title: Seeing the sound after visual loss: functional MRI in acquired auditory-visual synesthesia.
abstract: Acquired auditory-visual synesthesia (AVS) is a rare neurological sign, in which specific auditory stimulation triggers visual experience. In this study, we used event-related fMRI to explore the brain regions correlated with acquired monocular sound-induced phosphenes, which occurred 2 months after unilateral visual loss due to an ischemic optic neuropathy. During the fMRI session, 1-s pure tones at various pitches were presented to the patient, who was asked to report occurrence of sound-induced phosphenes by pressing one of the two buttons (yes/no). The brain activation during phosphene-experienced trials was contrasted with non-phosphene trials and compared to results obtained in one healthy control subject who underwent the same fMRI protocol. Our results suggest, for the first time, that acquired AVS occurring after visual impairment is associated with bilateral activation of primary and secondary visual cortex, possibly due to cross-wiring between auditory and visual sensory modalities.
authors.affiliation: Neuroscience and Behavioral Disorders Program, Duke-NUS Medical School, 8 College Road, Singapore, 169857, Singapore.
authors.forename: Zixin
authors.initials: Z
authors.lastname: Yong
authors.affiliation: Neuroscience and Behavioral Disorders Program, Duke-NUS Medical School, 8 College Road, Singapore, 169857, Singapore. pojang.hsieh@duke-nus.edu.sg.
authors.forename: Po-Jang
authors.initials: PJ
authors.lastname: Hsieh
authors.affiliation: Neuroscience and Behavioral Disorders Program, Duke-NUS Medical School, 8 College Road, Singapore, 169857, Singapore. dan.milea@snec.com.sg.|Singapore National Eye Centre, 11 Third Hospital Ave, Singapore, 168751, Singapore. dan.milea@snec.com.sg.|Singapore Eye Research Institute, Singapore, Singapore. dan.milea@snec.com.sg.
authors.forename: Dan
authors.initials: D
authors.lastname: Milea
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D001766:Blindness / Q000209:etiology / Q000503:physiopathology*; D001921:Brain / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D018917:Optic Neuropathy, Ischemic / Q000150:complications; D010100:Oxygen / Q000097:blood; D010468:Perceptual Disorders / Q000209:etiology*; D010719:Phosphenes / Q000502:physiology*; D000080311:Synesthesia; D014796:Visual Perception / Q000502:physiology*
chemical_list: D010100:Oxygen
keywords: Auditory-visual; Functional MRI; Ischemic optic neuropathy; Synesthesia