Email updates

Keep up to date with the latest news and content from BMC Neuroscience and BioMed Central.

This article is part of the supplement: Seventeenth Annual Computational Neuroscience Meeting: CNS*2008

Open Access Poster presentation

Modeling the transformation from LGN to V1 color-opponent receptive fields

Sarah M Maynard1, Bevil R Conway1 and Mark S Goldman2*

Author Affiliations

1 Neuroscience Program, Wellesley College, Wellesley, MA 02481, USA

2 Center for Neuroscience; Department of Neuroscience, Physiology, & Behavior; Department of Ophthalmology & Visual Sciences, University of California Davis, Davis, CA 95618, USA

For all author emails, please log on.

BMC Neuroscience 2008, 9(Suppl 1):P126  doi:10.1186/1471-2202-9-S1-P126

The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1471-2202/9/S1/P126


Published:11 July 2008

© 2008 Maynard et al; licensee BioMed Central Ltd.

Poster presentation

Color arises from a network that begins with the cones and progresses through stages of processing involving cells in the lateral geniculate nucleus (LGN), primary visual cortex (V1), and prestriate areas. Color is a three-dimensional percept defined by an achromatic luminance axis along with two chromatic axes, red vs. green and blue vs. yellow. Representation of color along the red-green axis is derived from an opponent process whereby responses from medium-wavelength-selective (M) cones are subtracted from those of long-wavelength-selective (L) cones [1], leading to Type I L/M cells in the LGN [2]: L-ON cells are excited by L-cone activity in the receptive field center and suppressed by M-cone activity in the surround. Type I neurons are by themselves incapable of encoding spatial color contrast, a hallmark of color vision. Color contrast is instead thought to arise through double-opponent receptive fields defined by spatial opponency and color opponency in both center and surround [3,4]. Recent physiological studies have identified double-opponent receptive fields in V1 and characterized them with high-resolution spatial maps [5], which prompts this study modeling how double-opponent receptive fields are established from Type I inputs.

Our model considers known variations of red-green Type I cells as building blocks of physiologically characterized double-opponent cells. A two-dimensional array of Type I cells was defined by a difference of Gaussians, with sizes of center and surround based on experimentally observed values [6]. Spatiotemporal responses of V1 neurons were taken from receptive field mapping experiments using sparse noise stimuli [5]. To model the transformation between LGN and V1 cells, we constructed a feed forward network in which the receptive field of each V1 neuron was fit to a weighted sum of LGN neuron responses, with optimal weights calculated using a linear regression procedure.

We find that the spatial organization of V1 neuron receptive fields can be well accounted for by a threshold linear summation of responses from LGN cells. Present work is taking into account the temporal properties of LGN cells to understand the extent to which temporal receptive fields of V1 cells are inherited from their LGN inputs. By testing the ability of a feed forward model to explain the spatiotemporal response properties of V1 neurons, our model complements previous work in non-color pathways suggesting that many aspects of V1 responses can be accounted for by a feed forward transformation of LGN inputs, while providing a starting point for construction of cortical models of color processing.

Acknowledgements

This work was funded by Wellesley College and UC Davis.

References

  1. DeValois RL, Smith CJ, Kitai ST, Karoly AJ: Response of single cells in monkey lateral geniculate nucleus to monochromatic light.

    Science 1958, 127:238-239. PubMed Abstract | Publisher Full Text OpenURL

  2. Wiesel TN, Hubel DH: Spatial and chromatic interactions in the lateral geniculate body of the rhesus monkey.

    J Neurophysiol 1966, 29:1115-1156. PubMed Abstract | Publisher Full Text OpenURL

  3. Land EH: Recent advances in retinex theory and some implications for cortical computation: color vision and the natural image.

    Proc Natl Acad Sci USA 1983, 80(16):5163-5169. PubMed Abstract | Publisher Full Text | PubMed Central Full Text OpenURL

  4. Dufort PA, Lumsden CJ: Color categorization and color constancy in a neural network model of V4.

    Biological Cybernetics 1991, 65(4):293-303. PubMed Abstract | Publisher Full Text OpenURL

  5. Conway BR, Livingstone MS: Spatial and temporal properties of cone signals in alert macaque primary visual cortex.

    J Neurosci 2006, 26(42):10826-10846. PubMed Abstract | Publisher Full Text OpenURL

  6. Reid RC, Shapley RM: Space and time maps of cone photoreceptor signals in macaque lateral geniculate nucleus.

    J Neurosci 2002, 22(14):6158-6175. PubMed Abstract | Publisher Full Text OpenURL