Fig 1.
(a) Timeline illustrating the different steps in the study. Both EB (early blind) and SC (sighted control) subjects took part in behavioral tasks with the Sensory Substitution Device (SSD) and in fMRI tasks with images that were sound-encoded by means of the SSD. In a subsequent step, the 10 SC took part in visual tasks with schematic and real images. (b) The PSVA SSD and its ‘artificial retina’, illustrating a schematic face being perceived. (c) Schematic stimuli used in both SSD and visual schematic fMRI one-back comparison task. Three stimulus categories were tested: schematic faces (SF); schematic houses (SH); and schematic shapes (SS).
Table 1.
Early blind subjects characteristics.
Fig 2.
Visual activation of the fusiform face area (FFA) in SC subjects viewing schematic faces.
The upper part of the Fig shows the activation maps obtained using the contrast [Schematic Faces minus Rest] in 10 subjects. The lower part of the Fig shows the activation maps obtained using the contrast [Schematic Faces minus Schematic Houses]. Activation maps were obtained using a threshold of qFDR < 0.05 in combination with a cluster size threshold correction of p < 0.01. Brain activation foci (positive values only) were superimposed on sagittal, coronal and transverse views of the normalized MRI brain of a representative subject.
Fig 3.
Brain activity within the Fusiform Face Area Region of Interest (FFA-ROI) in early blind (EB) and sighted control (SC) subjects.
Fig 4.
Individual beta values for responses to SSD faces and houses within the left FFA-ROI.
Scatter plots of the single-subject (raw) beta values are displayed for the EB group.