The cone/horizontal cell network: A possible site for color constancy

Abstract

Color vision is spectrally opponent, suggesting that spectrally opponent neurons, such as the horizontal cells in fish and turtle retinae, play a prominent role in color discrimination. In the accompanying paper (Kraaij et al., 1998), it was shown that the output signal of the horizontal cell system to the cones is not at all spectrally opponent. Therefore, a role for the spectrally opponent horizontal cells in color discrimination seems unlikely. In this paper, we propose that the horizontal cells play a prominent role in color constancy and simultaneous color contrast instead of in color discrimination. We have formulated a model of the cone/horizontal cell network based on measurements of the action spectra of the cones and of the feedback signal of the horizontal cell system to the various cone types. The key feature of the model is (1) that feedback is spectrally and spatially very broad and (2) that the gain of the cone synapse strongly depends on the feedback strength. This makes the synaptic gain of the cones strongly dependent on the spectral composition of the surround. Our model, which incorporates many physiological details of the outer retina, displays a behavior that can be interpreted as color constancy and simultaneous color contrast. We propose that the horizontal cell network modulates the cone synaptic gains such that the ratios of the cone outputs become almost invariant with the spectral composition of the global illumination. Therefore, color constancy appears to be coded in the retina.

Teleost polarization vision: how it might work and what it might be good for

“…The second issue concerns the function of spectral coding in HCs, and this has been extensively discussed in Kamermans et al [79] and VanLeeuwen et al [63]. Kraaij et al [66] found that although the spectral sensitivity of HCs is opponent, their combined output to the cones is spectrally very broad and not opponent.…”

“…As was shown by Buchsbaum, opponent -non-opponent coding leads to a reduction in redundancy in the neural representation of the signals. The logical consequence of this is that spectral coding of HCs is a highly efficient way of processing spectral information, but it is not related to colour vision per se [78,79]. This coding strategy seems to hold for many sensory modalities and it is therefore highly likely that a similar coding strategy is used for polarization vision as well.…”

“…We have shown that such a system will induce some form of colour constancy. The mean colour is subtracted from the scene and the representation of objects with a colour deviating from the mean is enhanced [63,79].…”

Retinal processing and opponent mechanisms mediating ultraviolet polarization sensitivity in rainbow trout (Oncorhynchus mykiss)

“…Cobalt is known to block horizontal cell-mediated feedback on cones in goldfish retina (Fahrenfort et al, 2004;Thoreson and Burkhardt, 1990). The result of blocking negative feedback of horizontal cells on cones is that the cone synapse is rendered out of its working range (Kamermans et al, 1998;Kamermans et al, 2001). Furthermore, blocking feedback of horizontal cells on cones will lead to a reduction of the high pass filter characteristics of the synapse.…”

Het Zien van het Onvoorspelde - Het Onvoorspelde van het Zien

“…Het gevolg is dat de verhouding van de rode, groene en blauwe signalen wordt gecorrigeerd, hetgeen resulteert in kleurconstantie. 5,11 Dit doet recht aan het basale karakter van dit fenomeen. We zullen er dus steeds heel alert op moeten zijn dat de kritische berekening voor een eigenschap op een geheel andere locatie kan plaatsvinden dan waar de eigenschap expliciet wordt.…”