The answer lies in the nature of the human retina, the receptor surface within the eye that transduces (translates) light, the adequate (most effective) stimulus for vision, into bioelectrical signals that are carried to the higher levels of the visual brain. These centers are responsible for our ability to see a world of colored objects, of various sizes and at various distances, moving or stationary with respect to each other, as well as moving or stationary with respect to ourselves. The retinal surface is very heterogeneous (diverse) with respect to its functional properties. A very small central depression (only about 1/40th of 1% of the retinal surface area), called the fovea, is responsible for our best visual acuity, that is, our ability to discriminate (distinguish) very fine details. The fovea is also responsible for our best color vision, while the regions outside of the fovea are particularly well suited for detecting very low levels of light and motion. The fact that the human retina had very heterogeneous functional properties was well established by the last quarter of the nineteenth century. (See Brindley, 1960, for many important older references and Oyster, 1999, for an up-to-date treatment of what is now known about the structure and function of the human eye.)