Transcranial direct current stimulation of the posterior parietal cortex modulates arithmetic learning.

Area of Science:

• Neuroscience
• Cognitive Science
• Educational Psychology

Background:

• Mathematical competencies, including arithmetic skills, are crucial for cognitive development.
• The left posterior parietal cortex (PPC) is associated with arithmetic processing, but its causal role in skill acquisition is debated.
• Non-invasive brain stimulation techniques offer potential for modulating cognitive functions.

Purpose of the Study:

• To investigate the causal role of the left PPC in arithmetic skill acquisition.
• To determine if transcranial direct current stimulation (tDCS) over the left PPC can modulate arithmetic learning.
• To examine the effects of anodal and cathodal tDCS on learning strategies and performance.

Main Methods:

• Sixty participants underwent a short-term arithmetic training program simulating the shift from procedural to memory-based strategies.
• Transcranial direct current stimulation (tDCS) was applied over the left PPC, with conditions including anodal, cathodal, and sham stimulation.
• Learning progress was assessed during training, and the stability of effects was evaluated 24 hours post-stimulation.

Main Results:

• Cathodal tDCS significantly decreased learning rates and led to sustained poorer performance compared to sham stimulation.
• Anodal tDCS demonstrated an operation-specific enhancement, improving subtraction learning.
• Learning effects were observable and stable for at least 24 hours after the intervention.

Conclusions:

• The left PPC is causally involved in the acquisition of arithmetic skills, not just performance.
• Short-term tDCS application can effectively modulate the success of arithmetic knowledge acquisition.
• tDCS effects on learning can be specific to particular cognitive processes within the stimulated brain region.