Percent signal change associated with sensory stimulation of the palms or cheeks within normal SI hand representations defined functionally on the basis of control data (see Methods). Panel A. Left hemisphere: S1 hand representation. Within the right hand S1 representation, D.S. and controls showed a strong increase during stimulation of the right hand. D.S. also showed a modest increase in activity during stimulation of the left hand (see text). Panel B. Right hemisphere: S1 hand representation. In the left hand S1 representation, both D.S. and controls showed comparable increases in activity during stimulation of the contralateral left hand. D.S. showed no greater response to stimulation of the cheeks than controls in either hemisphere.

Activations associated with hand stimulation in D.S. and controls represented in standard space. The multi-fiducial mapping procedure [29] was used to transform data from patient D.S. (blue overlay) into standard space for direct visual comparison with mean activations of the control group (see Supplementary Data). For D.S. all significant activations within preCG, postCG, parietal operculum and insula are included (see Figure 1). These flattened representations illustrate the high degree of overlap between D.S.’s contralateral SI responses and those of the control group. Panel A. Responses associated with stimulation of the left palm. In contrast to controls, stimulation of D.S.’s left palm elicited a strong ipsilateral response along the length of the postCG extending into the operculum. Panel B. Responses associated with stimulation of the right palm. Note the high degree of overlap between data from D.S. and control participants.

Statistical parametric maps representing areas of increased activity associated with tactile stimulation versus rest. All areas in color showed significant increases in activity during movement (z > 2.3, p <.05 cluster-based correction for multiple comparisons). Areas of peak activation (i.e., z > 4.0) are represented in warm colors corresponding to values indicated in the color bar. Non-peak areas of significantly increased activity (z = 2.3 – 3.99) are represented in green. Mean control data are displayed on the PALs template brain (see Supplementary Data) that has been partially inflated (upper rows) or flattened (lower rows) to visualize activations located in sulcal folds. Patient D.S.’s data are displayed on inflated and flattened surface renderings created from high resolution anatomical images of his own brain. Panel A: Stimulation of the left or right palms of control subjects increased activity in contralateral SI with the peak located in the CS and activity extending rostrally into the the preCG and caudally into postCG. Contralateral activation is also detected in the parietal operculum (including putative SII). During right hand stimulation, left parietal operculum also showed a small but significant increase in activity (Supplementary Data, Table 1). However, due to individual variation in cortical topography, this ipsilateral cluster did not survive the multi-fiducial adjustment for individual differences in cortical topography and is therefore not visible in these surface renderings (see Methods). Lower Panel: Similarly, stimulation of the palms of the transplanted or intact hands evoked peak responses within contralateral SI (see text). In addition, stimulation of the intact left palm was associated with a large region of increased activity along the ipsilateral post-central gyrus. Bilateral responses were also observed in putative SII, CCZ and insula (see text).