Color opponent retinal ganglion cells in the tammar wallaby retina.
In behavioral tests, tammar wallabies (Macropus eugenii) are dichromats. We investigated the neural basis for this color discrimination by making patch clamp recordings from retinal ganglion cells in an in vitro preparation. Pseudo-random noise stimuli were used to probe the spectral and temporal properties of the receptive fields. Color opponent ganglion cells were excited by medium wavelength-sensitive cones and inhibited by short wavelength-sensitive cones, and were classified as M-on/S-off cells. The S-off response was delayed by 15 ms relative to the M-on response, but, otherwise, the time course of the two responses was very similar. Second-order nonlinear response components, estimated by nonlinear systems analysis, served to accentuate the color opponency. Possible synaptic mechanisms underlying the cone opponent inputs are discussed.
Hemmi
Jan M
JM
Visual Sciences, Research School of Biological Sciences and Centre for Visual Sciences, Australian National University, Canberra, Australia. jan.hemmi@anu.edu.au
James
Andrew
A
Taylor
W Rowland
WR
D000818:Animals; D003118:Color Perception / Q000502:physiology*; D007614:Macropodidae / Q000502:physiology*; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*; D012165:Retinal Ganglion Cells / Q000502:physiology*