כאשר העיוורים "רואים", באמצעות מכשיר התמרה חושית : מחקרים התנהגותיים וקישורים עצביים
WHEN THE BLIND 'SEES', USING SENSORY SUBSTITUTION DEVICE:
BEHAVIORAL AND NEURAL CORRELATES.
Ornella Dakwar-Kawar1, Uri Hertz1,2, Ilan Goldberg1, Nadine Sigalov1,2 and Amir Amedi1,2,3
אורנילה דכוור-קעואר, אורי הרץ, אילן גולדבירג, נאדין סיגלוב ואמיר עמדי
1Department of Medical Neurobiology, Faculty of Medicine,2 Interdisciplinary Center for Neural Computation, 3Program of Cognitive Science, The Hebrew University of Jerusalem, Jerusalem 91220, Israel
Introduction: For the tens of millions of blind people worldwide sight restoration remains a major scientific and practical goal. As both invasive surgical sight restoration and neuroprostheses are still far from being applicable, non-invasive sensory substitution devices (SSDs) are a natural direction to follow.
Materials and Methods: “The vOICe” (P. Meijer) is a visual-to-auditory SSD capable of mapping high-resolution visual images to sound representations termed ‘soundscapes’ using predetermined transformation algorithm. We used cutting edge neuroimaging methods in order to test the ‘visual’ acuity of visual-to-auditory SSD.
Results: The behavioral results show that blind people have improved in learning guiding principles of processing hundreds of images (geometrical shapes, Hebrew letters, everyday objects, faces and houses). This acquired learning was generalized across visual stimuli varying in shape and size. The neuroimaging findings show that blind individuals appear to utilize their highly-specialized visual system for analyzing visual-to-auditory transformation, the early visual cortex presented significant preferential activation for higher acuity tasks. This visual cortex’s functional specialization emerges regardless of visual input or experience.
Conclusions: These results demonstrate the impressive plasticity of the "visual" cortex in the congenitally blind. Finally, since sight restoration following years of blindness, and particularly after early-onset blindness may be different from short term blindness in children, it would be interesting to explore plastic changes resulting from the use of SSDs in children versus adult blind subjects. We suggest that blind children may be more adaptable to learning the cross-modal transformations of the SSD than adults.