title: Temporal properties of colour opponent receptive fields in the cat lateral geniculate nucleus.
abstract: The primordial form of mammalian colour vision relies on opponent interactions between inputs from just two cone types, 'blue' (S-) and 'green' (ML-) cones. We recently described the spatial receptive field structure of colour opponent blue-ON cells from the lateral geniculate nucleus of cats. Functional inputs from the opponent cone types were spatially coextensive and equally weighted, supporting their high chromatic and low achromatic sensitivity. Here, we studied relative cone weights, temporal frequency tuning and visual latency of cat blue-ON cells and non-opponent achromatic cells to temporally modulated cone-isolating and achromatic stimuli. We confirmed that blue-ON cells receive equally weighted antagonistic inputs from S- and ML-cones whereas achromatic cells receive exclusive ML-cone input. The temporal frequency tuning curves of S- and ML-cone inputs to blue-ON cells were tightly correlated between 1 and 48 Hz. Optimal temporal frequencies of blue-ON cells were around 3 Hz, whereas the frequency optimum of achromatic cells was close to 10 Hz. Most blue-ON cells showed negligible response to achromatic flicker across all frequencies tested. Latency to visual stimulation was significantly greater in blue-ON than in achromatic cells. The S- and ML-cone responses of blue-ON cells had on average, similar latencies to each other. Altogether, cat blue-ON cells showed remarkable balance of opponent cone inputs. Our results also confirm similarities to primate blue-ON cells suggesting that colour vision in mammals evolved on the basis of a sluggish pathway that is optimized for chromatic sensitivity at a wide range of spatial and temporal frequencies.
authors.affiliation: Institute of Physiology, Medical School, University of Pécs, 7624, Pécs, Hungary.|Centre for Neuroscience, University of Pécs, Pécs, Hungary.
authors.forename: Péter
authors.initials: P
authors.lastname: Kóbor
authors.affiliation: Institute of Physiology, Medical School, University of Pécs, 7624, Pécs, Hungary.|Centre for Neuroscience, University of Pécs, Pécs, Hungary.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Petykó
authors.affiliation: Institute of Physiology, Medical School, University of Pécs, 7624, Pécs, Hungary.|Centre for Neuroscience, University of Pécs, Pécs, Hungary.
authors.forename: Ildikó
authors.initials: I
authors.lastname: Telkes
authors.affiliation: Australian Research Council Centre of Excellence for Integrative Brain Function, University of Sydney, Sydney, NSW, Australia.|Save Sight Institute, University of Sydney, Sydney, NSW, Australia.|School of Medical Sciences, University of Sydney, Sydney, NSW, Australia.
authors.forename: Paul R
authors.initials: PR
authors.lastname: Martin
authors.affiliation: Institute of Physiology, Medical School, University of Pécs, 7624, Pécs, Hungary.|Centre for Neuroscience, University of Pécs, Pécs, Hungary.
authors.forename: Péter
authors.identifier: 0000-0002-4390-3360
authors.initials: P
authors.lastname: Buzás
mesh_terms: D000818:Animals; D002415:Cats; D055253:Color Vision; D005260:Female; D005829:Geniculate Bodies / Q000166:cytology / Q000502:physiology*; D008297:Male; D011930:Reaction Time; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*; D014794:Visual Fields; D014795:Visual Pathways / Q000166:cytology / Q000502:physiology
keywords: colour vision; medium wavelength sensitive cone; short wavelength sensitive cone; temporal frequency tuning; visual latency