<p>I can't speak to color blindness, but a little about the neural correlates of color processing in general.  There has been some thought that macaque V4 (non-primary or extrastriate visual cortex) and the <strong>human V4 topologue may be responsible for color processing</strong>--some studies have found wavelength-specific cells in V4, but other studies have found no greater concentration of these in V4 than in V1.  There has been significant disagreement about this depending on methodology and task details; it seems that overall, <strong>imaging studies tend to find selective activity for color in V4 but lesion studies with damage to V4 often do not find damaged color discrimination</strong>.  It also seems that the macaque V4 has both a dorsal and a ventral component, where the human dorsal component does not seem to respond to color, complicating the topologue comparison.</p>

<p>Imaging studies<br>
Brouwer and Heeger (2013). Clustering of the Neural Representation of Color. J. Neurosci.,  33(39):15454 –15465. DOI:10.1523/JNEUROSCI.2472-13.2013<br>
Brouwer and Heeger (2009). Decoding and Reconstructing Color. J. Neurosci.,  29(44):13992–14003. DOI:10.1523/JNEUROSCI.3577-09.2009<br>
Goddard et al. (2011). Color responsiveness argues against a dorsal
component of human V4. Journal of Vision, 11(4):3, 1–21. doi: 10.1167/11.4.3<br></p>

<p>Lesion studies<br>
Schiller PH (1993) The effects of V4 and middle temporal (MT) area lesions on visual performance in the rhesus monkey. Vis Neurosci 10:717–746.<br>
Walsh V, Carden D, Butler SR, Kulikowski JJ (1993) The effects of V4 lesions on the visual abilities of macaques: hue discrimination and colour constancy. Behav Brain Res 53:51–62.<br>
Heywood CA, Gadotti A, Cowey A (1992) Cortical area V4 and its role in the perception of color. J Neurosci 12:4056–4065.<br>
Heywood CA, Gaffan D, Cowey A (1995) Cerebral achromatopsia in monkeys. Eur J Neurosci 7:1064–1073.</p>

CC BY-SA 3.0
2014-12-16T12:09:48.337Z
Indeed V4 lesions have a more pronounced effect on object recognition than on color vision. Therefore, V4 is probably not of much interest in terms of structural differences in color blind people.
AliceD
CC BY-SA 3.0
2014-12-16T12:40:18.503Z
Any idea why imaging studies have found color responsiveness in V4 so often?
Krysta
CC BY-SA 3.0
2014-12-16T12:41:24.003Z
Nope, sorry. V4 is definitely involved in color vision, don't get me wrong, but it also serves other, perhaps more prominent purposes as far as I know.
AliceD
CC BY-SA 3.0
2015-05-15T07:33:00.983Z
bevil conway has interesting theories on v4 function in color perception http://academics.wellesley.edu/Neuroscience/Faculty_page/Conway/science/my_papers/ConwayVisNeurosci2013.pdf.  In particular, he says that color perception is primarily for object recognition (stop signs are red, yield signs are yellow) and for emotional valence.
honi
CC BY-SA 3.0
2014-12-15T13:14:43.323Z
2014-12-15T13:14:43.323Z
Krysta
<p>Interesting question! I performed a fairly extensive search in Google Scholar and Scopus using various keyword searches, including, but not limited to "<em>color blindness and plasticity</em>", "<em>color blind and brain</em>", "<em>dichromates brain</em>", and "<em>monochromates brain</em>". Strikingly, I found nothing. The reason is aptly explained by <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4126041/" rel="nofollow">Solomon &amp; Rosa, 2014</a> and I quote from their interesting review:</p>

<blockquote>
  <p>As yet <strong>no anatomical correlates of color blindness</strong> have been found in the <strong>retina</strong> (Chan and Grünert,1998; Chan et al.,2001; Jusuf et al.,2006a,b), <strong>thalamus</strong>, or <strong>primary visual cortex</strong> (Goodchild and Martin,1998; Solomon, 2002). </p>
</blockquote>

<p>If desirable, you should be able to re-trace the relevant citations from the cited review, as it is open source.</p>

CC BY-SA 3.0
2014-12-15T03:02:01.377Z
I am **VERY** curious to more answers! Nice question!
AliceD
CC BY-SA 3.0
2014-12-15T03:01:00.843Z
2014-12-15T10:40:11.793Z
2014-12-15T10:40:11.793Z
AliceD
<p>Studying the structure of the visual cortex, it seems there are many neural structures specifically dedicated to detecting and interpreting colour. For example, parvocellular cells are particularly sensitive to colour. Consequently, in a colour blind person, are parvocellular cells or other neural structures less prominent? What are the differences in brain structure between a colour blind person and a normal seeing person?</p>

CC BY-SA 3.0
2014-12-16T17:35:48.017Z
One important note, which I believe is important here, is to consider that (a) true color-blindness is extremely rare - much more common is a *deficiency,* where the individual can perceive the colors but at a reduced intensity; also (b) there are several forms of color-deficiencies out there, as well as levels of severity. You would almost certainly need to conduct your own research into this question.
theMayer
<neuroscience><cognitive-neuroscience><vision><plasticity>
Do the colour blind have a distinct visual cortex structure?
Seanny123
# Do the colour blind have a distinct visual cortex structure?

