@article {Gigliotta129171, author = {Onofrio Gigliotta and Tal Seidel Malkinson and Orazio Miglino and Paolo Bartolomeo}, title = {Artificial pseudoneglect: Connectional constraints leading to the emergence of spatial bias in neurorobots}, elocation-id = {129171}, year = {2017}, doi = {10.1101/129171}, publisher = {Cold Spring Harbor Laboratory}, abstract = {Most people tend to bisect horizontal lines slightly to the left of their true center (pseudoneglect), and start visual search from left-sided items. This physiological leftward spatial bias may depend on hemispheric asymmetries in the organization of attentional networks, but the precise mechanisms are unknown. In this study, we aimed at testing and specifying this hypothesis by modeling relevant aspects of the ventral and dorsal attentional networks (VAN and DAN) of the human brain. First, we demonstrated pseudoneglect in visual search by asking 101 right-handed psychology students to perform a cancellation task. Participants consistently tended to start the task from a left-sided item, thus showing pseudoneglect. Second, we trained five populations of simulated neurorobots to perform a similar task, by using a genetic algorithm. The neurorobots{\textquoteright} behavior was controlled by artificial neural networks, which simulated the human VAN and DAN in the two brain hemispheres. The five populations of neurorobots differed in the connectional constraints that were applied to the anatomy and function of the attention networks. Results indicated that (1) neurorobots provided with a biologically plausible hemispheric asymmetry of the VAN-DAN connections displayed the best match with human data, confirming that such connectional asymmetries may well play a causal role in pseudoneglect; however, (2) anatomical asymmetry per se was not sufficient to generate pseudoneglect; in addition, the VAN must have an excitatory influence on the ipsilateral DAN for such a bias to consistently occur. These findings provide a proof of concept of the causal link between connectional asymmetries and pseudoneglect, and specify important biological constraints that result in physiological asymmetries of human behavior.Author summary When exploring our environment, most of us tend to start their exploration from the left side. In this study, we first provided a demonstration of this tendency in a population of undergraduate students, who tended to start a visual search task by detecting a target on the left side of the display. We then investigated the possible mechanisms of this spatial bias by training artificial agents (neurorobots) to perform a similar visual search task. The neurorobots{\textquoteright} behavior was controlled by artificial neural networks, whose architecture was inspired by the human fronto-parietal attentional system. In five distinct populations of neurorobots, different constraints were applied on the connections of the attentional networks, within and between the brain hemispheres. Only one of the artificial populations demonstrated a spatial bias that closely mirrored that shown by the human participants. The specific connectional constraints applied to this population included known characteristics of the human fronto-parietal networks, but had also additional properties not previously described. Thus, our findings specify important biological constraints that result in physiological asymmetries of human behavior.}, URL = {https://www.biorxiv.org/content/early/2017/04/20/129171}, eprint = {https://www.biorxiv.org/content/early/2017/04/20/129171.full.pdf}, journal = {bioRxiv} }