title: TMS of the occipital cortex induces tactile sensations in the fingers of blind Braille readers.
abstract: Various non-visual inputs produce cross-modal responses in the visual cortex of early blind subjects. In order to determine the qualitative experience associated with these occipital activations, we systematically stimulated the entire occipital cortex using single pulse transcranial magnetic stimulation (TMS) in early blind subjects and in blindfolded seeing controls. Whereas blindfolded seeing controls reported only phosphenes following occipital cortex stimulation, some of the blind subjects reported tactile sensations in the fingers that were somatotopically organized onto the visual cortex. The number of cortical sites inducing tactile sensations appeared to be related to the number of hours of Braille reading per day, Braille reading speed and dexterity. These data, taken in conjunction with previous anatomical, behavioural and functional imaging results, suggest the presence of a polysynaptic cortical pathway between the somatosensory cortex and the visual cortex in early blind subjects. These results also add new evidence that the activity of the occipital lobe in the blind takes its qualitative expression from the character of its new input source, therefore supporting the cortical deference hypothesis.
authors: Chaire Harland Sanders en sciences de la vision, Ecole d'optométrie, Université de Montréal, Montréal, Canada. maurice.ptito@umontreal.ca
authors: M
authors: M
authors: Ptito
authors: A
authors: A
authors: Fumal
authors: A Martens
authors: AM
authors: de Noordhout
authors: J
authors: J
authors: Schoenen
authors: A
authors: A
authors: Gjedde
authors: R
authors: R
authors: Kupers
mesh_terms: D000328:Adult; D001766:Blindness / Q000503:physiopathology*; D001931:Brain Mapping; D005260:Female; D005385:Fingers / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007802:Language; D007858:Learning / Q000502:physiology; D008297:Male; D009434:Neural Pathways / Q000033:anatomy & histology / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D011932:Reading; D012682:Sensory Aids; D012683:Sensory Deprivation / Q000502:physiology; D013003:Somatosensory Cortex / Q000033:anatomy & histology / Q000502:physiology; D014110:Touch / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation; D014705:Verbal Behavior / Q000502:physiology; D014793:Visual Cortex / Q000033:anatomy & histology / Q000502:physiology*
references: Proc Natl Acad Sci U S A. 2004 Feb 17;101(7):2167-72
references: 14766982
references: Cereb Cortex. 2006 Nov;16(11):1653-61
references: 16400157
references: Curr Biol. 2005 Jul 12;15(13):R488-90
references: 16005276
references: Nature. 1996 Apr 11;380(6574):526-8
references: 8606771
references: PLoS Biol. 2005 Nov;3(11):e362
references: 16218766
references: Neuroreport. 1993 May;4(5):569-70
references: 8513141
references: Eur J Neurosci. 2006 Apr;23(7):1919-30
references: 16623848
references: Adv Neurol. 2003;93:159-77
references: 12894407
references: Neuroreport. 2000 Sep 28;11(14):3269-73
references: 11043562
references: Brain. 2007 Aug;130(Pt 8):2085-96
references: 17533167
references: Eur J Neurosci. 2002 Sep;16(5):957-64
references: 12372032
references: Brain. 1998 Mar;121 ( Pt 3):409-19
references: 9549517
references: J Neurosci. 2002 Jul 1;22(13):5749-59
references: 12097528
references: Hum Brain Mapp. 2004 Dec;23(4):210-28
references: 15449356
references: Neuropsychologia. 1971 Mar;9(1):97-113
references: 5146491
references: Brain. 1991 Dec;114 ( Pt 6):2505-20
references: 1782528
references: Exp Brain Res. 1981;42(1):1-8
references: 7215506
references: Brain. 2002 Mar;125(Pt 3):479-90
references: 11872606
references: Int J Psychophysiol. 2003 Oct;50(1-2):19-26
references: 14511833
references: J Neurophysiol. 1998 Jan;79(1):126-36
references: 9425183
references: Dev Psychobiol. 2005 Apr;46(3):279-86
references: 15772968
references: Neurology. 2007 Feb 27;68(9):691-3
references: 17325278
references: Trends Cogn Sci. 2003 Dec;7(12):541-6
references: 14643370
references: Eur J Neurosci. 2004 Oct;20(7):1923-7
references: 15380014
references: Science. 1988 Dec 9;242(4884):1437-41
references: 2462279
references: J Neurophysiol. 2002 Jan;87(1):589-607
references: 11784773
references: Neuroscientist. 2005 Dec;11(6):577-82
references: 16282598
references: Brain. 2005 Mar;128(Pt 3):606-14
references: 15634727
references: Neuroimage. 2002 Jun;16(2):389-400
references: 12030824
references: Brain. 1998 Jul;121 ( Pt 7):1213-29
references: 9679774
references: Exp Brain Res. 2005 Jan;160(1):129-40
references: 15368087
references: J Comp Neurol. 2003 May 26;460(2):223-37
references: 12687687
references: Brain. 2001 May;124(Pt 5):916-27
references: 11335694
references: Nature. 1997 Sep 11;389(6647):180-3
references: 9296495
references: Exp Brain Res. 2007 Jan;176(2):288-98
references: 16858597
references: Proc Natl Acad Sci U S A. 2006 Aug 29;103(35):13256-60
references: 16916936
references: Clin Neurophysiol. 2001 Feb;112(2):250-8
references: 11165526
references: Lancet. 1985 May 11;1(8437):1106-7
references: 2860322
references: Nat Rev Neurosci. 2002 Jun;3(6):443-52
references: 12042879
references: Neuron. 2001 Jan;29(1):287-96
references: 11182099
references: J Neurophysiol. 1964 Jul;27:546-78
references: 14194958
references: Behav Brain Sci. 2001 Oct;24(5):939-73; discussion 973-1031
references: 12239892
references: Prog Brain Res. 2001;134:447-58
references: 11702560
references: J Integr Neurosci. 2005 Dec;4(4):479-88
references: 16385642
references: Optom Vis Sci. 1999 Nov;76(11):755-63
references: 10566860