When emulation becomes reciprocity

Abstract

It is well known that perceiving another's body movements activates corresponding motor representations in an observer's brain. It is nevertheless true that in many situations simply imitating another's actions would not be an effective or appropriate response, as successful interaction often requires complementary rather than emulative movements. At what point does the automatic tendency to mirror another's actions become the inclination to carry out appropriate, complementary movements? In the present study, single-pulse transcranial magnetic stimulation (TMS) was used to explore corticospinal excitability in participants observing action sequences evoking imitative or complementary movements. TMS was delivered at five time points corresponding to different moments in time when key kinematic landmarks characterizing an observed action occurred. A variation in motor evoked potentials (MEPs) confirmed that the motor system flexibly shifts from imitative to complementary action tendencies. That shift appears to take place very precociously in time. Observers are attuned to advance movement information and can use it to anticipate a future course of action and to prepare for an appropriate, complementary action. Altogether, these findings represent a step forward in research concerning social action-perception coupling mechanisms providing important data to better understand the role of predictive simulation in social contexts.

The multiform motor cortical output: Kinematic, predictive and response coding

“…A finding in accordance with behavioral (Bertenthal, Longo, & Kosobud, 2006;Liepelt et al, 2010) and neurophysiological (Press, Bird, Walsh, & Heyes, 2008) studies showing motor facilitation effects for transitive as well as intransitive actions . 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 15 Moreover, the present findings extends previous evidence on response preparation in hand muscles (Newman-Norlund, Noordzij, Meulenbroek, & Bekkering, 2007;Ocampo & Kritikos, 2010;Sartori, Cavallo, Bucchioni, & Castiello, 2011b, 2012bSartori, Betti, & Castiello, 2013a, 2013bSartori et al, 2013c) showing a modulation of CS excitability also when the observed action calls for a gesture involving different body parts with respect to the observed ones. In the present study, observers' upper limb muscles were activated while observing a soccer player kicking a ball straight in their direction.…”

“…In particular, recent evidence suggests that compatibility effects in automatic imitation can be overridden by social response preparation (Liepelt et al, 2010;Sartori, Bucchioni, & Castiello, 2013c). …”

Primary Motor Cortex Activation during Action Observation of Tasks at Different Video Speeds Is Dependent on Movement Task and Muscle Properties

“…Some studies have shown that M1 excitability is enhanced by the social features that characterize an observed action (Donne et al, 2011; Bucchioni et al, 2013; Sartori et al, 2013). These studies suggest that M1 excitability is modulated by the participant’s understanding of the social intention and context implied by the observed action.…”

Dissociated Representations of Deceptive Intentions and Kinematic Adaptations in the Observer's Motor System

“…These task differences might explain the different degree of muscle specificity in motor facilitation obtained in the 2 studies. Indeed, recent studies have demonstrated the high flexibility of motor resonance in the observers' brain, as the amount of motor facilitation can be modulated by the instructions given to the participants (Bardi et al 2015) and can reflect either direct mirroring or complementing an observed action according to contextual variables (Sartori et al 2013).…”