Neuropsychologia 45 (2007) 1108–1121 Pattern recognition using a device substituting audition for vision in blindfolded sighted subjects C. Poirier a , A. De Volder a , D. Tranduy a , C. Scheiber b,∗ a Neural Rehabilitation Engineering Laboratory, Universit´ e Catholique de Louvain, Brussels, Belgium b Neurofunctional Imaging Nuclear Medicine, MRI Department, UMR-7004 ULP/CNRS, Strasbourg, France Received 31 May 2005; received in revised form 18 September 2006; accepted 24 September 2006 Available online 20 November 2006 Abstract A major question in the field of sensory substitution concerns the nature of the perception generated by sensory substitution devices. In the present fMRI study, we investigated the neural substrates of pattern recognition through a device substituting audition for vision in blindfolded sighted subjects, before and after a short training period. Before training, pattern recognition recruited dorsal and ventral extra-striate areas. After training, the recruitment of these visual areas was found to have increased. These results suggest that visual imagery processes could be involved in pattern recognition and that perception through the substitution device could be visual-like. © 2006 Elsevier Ltd. All rights reserved. Keywords: Sensory substitution; Neural correlates; Visual perception; fMRI 1. Introduction Sensory substitution refers to the use of one sensory modality to supply information normally gathered from one of the other senses (Bach-y-Rita, Collins, Saunders, White, & Scadden, 1969). Tactile- or auditory-for-visual substitution devices have allowed blindfolded sighted subjects to match vibrotactile and visual patterns (Epstein, Hughes, Schneider, & Bach-y-Rita, 1989), to discriminate pattern orientations (Sampaio, Maris, & Bach-y-Rita, 2001) and to recognise visual patterns (Arno, Capelle, Wanet-Defalque, Catalan-Ahumada, & Veraart, 1999; Arno, Vanlierde et al., 2001; Poirier, Richard, Tranduy, & Veraart, 2006). Training is necessary to achieve these perfor- mances. A major question in the field of sensory substitution for vision is to understand the nature of the perception generated by sensory substitution devices. Is the perception determined by the nature of the substitutive modality (i.e. tactile or auditory) or is it determined by the nature of the information transmitted by the device (i.e. visual)? Is it a totally new kind of perception? According to the sensory substitution theory, the processing of ∗ Corresponding author at: Centre de M´ edecine, Nucl´ eaire Hˆ opital Neuro- Cardiologique, 59 Bd Pinel, 69677 Bron Cedex, France. Tel.: +33 472684961; fax: +33 472357345. E-mail address: christian.scheiber@chu-lyon.fr (C. Scheiber). stimuli perceived via such devices should rapidly result, through learning, in visual perception (Bach-y-Rita, 1972). A more par- simonious hypothesis predicts that the use of mental imagery strategies will result in visual-like perception (Renier, Collignon et al., 2005). In a recent work focused on procedural learning we inves- tigated the neural network recruited during the training to use a device developed in the Neural Rehabilitation Engineering Laboratory by Capelle, Trullemans, Arno, and Veraart (1998) and called PSVA (Poirier, De Volder, Tranduy, & Scheiber, 2006). Here we reanalyzed these data, and focused on pattern recognition, in order to determine whether auditory-for visual substitution devices generate visual (or visual-like) perception rather than auditory perception. We hypothesised that if perception through this prosthesis was visual or visual-like, pattern recognition should recruit the visual areas. Since the nature of the perception could be linked to the expertise level of the device users, we studied the neural bases of the pattern recognition task when the subjects were na¨ ıve to the prosthesis and after a short period of training. 2. Materials and methods 2.1. Subjects Six right-handed male volunteers (mean 23 years, range 20–33 years) na¨ ıve with respect to the PSVA device took part in the experiment. All gave prior 0028-3932/$ – see front matter © 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.neuropsychologia.2006.09.018