Mirror neurons and synchronization between robots

The discovery of "mirror neurons" in the ventral premotor cortex of the macaque monkey by Rizzolatti and colaborators has generated a genuine impact in Neuroscience. In humans it is impossible to registry the neurophysiological activation of simple neurons but disregarding criticisms (see Alison Gopnik-http://www.slate.com/id/2165123/pagenum/all/-), the influence in many fields of the knowledge (study of social relations, robotics, programming, etc.) is enormous. Privileged witness is the recent work of Barakova, Lourens and Yamaguchi. Barakova and Lourens (2008) design a setup for synchronization and turn-taking behaviour in robots. For it, they connect some aspects of the neuroanatomy of the mirror system in humans with an oscillatory dynamics for neural networks.

In brief, the frontal motor areas receive sensory input from the parietal lobe. Another area is situated in the rostral part of the inferior parietal lobule. Both regions form the mirror neuron system. Besides, the posterior sector of the superior temporal sulcus form a core circuit for imitation. Modelling of the superior temporal sulcus area can be reduced to the influence of the inhibitory neurons, projecting the sensory signals to the inferior parietal lobule, area which is associated with multisensory integration. Each robot has 8 range sensors projecting to the sensory integration area that resembles the functionality of the joined temporal sulcus-inferior parietal areas. The two wheels of the robot project to the sensorimotor integration area, resembling the function of the ventral premotor cortex. Self-organization of rhythmic activity of this system can be simulated by means of endogenous oscillators an so, the change of rate of the phase with the time, is the cycle of the limit cycle oscilation, being the phase periodic over the range.

The experimental setting conceived by Barakova and Lourens presents, in the first place, robots that are taking the role of the follower, in order to establish "mirroring" couplings between the nets that simulate the inferior parietal lobule and premotor ventral areas. Hebbian connections between these nets are modelled such that the interaction behaviour is reflected by the average activation values of unikts over a certain time interval. So, the robot playing the role as a follower, tends to synchronize its motion direction with the motion direction of the leading robot. In the second place, the experiment shows the emergence of turn taking between the robots. The role of the robot, being follower or leader depends on which robot is within the visual field of its partner. The emergent turn taking is expressed by symmetry breaking process after a period of synchronization: the leading robot can become a follower and later the lead can be taken over by it.

Inspired by the mirror system in human beings, Barakova and Lourens simulate very interesting interaction behaviours of following and turn taking such that the mirroring functionality is obtained by means of the selforganization of synchronized neural firing in two robots that share perceptual space. No doubt that many extensions of this work remain to develop and promise great advances in the area of robotics.