Abstract
Transcranial direct current stimulation (tDCS) is an innovative method to explore the causal structure-function relationship of brain areas. We investigated the specificity of bilateral bi-cephalic tDCS with two active electrodes of the same polarity (e.g., cathodal on both hemispheres) applied to intraparietal cortices bilaterally using a combined between- and within-task approach. Regarding between-task specificity, we observed that bilateral bi-cephalic tDCS affected a numerical (mental addition) but not a control task (colour word Stroop), indicating a specific influence of tDCS on numerical but not on domain general cognitive processes associated with the bilateral IPS. In particular, the numerical effect of distractor distance was more pronounced under cathodal than under anodal stimulation. Moreover, with respect to within-task specificity we only found the numerical distractor distance effect in mental addition to be modulated by direct current stimulation, whereas the effect of target identity was not affected. This implies a differential influence of bilateral bi-cephalic tDCS on the recruitment of different processing components within the same task (number magnitude processing vs. recognition of familiarity). In sum, this first successful application of bilateral bi-cephalic tDCS with two active electrodes of the same polarity in numerical cognition research corroborates the specific proposition of the Triple Code Model that number magnitude information is represented bilaterally in the intraparietal cortices.
Highlights
In almost all instances when cognitive functions are investigated with functional Magnetic Resonance Imaging, bilateral activation patterns are revealed
An innovative method to investigate bilateral processing is the use of transcranial direct current stimulation, which will be described in more detail in the following
In the current study we successfully applied bilateral bi-cephalic transcranial direct current stimulation (tDCS) with two active electrodes of the same polarity with particular interest being paid to the specificity of this stimulation setting in a combined between- and within-task approach
Summary
In almost all instances when cognitive functions are investigated with functional Magnetic Resonance Imaging (fMRI), bilateral activation patterns are revealed. This is the case for numerical cognition [1], attention networks [2,3], memory [4] or conscious processing [5]; but even for functions like language processing, which are commonly assumed to be lateralized, bilateral activation patterns are observed (e.g., [6]; see [7] for a review). An innovative method to investigate bilateral processing is the use of transcranial direct current stimulation (tDCS), which will be described in more detail in the following. Fregni and colleagues [10] applied tDCS over the dorsolateral prefrontal cortex and observed enhanced working memory capacity
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