(Asked by: username_0 on 2014-12-14)

Studying the structure of the visual cortex, it seems there are many neural structures specifically dedicated to detecting and interpreting colour. For example, parvocellular cells are particularly sensitive to colour. Consequently, in a colour blind person, are parvocellular cells or other neural structures less prominent? What are the differences in brain structure between a colour blind person and a normal seeing person?

**Tags:** neuroscience, cognitive-neuroscience, vision, plasticity

> **Comments:**
> **username_1**: One important note, which I believe is important here, is to consider that (a) true color-blindness is extremely rare - much more common is a *deficiency,* where the individual can perceive the colors but at a reduced intensity; also (b) there are several forms of color-deficiencies out there, as well as levels of severity. You would almost certainly need to conduct your own research into this question.  

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## 2 answers

### Answer by username_3 on 2014-12-15. Score: 6 | Accepted answer

Interesting question! I performed a fairly extensive search in Google Scholar and Scopus using various keyword searches, including, but not limited to "*color blindness and plasticity*", "*color blind and brain*", "*dichromates brain*", and "*monochromates brain*". Strikingly, I found nothing. The reason is aptly explained by [Solomon & Rosa, 2014](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4126041/) and I quote from their interesting review:

> As yet **no anatomical correlates of color blindness** have been found in the **retina** (Chan and Grünert,1998; Chan et al.,2001; Jusuf et al.,2006a,b), **thalamus**, or **primary visual cortex** (Goodchild and Martin,1998; Solomon, 2002).

If desirable, you should be able to re-trace the relevant citations from the cited review, as it is open source.

> **Comments:**
> **username_3**: I am **VERY** curious to more answers! Nice question!  

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### Answer by username_2 on 2014-12-15. Score: 1

I can't speak to color blindness, but a little about the neural correlates of color processing in general. There has been some thought that macaque V4 (non-primary or extrastriate visual cortex) and the **human V4 topologue may be responsible for color processing**--some studies have found wavelength-specific cells in V4, but other studies have found no greater concentration of these in V4 than in V1. There has been significant disagreement about this depending on methodology and task details; it seems that overall, **imaging studies tend to find selective activity for color in V4 but lesion studies with damage to V4 often do not find damaged color discrimination**. It also seems that the macaque V4 has both a dorsal and a ventral component, where the human dorsal component does not seem to respond to color, complicating the topologue comparison.

Imaging studies  
Brouwer and Heeger (2013). Clustering of the Neural Representation of Color. J. Neurosci., 33(39):15454 –15465. DOI:10.1523/JNEUROSCI.2472-13.2013  
Brouwer and Heeger (2009). Decoding and Reconstructing Color. J. Neurosci., 29(44):13992–14003. DOI:10.1523/JNEUROSCI.3577-09.2009  
Goddard et al. (2011). Color responsiveness argues against a dorsal
component of human V4. Journal of Vision, 11(4):3, 1–21. doi: 10.1167/11.4.3

Lesion studies  
Schiller PH (1993) The effects of V4 and middle temporal (MT) area lesions on visual performance in the rhesus monkey. Vis Neurosci 10:717–746.  
Walsh V, Carden D, Butler SR, Kulikowski JJ (1993) The effects of V4 lesions on the visual abilities of macaques: hue discrimination and colour constancy. Behav Brain Res 53:51–62.  
Heywood CA, Gadotti A, Cowey A (1992) Cortical area V4 and its role in the perception of color. J Neurosci 12:4056–4065.  
Heywood CA, Gaffan D, Cowey A (1995) Cerebral achromatopsia in monkeys. Eur J Neurosci 7:1064–1073.

> **Comments:**
> **username_3**: Indeed V4 lesions have a more pronounced effect on object recognition than on color vision. Therefore, V4 is probably not of much interest in terms of structural differences in color blind people.  
> **username_2**: Any idea why imaging studies have found color responsiveness in V4 so often?  
> **username_3**: Nope, sorry. V4 is definitely involved in color vision, don't get me wrong, but it also serves other, perhaps more prominent purposes as far as I know.  
> **username_4**: bevil conway has interesting theories on v4 function in color perception http://academics.wellesley.edu/Neuroscience/Faculty_page/Conway/science/my_papers/ConwayVisNeurosci2013.pdf.  In particular, he says that color perception is primarily for object recognition (stop signs are red, yield signs are yellow) and for emotional valence.  

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