Search

Previous evidence indicates that we understand others' actions not only by perceiving their visual features but also by their sound. This raises the possibility that brain regions responsible for action understanding respond to cues coming from different sensory modalities. Yet no studies, to date, have examined if this extends to olfaction. Here we addressed this issue by using functional magnetic resonance imaging. We searched for brain activity related to the observation of an action executed towards an object that was smelled rather than seen. The results show that temporal, parietal, and frontal areas were activated when individuals observed a hand grasping a smelled object. This activity differed from that evoked during the observation of a mimed grasp. Furthermore, superadditive activity was revealed when the action target-object was both seen and smelled. Together these findings indicate the influence of olfaction on action understanding and its contribution to multimodal action representations.

Our social abilities depend on specialized brain systems that allow us to perform crucial operations such as interpreting the actions of others. This functional magnetic resonance imaging (fMRI) study investigated whether human brain activity evoked by the observation of social interactions is modulated by gaze. During scanning participants observed social or individual actions performed by agents whose gaze could be either available or masked. Results demonstrated that the observation of social interactions evoked activity within a dorsal sector of the medial prefrontal cortex (MPFC), an area classically involved in social cognition. Importantly, activity within this area was modulated by whether the gaze of the agents performing the observed action was or was not available. The implications of these findings for a role played by the dorsal medial prefrontal cortex (dMPFC) in terms of inferential processes concerned with social interactions are considered.