Abstract

Motor Resonance Mechanisms during Action Imitation in Depression

Author(s): Djamila Bennabi, Nicolas Carvalho, Ambra Bisio, Emmanuel Haffen, Thierry Pozzo

Objectives

Major depressive disorder has been associated with impairments in social cognition. However, studies exploring the processing of social information focused on facial discrimination. The aim of this study was to better characterize the sensorimotor mechanisms underlying motor resonance in depressed patients.

Method

Twenty-three right-handed patients meeting DSM-IV criteria for unipolar depression were compared to 14 matched healthy controls. In a simple imitation paradigm, the kinematic features of movements in natural condition were compared to those of motions performed after the observation of a moving dot. Reaction time and pointing velocity were considered to evaluate if the motor performance was contaminated by the observed stimulus.

Results

Patient’s velocity varied in agreement with dot velocity, proving that they were able to extract the correct information from the stimuli and use it to plan their responses. Depressed patients’ actions, as well as healthy controls, were influenced by the dot velocity, suggesting that motor resonance mechanisms are not prevented by depression. In contrast, only patients had anticipatory motor response and started moving before the end of the stimulus motion.

Conclusion

Our findings suggest that motor resonance mechanisms are not altered by the disease. However, depressed patients exhibit a specific deficit in motor inhibition in the selection of motor responses.