The Effects of Transcranial Direct Current Stimulation on Dual-Task Interference Depend on the Dual-Task Content

Area of Science:

• Neuroscience
• Cognitive Psychology
• Human Motor Control

Background:

• Transcranial direct current stimulation (tDCS) has shown potential in reducing dual-task interference.
• The variability in dual-task combinations makes it unclear if tDCS effects are consistent.
• Investigating task-specific effects of tDCS is crucial for understanding its application in cognitive enhancement.

Purpose of the Study:

• To examine if the impact of tDCS on dual-task interference is modulated by the specific tasks involved.
• To compare the effects of tDCS on a word-tandem dual-task versus a Stroop-tandem dual-task.
• To test the hypothesis that anodal tDCS over the dorsolateral prefrontal cortex (DLPFC) would differentially affect executive functions based on task demands.

Main Methods:

• Two dual-task paradigms were used: word-tandem and Stroop-tandem tasks.
• Anodal or cathodal tDCS was applied over the left DLPFC or supplementary motor area (2.0 mA for 20 min).
• Task performance was assessed under single-task and dual-task conditions before and after stimulation.

Main Results:

• tDCS did not alter single-task performance or dual-task interference across all tested conditions.
• However, anodal tDCS applied over the left DLPFC significantly enhanced word task performance during the dual-task condition.
• This improvement was observed immediately following the stimulation session.

Conclusions:

• The efficacy of anodal tDCS over the left DLPFC in modulating performance under dual-task conditions is task-dependent.
• tDCS may selectively benefit specific cognitive processes involved in complex task execution.
• Future research should consider task composition when designing tDCS protocols for cognitive enhancement.