Mu-wave Activity in Schizophrenia: Evidence of a Dysfunctional Mirror Neuron System from an Indian Study

BACKGROUND: The ‘mirror-neuron system’ is thought to play an important role in automatic decoding of biological motions and interpretation of socially adaptive environmental stimuli. Accordingly, a dysfunction in this system in schizophrenia has been hypothesised to mediate the psychotic manifestations. MATERIALS AND METHODS: As a part of an ongoing study, we evaluated the mirror neuron system using ‘EEG mu-wave (8-13 Hz) suppression’ paradigm in 15 drug naïve/drug free patients and compared the working to 15 age, sex and education matched controls. We also correlated the psychopathology scores on PANSS with the mu wave suppression in the schizophrenia patients, at baseline. We used high (192-channel) resolution EEG to record the mu rhythm while the subjects watched alternating sequences of a socially-relevant biological motion and white visual-noise on a custom made video-clip. RESULTS: We found a significant difference in the degree of mu wave suppression between the two groups. We also found that the degree of mu suppression over right sensorimotor cortex at presentation correlated significantly and negatively with thought disorder in the patient group, and had a strong linear relationship. CONCLUSION: This study replicates past findings regarding a dysfunctional mirror neuron system in schizophrenia patients, and also emphasizes the role of rMNS in schizophrenic thought disorders.