Dual-tDCS over the right prefrontal cortex does not modulate stop-signal task performance.

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Brain Stimulation

Background:

• Response inhibition is critical for daily behavior, with the prefrontal cortex, specifically the right inferior frontal gyrus (IFG) and dorsolateral prefrontal cortex (DLPFC), consistently implicated.
• Non-invasive brain stimulation techniques offer a way to investigate the causal roles of specific brain regions in cognitive functions.

Purpose of the Study:

• To investigate the role of the right IFG and DLPFC in response inhibition using dual-prefrontal transcranial direct current stimulation (tDCS).
• To compare the effects of anodal/cathodal tDCS over IFG and DLPFC against sham stimulation on performance in the stop-signal task (SST).

Main Methods:

• A repeated measures design was employed with 45 participants randomly assigned to three groups receiving different stimulation protocols.
• Dual-prefrontal tDCS (9 cm² electrodes) targeted both IFG and DLPFC with anodal/cathodal stimulation or sham stimulation.
• Inhibition capabilities were assessed using the stop-signal task (SST) before and after the tDCS intervention.

Main Results:

• Dual-frontal tDCS, targeting both IFG and DLPFC, did not significantly alter performance on the stop-signal task compared to sham stimulation.
• Bayesian analysis corroborated the null findings, indicating no evidence for a performance enhancement due to the applied stimulation.
• No significant differences in response inhibition were observed across the different stimulation conditions.

Conclusions:

• The study's findings suggest that dual-frontal tDCS, as applied in this protocol, does not effectively modulate response inhibition.
• Limitations of the study, such as stimulation parameters and task demands, may account for the null result.
• Further research is needed to explore optimal parameters for tDCS interventions targeting prefrontal regions involved in inhibitory control.