title: Grapheme-color synesthesia interferes with color perception in a standard Stroop task.
abstract: This study examined the proposed automatic and involuntary nature of synesthetic experiences in grapheme-color synesthetes by comparing behavioral and blood-oxygen level dependent (BOLD) responses in a synesthetic and a standard version of the Stroop task. Clear interference effects in terms of slower reaction times and stronger BOLD responses in the rostral cingulate zone (RCZ) were found in synesthetes performing the synesthetic version of the Stroop task. Surprisingly, less interference was found in synesthetes compared with controls performing the standard Stroop task. This smaller interference effect, expressed as the difference in reaction time between incongruent and neutral stimuli, was explained in terms of experienced interference during the neutral condition of the Stroop task in synesthetes. This was confirmed by stronger BOLD responses in the RCZ for synesthetes specifically in the neutral condition. To the best of our knowledge, this is the first study to show different performance of synesthetes in a standard Stroop task and the presented data can be seen as strong evidence for the automatic and involuntary nature of synesthetic experiences.
authors.affiliation: Department of Psychiatry, Erasmus MC, P.O. Box 2040, 3000CA Rotterdam, The Netherlands; Institute of Psychology, Erasmus University Rotterdam, P.O. Box 1738, 3000DR Rotterdam, The Netherlands. Electronic address: f.vanderveen@fsw.eur.nl.
authors.forename: F M
authors.initials: FM
authors.lastname: van der Veen
authors.affiliation: Department of Psychiatry, Erasmus MC, P.O. Box 2040, 3000CA Rotterdam, The Netherlands. Electronic address: hugoaben@gmail.com.
authors.forename: H P
authors.initials: HP
authors.lastname: Aben
authors.affiliation: Department of Radiology, Erasmus MC, P.O. Box 2040, 3000CA Rotterdam, The Netherlands. Electronic address: c.roder@erasmusmc.nl.
authors.forename: M
authors.initials: M
authors.lastname: Smits
authors.affiliation: Department of Psychiatry, Erasmus MC, P.O. Box 2040, 3000CA Rotterdam, The Netherlands. Electronic address: c.roder@erasmusmc.nl.
authors.forename: C H
authors.initials: CH
authors.lastname: Röder
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000098:blood supply / Q000503:physiopathology*; D002755:Choice Behavior / Q000502:physiology*; D003118:Color Perception / Q000502:physiology*; D005260:Female; D006179:Gyrus Cinguli / Q000503:physiopathology; D006801:Humans; D007600:Judgment / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010468:Perceptual Disorders / Q000503:physiopathology*; D011930:Reaction Time; D011932:Reading; D057190:Stroop Test; D000080311:Synesthesia; D013647:Task Performance and Analysis; D014796:Visual Perception / Q000502:physiology; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: CON; DLPFC; EPI; FFG; GLM; IC; NEU; RCZ; ROI; RT; Stroop; TE; TOG; TR; Test of Genuineness; anterior cingulate cortex; congruent; dorsolateral prefrontal cortex; echo time; echo-planar imaging; fMRI; functional Magnetic Resonance Imaging; fusiform gyrus; general linear model; grapheme-color synesthesia; incongruent; interference; neutral; reaction time; region of interest; repetition time; rostral cingulate zone