Multimedia Library
Reproducibility in TMS–EEG studies: A call for data sharing, standard procedures and effective experimental control
A recent study by Conde, Tomasevic et al. (2019) [1] puts a spotlight on the subtleties of experimental design and analysis of studies involving TMS-evoked EEG potentials (TEPs), specifically focusing on the challenge of disentangling genuine cortical responses to TMS from those resulting from concomitant sensory activation. This is a relevant topic that the TMS–EEG community has previously identified [2] and addressed with different strategies [3–6]. Based on the similarity of the evoked EEG responses they obtained in real TMS at different sites and in sham conditions (auditory and somatosensory scalp stimulation), the authors of [1] inferred that TEPs can be significantly contaminated by the effects of concurrent, non-transcranial stimulation.EEG-triggered TMS reveals stronger brain state-dependent modulation of motor evoked potentials at weaker stimulation intensities
Corticospinal excitability depends on the current brain state. The recent development of real-time EEG-triggered transcranial magnetic stimulation (EEG-TMS) allows studying this relationship in a causal fashion. Specifically, it has been shown that corticospinal excitability is higher during the scalp surface negative EEG peak compared to the positive peak of μ-oscillations in sensorimotor cortex, as indexed by larger motor evoked potentials (MEPs) for fixed stimulation intensity.Modulation of cortical responses by transcranial direct current stimulation of dorsolateral prefrontal cortex: A resting-state EEG and TMS-EEG study
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique with potential for cost-effective therapeutic neuromodulation. Although positive therapeutic effects were found by stimulating the dorsolateral prefrontal cortex (DLPFC), few studies have investigated physiological effects of DLPFC-tDCS.Real-time EEG-defined excitability states determine efficacy of TMS-induced plasticity in human motor cortex
Rapidly changing excitability states in an oscillating neuronal network can explain response variability to external stimulation, but if repetitive stimulation of always the same high- or low-excitability state results in long-term plasticity of opposite direction has never been explored in vivo.Inter-subject Variability of LTD-like Plasticity in Human Motor Cortex: A Matter of Preceding Motor Activation
Continuous theta burst stimulation (cTBS) of the human primary motor cortex (M1) induces long-term depression (LTD)-like plastic changes in corticospinal excitability, but several studies have reported high inter-subject variability of this effect. Most studies use a tonic voluntary contraction of the target muscle before cTBS to set stimulation intensity; however, it is unclear how this might affect response variability.
