The Brain Valuation System and its role in decision making
Neural processes engaged in decision making remain unclear. A decomposition of these processes might help us to understand the involved mechanisms. Indeed, first we need to assign what we will call a 'subjective value' to each option i.e. the quantification of how much we like each of these options. Then, we need to compare those values to finally being able to select one of them. Assigning a value seems to be the function of an interesting brain network which overlaps the reward circuitry identified in animal studies and which is called the Brain Valuation System (BVS) In the first study of this PhD thesis, we investigated and compared three behavioral ways to have an access to these 'subjective values' We found that subjective values were relatively robust to the way they were elicited. In the second study, we investigated the specific properties of the Brain Valuation System established through fMRI in humans in a large dataset of intra EEG recordings in epileptic patients. Finally, in the last study we investigated how this brain network was involved during a binary choice in fMRI. Altogether, our findings shed light on the distinct cognitive mechanisms underlying value based decision making i) by exploring the neural properties of value assignment and ii) by proposing a general solution to the neural implementation of the comparison between option values. We believe this demonstration points to hidden default policies as sources of bias in choices.