The low frequency drop-off is due to lateral inhibition within the retinal ganglion cells. A typical retinal ganglion cell presents a centre region with either excitation or inhibition and a surround region with the opposite sign. By using coarse gratings, the bright bands fall on the inhibitory as well as the excitatory region of the ganglion cell resulting in [http://en.wikipedia.org/wiki/Lateral_inhibition lateral inhibition] and account for the low-frequency drop-off of the [http://en.wikipedia.org/wiki/Contrast_(vision)#Contrast_sensitivity human contrast sensitivity function]. | The low frequency drop-off is due to lateral inhibition within the retinal ganglion cells. A typical retinal ganglion cell presents a centre region with either excitation or inhibition and a surround region with the opposite sign. By using coarse gratings, the bright bands fall on the inhibitory as well as the excitatory region of the ganglion cell resulting in [http://en.wikipedia.org/wiki/Lateral_inhibition lateral inhibition] and account for the low-frequency drop-off of the [http://en.wikipedia.org/wiki/Contrast_(vision)#Contrast_sensitivity human contrast sensitivity function]. |