Modulating Neuronal Activity Produces Specific and Long-Lasting Changes in Numerical Competence

Abstract

SummaryAround 20% of the population exhibits moderate to severe numerical disabilities [1–3], and a further percentage loses its numerical competence during the lifespan as a result of stroke or degenerative diseases [4]. In this work, we investigated the feasibility of using noninvasive stimulation to the parietal lobe during numerical learning to selectively improve numerical abilities. We used transcranial direct current stimulation (TDCS), a method that can selectively inhibit or excitate neuronal populations by modulating GABAergic (anodal stimulation) and glutamatergic (cathodal stimulation) activity [5, 6]. We trained subjects for 6 days with artificial numerical symbols, during which we applied concurrent TDCS to the parietal lobes. The polarity of the brain stimulation specifically enhanced or impaired the acquisition of automatic number processing and the mapping of number into space, both important indices of numerical proficiency [7–9]. The improvement was still present 6 months after the training. Control tasks revealed that the effect of brain stimulation was specific to the representation of artificial numerical symbols. The specificity and longevity of TDCS on numerical abilities establishes TDCS as a realistic tool for intervention in cases of atypical numerical development or loss of numerical abilities because of stroke or degenerative illnesses.

Balancing the 2 Hemispheres in Simple Calculation: Evidence From Direct Cortical Electrostimulation

“…Based on the idea of interhemispheric inhibition/interference between the left and right parietal lobes (Cappelletti et al, 2007;Cohen-Kadosh et al, 2010), interference on the right hemisphere would leave more space to the action of the left hemisphere; errors thus tend to reflect left hemisphere predominance in the search for a solution through retrieval. Conversely, interference on the left tend to result in enhanced right hemisphere processing, which is reflected in a different type of error guided by approximation.…”

Increasing propensity to mind-wander with transcranial direct current stimulation

“…For stimulation conditions, we used a combination of online and offline stimulations (e.g., refs. 46,47), where the first half of the experimental task was executed during the stimulation (20 min) and the second half of the experimental task was executed after the stimulation (20 min). None of the participants noticed or felt a change in stimulation over the course of the experiment.…”

Dance and emotion in posterior parietal cortex: A low-frequency rTMS study

“…Previous brain stimulation studies have also shown that interfering with this region impairs cognitive tasks such as working memory (33; 34). On the other hand, enhancing the activity of this and adjacent brain areas by cathodal transcranial direct current stimulation can improve cognitive functions such as numerical learning (35). We are not aware of any brain stimulation study having investigated the role of posterior parietal cortex in emotion processing.…”