![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
door_of_timeIt's an "unlikely concidence," says Ramachandran, that "the most common type of synaesthesia is number/color synaesthesia and the number area and color areas are right next to each other in the same part of the brain." Experiments showed that when numbers were shown to people with this form of synaesthesia, V4, the colour area, was activated, supporting the idea that there were connections between the two areas. The researchers also met a colour-blind synaesthete: "Because of a deficiency in his cone pigments (in the retina) he couldn't see he full range of colors in the world. Yet when looking at numbers he could see colors that he could never experience otherwise. He referred to them charmingly as 'Martian colours'." His eyes couldn't see those colours, but his brain could.
Another test showed that it wasn't the concept of the numbers which triggered the synaethesia, but the shape of the numbers: the subjects saw no colours when shown Roman numerals (V and VI) instead of Arabic numerals (5 and 6). (I see the colours associated with the letters!)
Colour processing is done in the brain in a series of steps, moving through different areas. Ramanchandran suggests that different kinds of synaesthesia might involve cross-wiring at different steps: for example, a synaesthete who associated colours with days of the week might have a cross-connection in the next step up from V4, the TPO junction, which handles the concept of sequences - a kind of "higher synaesthesia" which is "driven by numerical concept rather than visual appearance."
Ramanchandran suggests that the cross-wiring is the result of a faulty gene which hasn't done its job, in the forming brain, of pruning away excess connections. Faulty genes are normally weeded out by natural selection, so perhaps this one is actually doing something useful. Synaesthesia is much more common in "artists, poets, and novelists". Different kinds of synaesthesia result when the gene is expressed in different parts of the brain, but what it it's expressed throughout the brain? That would make "that person more prone to metaphor, the ability to link seemingly unrelated things." If "high level" concepts are processed in specific parts of the brain, like sequences are in the TPO junction, then "artistic people, with their excess connections, can make these associations much more fluidly and effortlessly". These are fascinating speculations. Ramachandran goes on to suggest that language may have arisen from these sorts of metaphorical connections.
Another test showed that it wasn't the concept of the numbers which triggered the synaethesia, but the shape of the numbers: the subjects saw no colours when shown Roman numerals (V and VI) instead of Arabic numerals (5 and 6). (I see the colours associated with the letters!)
Colour processing is done in the brain in a series of steps, moving through different areas. Ramanchandran suggests that different kinds of synaesthesia might involve cross-wiring at different steps: for example, a synaesthete who associated colours with days of the week might have a cross-connection in the next step up from V4, the TPO junction, which handles the concept of sequences - a kind of "higher synaesthesia" which is "driven by numerical concept rather than visual appearance."
Ramanchandran suggests that the cross-wiring is the result of a faulty gene which hasn't done its job, in the forming brain, of pruning away excess connections. Faulty genes are normally weeded out by natural selection, so perhaps this one is actually doing something useful. Synaesthesia is much more common in "artists, poets, and novelists". Different kinds of synaesthesia result when the gene is expressed in different parts of the brain, but what it it's expressed throughout the brain? That would make "that person more prone to metaphor, the ability to link seemingly unrelated things." If "high level" concepts are processed in specific parts of the brain, like sequences are in the TPO junction, then "artistic people, with their excess connections, can make these associations much more fluidly and effortlessly". These are fascinating speculations. Ramachandran goes on to suggest that language may have arisen from these sorts of metaphorical connections.
![[identity profile]](https://www.dreamwidth.org/img/silk/identity/openid.png){kind=small}
no subject
Date: 2009-05-19 02:22 pm (UTC)no subject
Date: 2009-05-20 09:07 am (UTC)Oh, that's fascinating!