Fig. 3

Surface-based single digit activation patterns of all seven participants across designs and sessions. Each row depicts the thresholded statistical map of the BOLD-activation in response to vibrotactile stimulation projected to the flattened brain surface of the individual participant. The left-most dark gray line in each image represents the central sulcus (CS; marked with a white arrowhead) and the light gray line on the right to the CS represents the postcentral gyrus. The top left inset indicates superior (s), posterior (p), inferior (i), anterior (a) directions. Activations of different digits are represented using color gradients in different colors (D1 = magenta; D2 = yellow; D3 = green; D4 = blue; D5 = red). For both Traveling Wave and Blocked Design, the lowest statistical value that is included in the color gradient corresponds to the statistical value at the threshold of q(FDR) < 0.05. The upper limit of the color gradient corresponds to a Fisher’s Z-value of 0.5 for the Traveling Wave maps and to a t-value of 8.0 for the Blocked Design Maps. Vertices above these values are colored in the same color. Overlap of digit activations is displayed as a mixture of colors belonging to the overlapping digits. All seven participants show significant activations in response to stimulation of all five digits along the posterior wall of the CS, creating a topographic digit map. The location of activation as well as the extent of activation is stable across sessions and designs with the exception of two cases (first row and fourth row)