Brain areas significantly correlated with the pleasurability of scratching (pink) and with itch relief (blue) induced by actively scratching an itch, as identified by multiple regression analysis.
VAS ratings of pleasurability and itch relief (calculated as the difference in itch ratings before and after scratching) were used as covariates of interest. PAG = periaqueductal gray; VTA = ventral tegmental area; SN= substantia nigra; ACC = anterior cingulate cortex; PCC = posterior cingulate cortex; rmTgm = rostromedial tegmentum. Talairach standard space coordinates (x, y, z). Areas significantly correlated with a Z score > 2.3, p < 0.05 are displayed. The color tones displayed correspond to Z score values as depicted in the color bars (at the same scale). R = Right; L = Left.