title: Mirror neuron dysfunction in schizophrenia and its functional implications: a systematic review.
abstract: Dysfunctional mirror neuron activity (MNA) has been posited to underlie diverse symptoms of schizophrenia (e.g., ego-boundary disturbances, negative symptoms, social cognition impairments and catatonic symptoms). In this paper, we systematically review studies that have empirically compared putative MNA in schizophrenia patients and healthy subjects using different neurophysiological probes. Majority of the studies (n=9) reported reduced MNA in patients. Two each reported either increased MNA or mixed (both increased and decreased) results, while only one study reported normal findings. Reduced MNA was associated with greater negative symptoms and theory of mind deficits. The neurophysiological technique, task paradigms used, specific brain regions studied and laterality did not influence these findings. Further, we propose an overarching model to understand the heterogeneous symptom dimensions of schizophrenia, in which an inherent mirror system deficit underlying persistent negative symptoms, social cognition impairments and self-monitoring deficits triggers a pathological metaplastic reorganization of this system resulting in aberrant excessive MNA and the phasic catatonic symptoms, affective instability and hallucinations. Despite being preliminary in nature, evidence of abnormal MNA in schizophrenia reported necessitates more detailed investigation. Future research directions of using this model within the Research Domain Criteria framework of the National Institute of Mental Health are discussed.
authors.affiliation: Department of Psychiatry, National Institute of Mental Health & Neurosciences (NIMHANS), Bangalore 560029, India; Department of Psychiatry, Beth Israel Deaconess Medical Center and Massachusetts Mental Health Center, Harvard Medical School, Boston MA 02115, USA. Electronic address: urvakhsh@gmail.com.
authors.forename: Urvakhsh Meherwan
authors.initials: UM
authors.lastname: Mehta
authors.affiliation: Department of Psychiatry, National Institute of Mental Health & Neurosciences (NIMHANS), Bangalore 560029, India.
authors.forename: Jagadisha
authors.initials: J
authors.lastname: Thirthalli
authors.affiliation: Department of Psychiatry, National Institute of Mental Health & Neurosciences (NIMHANS), Bangalore 560029, India.
authors.forename: Dhandapani
authors.initials: D
authors.lastname: Aneelraj
authors.affiliation: Department of Psychiatry, National Institute of Mental Health & Neurosciences (NIMHANS), Bangalore 560029, India.
authors.forename: Prabhu
authors.initials: P
authors.lastname: Jadhav
authors.affiliation: Department of Psychiatry, National Institute of Mental Health & Neurosciences (NIMHANS), Bangalore 560029, India.
authors.forename: Bangalore N
authors.initials: BN
authors.lastname: Gangadhar
authors.affiliation: Department of Psychiatry, Beth Israel Deaconess Medical Center and Massachusetts Mental Health Center, Harvard Medical School, Boston MA 02115, USA.
authors.forename: Matcheri S
authors.initials: MS
authors.lastname: Keshavan
mesh_terms: D001921:Brain / Q000503:physiopathology*; D006801:Humans; D059167:Mirror Neurons / Q000502:physiology*; D009434:Neural Pathways / Q000503:physiopathology; D012559:Schizophrenia / Q000503:physiopathology*
keywords: Mirror neurons; Negative symptoms; Neurobiology; Psychosis; Self-monitoring; Social cognition