I don't know, but a clue can be flound in the book "The Other Brain"by R. Douglas Fields. The author puts an emphasis on the computational roles of oligodendrocytes, arguing that "white matter"is related to human intelligence

Dear Alfredo,

Thank you very much for this great reference! I didn't know Douglas Field's work. The first look into the internet looks very promising!

Ursula

Here is an article that might interest you.

http://onlinelibrary.wiley.com/doi/10.1002/cne.20886/pdf