FIG 10. Comparison of cross-correlation analysis and SPM methods with the same data set. The cross-correlation analysis (top left) revealed that tongue tapping against the hard palate activated cervical spinal cord regions C1, C2. and C3, which provide the motor innervation of the strap muscles that stabilize the tongue. Similarly, activation of C1 and C2 is shown with the SPM method in its nonsmoothed mode (top middle), but not in its smoothed mode (top right). The unsmoothed SPM analysis revealed a more discrete and delimited localization, more similar to the cross-correlation analysis than the results of smoothed SPM analysis. Findings from cross-correlation (bottom left, bottom middle) and head motion analyses (bottom right) are also shown. Note also the cortical activation at the level of the homuncular tongue region (near the lateral sulcus, top middle, top right).