Amir Amedi ¹, William Stern ¹, Joan A. Camprodon ¹, Felix Bermpohl ¹, Lotfi Merabet ¹, Peter Meijer ² and Alvaro Pascual-Leone ¹.

¹ Berenson-Allen Center for Noninvasive Brain Stimulation, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School.
² NXP Semiconductors, formerly at Philips Research, Eindhoven, The Netherlands.

Extracting shape and location information conveyed by visual-to-auditory sensory substitution activates the lateral occipital complex and dorsal visual stream respectively in blind and sighted individuals

 Abstract

In sensory substitution, visual information captured by an artificial receptor is delivered to the brain using non-visual sensory information via a human-machine interface. Part of the Lateral-Occipital-Complex (LOtv) is activated when objects are recognized by vision or touch. We report here that both sighted and blind individuals who recognize objects by extracting shape information from soundscapes created by a visual-to-auditory sensory substitution device called "The vOICe" also activated LOtv. Recognizing objects by their typical sounds or learning to associate specific soundscapes with specific objects fail to activate this region. This suggests that LOtv rather then being driven by the sensory information modality is driven by the presence of shape information. We also studied shape versus location processing of visual geometrical shapes transformed into soundscapes. We find specific recruitment of ventral visual stream (used in sighted to perceive form) to the shape soundscapes condition while dorsal stream (used in sighted to perceive space) was recruited in the location condition. These results support the meta-modal theory of the brain, in which cortical regions are defined by the computation they apply rather than their dominant sensory input modality.