Motor ontology in representing gaze–object relations

Event-related functional magnetic resonance imaging (fMRI) was used to explore how the human brain models gaze–object relations. During scanning participants observed a human model gazing towards or away a target object presented either in isolation or flanked by a distractor object. In two further conditions the model's gaze was shifted and subsequently maintained away from the stimulus/i. These four conditions were implemented within a factorial design in which the main factors were “type of observed behavior” (gaze vs. gaze-away) and “context” (target alone vs. target flanked by a distractor). Results revealed that premotor, parietal and temporal areas, known to sub-serve the understanding of other people actions, were significantly more activated by the observation of the model gazing towards rather than away from the stimulus/i. In addition, a significant interaction indicated that, when the target was presented in isolation, neural activity within the inferior frontal gyrus, another key area for action understanding, was influenced by gaze–object relations. Our findings suggest that this area is important for the establishment of intentional gaze–object relations and indicate that the presence of a distractor interferes with the representation of such relations.