Ramachandran discusses phantom limbs and synesthesia (esp. color-blind synesthete) as a function of neuron innervation. Specifically, he focuses on cross-linking between nearby cortical regions, which he believes to be genetically caused (e.g. synesthesia appears to be found frequently in family lineages). He also discusses the link between mirror neurons and autism, and how language invention is due to an inherent cross-linking between portions of the visual and auditory regions (e.g. Buba/Kiki effect).