Role of the extensive area outside the X-cell receptive field in brightness information transmission.

Stimulus area-response functions of retinal ganglion cells show an extensive disinhibitory region (DIR) outside the classical receptive field (RF). The DIR has a wide summation area but low sensitivity. Spatial responses of the retinal ganglion cells have been simulated in a model which takes into account also the properties of the DIR. By scanning the RF and its DIR with a visual image and reconstructing the transferred image for single cells, it is shown that these properties of the DIR are beneficial in the transmission of area brightness and image grey scales.