Neuropsychologia 48 (2010) 3961–3966 Contents lists available at ScienceDirect Neuropsychologia journal homepage: www.elsevier.com/locate/neuropsychologia Brief communication Anticipation of body-scaled action is modified in anorexia nervosa Dewi Guardia a,b , Gilles Lafargue a , Pierre Thomas a , Vincent Dodin c , Olivier Cottencin a,b , Marion Luyat a,∗ a Laboratoire de Neurosciences Fonctionnelles et Pathologies CNRS FRE 3291, Lille, France b Service d’Addictologie du Centre Hospitalier et Universitaire de Lille, France c Service de psychiatrie de l’hôpital Saint-Vincent de Paul de Lille, France article info Article history: Received 1 May 2010 Received in revised form 19 July 2010 Accepted 3 September 2010 Available online 15 September 2010 Keywords: Anorexia nervosa Body schema Parietal networks Body-scaled action abstract Patients with anorexia nervosa frequently believe they are larger than they really are. The precise nature of this bias is not known: is it a false belief related to the patient’s aesthetic and emotional attitudes towards her body? Or could it also reflect abnormal processing of the representation of the body in action? We tested this latter hypothesis by using a body-scaled action-anticipation task in which 25 anorexics and 25 control participants had to judge whether or not an aperture was wide enough for them to pass through. The anticipation of body-scaled action was severely disturbed in anorexic patients; they judged that they could not pass through an aperture, even when it was wide enough (i.e. they behave as if their body was larger than in reality). The abnormally high “passability ratio” (the critical aperture size to shoulder width ratio) was also correlated with the duration of illness and the degree of body concern/dissatisfaction. Our results suggest that body size overestimation in anorexia nervosa is not solely due to psycho-affective factors but rather suggest impaired neural processing of body dimensions that might take its source in parietal networks. © 2010 Elsevier Ltd. All rights reserved. 1. Introduction When watching oneself on video, it is commonplace to experi- ence a feeling of strangeness about one’s face and body. It is as if a person’s representation of his/her anatomical features does not strictly correspond to the “reality” that the video provides. In some extreme cases, the distortion of this representation is so strong that it becomes pathological, such as in anorexia nervosa (AN). Anorexic patients usually report feeling fatter and larger than they really are. Even though a slight (<5%) overestimation bias is found in normal subjects, the phenomenon is significantly exaggerated in anorexics (Smeets, Ingleby, Hoek, & Panhuysen, 1999). This body size overes- timation is considered to be a major clinical symptom of AN (cf. DSM IV; American Psychiatric Association, 1994) and is a cause for concern for several reasons. Firstly, the feeling of dissatisfac- tion generated by body size overestimation may be a risk factor for developing eating disorders (Stice & Shaw, 2002). Secondly, it could reinforce depression and suicide attempts in adolescents (Franko & Striegel-Moore, 2002; Rodriguez-Cano, Beato-Fernandez, & Llario, 2006). Thirdly, body size overestimation in AN could counteract the benefits of therapy by increasing the obsessive will to lose weight ∗ Corresponding author at: Laboratoire de Neurosciences Fonctionnelles et Pathologies - CNRS FRE 3291, 150 rue du Docteur Yersin, Parc Eurasanté, F-59120 Loos, France. Tel.: +33 6 62 86 70 53; fax: +33 3 20 44 67 32. E-mail address: marion.luyat@univ-lille3.fr (M. Luyat). and, as a consequence, maintaining restrictive eating behaviours (Heilbrun & Friedberg, 1990). Hence, understanding the nature and cause of body size overestimation in AN is a major challenge in public health. Although the exact nature of this cognitive bias and its conse- quences are poorly known, it is generally accepted that body size overestimation reflects a distortion of body representation. There are at least two types of body representation: the body schema and the body image (for a recent review, see De Vignemont, 2010). The body schema is a dynamic sensorimotor representation of the body which initiates and guides actions. It is elicited by action, regardless of whether the latter is imagined, anticipated or exe- cuted (Gallagher, 2005; Paillard, 1999; Schwoebel & Coslett, 2005). The notion of body image is more complex and concerns percep- tual, semantic, aesthetic and emotional representations of the body which are not used for action (De Vignemont, 2010). Thus, the body overestimation bias found in anorexia ner- vosa could be a mere ‘state of mind’ – a false belief caused by psycho-affective factors and restricted to the aesthetic-emotional body representation: the body image. Alternatively, it could reflect abnormal neural processing of the embodied self which disturbs the representation of the body in action, i.e. the body schema. Even though most of the studies to date have stressed emo- tions/attitudes towards the body (for a review, see Cash & Deagle, 1997; Skrzypek, Wehmeier, & Remschmidt, 2001), very few researchers (Nico et al., 2009, for example) have suggested that the body schema could be also distorted in AN. One likely reason for this 0028-3932/$ – see front matter © 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.neuropsychologia.2010.09.004