High-definition transcranial direct current stimulation modulates performance and alpha/beta parieto-frontal...

Area of Science:

• Neuroscience
• Cognitive Science
• Psychology

Background:

• Fluid intelligence (Gƒ), encompassing logical reasoning, is crucial for cognition.
• Parieto-prefrontal connectivity is vital for Gƒ, but its dynamics during reasoning and neuromodulation effects are unclear.
• Previous studies on non-invasive brain stimulation for Gƒ lack consistent findings.

Purpose of the Study:

• To investigate the effects of high-definition transcranial direct current stimulation (HD-tDCS) on logical reasoning performance and brain activity.
• To examine how stimulating the left and right dorsolateral prefrontal cortex (DLPFC) impacts functional connectivity during logical reasoning.
• To assess the consistency of findings with the parieto-frontal integration theory of intelligence (P-FIT) and the neural efficiency hypothesis (NEH).

Main Methods:

• 24 healthy adults received 20-minute HD-tDCS sessions (sham, left DLPFC, right DLPFC).
• Participants completed a logical reasoning task post-stimulation while undergoing magnetoencephalography (MEG).
• Sensor-level neural responses were imaged, and dynamic functional connectivity was analyzed.

Main Results:

• Right DLPFC stimulation significantly decreased reaction time compared to sham.
• Both left and right DLPFC stimulation reduced left parieto-frontal connectivity.
• The reduction in parieto-frontal connectivity after right DLPFC stimulation correlated with faster reaction times.

Conclusions:

• Right DLPFC stimulation offers a beneficial effect on logical reasoning performance.
• Findings support the P-FIT and NEH by demonstrating how DLPFC neuromodulation affects cognitive processes and neural efficiency.
• Future research could explore other stimulation parameters for DLPFC targeting.