Validating a Sham Condition for Use in High Definition Transcranial Direct Current Stimulation

Garnett, Emily O.; Ouden, Dirk-Bart den

doi:10.1016/j.brs.2015.01.399

Cited by 45 publications

(36 citation statements)

References 6 publications

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“…For the actual stimulation, the current was applied for approximately 20 min (the exact length depended on the time that the subject completed the task), including an initial 30 s of ramping up and final 30 s of ramping down at the end. For the sham stimulation, the current was ramped up to 1.5 mA in 30 s and immediately ramped down to 0 in the following 30 s. This procedure was useful to blind the subjects to whether they received the sham stimulation (Garnett & Ouden, ). Previous studies have shown that 1.5‐mA HD‐tDCS is safe in healthy subjects (Gözenman & Berryhill, ).…”

Section: Methodsmentioning

confidence: 99%

High‐definition transcranial direct current stimulation (HD‐tDCS) of left dorsolateral prefrontal cortex affects performance in Balloon Analogue Risk Task (BART)

Guo

Zhang

et al. 2018

Brain and Behavior

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BackgroundStudies on risk preferences have long been of great concern and have examined the neural basis underlying risk‐based decision making. However, studies using conventional transcranial direct current stimulation (tDCS) revealed that bilateral stimulation could change risk propensity with limited evidence of precisely focalized unilateral high‐definition transcranial direct current stimulation (HD‐tDCS). The aim of this experiment was to investigate the effect of HD‐tDCS focalizing the left dorsal lateral prefrontal cortex (DLPFC) on risk‐taking behavior during the Balloon Analogue Risk Task (BART).MethodsThis study was designed as a between‐subject, single‐blind, sham‐controlled experiment. University students were randomly assigned to three groups: the anodal group (F3 anode, AF3, F1, F5, FC3 returned), the cathodal group (F3 cathodal, AF3, F1, F5, FC3 returned) and the sham group. Subsequently, 1.5‐mA 20‐min HD‐tDCS was applied during the BART, and the Positive Affect and Negative Affect Scale (PANAS), the Sensation Seeking Scale‐5 (SSS‐5), and the Behavioral Inhibition System and Behavioral Approach System scale (BIS/BAS) were measured as control variables.ResultsThe cathodal group earned less total money than the sham group, and no significant difference was observed between the anodal group and the sham group.ConclusionsThese results showed that, to some extent, focalized unilateral cathodal HD‐tDCS on left DLPFC could change performance during risky tasks and diminish risky decision making. Further studies are needed to investigate the dose effect and electrode distribution of HD‐tDCS during risky tasks and examine synchronous brain activity to show the neural basis.

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Section: Methodsmentioning

confidence: 99%

High‐definition transcranial direct current stimulation (HD‐tDCS) of left dorsolateral prefrontal cortex affects performance in Balloon Analogue Risk Task (BART)

Guo

Zhang

et al. 2018

Brain and Behavior

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“…During active DLPFC or ATL stimulation, participants received 2mA of stimulation for 20 minutes, plus a 30 sec ramp up time at the start of stimulation and a 30 sec ramp down time at the end of stimulation. During sham HD-tDCS [61], the current ramped up to 2 mA and then back down during the first 30 sec, remained at 0.1 mA for 20 minutes, and then ramped up to 2mA and down again at the end of the sham period for the last 30 seconds. Participants completed 3 sessions (~1 week apart), with separate DLPFC, ATL, and sham HD-tDCS sessions; sessions were counterbalanced for stimulation and order across subjects (Figure 1).…”

Section: Methodsmentioning

confidence: 99%

Effects of HD-tDCS on memory and metamemory for general knowledge questions that vary by difficulty

2017

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Background The ability to monitor one’s own memory is an important feature of normal memory and is an aspect of ‘metamemory’. Lesion studies have shown dissociations between memory and metamemory, but only single dissociations have been shown using transcranial direct current stimulation (tDCS). One potential reason that only single dissociations have been shown is that tDCS effects may be moderated by task difficulty. Objective/Hypothesis We used high definition (HD) tDCS to test for dissociable roles of the dorsolateral prefrontal cortex (DLPFC) and anterior temporal lobe (ATL) in semantic long-term memory and metamemory tasks. We also tested whether general knowledge question difficulty moderated the effects of HD-tDCS. Methods Across 3 sessions, participants received active HD-tDCS over the left DLPFC or left ATL, or sham HD-tDCS during general knowledge recall and recognition tests, and a ‘feeling-of-knowing’ metamemory task. General knowledge questions were blocked by difficulty. Repeated measures ANOVAs were used to examine the effects of HD-tDCS on memory and metamemory tasks by memory question difficulty. Results HD-tDCS over the ATL led to improved recall compared to DLPFC and sham HD-tDCS, and this occurred only for medium difficulty questions. In contrast, for non-recalled questions, HD-tDCS over the DLPFC led to improved recognition accuracy and improved feeling-of-knowing accuracy compared to ATL and sham HD-tDCS, and this was not moderated by memory question difficulty. Conclusion(s) HD-tDCS can be used to dissociate the roles of the ATL and DLPFC in different memory and ‘metamemory’ tasks. The effects of HD-tDCS on task may be moderated by task difficulty, depending on the nature of the task and site of stimulation.

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“…A continuous‐stimulation sham condition used the same electrode positions, but with current flowing directly between the two pairs of adjacent electrodes (FT9‐FT7 and TP7‐CP5, at 1 mA in each pair). Current was thus modeled to pass the cortex only minimally without participants sensing the difference between sham and cortical stimulation .…”

Section: Methodsmentioning

confidence: 99%

On the Use of the Terms Anodal and Cathodal in High-Definition Transcranial Direct Current Stimulation: A Technical Note

Garnett

Malyutina

Datta

et al. 2015

Neuromodulation: Technology at the Neural Interface

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Validating a Sham Condition for Use in High Definition Transcranial Direct Current Stimulation

Cited by 45 publications

References 6 publications

High‐definition transcranial direct current stimulation (HD‐tDCS) of left dorsolateral prefrontal cortex affects performance in Balloon Analogue Risk Task (BART)

High‐definition transcranial direct current stimulation (HD‐tDCS) of left dorsolateral prefrontal cortex affects performance in Balloon Analogue Risk Task (BART)

Effects of HD-tDCS on memory and metamemory for general knowledge questions that vary by difficulty

On the Use of the Terms Anodal and Cathodal in High-Definition Transcranial Direct Current Stimulation: A Technical Note

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