scholarly journals Study of the Functional Brain Connectivity and Lower-Limb Motor Imagery Performance After Transcranial Direct Current Stimulation

2020 ◽  
Vol 30 (08) ◽  
pp. 2050038
Author(s):  
Mario Ortiz ◽  
Eduardo Iáñez ◽  
Jorge A. Gaxiola-Tirado ◽  
David Gutiérrez ◽  
José M. Azorín

The use of transcranial direct current stimulation (tDCS) has been related to the improvement of motor and learning tasks. The current research studies the effects of an asymmetric tDCS setup over brain connectivity, when the subject is performing a motor imagery (MI) task during five consecutive days. A brain–computer interface (BCI) based on electroencephalography is simulated in offline analysis to study the effect that tDCS has over different electrode configurations for the BCI. This way, the BCI performance is used as a validation index of the effect of the tDCS setup by the analysis of the classifier accuracy of the experimental sessions. In addition, the relationship between the brain connectivity and the BCI accuracy performance is analyzed. Results indicate that tDCS group, in comparison to the placebo sham group, shows a higher significant number of connectivity interactions in the motor electrodes during MI tasks and an increasing BCI accuracy over the days. However, the asymmetric tDCS setup does not improve the BCI performance of the electrodes in the intended hemisphere.

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Marta Parazzini ◽  
Serena Fiocchi ◽  
Ilaria Liorni ◽  
Paolo Ravazzani

Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that delivers low intensity, direct current to cortical areas facilitating or inhibiting spontaneous neuronal activity. This paper investigates how normal variations in anatomy may affect the current flow through the brain. This was done by applying electromagnetic computational methods to human models of different age and gender and by comparing the electric field and current density amplitude distributions within the tissues. Results of this study showed that the general trend of the spatial distributions of the field amplitude shares some gross characteristics among the different human models for the same electrode montages. However, the physical dimension of the subject and his/her morphological and anatomical characteristics somehow influence the detailed field distributions such as the field values.


2021 ◽  
Vol 33 (1) ◽  
pp. 146-157
Author(s):  
Chong Zhao ◽  
Geoffrey F. Woodman

It is not definitely known how direct-current stimulation causes its long-lasting effects. Here, we tested the hypothesis that the long time course of transcranial direct-current stimulation (tDCS) is because of the electrical field increasing the plasticity of the brain tissue. If this is the case, then we should see tDCS effects when humans need to encode information into long-term memory, but not at other times. We tested this hypothesis by delivering tDCS to the ventral visual stream of human participants during different tasks (i.e., recognition memory vs. visual search) and at different times during a memory task. We found that tDCS improved memory encoding, and the neural correlates thereof, but not retrieval. We also found that tDCS did not change the efficiency of information processing during visual search for a certain target object, a task that does not require the formation of new connections in the brain but instead relies on attention and object recognition mechanisms. Thus, our findings support the hypothesis that direct-current stimulation modulates brain activity by changing the underlying plasticity of the tissue.


2018 ◽  
Author(s):  
M. Ruttorf ◽  
S. Kristensen ◽  
L.R. Schad ◽  
J. Almeida

AbstractTranscranial direct current stimulation (tDCS) is routinely used in basic and clinical research, but its efficacy has been challenged on a methodological and statistical basis recently. The arguments against tDCS derive from insufficient understanding of how this technique interacts with brain processes physiologically. Because of its potential as a central tool in neuroscience, it is important to clarify whether and how tDCS affects neuronal activity. Here, we investigate influences of offline tDCS on network architecture measured by functional magnetic resonance imaging. Our results reveal a tDCS-induced reorganisation of a functionally-defined network that is dependent on whether we are exciting or inhibiting a node within this network, confirming in a functioning brain, and in a bias free and independent fashion that tDCS influences neuronal activity. Moreover, our results suggest that network-specific connectivity has an important role in defining the effects of tDCS and the relationship between brain states and behaviour.


2015 ◽  
Vol 20 (4) ◽  
pp. 453-468 ◽  
Author(s):  
Shoko Kasuga ◽  
Yayoi Matsushika ◽  
Yuko Kasashima-Shindo ◽  
Daiki Kamatani ◽  
Toshiyuki Fujiwara ◽  
...  

Metallomics ◽  
2018 ◽  
Vol 10 (3) ◽  
pp. 397-405
Author(s):  
Agata Ziomber ◽  
Artur Dawid Surowka ◽  
Lucyna Antkiewicz-Michaluk ◽  
Irena Romanska ◽  
Pawel Wrobel ◽  
...  

A new methodology for a combined Fe, Cu, Zn and neurometabolite analysis in the brain is reported.


Author(s):  
Jacky Au ◽  
Martin Buschkuehl ◽  
Susanne M. Jaeggi

The aim of this chapter is to contribute to the discussion of the cognitive neuroscience of brain stimulation. In doing so, the authors emphasize work from their own laboratory that focuses both on working memory training and transcranial direct current stimulation. Transcranial direct current stimulation is one of the most commonly used and extensively researched methods of transcranial electrical stimulation. The chapter focuses on implementation of transcranial direct current stimulation to enhance and inform research on working memory training, and not on the underlying mechanisms of transcranial direct current stimulation. Thus, while respecting the intricacies and unknowns of the inner workings of electrical stimulation on the brain, the chapter relies on the premise that transcranial direct current stimulation is able to directly affect the electrophysiological profile of the brain and provides evidence that this in turn can influence behavior given the right parameters.


2019 ◽  
Vol 12 (4) ◽  
pp. 1086-1088 ◽  
Author(s):  
Ashlee M. Hendy ◽  
Helen Macpherson ◽  
Nathan D. Nuzum ◽  
Paul A. Della Gatta ◽  
Sarah E. Alexander ◽  
...  

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