Brain Stimul
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It is well known that transcranial direct current stimulation (tDCS) is capable of modulating corticomotor excitability. However, a source of growing concern has been the observed inter- and intra-individual variability of tDCS-responses. Recent studies have assessed whether individuals respond in a predictable manner across repeated sessions of anodal tDCS (atDCS). The findings of these investigations have been inconsistent, and their methods have some limitations (i.e. lack of sham condition or testing only one tDCS intensity). ⋯ 2 mA anodal tDCS results in consistent intra- and inter-individual increases of M1 excitability.
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Randomized Controlled Trial
Stimulating cognition in schizophrenia: A controlled pilot study of the effects of prefrontal transcranial direct current stimulation upon memory and learning.
Schizophrenia is characterized by prominent cognitive deficits, impacting on memory and learning; these are strongly associated with the prefrontal cortex. ⋯ This is the first study to show a significant longer-term effect of tDCS on working memory in schizophrenia. Given the current lack of effective therapies for cognitive deficits, tDCS may offer an important novel approach to modulating brain networks to ameliorate cognitive deficits in schizophrenia.
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Randomized Controlled Trial
Cortical excitability after pediatric mild traumatic brain injury.
Mild traumatic brain injury (mTBI) outcomes are variable, and 10-15% may suffer from prolonged symptoms beyond 3 months that impair the child's return to normal activities. Neurophysiological mechanisms of mTBI are incompletely understood, particularly in children, but alterations in cortical excitability have been proposed to underlie post-concussion syndrome. Improved understanding is required to advance interventions and improve outcomes. ⋯ TMS measures of cortical excitability are altered at one month in children with mTBI. Long interval cortical inhibition is decreased in children who remain symptomatic at one month post-injury.
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Continuous theta burst stimulation (cTBS) and intermittent TBS (iTBS) are powerful patterns of repetitive transcranial magnetic stimulation (rTMS), with substantial potential for motor function rehabilitation post-stroke. However, TBS of suprahyoid motor cortex excitability has not been investigated. This study investigated TBS effects on suprahyoid motor cortex excitability and its potential mechanisms in healthy subjects. ⋯ TBS effectively regulates suprahyoid motor cortex excitability. Suppression of excitability in one hemisphere leads to further activation of the corresponding contralateral motor cortex. iTBS reverses the inhibitory effect induced by cTBS of the contralateral suprahyoid motor cortex.
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Long-interval intracortical inhibition (LICI) is a transcranial magnetic stimulation (TMS) paradigm that uses paired magnetic stimuli separated by 100-200 ms to investigate the activity of cortical GABAergic interneurons. While commonly applied, the mechanisms contributing to LICI are not well understood, and growing evidence suggests that inhibition observed at different interstimulus intervals (ISI) may involve non-identical processes. ⋯ These findings suggest that LICI100 and LICI150 reflect complex measurements of cortical inhibition with differential contributions from comparable circuits.