Research Article

A Two-Layered Diffusion Model Traces the Dynamics of Information Processing in the Valuation-and-Choice Circuit of Decision Making

Figure 3

The two-layered diffusion model (2LDM) for decision making. Both stages (valuation and choice) are affected by noise. In the valuation stage the critical threshold indicates the firing rate of the neuronal populations involved, to which would correspond the expected reward. The outputs of this stage then are the differences between the responses of observed neuronal activity at the stimuli provided by the alternatives and the target. These measurements enter the next stage, where the decision is taken so as to optimize some utility criterion (reward). Hence, the attainment of the threshold in the decision stage indicates the preferred alternative. Feedback information flows from the decision stage in order to elicit the adaptation of the boundary in the valuation layer. In this way, a mechanism of reinforcement determines the competition between the alternatives and the valuation is biased to the most probable rewarded one.
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