Abnormal visuomotor processing in schizophrenia.

Siân E Robson,Peter F Liddle,Mohammad Z Katshu,Fiesal Jan,Elizabeth B Liddle,Matthew J Brookes,Lena Palaniyappan,Michael Skelton,Peter G Morris,Jyothika Kumar,Nikolaos G Christodoulou,Emma L Hall,Ayaz Qureshi

doi:10.1016/j.nicl.2015.08.005

Abstract

Subtle disturbances of visual and motor function are known features of schizophrenia and can greatly impact quality of life; however, few studies investigate these abnormalities using simple visuomotor stimuli. In healthy people, electrophysiological data show that beta band oscillations in sensorimotor cortex decrease during movement execution (event-related beta desynchronisation (ERBD)), then increase above baseline for a short time after the movement (post-movement beta rebound (PMBR)); whilst in visual cortex, gamma oscillations are increased throughout stimulus presentation. In this study, we used a self-paced visuomotor paradigm and magnetoencephalography (MEG) to contrast these responses in patients with schizophrenia and control volunteers. We found significant reductions in the peak-to-peak change in amplitude from ERBD to PMBR in schizophrenia compared with controls. This effect was strongest in patients who made fewer movements, whereas beta was not modulated by movement in controls. There was no significant difference in the amplitude of visual gamma between patients and controls. These data demonstrate that clear abnormalities in basic sensorimotor processing in schizophrenia can be observed using a very simple MEG paradigm.

Highlights

Schizophrenia is a psychiatric disorder characterised by a range of symptoms including hallucinations, delusions, disorganised thought and behaviour, and reduced cognitive and emotional capacity
Electrophysiological data show that beta band oscillations in sensorimotor cortex decrease during movement execution (event-related beta desynchronisation (ERBD)), increase above baseline for a short time after the movement (post movement beta rebound (PMBR)); while in visual cortex, gamma oscillations are increased throughout stimulus presentation
Both groups exhibit the expected changes in oscillatory power in the beta and gamma bands throughout the trial: in motor cortex, beta amplitude decreases during stimulation with a PMBR on movement cessation; and in visual cortex, there is a decrease in alpha oscillatory amplitude and a concomitant increase in gamma amplitude during stimulation

Summary

Introduction

Schizophrenia is a psychiatric disorder characterised by a range of symptoms including hallucinations, delusions, disorganised thought and behaviour, and reduced cognitive and emotional capacity. Abnormalities in motor function have been noted since the earliest descriptions of the disorder (Kraepelin, 1919) and are a well-accepted feature of schizophrenia, with the vast majority of patients exhibiting at least one type of motor symptom (Peralta et al, 2010; Walther et al, 2012). These symptoms include involuntary movements, catatonia, Parkinsonism and deficits in the production of both simple and complex movements such as coordination, reflexes and motor sequencing (Bombin et al, 2005; Kraepelin, 1919; Vrtunski et al, 1989). Visual and motor deficits, as well as other neurological abnormalities, correlate with the primary symptoms of schizophrenia such as affective flattening, apathy and disorganisation (Bombin et al, 2005; Jahn et al, 2006; Liddle, 1987; Peralta et al, 2010) , and with illness severity (Jahn et al, 2006), social functioning (Dickerson et al, 1996; Jahn et al, 2006; Lehoux, 2003) and functional outcome (Boden et al, 2014; Javitt, 2009), suggesting they could be used as a biomarker for the disorder

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Conclusion