title: Grapheme-color and tone-color synesthesia is associated with structural brain changes in visual regions implicated in color, form, and motion.
abstract: Synesthesia is a rare condition in which stimulation in one modality leads to a secondary experience in another sensory modality. Varying accounts attribute the condition to either neuroanatomical differences between the synesthetes and non-synesthetes or functional differences in how sensory brain regions interact. This study employed voxel-based morphometry to examine whether synesthetes who experience both grapheme-color and tone-color synesthesia as their evoked sensation show neuroanatomical differences in gray matter volume compared to non-synesthetes. We observed that synesthetes showed an increase in gray matter volume in left posterior fusiform gyrus (FG), but a concomitant decrease in anterior regions of left FG and left MT/V5. These findings imply that synesthesia for color is linked to neuroanatomical changes between adjacent regions of the visual system.
authors.affiliation: a UCL Institute of Cognitive Neuroscience , University College London , London , UK.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Banissy
authors.forename: Lauren
authors.initials: L
authors.lastname: Stewart
authors.forename: Neil G
authors.initials: NG
authors.lastname: Muggleton
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Griffiths
authors.forename: Vincent Y
authors.initials: VY
authors.lastname: Walsh
authors.forename: Jamie
authors.initials: J
authors.lastname: Ward
authors.forename: Ryota
authors.initials: R
authors.lastname: Kanai