Botulinum toxin and the facial feedback hypothesis: Can looking better make you feel happier?  Murad Alam, MD, Karen C. Barrett, PhD, Robert M. Hodapp, PhD, Kenneth A. Arndt, MD  Journal of the American Academy of Dermatology  Volume 58, Issue 6, Pages 1061-1072 (June 2008) DOI: 10.1016/j.jaad.2007.10.649 Copyright © 2008 American Academy of Dermatology, Inc. Terms and Conditions

Fig 1 Forehead and brow superficial muscular anatomy, including frontalis, procerus, corrugator supercilii, orbicularis oculi, and zygomaticus major. In order from top to bottom, flat muscle of forehead is frontalis (note lateral and medial, or inner and outer, fibers); V-shaped muscle above nose is procerus; diagonal muscle extending medially from nose to periocular area is corrugator supercilii; muscle encircling eye is orbicularis oculi (note inner and outer fibers); and diagonal muscle on cheek from lateral face to perioral area is zygomaticus major. Journal of the American Academy of Dermatology 2008 58, 1061-1072DOI: (10.1016/j.jaad.2007.10.649) Copyright © 2008 American Academy of Dermatology, Inc. Terms and Conditions

Fig 2 Subjects asked to hold a pen between their teeth so as to simulate a grin found a cartoon to be funnier than did subjects who were not asked to perform this maneuver.27 Journal of the American Academy of Dermatology 2008 58, 1061-1072DOI: (10.1016/j.jaad.2007.10.649) Copyright © 2008 American Academy of Dermatology, Inc. Terms and Conditions

Fig 3 Subjects who had two golf tees attached to either side of their foreheads and were asked to try to move these together so as to simulate a frown concurrently rated unpleasant photographs more negatively than subjects who viewed the same photographs but did not simultaneously attempt the movement.28 Journal of the American Academy of Dermatology 2008 58, 1061-1072DOI: (10.1016/j.jaad.2007.10.649) Copyright © 2008 American Academy of Dermatology, Inc. Terms and Conditions

Fig 4 Fear. Contraction of Action Unit 1 (AU1), which raises the inner corner of the brow (via inner fibers of the frontalis). See also Fig 1. (Reprinted with the permission of Paul Ekman, from: Ekman P, Friesen WV, Hager JC. Facial action coding system: the manual network. Salt Lake City [UT]: Information Research Corporation; 2002. p. 466.) Journal of the American Academy of Dermatology 2008 58, 1061-1072DOI: (10.1016/j.jaad.2007.10.649) Copyright © 2008 American Academy of Dermatology, Inc. Terms and Conditions

Fig 5 Intense fear. Simultaneous contraction of Action Unit 1 (AU1), which raises the inner corner of the brow (via inner fibers of the frontalis), and AU4i, which lowers and draws the eyebrows together (via the procerus and corrugator). The contraction of AU4 is mild (as designated by “i”) rather than intense (“ii”). The combined effect of AU (1+4i) entails pulling of the medial portion of the eyebrows upwards and together, producing of an oblique, triangular shape to the eyebrows, causing of the skin in the center of the forehead to wrinkle horizontally, and possibly creating vertical lines, wrinkles, or bunching of the skin between the brows. See also Fig 1. (Reprinted with the permission of Paul Ekman, from: Ekman P, Friesen WV, Hager JC. Facial action coding system: the manual network. Salt Lake City [UT]: Information Research Corporation; 2002. p. 470.) Journal of the American Academy of Dermatology 2008 58, 1061-1072DOI: (10.1016/j.jaad.2007.10.649) Copyright © 2008 American Academy of Dermatology, Inc. Terms and Conditions

Fig 6 Fear/surprise. Contraction of Action Unit 2 (AU2), which raises the outer corner of the brow (via the outer fibers of the frontalis). See also Fig 1. (Reprinted with the permission of Paul Ekman, from: Ekman P, Friesen WV, Hager JC. Facial action coding system: the manual network. Salt Lake City [UT]: Information Research Corporation; 2002. p. 466.) Journal of the American Academy of Dermatology 2008 58, 1061-1072DOI: (10.1016/j.jaad.2007.10.649) Copyright © 2008 American Academy of Dermatology, Inc. Terms and Conditions

Fig 7 Genuine Duchenne smile. Simultaneous contraction of Action Unit 6 (AU6), which circles the eye, narrowing it by pulling more skin from around the eye (via the outer fibers of the orbicularis oculi); AU12, which pulls the corners of the lips back and upward (obliquely) creating a bow-shape to the mouth while deepening the nasolabial furrow thus pulling it laterally and up; and AU25ii, which permits parting of the lips, with resulting possible exposure of the inner mucosal area and teeth and gums. The combined effect of AU(6+12+25ii) entails the lip corners being pulled up obliquely, deepening of the nasolabial furrow, appearing of crow's feet wrinkles, raising of the infraorbital triangle, and deepening of the infraorbital furrow. (Reprinted with the permission of Paul Ekman, from: Ekman P, Friesen WV, Hager JC. Facial action coding system: the manual network. Salt Lake City [UT]: Information Research Corporation; 2002. p. 485.) Journal of the American Academy of Dermatology 2008 58, 1061-1072DOI: (10.1016/j.jaad.2007.10.649) Copyright © 2008 American Academy of Dermatology, Inc. Terms and Conditions

Fig 8 Anger. Contraction of Action Unit w4 (AUw4), which lowers and draws the eyebrows together (using the procerus and corrugator) but, unlike AU4i, creates wrinkles between the brows that are more angular than vertical. See also Fig 1. (Reprinted with the permission of Paul Ekman, from: Ekman P, Friesen WV, Hager JC. Facial action coding system: the manual network. Salt Lake City [UT]: Information Research Corporation; 2002. p. 465.) Journal of the American Academy of Dermatology 2008 58, 1061-1072DOI: (10.1016/j.jaad.2007.10.649) Copyright © 2008 American Academy of Dermatology, Inc. Terms and Conditions

Fig 9 Facial feedback as it may pertain to botulinum toxin therapy and other facial rejuvenation procedures. Chemical manipulation alters facial expression, reducing frown lines, leaving the face appearing more happy and less sad or angry. This more positive facial expression leads to internal emotional experience of happiness in the affected individual. Additionally, the happy expression elicits happier expressions from bystanders, thus further reinforcing the happy expression and happy emotional state of the index person. Journal of the American Academy of Dermatology 2008 58, 1061-1072DOI: (10.1016/j.jaad.2007.10.649) Copyright © 2008 American Academy of Dermatology, Inc. Terms and Conditions

Fig 10 A middle-aged woman with (A) brows knitted and (B) upward gaze before treatment. The same maneuvers, shown in (C) and (D), induce fewer dynamic creases and less angry and anxious expression 2 weeks after injection of the glabellar and forehead complex with botulinum toxin. Journal of the American Academy of Dermatology 2008 58, 1061-1072DOI: (10.1016/j.jaad.2007.10.649) Copyright © 2008 American Academy of Dermatology, Inc. Terms and Conditions