Martian Colours

We also observed one case in which we believe cross activation enables a colorblind synesthete to see numbers tinged with hues he otherwise cannot perceive; charmingly, he refers to these as “Martian colors.” Although his retinal color receptors cannot process certain wavelengths, we suggest that his brain color area is working just fine and being cross-activated when he sees numbers…

The effect is most obvious and pronounced in the colorblind synesthetes, but occurs in “regular” synesthetes as well. The colors evoked by cross activation in the fusiform gyrus “bypass” earlier stages of color processing in the brain, which may confer an unusual tint to the colors evoked. This is important for understanding the phenomenon of synesthesia, because it suggests that the qualia label–that is, the subjective experience of the color sensation–depends not merely on the final stages of processing but on the total pattern of neural activity, including earlier stages. (http://blogs.discovermagazine.com/cosmicvariance/2007/11/05/martian-colors/#.WAjtrIReCqC)

I have found that many synaesthetes often see colours that they cannot explain, reproduce, or relate to any colour that they have seen in the real world. This is another example of 'martian colours' and opens debate about whether synaesthetes can see colours past the visible spectrum that can be seen by humans.

Martian colours are thought to be so unusual because information has not taken the usual route (eye -> V1 -> V4) but instead went to a grapheme area first and then entered V4 (eye -> V1 -> grapheme area -> V4). Similarly, musically induced Martian colours may look so weird because auditory information recoded in V4 simply isn’t of the same quality as visual information which comes from V1. (https://brainsidea.wordpress.com/2012/07/02/how-are-invisible-colours-possible/)