title: No evidence for mirror system dysfunction in schizophrenia from a multimodal TMS/EEG study.
abstract: Dysfunctional mirror neuron systems have been proposed to contribute to the social cognitive deficits observed in schizophrenia. A few studies have explored mirror systems in schizophrenia using various techniques such as TMS (levels of motor resonance) or EEG (levels of mu suppression), with mixed results. This study aimed to use a novel multimodal approach (i.e. concurrent TMS and EEG) to further investigate mirror systems and social cognition in schizophrenia. Nineteen individuals with schizophrenia or schizoaffective disorder and 19 healthy controls participated. Single-pulse TMS was applied to M1 during the observation of hand movements designed to elicit mirror system activity. Single EEG electrodes (C3, CZ, C4) recorded brain activity. Participants also completed facial affect recognition and theory of mind tasks. The schizophrenia group showed significant deficits in facial affect recognition and higher level theory of mind compared to healthy controls. A significant positive relationship was revealed between mu suppression and motor resonance for the overall sample, indicating concurrent validity of these measures. Levels of mu suppression and motor resonance were not significantly different between groups. These findings indicate that in stable outpatients with schizophrenia, mirror system functioning is intact, and therefore their social cognitive difficulties may be caused by alternative pathophysiology.
authors.affiliation: School of Psychological Sciences, Monash University, Clayton, Victoria, Australia; Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School Monash University, Melbourne, Victoria, Australia. Electronic address: sophie.andrews@monash.edu.
authors.forename: Sophie C
authors.initials: SC
authors.lastname: Andrews
authors.affiliation: Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School Monash University, Melbourne, Victoria, Australia; Cognitive Neuroscience Unit, School of Psychology, Deakin University, Burwood, Victoria, Australia.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Enticott
authors.affiliation: Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School Monash University, Melbourne, Victoria, Australia.
authors.forename: Kate E
authors.initials: KE
authors.lastname: Hoy
authors.affiliation: Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School Monash University, Melbourne, Victoria, Australia.
authors.forename: Richard H
authors.initials: RH
authors.lastname: Thomson
authors.affiliation: Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School Monash University, Melbourne, Victoria, Australia.
authors.forename: Paul B
authors.initials: PB
authors.lastname: Fitzgerald
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D003072:Cognition Disorders / Q000209:etiology* / Q000503:physiopathology; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D059167:Mirror Neurons / Q000502:physiology*; D064847:Multimodal Imaging; D011618:Psychotic Disorders / Q000150:complications / Q000503:physiopathology*; D012559:Schizophrenia / Q000150:complications / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
keywords: Electroencephalography; Mirror neurons; Schizoaffective disorder; Social perception; Theory of mind; Transcranial magnetic stimulation