On-centre, off-surround and off-centre, on-surround receptive field

Figure 5b
(Photographs taken from Discovering Biological Psychology on-line video)

Figure 5b shows that when light passes through the middle off-centre, on-surround receptive filed, the firing rate is faster at the on-surround and is moderately fired at the off-centre, and again at a faster firing rate at the on-surround receptive field.