Brain Stimul
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Functional magnetic resonance imaging (fMRI) has shown that transcranial direct current stimulation (tDCS) of the hand motor cortex modulates cortical activity of the healthy human brain. However, few studies have assessed the effects of tDCS on the leg motor cortex. We therefore used fMRI to examine the modulating effects of tDCS on lower limb motor cortex responses. ⋯ Anodal tDCS increased corticospinal excitability of the lower limb motor cortex in healthy subjects, suggesting that multiple brain cortical areas may be associated with leg motor performance via involvement of variable corticocortical connections.
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The ventrointermediate nucleus (Vim) of the thalamus is still considered "invisible" on current magnetic resonance imaging (MRI), requiring indirect methods based on stereotactic atlases for estimation of its location. Direct visualization of Vim is desirable to improve targeting. ⋯ 1.5-T MRI with WAIR sequence provides high-quality images of Vim suitable in DBS surgery, for accurate preoperative planning, direct targeting and anatomic analysis.
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Transcranial direct current stimulation (tDCS) is a noninvasive method of modulating cortical excitability. The aim of this study was to investigate the effects of short-duration tDCS (1.6 seconds per trial) on memory performance, and whether the effects were affected by stimulation administered early or late in a trial. Participants memorize words under anodal and cathodal tDCS to the left dorsolateral prefrontal cortex (DLPFC) in two separate sessions in no-stimulation, early stimulation, and late stimulation trials. ⋯ Early anodal tDCS led to significantly better accuracy and speed in a subsequent recognition test compared to anodal late or no-stimulation conditions. Early cathodal tDCS, on the other hand, led to significantly worse accuracy and speed in a subsequent recognition test compared with cathodal late or no-stimulation conditions. The results of this study suggest that short-duration tDCS can modulate memory performance and highlight the importance of period of stimulation.
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Clinical Trial
Intraoperative microelectrode recording for the delineation of subthalamic nucleus topography in Parkinson's disease.
The subthalamic nucleus (STN) as an effective target for deep brain stimulation (DBS) in advanced Parkinson's disease is functionally divided into the dorsolateral sensorimotor and the ventromedial limbic and associative parts. To implant electrodes for DBS close to the sensorimotor region is considered crucial for optimal motor benefit and for avoidance of potential cognitive and behavioral side effects. ⋯ Among all parameters analyzed in the study, spike pattern is the only convenient electrophysiologic parameter for the differentiation of STN subregions in patients with Parkinson's disease. The autocorrelogram-based analysis of spike activity seems to be of certain value for the delineation of the dorsolateral STN and might therefore facilitate the precise electrode implantation for DBS.
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Randomized Controlled Trial
Transcranial direct current stimulation in treatment resistant depression: a randomized double-blind, placebo-controlled study.
Anodal transcranial direct current stimulation (tDCS) of the prefrontal cortex has been proposed as therapeutic intervention in major depression. According to clinical needs, this study addresses the question whether tDCS is effective in treatment resistant major depressive episodes. ⋯ Anodal tDCS, applied for 2 weeks, was not superior to placebo treatment in patients with treatment resistant depression. However, secondary outcome measures are pointing to a positive effect of tDCS on emotions. Therefore, modified and improved tDCS protocols should be carried out in controlled pilot trials to develop tDCS towards an efficacious antidepressant intervention in therapy-resistant depression.