Exp Brain Res (2009) 192:521–525 DOI 10.1007/s00221-008-1578-3 123 RESEARCH ARTICLE Planning actions in autism Maddalena Fabbri-Destro · Luigi Cattaneo · Sonia Boria · Giacomo Rizzolatti Received: 25 August 2008 / Accepted: 11 September 2008 / Published online: 7 October 2008  Springer-Verlag 2008 Abstract It has been suggested that the deWcit in under- standing others’ intention in autism depends on a malfunc- tioning of the mirror system. This malfunction could be due either to a deWcit of the basic mirror mechanism or to a dis- organization of chained action organization on which the mirror understanding of others’ intention is based. Here we tested this last hypothesis investigating the kinematics of intentional actions. Children with autism and typically developing children (TD) were asked to execute two actions consisting each of three motor acts: the Wrst was identical in both actions while the last varied for its diY- culty. The result showed that, unlike in TD children, in children with autism the kinematics of the Wrst motor act was not modulated by the task diYculty. This Wnding strongly supports the notion that children with autism have a deWcit in chaining motor acts into a global action. Keywords Autism · Motor acts · Action planning · Mirror neuron system Introduction The present study was prompted by a recent experiment in which the EMG activity of the myloioideus muscle (MH), a muscle involved in mouth opening, was recorded in typically developing (TD) and children with autism during an action in which they were required to reach and grasp a piece of food and bring it to the mouth (Cattaneo et al. 2007). The data showed that, in TD children, the EMG activity of MH muscle started to increase several hundred millisec- onds before the participant’s hand grasped the food, contin- ued to increase during food grasping, and reached its peak when the participant started to open the mouth. These Wnd- ings indicate that TD children when start an action, have clear from the very beginning of the action, not only its Wnal goal, but also how to implement it motorically. The motor behavior of children with autism was strikingly diVerent. In these children no activity increase of MH mus- cle was found during reaching and grasping phases of the action. The MH muscle became active only during the Wnal bringing-food-to-the-mouth phase. How can these Wndings be interpreted? From the mere fact that children with autism brought the food to their mouths, it is clear that they had the intention to perform the action. However, this intention was not reXected in their motor organization. Children with autism knew their own intention but appeared to be unable to translate it into an appropriate motor sequence. The muscle activation observed in TD children is, most likely, the external manifestation of the chained neural organization of motor acts described by Fogassi et al. (2005). These authors recorded neurons discharging in association with grasping movements from the inferior parietal lobule (IPL) of monkeys. The animals were tested in two experimental conditions. In the Wrst, they had to grasp an object in order to place it into a container; in the second they had to grasp a piece of food to eat it. The ini- tial motor acts, reaching and grasping, were identical in the two conditions, while the last one, that determining M. Fabbri-Destro · L. Cattaneo · S. Boria · G. Rizzolatti (&) Dipartimento di Neuroscienze, Università di Parma, Via Volturno 39, 43100 Parma, Italy e-mail: giacomo.rizzolatti@unipr.it M. Fabbri-Destro Dipartimento di Scienze Biomediche e Terapie Avanzate, Università di Ferrara, Via Fossato di Mortara 17, 44100 Ferrara, Italy