Inter- and intra-subject variability of motor cortex plasticity following continuous theta-burst stimulation

Abstract

Background: The potential of non-invasive brain stimulation (NIBS) for studying, and

The interindividual variability of transcranial magnetic stimulation effects: Implications for diagnostic use in movement disorders

“…The same variability has been observed in repetitive TMS (rTMS) after‐effects . rTMS includes several techniques (Supplementary Table) able to induce changes in the excitability of the stimulated cortical site that outlast the period of stimulation by minutes or hours; they are thought to represent long‐term potentiation (LTP)/depression (LTD)–like phenomena (ie, plasticity) .…”

“…rTMS includes several techniques (Supplementary Table) able to induce changes in the excitability of the stimulated cortical site that outlast the period of stimulation by minutes or hours; they are thought to represent long‐term potentiation (LTP)/depression (LTD)–like phenomena (ie, plasticity) . Recent studies have shown that the interindividual variability of rTMS is considerable and that most plasticity protocols induce the “expected” effects only in 40% to 60% of participants . It has been proposed that the different response to rTMS might depend on the subset of cortical neurones preferentially recruited or on the excitability of the cortex at the time of the stimulation or may be the result of the outcome measure used to probe plasticity .…”

Controllable Pulse Parameter TMS and TMS-EEG As Novel Approaches to Improve Neural Targeting with rTMS in Human Cerebral Cortex

“…Recent studies suggest that, at least for some rTMS protocols (i.e., intermittent and continuous theta burst stimulation), the variance in outcomes accounted for by intra-individual variability is less than a third of that due to inter-individual variability (Hinder et al, 2014; Vallence et al, 2015). The inter-individual variability is, however, quite substantial and evidence suggests most protocols only produce the “expected” effects in 40–60% participants (Hamada et al, 2013; Hinder et al, 2014; López-Alonso et al, 2014; Vallence et al, 2015; Simeoni et al, 2016). Exploration of factors contributing to inter-individual differences has shown that they involve genetics, sex, age, physical fitness, hormone levels, and brain anatomy (Ridding and Ziemann, 2010).…”

“…A major issue with rTMS protocols is that the effects vary considerably within and between individuals (Maeda et al, 2000; Hamada et al, 2013; Vernet et al, 2013; Goldsworthy et al, 2014; Hinder et al, 2014; López-Alonso et al, 2014; Vallence et al, 2015; Simeoni et al, 2016), which causes problems in replication of results in a research setting (Héroux et al, 2015), and is an obstacle to using rTMS in a therapeutic setting. A separate, but related, issue is that rTMS over a given cortical area is often assumed to affect all neuronal populations equally and thus affect all behaviors involving that area similarly, but this may not be true.…”

Anhedonia across borders: Transdiagnostic relevance of reward dysfunction for noninvasive brain stimulation endophenotypes

“…Also, following the neuronal projections of the targeted areas, it has been hypothesized that there could be a wider‐range action, while is not clear if in its mechanism of action, a modulation of the synaptic plasticity could be involved . The application of NIBS in different conditions has been found to determine a clinical response in a portion, but not all, of the treated patients . Nowadays, the efforts in medical research to improve and promote the neuromodulation interventions are focused on detecting different endophenotypes of mental diseases that could be more predictive of a better response to treatment.…”