Hemispheric mPFC asymmetry in decision making under ambiguity and risk: An fNIRS study.

The Iowa Gambling Task (IGT) is a commonly used task for testing decision-making under ambiguity (the early stage) and risk (the late stage). However, differences between the temporal dynamic signals underlying these two types of decision-making as well as the hemispheric specificity of decision making during the IGT remain unknown. The present study sought to address this gap by focusing on the medial prefrontal cortex (mPFC), which plays an important role in decision-making across life domains. We used functional near-infrared spectroscopy (fNIRS) with high spatial and temporal resolution and measured oxy-hemoglobin concentration within the mPFC in 25 healthy participants who performed the IGT. Results showed that there are different activations of the right and left hemispheres of the mPFC during the different stages of IGT and types of decisions. This implies that the left and right mPFC can have different patterns of involvement in decision making, at least in IGT decisions, including making good (low risk) and bad (high risk) choices, under ambiguity and under risk conditions.