How moving objects become animated: The human mirror neuron system assimilates non-biological movement patterns

Abstract

The so-called mirror neuron system (MNS) responds when humans observe actions performed by a member of their own species. This activity is understood as an internal motor representation of the observed movement pattern. By contrasting meaningless human hand movements with meaningless artificial movements of objects in space, we tested the claim that exclusively movements belonging to the human motor repertoire have direct access to the MNS. Eighteen participants observed video clips of moving hands and objects while the hemodynamic response was recorded with functional magnetic resonance imaging. Second-level analysis of the hemodynamic response revealed substantially overlapping activation patterns for both types of movements including relevant structures of the MNS (bilateral premotor and parietal areas, occipito-temporal junction, postcentral gyrus and the right superior temporal sulcus). This suggests that perceptual processing of moving hands and objects recruits similar and overlapping cortical networks. Direct comparison of the two movement types revealed stronger activations for hand movements mainly in structures of the MNS suggesting an “expertise effect”. Overall, our results provide evidence that observing movements not explicitly belonging to the human motor repertoire can activate the human MNS, most likely because an association with a biological movement is evoked.

Acknowledgements

This research was supported by the research training group “Neural representation and action control” (DFG 885/1), the Max-Planck award for international cooperation assigned to FR, and a grant of the German Research Council (DFG Ro529/18–1).

We thank Valeria Gazzola and Christian Keysers for their support in providing their activation maps of the execution condition of their study and Ferdinand Binkofski and two anonymous reviewers for helpful comments on an earlier version of the manuscript.

Notes

¹The two supplementary movies can be accessed at: http://www.uni-marburg.de/fb04/team-roesler/stimuli/engel_etal_2007/. Movie 1 shows examples of three different hand movements presented during encoding for difficulty level 3. Movie 2 shows examples of three different object movements presented during encoding for difficulty level 3.