AUTHOR=Vignaud Philippe , Damasceno Caroline , Poulet Emmanuel , Brunelin Jérôme 

TITLE=Impaired Modulation of Corticospinal Excitability in Drug-Free Patients With Major Depressive Disorder: A Theta-Burst Stimulation Study

JOURNAL=Frontiers in Human Neuroscience

VOLUME=Volume 13 - 2019

YEAR=2019

URL=https://www.frontiersin.org/journals/human-neuroscience/articles/10.3389/fnhum.2019.00072

DOI=10.3389/fnhum.2019.00072

ISSN=1662-5161

ABSTRACT=Impaired neural plasticity may be an important mechanism in the pathophysiology of major depressive disorder (MDD). Coupled with electromyography, repetitive transcranial magnetic stimulation (rTMS) is a useful tool to evaluate corticospinal excitability and cortical neuroplasticity in living humans. The goal of this study was to compare rTMS-induced cortical plasticity changes in patients with MDD and in healthy volunteers. In this single-blind controlled study, 11 drug-free patients with MDD and 11 matched healthy controls were included. Cortical excitability, measured by the amplitude of motor evoked potentials (MEPs) evoked by single-pulse TMS, was assessed before and repeatedly after (for 30 min) participants received a single session of intermittent (iTBS) and continuous theta-burst stimulation (cTBS). rTMS was applied over the left motor cortex using a neuronavigation system. Intensity was set at 80% of the active motor threshold.
A large interindividual variability was observed after both iTBS and cTBS in the 2 groups. At the group level, we observed impaired iTBS-induced neuroplasticity in patients with MDD compared to that in controls. No differences were observed between the groups regarding cTBS-induced neuroplasticity. Our results suggest impaired long-term potentiation (LTP)-like mechanisms in MDD but preservation of long-term depression (LTD)-like mechanisms.
clinicaltrials.gov identifier: NCT02438163.