For example, pianists showed stronger activations within a fronto–parietal–temporal network while observing piano playing compared to controls (Haslinger et al. 2005). In addition, dancers showed stronger responses in the premotor, parietal cortices, and STS when they observed dance movements that they had previous experience with (Calvo-Merino et al. 2005). An alternative hypothesis is that mirror neurons may be an adaptation for action understanding. From an evolutionary point of view, it seems reasonable that there may be some innate mechanisms in place that would be facilitated through sensorimotor learning (Del Giudice et al. 2009). However, to date, there has

not been any evidence showing the existence Inhibitors,research,lifescience,medical of a mirror neuron system at birth. Another approach is Inhibitors,research,lifescience,medical to investigate the influence of previous motor experience on the perception of Fasudil actions that are not within the repertoire of young infants. Van elk et al. (2008) investigated whether infants’ own motor experience (crawling and walking) is related to the activation of their motor system during the perception of these actions carried out by Inhibitors,research,lifescience,medical other infants. They did not find significant differences between the two actions in the sensorimotor areas suggesting perhaps, that infants have a predisposition to perceiving all human actions. One index of mirror neuron activity that has been extensively studied

in humans is mu (8–13 Hz) suppression. At rest, neurons in the sensorimotor area fire synchronously resulting in large amplitude EEG oscillations in mu frequency band. When subjects perform an action, imagine, or observe movements, these neurons fire asynchronously decreasing the power of the mu band Inhibitors,research,lifescience,medical (Pfurtscheller and Neuper 1997; Muthukumaraswamy et al. 2006). It has been hypothesized that the mu rhythms reflect downstream modulation of primary sensorimotor areas by mirror neuron activity,

representing a critical information processing function, translating perception into action (Pineda 2005). To date, studies on infants have studied motor resonance to human actions (i.e., reaching/grasping Inhibitors,research,lifescience,medical or walking/crawling) but have not included a condition of object motion to determine whether infants show a general Parvulin motor resonance to all motion or whether motor resonance is specific to human actions. In the present study, the questions we asked were: (a) do infants show motor resonance only during observation of human actions or to both human and object motion and (b) to what extent does previous motor experience influence the network of brain regions activated during action observation? We used high-density EEG to investigate the pattern of mu rhythm modulation and study the latencies of activation of the sensorimotor regions in infants during observation of three types of actions: actions that are developmentally within the motor repertoire of infants (i.e.