Social Mirroring: The Role of Mirror Neurons in Decoding Emotions and Intentions From Actions in Autism

Background: Although the role of mirror neurons in action understanding and action imitation has been well documented, its specific role in processing social and affective stimuli needs more clarity. Mirror neurons may play a vital role in action understanding, emotion recognition, and attribution of intentions. These functions may be impaired in autism due to deficits in anatomical and functional integrity of mirror neurons. The current study investigated the role of different components of mirror neurons in inferring emotion and intention.

Objectives: The primary goal of this fMRI study is to examine the role of mirror neurons in action recognition in general, and in decoding emotions and intentions from actions in high-functioning individuals with autism.

Methods: Data from two studies are reported here: in the first one, participants were presented with still images of stick figure characters depicting actions in a randomized blocked design format. In the physical task, participants identified the physical action depicted by the stick figure (e.g. cartwheeling), and in the emotion task, participants identified the emotion or mood depicted by the stick figure (e.g. sad). This study has four high-functioning individuals with autism and two control participants (data collection is progressing). In the second study, non-verbal comic strip vignettes involving physical and intentional causal scenarios were presented randomly and the participants had to choose the most logical ending to each vignette from given alternatives. This study has 12 high-functioning adolescents with autism and fourteen matched controls. The data acquired from a Siemens 3T Allegra scanner were analyzed using Statistical Parametric Mapping (SPM8).

Results: In study 1, while the control participants showed greater activation in inferior frontal aspect of the mirror neuron system while detecting emotions, participants with autism activated inferior parietal area. In study 2, while intentional causal attribution was associated with greater activation in bilateral temporoparietal junction (TPJ) and inferior frontal gyrus (IFG), participants with autism did not show activation in the inferior frontal cortex. In addition the participants with autism showed reliably weaker functional connectivity between TPJ and IFG.

Conclusions: The findings of these studies indicate the specific role of mirror neurons (especially the anterior components of MNS) in emotional and intentional aspects of action understanding, which has direct implications for core social functions like empathy. In addition, participants with autism seem to show reduced activation and reduced connectivity in anterior areas of the MNS associated with processing intentions and emotions. The findings of this study underscore the impairments in social cognition and theory-of-mind in people with autism, in particular their difficulty in attributing intentions to social agents.