Reduced mu suppression and altered motor resonance in euthymic bipolar disorder: evidence for a dysfunctional mirror system?

TY - JOUR

T1 - Reduced mu suppression and altered motor resonance in euthymic bipolar disorder: evidence for a dysfunctional mirror system?

AU - Andrews, Sophie C

AU - Enticott, Peter G

AU - Hoy, Kate E

AU - Thomson, Richard H

AU - Fitzgerald, Paul B

N1 - PGE was supported by Clinical Research Fellowship grant from the National Health and Medical Research Council (NHMRC). KEH was also supported by an NHMRC Fellowship grant. PBF was supported by an NHMRC Practitioner Fellowship grant

PY - 2016

Y1 - 2016

N2 - Social cognitive difficulties are common in the acute phase of bipolar disorder and, to a lesser extent, during theeuthymic stage, and imaging studies of social cognition in euthymic bipolar disorder have implicated mirrorsystem brain regions. This study aimed to use a novel multimodal approach (i.e., including both transcranialmagnetic stimulation (TMS) and electroencephalogram (EEG)) to investigate mirror systems in bipolar disorder.Fifteen individuals with euthymic bipolar disorder and 16 healthy controls participated in this study. Single-pulseTMS was applied to the optimal site in the primary motor cortex (M1), which stimulates the muscle of interestduring the observation of hand movements (goal-directed or interacting) designed to elicit mirror system activity.Single EEG electrodes (C3, CZ, C4) recorded mu rhythm modulation concurrently. Results revealed that thepatient group showed significantly less mu suppression compared to healthy controls. Surprisingly, motorresonance was not significantly different overall between groups; however, bipolar disorder participants showeda pattern of reduced reactivity on some conditions. Although preliminary, this study indicates a potential mirrorsystem deficit in euthymic bipolar disorder, which may contribute to the pathophysiology of the disorder.

AB - Social cognitive difficulties are common in the acute phase of bipolar disorder and, to a lesser extent, during theeuthymic stage, and imaging studies of social cognition in euthymic bipolar disorder have implicated mirrorsystem brain regions. This study aimed to use a novel multimodal approach (i.e., including both transcranialmagnetic stimulation (TMS) and electroencephalogram (EEG)) to investigate mirror systems in bipolar disorder.Fifteen individuals with euthymic bipolar disorder and 16 healthy controls participated in this study. Single-pulseTMS was applied to the optimal site in the primary motor cortex (M1), which stimulates the muscle of interestduring the observation of hand movements (goal-directed or interacting) designed to elicit mirror system activity.Single EEG electrodes (C3, CZ, C4) recorded mu rhythm modulation concurrently. Results revealed that thepatient group showed significantly less mu suppression compared to healthy controls. Surprisingly, motorresonance was not significantly different overall between groups; however, bipolar disorder participants showeda pattern of reduced reactivity on some conditions. Although preliminary, this study indicates a potential mirrorsystem deficit in euthymic bipolar disorder, which may contribute to the pathophysiology of the disorder.

KW - Mirror neurons

KW - Transcranial magnetic stimulation

KW - Electroencephalogram

KW - Social cognition

KW - Theory of mind

UR - http://www.tandfonline.com/doi/pdf/10.1080/17470919.2015.1029140

U2 - 10.1080/17470919.2015.1029140

DO - 10.1080/17470919.2015.1029140

M3 - Article

VL - 11

SP - 60

EP - 71

JO - Social Neuroscience

JF - Social Neuroscience

SN - 1747-0919

IS - 1

ER -