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Mini Review ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Hum. Neurosci. | doi: 10.3389/fnhum.2019.00332

Low or high-level motor coding? The role of stimulus complexity

  • 1Basque Center on Cognition, Brain and Language, Spain
  • 2IKERBASQUE Basque Foundation for Science, Spain
  • 3Department of Languages and Literatures, Communication, Education and Society, University of Udine, Italy
  • 4Eugenio Medea (IRCCS), Italy

Transcranial magnetic stimulation (TMS) studies have shown that observing an action induces activity in the onlooker’s motor system. In light of the muscle specificity and time-locked mirroring nature of the effect, this motor resonance has been traditionally viewed as an inner automatic replica of the observed movement. Notably, studies highlighting this aspect have classically considered movement in isolation (i.e., using non-realistic stimuli such as snapshots of hands detached from background). However, a few recent studies accounting the role of contextual cues, motivational states and social factors, have challenged this view by showing that motor resonance is not completely impervious to top-down modulations. A debate is still present. We reasoned that motor resonance reflects the inner replica of the observed movement only when its modulation is assessed during the observation of movements in isolation. Conversely, the presence of top-down modulations of motor resonance emerges when other high-level factors (i.e., contextual cues, past experience, social and motivational states) are taken into account. Here, we attempt to lay out current TMS studies assessing this issue and discuss the results in terms of their potential to favor the inner replica or the top-down modulation hypothesis. By doing so, we seek to shed light on this actual debate and suggest specific avenues for future research, highlighting the need for a more ecological approach when studying motor resonance phenomenon.

Keywords: Kinematics mapping, Top down modulation, action observation, action representation, CSE, Transcranial Magnetic Stimulation, motor resonance

Received: 15 Apr 2019; Accepted: 09 Sep 2019.

Copyright: © 2019 Amoruso and Finisguerra. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Mx. Alessandra Finisguerra, Eugenio Medea (IRCCS), Bosisio Parini, Italy, afinisguerra@gmail.com