Mapping Implied Body Actions in the Human Motor System

Abstract

The human visual system is highly tuned to perceive actual motion as well as to extrapolate dynamic information from static pictures of objects or creatures captured in the middle of motion. Processing of implied motion activates higher-order visual areas that are also involved in processing biological motion. Imagery and observation of actual movements performed by others engenders selective activation of motor and premotor areas that are part of a mirror-neuron system matching action observation and execution. By using single-pulse transcranial magnetic stimulation, we found that the mere observation of static snapshots of hands suggesting a pincer grip action induced an increase in corticospinal excitability as compared with observation of resting, relaxed hands, or hands suggesting a completed action. This facilitatory effect was specific for the muscle that would be activated during actual execution of the observed action. We found no changes in responsiveness of the tested muscles during observation of nonbiological entities with (e.g., waterfalls) or without (e.g., icefalls) implied motion. Thus, extrapolation of motion information concerning human actions induced a selective activation of the motor system. This indicates that overlapping motor regions are engaged in the visual analysis of physical and implied body actions. The absence of motor evoked potential modulation during observation of end posture stimuli may indicate that the observationexecution matching system is preferentially activated by implied, ongoing but not yet completed actions.

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

“…However, it is unclear whether such facilitation reflects the mapping of low-level action descriptors, as suggested by the match with the observed or inferred pattern of muscle activation in terms of muscle somatotopy and temporal deployment (Gangitano et al 2001;Borroni et al 2005;Urgesi et al 2006;Valchev et al 2015), or the higher-level aspects such as goals (Cattaneo et al 2009(Cattaneo et al , 2013Cavallo et al 2013) and intentions (Tidoni et al 2013), as suggested by the generalization of effects across muscles (Borroni et al 2008) or effectors (Senna et al 2014;Finisguerra et al 2015). In the present study, we aimed to test whether the modulation of the observer's motor system during observation of deceptive actions (Tidoni et al 2013) reflects the decoding of the actor's intentions or the mapping of the kinematic adaptations required to fool the observer.…”

Dance as a subject for empirical aesthetics.

“…Thus, most brain regions classically associated with movement processing, such as the complex visual motion areas (Kourtzi & Kanwisher, 2000;Senior, Barnes, Giampietro, Simmons, Bullmore, Brammer, et al, 2000) and the motor regions (Urgesi, Moro, Candidi, & Aglioti, 2006), are also sensitive to static body postures. Their involvement while viewing static images suggests that the brain is able to extract the sense of movement even from a mere snapshot of it (Urgesi, Moro, Candidi, & Aglioti, 2006).…”

Observing shadow motions: Resonant activity within the observer's motor system?

“…However, linking these phenomena, suggests that any visual input depicting biological motions should be sufficient to mediate simulating activity in the observer's motor system. In this context, a previous transcranial magnetic stimulation (TMS) study showed that the mere observation of 'implied' motion stimuli (i.e., static snapshots of hands showing a grip action) was able to induce an increase in resonant motor activity as compared with observation of resting, relaxed hands [18].…”