High-definition tDCS alters impulsivity in a baseline-dependent manner.

Area of Science:

• Neuroscience
• Cognitive Psychology
• Decision-Making

Background:

• Intertemporal choice (ITC) involves discounting future rewards based on delay.
• Previous studies suggest a role for the dorsolateral prefrontal cortex (dlPFC) in ITC impulsivity, but findings are inconsistent.
• The functional specificity of dlPFC in ITC remains unclear.

Purpose of the Study:

• To investigate the causal role and functional specificity of the left and right dlPFC in ITC impulsivity.
• To explore how modulating dlPFC activity affects decision-making in intertemporal choice tasks.
• To determine if the effects of dlPFC stimulation on impulsivity are dependent on individual differences.

Main Methods:

• Utilized high-definition transcranial direct current stimulation (HD-tDCS) for bi-directional modulation of left and right dlPFC.
• Assessed changes in impulsivity during ITC using model-free and model-based analyses.
• Conducted an individual differences analysis to examine baseline impulsivity effects.

Main Results:

• Anodal stimulation of the left dlPFC decreased ITC impulsivity.
• Cathodal stimulation of the left dlPFC increased ITC impulsivity.
• Neither anodal nor cathodal stimulation of the right dlPFC significantly affected ITC impulsivity.

Conclusions:

• Left dlPFC plays a causal, baseline-dependent role in regulating impulsivity during intertemporal choice.
• These findings reconcile discrepancies in the existing literature regarding dlPFC function in ITC.
• Suggests targeted neuromodulation of the left dlPFC could potentially influence decision-making in ITC.