Transcranial magnetic stimulation of the visual cortex induces somatotopically organized qualia in blind subjects

Kupers, Ron; Fumal, Arnaud; Noordhout, Alain Maertens De; Gjedde, Albert; Schoenen, Jean; Ptito, Maurice

doi:10.1073/pnas.0602925103

Cited by 112 publications

(105 citation statements)

References 40 publications

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“…Both groups commonly activated superior parietal cortex (slices 54, 42), superior occipital cortex (slices 30, 18), cuneus (slice 6), and parahippocampus (slice −6). explain the occipital activation by the strengthening of parietooccipital connectivity in congenitally blind subjects (19,(38)(39)(40).…”

Section: Discussionmentioning

confidence: 98%

Neural correlates of virtual route recognition in congenital blindness

Kupers

Chebat

Madsen

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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133

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Despite the importance of vision for spatial navigation, blind subjects retain the ability to represent spatial information and to move independently in space to localize and reach targets. However, the neural correlates of navigation in subjects lacking vision remain elusive. We therefore used functional MRI (fMRI) to explore the cortical network underlying successful navigation in blind subjects. We first trained congenitally blind and blindfolded sighted control subjects to perform a virtual navigation task with the tongue display unit (TDU), a tactile-to-vision sensory substitution device that translates a visual image into electrotactile stimulation applied to the tongue. After training, participants repeated the navigation task during fMRI. Although both groups successfully learned to use the TDU in the virtual navigation task, the brain activation patterns showed substantial differences. Blind but not blindfolded sighted control subjects activated the parahippocampus and visual cortex during navigation, areas that are recruited during topographical learning and spatial representation in sighted subjects. When the navigation task was performed under full vision in a second group of sighted participants, the activation pattern strongly resembled the one obtained in the blind when using the TDU. This suggests that in the absence of vision, cross-modal plasticity permits the recruitment of the same cortical network used for spatial navigation tasks in sighted subjects.cross-modal plasticity | parahippocampus | sensory substitution | spatial navigation | visual cortex T he ability to navigate efficiently in large-scale environments was always a predicate for human survival, now applied to the particular challenges of living in a modern, urban society. Visual cues signaling the location of landmarks play a key role in facilitating the formation of spatial cognitive maps used for path finding in a visual setting (1, 2). Despite the importance of vision in spatial cognition, the abilities to recognize a traveled route and to represent spatial information are maintained in blind individuals (3-5), probably through tactile, auditory, and olfactory cues, as well as motion-related cues arising from the vestibular and proprioceptive systems.During successful navigation, spatial information needs to be encoded and retrieved. The role of the hippocampus for navigation in large-scale environments has been amply demonstrated in both animal (6-8) and human studies (9-11). Besides the hippocampus, several other areas in the posterior mesial lobe and posterior parietal, occipital, and infero-temporal cortices also play an important role in navigation (9,(12)(13)(14)(15)(16)(17).The neural correlates of navigation in congenital blindness remain elusive, in part owing to the difficulty in testing navigational skills of blind subjects within the setting of a functional brain imaging study. To circumvent this difficulty, we trained blind and sighted subjects in a spatial navigation task using the tongue display unit (TDU), a vis...

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Section: Discussionmentioning

confidence: 98%

Neural correlates of virtual route recognition in congenital blindness

Kupers

Chebat

Madsen

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

133

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“…Such interpretation is in line with recent research using transcranial magnetic stimulation (TMS) of blind and blindfolded sighted participants' visual cortex before and after TDU training. Before training, the participants in Kupers and colleagues' study (Kupers et al, 2006) did not report any subjective tactile sensation when TMS was applied over their visual cortex (only phosphenes were reported by sighted participants). After training, some of the blind participants (three out of eight early blind and one out of five late blind) reported somatopically organized tactile sensations that were referred to the tongue when TMS was applied over the occipital cortex, whereas no such sensations were reported by sighted participants.…”

Section: Activation Of the Associated Brain Areasmentioning

confidence: 97%

Perception With Compensatory Devices: From Sensory Substitution to Sensorimotor Extension

