Do the colour blind have a distinct visual cortex structure? 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?
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 &amp; Rosa, 2014 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.