Multiple faces of pain: effects of chronic pain on the brain regulation of facial expression.
Vachon-Presseau E, Roy M, Woo CW, Kunz M, Martel MO, Sullivan MJ, Jackson PL, Wager TD, Rainville P. Multiple faces of pain: effects of chronic pain on the brain regulation of facial expression. Pain. 2016 08; 157(8):1819-1830.