This chapter discusses neural processes which result in visual perception, where the concepts about the central processing of the visual signal are based on the electrical activity of cells at different levels of the visual pathway in response to a variety of visual stimuli. The type of processing carried out in lateral geniculate nucleus, LGN may be assessed from the receptive field (RF) of LGN cells. Thus LGN may provide the station where selective control of visual information is exerted. A whole set of columns sensitive to information from both eyes about lines of all orientations from a particular region of the visual field has been called a hypercolumn. The stimulus requirements for visual cells at different levels suggest that retinal ganglion cells and LGN cells detect brightness and contrast, cortical simple and complex cells delineate linear orientation, whereas hypercomplex cells are sensitive to edges and corners.