Editing Opponent process (section)

==History==
[[Johann Wolfgang von Goethe]] first studied the physiological effect of opposed colors in his ''[[Theory of Colours]]'' in 1810.<ref>{{cite web | url = http://webexhibits.org/colorart/ch.html | title = Goethe's Color Theory | work = Vision science and the emergence of modern art | url-status = live | archive-url = https://web.archive.org/web/20080916130507/http://www.webexhibits.org/colorart/ch.html | archive-date = 2008-09-16 }}</ref> Goethe arranged his color wheel symmetrically "for the colours diametrically opposed to each other in this diagram are those which reciprocally evoke each other in the eye. Thus, yellow demands purple; orange, blue; red, green; and vice versa: Thus again all intermediate gradations reciprocally evoke each other."<ref>
{{cite book | vauthors = Goethe J | title = Theory of Colours, paragraph #50 | year = 1810 }}</ref><ref>
{{cite journal | journal = The Art-Union | volume = 2 | issue = 18 | title = Goethe on Colours | url = https://books.google.com/books?id=H7TlAAAAMAAJ&q=%22reciprocally+evoke+each+other+in+the+eye%22&pg=RA1-PA121 | date = July 15, 1840 | page = 107 | url-status = live | archive-url = https://web.archive.org/web/20171221235903/https://books.google.com/books?id=H7TlAAAAMAAJ&pg=RA1-PA121&dq=%22reciprocally+evoke+each+other+in+the+eye%22#v=onepage&q=%22reciprocally%20evoke%20each%20other%20in%20the%20eye%22&f=false | archive-date = December 21, 2017 }}</ref>

[[Ewald Hering]] proposed opponent color theory in 1892.<ref name=hering1964>Hering E, 1964. ''Outlines of a Theory of the Light Sense''. Cambridge, Mass: Harvard University Press.</ref> He thought that the colors red, yellow, green, and blue are special in that any other color can be described as a mix of them, and that they exist in opposite pairs.  That is, either red or green is perceived and never greenish-red: Even though yellow is a mixture of red and green in the RGB color theory, humans do not perceive it as such.

Hering's new theory ran counter to the prevailing [[Young–Helmholtz theory]] (''trichromatic theory''), first proposed by [[Thomas Young (scientist)|Thomas Young]] in 1802 and developed by [[Hermann von Helmholtz]] in 1850. The two theories seemed irreconcilable until 1925 when [[Erwin Schrödinger]] was able to reconcile the two theories and show that they can be complementary.<ref name=SCRHODINGER>{{cite journal |last1=Niall |first1=Keith K. |title=On the trichromatic and opponent-process theories: An article by E. Schrödinger |journal=Spatial Vision |date=1988 |volume=3 |issue=2 |pages=79–95 |doi=10.1163/156856888x00050|pmid=3153667 }}</ref>

===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''.

===In other fields===
{{main|Opponent-process theory}}
Others have applied the idea of opposing stimulations beyond visual systems, described in the article on ''[[opponent-process theory]]''. In 1967, [[Rod Grigg]] extended the concept to reflect a wide range of opponent processes in biological systems.<ref>{{cite book | vauthors = Grigg ER | date = 1967 | title = Biologic Relativity | publisher = Chicago: Amaranth Books }}</ref> In 1970, [[Richard Solomon (psychologist)|Solomon]] and Corbit expanded Hurvich and Jameson's general neurological opponent process model to explain emotion, drug addiction, and work motivation.<ref>{{cite journal | vauthors = Solomon RL, Corbit JD | title = An opponent-process theory of motivation. II. Cigarette addiction | journal = Journal of Abnormal Psychology | volume = 81 | issue = 2 | pages = 158–71 | date = April 1973 | pmid = 4697797 | doi = 10.1037/h0034534 }}</ref><ref>{{cite journal | vauthors = Solomon RL, Corbit JD | title = An opponent-process theory of motivation. I. Temporal dynamics of affect | journal = Psychological Review | volume = 81 | issue = 2 | pages = 119–45 | date = March 1974 | pmid = 4817611 | doi = 10.1037/h0036128 | citeseerx = 10.1.1.468.2548 }}</ref>