Vicarious motor activation during action perception: beyond correlational evidence

Abstract

Neurophysiological and imaging studies have shown that seeing the actions of other individuals brings about the vicarious activation of motor regions involved in performing the same actions. While this suggests a simulative mechanism mediating the perception of others' actions, one cannot use such evidence to make inferences about the functional significance of vicarious activations. Indeed, a central aim in social neuroscience is to comprehend how vicarious activations allow the understanding of other people's behavior, and this requires to use stimulation or lesion methods to establish causal links from brain activity to cognitive functions. In the present work, we review studies investigating the effects of transient manipulations of brain activity or stable lesions in the motor system on individuals' ability to perceive and understand the actions of others. We conclude there is now compelling evidence that neural activity in the motor system is critical for such cognitive ability. More research using causal methods, however, is needed in order to disclose the limits and the conditions under which vicarious activations are required to perceive and understand actions of others as well as their emotions and somatic feelings.

Keywords: action perception; action simulation; brain lesion; mirror neurons; transcranial magnetic stimulation (TMS).

Figure 1

Frontal and parietal brain sites whose non-invasive stimulation affected: (i) motor resonance, as shown by perturb-and-measure (Avenanti et al., 2007, 2013) and dual coil TMS (Koch et al., ; Catmur et al., 2011); (ii) proactive gaze shift during observation of actions toward objects, as shown by virtual lesion (Costantini et al., 2013); and (iii) visual action perception as shown by virtual lesion (Pobric and Hamilton, ; Urgesi et al., ,; Candidi et al., ; van Kemenade et al., ; Tidoni et al., 2013) and state-dependent TMS (Cattaneo, ; Cattaneo et al., 2010, 2011). In the study of Catmur et al. (2011) IFC and dorsal premotor cortices were stimulated in the right hemisphere but are represented on a left hemisphere. The white lines define frontal (IFC and dorsal premotor) and parietal (IPL and somatosensory) nodes of the AON and are based on a meta-analysis of 139 functional imaging studies investigating action perception (Caspers et al., 2010).