The rod-cone shift and its effect on ganglion cells in the cat's retina.
We examined how several characteristics of cat retinal ganglion cells--receptive field size, spatial resolution, and centre-surround antagonism--change with background illumination. Spectral sensitivity was also measured to see how these changes depend on the rod-cone shift. The radius of the centre mechanism changed very little across the mesopic range. The absence of a change can be attributed to the connections rods make with cones, and to the small spatial spread of rods which connect to a cone. The highest spatial frequency to which a cell could respond dropped sharply with falling background illumination. This loss of spatial resolution is due partly to increasing receptive field size, and partly to loss of contrast gain. Centre-surround antagonism approached zero as background illumination fell. The loss of antagonism could have been due to either a change in the subtractive relationship between centre and surround, or due to a loss of surround strength relative to centre strength; the latter was shown to be the case.
Chan
L H
LH
Department of Physiology, University of Sydney, N.S.W., Australia.
Freeman
A W
AW
Cleland
B G
BG
D000221:Adaptation, Ocular / Q000502:physiology*; D000818:Animals; D002415:Cats; D015350:Contrast Sensitivity / Q000502:physiology; D008027:Light; D010364:Pattern Recognition, Visual / Q000502:physiology; D010786:Photoreceptor Cells / Q000502:physiology*; D012165:Retinal Ganglion Cells / Q000502:physiology*; D013053:Spectrophotometry