Abstract
Processing biological motion is fundamental for everyday life activities, such as social interaction, motor learning and nonverbal communication. The ability to detect the nature of a motor pattern has been investigated by means of point-light displays (PLD), sets of moving light points reproducing human kinematics, easily recognizable as meaningful once in motion. Although PLD are rudimentary, the human brain can decipher their content including social intentions. Neuroimaging studies suggest that inferring the social meaning conveyed by PLD could rely on both the Mirror Neuron System (MNS) and the Mentalizing System (MS), but their specific role to this endeavor remains uncertain. We describe a functional magnetic resonance imaging experiment in which participants had to judge whether visually presented PLD and videoclips of human-like walkers (HL) were facing towards or away from them. Results show that coding for stimulus direction specifically engages the MNS when considering PLD moving away from the observer, while the nature of the stimulus reveals a dissociation between MNS -mainly involved in coding for PLD- and MS, recruited by HL moving away. These results suggest that the contribution of the two systems can be modulated by the nature of the observed stimulus and its potential for social involvement.
Highlights
During social interactions, people engage in active social perception processes, such as attending to others’ body motion (BM), to evaluate the social situation
The results show that while the Mentalizing System (MS) is massively recruited during the observation of Human-Like stimuli (HL) stimuli only when the stimulus is moving towards the observer, the Mirror Neurons System (MNS) appears to be more engaged during the observation of Point-Light Displays (PLD), and to be selectively influenced by the direction of the movement
To verify how the MS and the MNS contribute to BM processing, images of bistable PLD were presented while participants were laying in a scanner for Magnetic Resonance (MR), and were asked to judge whether the stimulus was a front of them (FT) or a FA type by pressing one of two keys on a response device
Summary
People engage in active social perception processes, such as attending to others’ body motion (BM), to evaluate the social situation. We were interested in exploring whether the awareness of dealing with a biological rather than a non-biological agent can significantly change our attitude towards a possible social interaction To this aim we compared Point-Light Displays (PLD)[5] with Human-Like stimuli (HL). The study of Saygin[14] measured brain activity while participants were observing PLD, matched scrambled biological motion and stationary point-light images, and showed that the observation of point-light biological motion activates regions of the frontal cortex, with particular reference to the premotor cortex, while the observation of scrambled biological motion does not These findings suggest that the motor system of the observer may be recruited to “fill in” these simplified displays, in a manner similar to the way mirror neurons are activated in order to assist in action understanding. The results revealed that PLD produced mu suppression relative to baseline, while scrambled versions of these animations did not, corroborating the hypothesis that the MNS is involved in inferring human actions by recovering object information from sparse input
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
