Transcranial direct current stimulation over the right dorsolateral prefrontal cortex increases oxyhemoglobin...

Area of Science:

• Neuroscience
• Cognitive Science
• Biomedical Engineering

Background:

• Transcranial direct current stimulation (tDCS) is investigated for cognitive enhancement.
• tDCS may alter cerebral oxygenation, but its interaction with cognition is unclear.
• Individual oxygenation variability is a confounding factor in tDCS research.

Purpose of the Study:

• To investigate the effects of anodal tDCS on the working memory-cerebral oxygenation interaction.
• To examine anodal tDCS over the right dorsolateral prefrontal cortex (DLPFC).
• To control for individual oxygenation variability during cognitive tasks.

Main Methods:

• A sham-controlled study involving 33 adults.
• Resting-state functional near-infrared spectroscopy (fNIRS) for prefrontal cortex oxygenation.
• Working memory assessment using the Toulouse n-back task concurrently with fNIRS before and after tDCS.

Main Results:

• Anodal tDCS increased oxyhemoglobin over the right DLPFC during 2-back and 3-back tasks.
• Working memory accuracy improved by 13.4% in the 3-back task.
• Response latency decreased by 250ms in the 3-back task.
• Increased oxyhemoglobin correlated with improved accuracy and reduced latency.

Conclusions:

• Anodal tDCS over the right DLPFC regionally increases oxyhemoglobin concentrations.
• tDCS improves working memory performance, particularly under higher cognitive load.
• The findings highlight the link between neurostimulation-induced oxygenation changes and cognitive function.