Figures and data
FEPS: a brain signature of the facial expression of pain.
A) Relationship between the actual and the predicted FACS composite scores for each cross-validation fold. B) Distribution of the Pearson’s r scores across the cross-validation folds. C) Predictive weight map of pain expression thresholded at p-uncorrected < .05 using bootstrap tests performed with 5000 samples (with replacement). The thresholded map is shown for visualization and interpretation purposes only, although the prediction was made using voxel weights across the whole brain. MNI coordinates of the clusters with the related z-score can be found in Table S1. The colour bar represents the z-scored regression weights reflecting the positive and negative association with the magnitude of the FACS composite score of pain expression.
Spatial similarity between the FEPS and other pain-related signatures.
A) Pattern similarity between the FEPS and other pain-related brain signatures using the weights of the full brain patterns. Pattern similarities were computed at the voxel level using the cosine similarity; a value of 1 reflects proportional patterns; a value of 0 reflects orthogonal patterns; a value of −1 reflects patterns of opposite direction. The left panel shows the similarity matrix, and the right panel shows only the significant similarities between the pain-related signatures (* p < .05; ** p < .01; *** p < .001). B) Deconstructing the pattern similarity with regards to seven cortical networks as defined in the Yeo atlas24: Visual Network (VN); Somatomotor Network (SMN); Dorsal Attention Network (DAN); Ventral Attention Network (VAN); Limbic Network (LN); Frontoparietal Network (FPN); Default Mode Network (DMN). Null distributions computed using permutation tests are shown, and the actual similarity values are represented by the vertical bar. Significant similarity values were found in the FPN (similarity = .24; p = .001), and the DMN (similarity = .18; p = .005) for the SIIPS-1, in the LN (similarity = .23; p = .003), and DMN (similarity = .11; p = .05) for the PVP, and in the LN (similarity = .11; p = .04) for the TPAS.
Predictive performance of the M1-based model.
A) Relationship between the actual and the predicted FACS composite scores for each cross-validation fold (k=10) using only the activity from the primary motor cortex as defined by the Oxford-Harvard Cortical Atlas (Caviness et al. 1996). B) Distribution of the Pearson-r scores across the 10 cross-validation folds (Pearson-r = .11 ± .08; R2 = -.29 ± .33; RMSE = 8.02 ± 0.96; p = .58).
