Plasticity of the Dorsal “Spatial” Stream in Visually Deprived Individuals
Figure 2
(a) The left part of the figure illustrates the activations obtained in the study of Collignon et al. [38] from the contrast testing which regions are specifically dedicated to the spatial processing of sounds in early blind subjects relative to sighted controls: [Blind > Sighted] [Spatial > Pitch]. Functional data are overlaid (uncorrected ) over a 3D render of the brain (left is left). The right part of the figure displays psychophysiological interaction results using the two main activity peaks as seed areas. (b)The 3D brain representation (left is left) displays the projection of the site of TMS application in the study of Collignon et al. [51]. This area corresponds to the right dorsal extrastriate occipital cortex (BA 18). The histograms denote the average error rate in early blind and sighted subjects after sham (control) and real rTMS targeting the dorsal occipital stream during auditory tasks involving the discrimination of intensity, pitch and spatial location of sounds. The data show a significant increase of the error rate after real rTMS only in the early blind group and selectively for the sound location task. The histogram on the right bottom of the figure represents the percentage of errors in the spatial location task in early blind and sighted subjects for the real rTMS condition minus the sham TMS condition (isolating the effect of the TMS), as a function of sound position. Negative values on the -axis are referring to the left external space, positive values on the -axis are referring to the right external space. Adapted with permission from [38, 51].
