Editing Opponent process (section)

===Validation===
In 1957, [[Leo Hurvich]] and [[Dorothea Jameson]] provided [[Psychophysics|psychophysical]] validation for Hering's theory. Their method was called ''hue cancellation''. Hue cancellation experiments start with a color (e.g. yellow) and attempt to determine how much of the opponent color (e.g. blue) of one of the starting color's components must be added to reach the neutral point.<ref>{{cite journal | vauthors = Hurvich LM, Jameson D | title = An opponent-process theory of color vision | journal = Psychological Review | volume = 64, Part 1 | issue = 6 | pages = 384–404 | date = November 1957 | pmid = 13505974 | doi = 10.1037/h0041403 | s2cid = 27613265 }}</ref><ref>{{cite book | vauthors = Wolfe JM, Kluender KR, Levi DM | date = 2009 | title = Sensation & Perception | publisher = Sinauer Associates, Inc. | edition = third | isbn = 978-1-60535-875-8 |location=New York }}</ref>

In 1959, [[Gunnar Svaetichin]] and MacNichol<ref>{{cite journal | vauthors = Svaetichin G, Macnichol EF | title = Retinal mechanisms for chromatic and achromatic vision | journal = Annals of the New York Academy of Sciences | volume = 74 | issue = 2 | pages = 385–404 | date = November 1959 | pmid = 13627867 | doi = 10.1111/j.1749-6632.1958.tb39560.x | bibcode = 1959NYASA..74..385S | s2cid = 27130943 }}</ref> recorded from the retinae of fish and reported of three distinct types of cells:
* One cell responded with [[hyperpolarization (biology)|hyperpolarization]] to all light stimuli regardless of wavelength and was termed a ''luminosity cell''.
* Another cell responded with hyperpolarization at short wavelengths and with depolarization at mid-to-long wavelengths. This was termed a ''chromaticity cell''.
* A third cell{{dash}}also a chromaticity cell{{dash}}responded with hyperpolarization at fairly short wavelengths, peaking about 490&nbsp;nm, and with depolarization at wavelengths longer than about 610&nbsp;nm.

Svaetichin and MacNichol called the chromaticity cells ''yellow–blue'' and ''red–green opponent color cells''.

Similar chromatically or spectrally opposed cells, often incorporating spatial opponency (e.g. red "on" center and green "off" surround), were found in the vertebrate retina and [[lateral geniculate nucleus]] (LGN) through the 1950s and 1960s by De Valois et al.,<ref>{{cite journal | vauthors = De Valois RL, Smith CJ, Kitai ST, Karoly AJ | title = Response of single cells in monkey lateral geniculate nucleus to monochromatic light | journal = Science | volume = 127 | issue = 3292 | pages = 238–9 | date = January 1958 | pmid = 13495504 | doi = 10.1126/science.127.3292.238 | bibcode = 1958Sci...127..238D }}</ref> Wiesel and Hubel,<ref>{{cite journal | vauthors = Wiesel TN, Hubel DH | title = Spatial and chromatic interactions in the lateral geniculate body of the rhesus monkey | journal = Journal of Neurophysiology | volume = 29 | issue = 6 | pages = 1115–56 | date = November 1966 | pmid = 4961644 | doi = 10.1152/jn.1966.29.6.1115 }}</ref> and others.<ref>{{cite journal | vauthors = Wagner HG, Macnichol EF, Wolbarsht ML | title = Opponent Color Responses in Retinal Ganglion Cells | journal = Science | volume = 131 | issue = 3409 | pages = 1314 | date = April 1960 | pmid = 17784397 | doi = 10.1126/science.131.3409.1314 | s2cid = 46122073 | bibcode = 1960Sci...131.1314W }}</ref><ref>{{cite journal | vauthors = Naka KI, Rushton WA | title = S-potentials from colour units in the retina of fish (Cyprinidae) | journal = The Journal of Physiology | volume = 185 | issue = 3 | pages = 536–55 | date = August 1966 | pmid = 5918058 | pmc = 1395833 | doi = 10.1113/jphysiol.1966.sp008001 }}</ref><ref>{{cite journal | vauthors = Daw NW | title = Goldfish retina: organization for simultaneous color contrast | journal = Science | volume = 158 | issue = 3803 | pages = 942–4 | date = November 1967 | pmid = 6054169 | doi = 10.1126/science.158.3803.942 | s2cid = 1108881 | bibcode = 1967Sci...158..942D }}</ref><ref>{{cite journal | vauthors = Byzov AL, Trifonov JA | title = The response to electric stimulation of horizontal cells in the carp retina | journal = Vision Research | volume = 8 | issue = 7 | pages = 817–22 | date = July 1968 | pmid = 5664016 | doi = 10.1016/0042-6989(68)90132-6 }}</ref>

Following [[Gunnar Svaetichin]]'s lead, the cells were widely called ''opponent color cells'': ''red–green'' and ''yellow–blue''. Over the next three decades, spectrally opposed cells continued to be reported in primate retinae and LGN.<ref>{{cite journal | vauthors = Gouras P, Zrenner E | title = Color coding in primate retina | journal = Vision Research | volume = 21 | issue = 11 | pages = 1591–8 | date = January 1981 | pmid = 7336591 | doi = 10.1016/0042-6989(81)90039-0 | s2cid = 46225236 }}</ref><ref>{{cite journal | vauthors = Derrington AM, Krauskopf J, Lennie P | title = Chromatic mechanisms in lateral geniculate nucleus of macaque | journal = The Journal of Physiology | volume = 357 | issue = 1 | pages = 241–65 | date = December 1984 | pmid = 6512691 | pmc = 1193257 | doi = 10.1113/jphysiol.1984.sp015499 }}</ref><ref>{{cite journal | vauthors = Reid RC, Shapley RM | title = Spatial structure of cone inputs to receptive fields in primate lateral geniculate nucleus | journal = Nature | volume = 356 | issue = 6371 | pages = 716–8 | date = April 1992 | pmid = 1570016 | doi = 10.1038/356716a0 | s2cid = 22357719 | bibcode = 1992Natur.356..716R }}</ref><ref>{{cite journal | vauthors = Lankheet MJ, Lennie P, Krauskopf J | title = Distinctive characteristics of subclasses of red–green P-cells in LGN of macaque | journal = Visual Neuroscience | volume = 15 | issue = 1 | pages = 37–46 | date = January 1998 | pmid = 9456503 | doi = 10.1017/s0952523898151027 | citeseerx = 10.1.1.553.5684 | s2cid = 1558413 }}</ref> A variety of terms are used in the literature to describe these cells, including ''chromatically opposed'' or ''chromatically opponent'', ''spectrally opposed'' or ''spectrally opponent'', ''opponent colour'', ''colour opponent'', ''opponent response'', and simply, ''opponent''.