The distribution of response spectra in the lateral geniculate nucleus compared with reflectance spectra of Munsell color chips.

This paper compares the spectral response curves of cells in the lateral geniculate nucleus (LGN) with the reflectance spectra of a large sample of Munsell color chips. By examining the color chips with methods used by neural response researchers and the LGN cells with methods used by psychophysical color researchers, we obtain insights that may be useful for advancing knowledge in both fields. For LGN cells, the prevailing view is that they tend to be clustered into distinct types or along discernible lines or planes when data obtained from selected light stimuli are represented in a three-dimensional space derived from cone contributions. In contrast, the Munsell color chips are viewed as rather evenly distributed in a three-dimensional perceptual space based on the psychophysical judgment of surface colors. We demonstrate that, when the Munsell chips are viewed in the space typically applied to LGN cells, the distribution appears similar to that of the cells and vice versa. We show why this result occurs and suggest that it has implications for studies in both fields.