title: Recruitment of occipital cortex during sensory substitution training linked to subjective experience of seeing in people with blindness.
abstract: Over three months of intensive training with a tactile stimulation device, 18 blind and 10 blindfolded seeing subjects improved in their ability to identify geometric figures by touch. Seven blind subjects spontaneously reported 'visual qualia', the subjective sensation of seeing flashes of light congruent with tactile stimuli. In the latter subjects tactile stimulation evoked activation of occipital cortex on electroencephalography (EEG). None of the blind subjects who failed to experience visual qualia, despite identical tactile stimulation training, showed EEG recruitment of occipital cortex. None of the blindfolded seeing humans reported visual-like sensations during tactile stimulation. These findings support the notion that the conscious experience of seeing is linked to the activation of occipital brain regions in people with blindness. Moreover, the findings indicate that provision of visual information can be achieved through non-visual sensory modalities which may help to minimize the disability of blind individuals, affording them some degree of object recognition and navigation aid.
authors.affiliation: Department of Psychiatry, Facultad de Medicina, Universidad Complutense, Madrid, Spain. tortiz@med.ucm.es
authors.forename: Tomás
authors.initials: T
authors.lastname: Ortiz
authors.forename: Joaquín
authors.initials: J
authors.lastname: Poch
authors.forename: Juan M
authors.initials: JM
authors.lastname: Santos
authors.forename: Carmen
authors.initials: C
authors.lastname: Requena
authors.forename: Ana M
authors.initials: AM
authors.lastname: Martínez
authors.forename: Laura
authors.initials: L
authors.lastname: Ortiz-Terán
authors.forename: Agustín
authors.initials: A
authors.lastname: Turrero
authors.forename: Juan
authors.initials: J
authors.lastname: Barcia
authors.forename: Ramón
authors.initials: R
authors.lastname: Nogales
authors.forename: Agustín
authors.initials: A
authors.lastname: Calvo
authors.forename: José M
authors.initials: JM
authors.lastname: Martínez
authors.forename: José L
authors.initials: JL
authors.lastname: Córdoba
authors.forename: Alvaro
authors.initials: A
authors.lastname: Pascual-Leone
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001519:Behavior / Q000502:physiology; D001766:Blindness / Q000503:physiopathology*; D004566:Electrodes; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009778:Occipital Lobe / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology; D012044:Regression Analysis; D012677:Sensation / Q000502:physiology*; D014785:Vision, Ocular / Q000502:physiology*; D055815:Young Adult