Synesthesia is a perceptual experience in one sensory modality following stimulation of another sensory modality. The most commonly encountered example is color-word synesthesia ("colored hearing" or chromesthesia), experiencing a visual color sensation on hearing a particular word. Synesthesia occurs in a small percentage of the normal population. Known synesthetes include the composers Messiaen and Scriabin, the artist Kandinsky, and the author Nabokov. There may be concurrent excellent memory (hypermnesia), sometimes of a photographic nature (eidetic memory). Symptomatic synesthesia is rare but has been described with epileptic seizures of temporal lobe origin and with drug use (LSD).
Neuropsychologically this phenomenon has been conceptualized as a break down of modularity. Functional imaging studies of colorword synesthetes show activation of visual associative areas of cortex (but not primary visual cortex), as well as perisylvian language areas, when listening to words which evoke the experience of color.



Baron-Cohen S, Harrison JE (eds.). Synaesthesia: classic and contem-porary readings. Oxford: Blackwell, 1997
Cytowic RE. The man who tasted shapes. Cambridge: MIT Press, 2003 Paulesu E, Harrison J, Baron-Cohen S, et al. The physiology of colored hearing: a PET activation study of color-word synaesthesia. Brain 1995; 118: 661-676


Cross References

Auditory-visual synesthesia; Phosphene