Non-invasive stimulation reveals ventromedial prefrontal cortex function in reward prediction and reward processing.

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Decision Neuroscience

Background:

• The ventromedial prefrontal cortex (vmPFC) is implicated in reward prediction and processing.
• Reward-based learning depends on neural signals for unpredicted rewards or non-rewards (reward prediction error, RPE).

Purpose of the Study:

• To investigate the causal role of the vmPFC in reward prediction, processing, and RPE signaling.
• To examine the effects of transiently modulating vmPFC excitability using transcranial Direct Current Stimulation (tDCS).

Main Methods:

• Participants received excitatory or inhibitory tDCS of the vmPFC.
• A gambling task was used to assess reward prediction and processing.
• Magnetoencephalography (MEG) and eye-tracking (pupil diameter) were employed to record neural activity and physiological responses.

Main Results:

• vmPFC excitation increased prefrontal activation preceding loss predictions and pupil dilations.
• Excitatory tDCS enhanced pleasantness ratings, vmPFC activation for gain RPEs, and pupil dilations.
• Stimulation led to decreased perseveration after negative feedback and improved behavioral flexibility.

Conclusions:

• The vmPFC plays a crucial role in reward prediction and processing.
• Transient vmPFC excitation via tDCS induces a positive bias, enhancing anticipation and appraisal of positive outcomes.
• This stimulation improves reward-based learning and behavioral flexibility, indicating enhanced response to feedback.