hear colors, taste shapes, or experience other curious sensory modality crossings, allegedly
related to abnormal functioning of the hippocampus, one of the limbic structures in the brain.
It has also been suggested that synesthesia constitutes a form of "supernormal integration"
involving the posterior parietal cortex.
The Russian composer Alexander Scriabin and Russian-born painter Wassily Kandinsky both pioneered
artistic links between sight and sound, while they may have been synesthetes themselves. Russian
mnemonist Solomon Shereshevskii, studied for decades by neuropsychologist Alexander Luria, appears
to have used his natural synesthesia to memorize amazing amounts of data.