Auvray¹,

Myin

2009

Cognitive Science

114

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Sensory substitution devices provide through an unusual sensory modality (the substituting modality, e.g., audition) access to features of the world that are normally accessed through another sensory modality (the substituted modality, e.g., vision). In this article, we address the question of which sensory modality the acquired perception belongs to. We have recourse to the four traditional criteria that have been used to define sensory modalities: sensory organ, stimuli, properties, and qualitative experience (Grice, 1962), to which we have added the criteria of behavioral equivalence (Morgan, 1977), dedication (Keeley, 2002), and sensorimotor equivalence (O'Regan & Noë, 2001). We discuss which of them are fulfilled by perception through sensory substitution devices and whether this favors the view that perception belongs to the substituting or to the substituted modality. Though the application of a number of criteria might be taken to point to the conclusion that perception with a sensory substitution device belongs to the substituted modality, we argue that the evidence leads to an alternative view on sensory substitution. According to this view, the experience after sensory substitution is a transformation, extension, or augmentation of our perceptual capacities, rather than being something equivalent or reducible to an already existing sensory modality. We develop this view by comparing sensory substitution devices to other ''mind-enhancing tools'' such as pen and paper, sketchpads, or calculators. An analysis of sensory substitution in terms of mind-enhancing tools unveils it as a thoroughly transforming perceptual experience and as giving rise to a novel form of perceptual interaction with the environment.

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“…Moreover, Braille reading habits predicted the number of occipital cortical sites in blind participants that elicited sensations in the fingers when stimulated with TMS (Ptito et al, 2008). Training of blind participants on a task involving the tongue was necessary both to induce cross-modal plasticity (Ptito et al, 2005) and for occipital TMS to elicit tactile sensations on the tongue (Kupers et al, 2006). Thus, cross-modal plasticity, like intra-modal somatosensory plasticity, may contribute to experience-dependent tactile perceptual enhancement in blindness.…”

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confidence: 97%

Tactile Spatial Acuity Enhancement in Blindness: Evidence for Experience-Dependent Mechanisms

Wong¹,

Gnanakumaran²,

Goldreich³

2011

J. Neurosci.

153

115

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Tactile spatial acuity is enhanced in blindness, according to several studies, but the cause of this enhancement has been controversial. Two competing hypotheses are the tactile experience hypothesis (reliance on the sense of touch drives tactile-acuity enhancement) and the visual deprivation hypothesis (the absence of vision itself drives tactile-acuity enhancement). Here, we performed experiments to distinguish between these two hypotheses. We used force-controlled grating orientation tasks to compare the passive (finger stationary) tactile spatial acuity of 28 profoundly blind and 55 normally sighted humans on the index, middle, and ring fingers of each hand, and on the lips. The tactile experience hypothesis predicted that blind participants would outperform the sighted on the fingers, and that Braille reading would correlate with tactile acuity. The visual deprivation hypothesis predicted that blind participants would outperform the sighted on fingers and lips. Consistent with the tactile experience hypothesis, the blind significantly outperformed the sighted on all fingers, but not on the lips. Additionally, among blind participants, proficient Braille readers on their preferred reading index finger outperformed nonreaders. Finally, proficient Braille readers performed better with their preferred reading index finger than with the opposite index finger, and their acuity on the preferred reading finger correlated with their weekly reading time. These results clearly implicate reliance on the sense of touch as the trigger for tactile spatial acuity enhancement in the blind, and suggest the action of underlying experience-dependent neural mechanisms such as somatosensory and/or cross-modal cortical plasticity.

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Transcranial magnetic stimulation of the visual cortex induces somatotopically organized qualia in blind subjects

Abstract: authors note that in Fig. 2, the ''myosin VI'' labels should be replaced with ''vinculin'' in D and with ''R-Tfn'' in E. The corrected figure and its legend appear below. In addition, the portion of the

Cited by 112 publications

References 40 publications

Neural correlates of virtual route recognition in congenital blindness

Neural correlates of virtual route recognition in congenital blindness

Perception With Compensatory Devices: From Sensory Substitution to Sensorimotor Extension

Tactile Spatial Acuity Enhancement in Blindness: Evidence for Experience-Dependent Mechanisms

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