title: Priming letters by colors: evidence for the bidirectionality of grapheme-color synesthesia.
abstract: In synesthesia, stimulation of one sensory modality leads to a percept in another nonstimulated modality, for example, graphemes trigger an additional color percept in grapheme-color synesthesia, which encompasses the variants letter-color and digit-color synesthesia. Until recently, it was assumed that synesthesia occurs strictly unidirectional: Although the perception of a letter induces a color percept in letter-color synesthetes, they typically do not report that colors trigger the percept of a letter. Recent data on number processing in synesthesia suggest, however, that colors can implicitly elicit numerical representations in digit-color synesthetes, thereby questioning unidirectional models of synesthesia. Using a word fragment completion paradigm in 10 letter-color synesthetes, we show here for the first time that colors can implicitly influence lexical search. Our data provide strong support for a bidirectional nature of grapheme-color synesthesia and, in general, may allude to the mechanisms of cross-modality interactions in the human brain.
authors.affiliation: Research Center Jülich, Germany. P.H.Weiss@fz-juelich.de
authors.forename: Peter H
authors.initials: PH
authors.lastname: Weiss
authors.forename: Andreas
authors.initials: A
authors.lastname: Kalckert
authors.forename: Gereon R
authors.initials: GR
authors.lastname: Fink
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D003118:Color Perception / Q000502:physiology*; D005260:Female; D006801:Humans; D009483:Neuropsychological Tests; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010468:Perceptual Disorders / Q000503:physiopathology*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D055815:Young Adult