The first contacted cortical cells are called simple cells . Some of these cells are similarly sensitive to bars of dark. Simple cells may also have areas around their field of sensitivity that are inhibiting to them. They may or may not have inhibitory areas at the ends of their fields that limit the length of light bar that will excite them. They all have limits as to the width of light bar that will excite them.
None are sensitive to general background light.
They have the same restrictions for becoming excited that simple cells have except they are not very restrictive to the precise area of the retina that the bar of light stimulates. They may be just as sensitive to the width and length of bar, but that bar can occur over a wider area of the retina. Simple cells of the same orientation are arranged in columns. Laterally in one direction are cells with input from nearby retina, laterally the other dimension are cells of progressively more light angle. Input from left and right eye are in adjacent columns.