Brain Mechanisms underlying prediction during conflict and value-based decision making

Abstract

People are able to solve conflictive situations and even anticipate them thanks to adaptive behavior derived from their experience and learning of contextual changes, that allows them to predict what might happen. This prediction is also known as proactive cognitive control, since it allows anticipating what is going to happen and to a possible conflict. According to scientific evidence, theta band oscillatory activity in the prefrontal cortex is associated with cognitive control. Specifically, findings are shown that lateral prefrontal areas are related to the capacity to anticipate an approaching conflict (proactive cognitive control). However, although theta oscillations have been described as a candidate mechanism for cognitive control, it remains unclear whether proactive cognitive control involves theta activity in lateral prefrontal areas in conflictive situations. In more complex scenarios, like value-based decision making, additional factors such as reward expectancy, reward sensitivity, prediction of what might happen, and choice of actions are also involved. It has been described that individuals choose what means the most value to them, according to the reward and the expectancy of the availability of that reward. In spite of reward sensitivity has shown to be fundamental in making decisions, it is still unclear how reward sensitivity modulates behavioral control in the context of prediction and choice during value-based decision making. Considering this background, we carried out two investigations described in sections 3 and 4 of this document. In the first research (section 3), we studied whether theta oscillatory activity plays a causal role in conflict expectancy. Functional Magnetic Resonance Imaging (fMRI), Electroencephalography (EEG), and Transcranial Magnetic Stimulation (TMS) were carried out during cognitive tasks (MSIT and Go Nogo tasks) to establish a causal relationship between theta brain oscillations and cognitive activity in the lateral prefrontal cortex. Results indicated that conflict expectancy increases reaction time, and that there is brain activity in the superior frontal gyrus (SFG) and the inferior frontal junction (IFJ) during the MSIT Task related to the expectancy of conflict and behavioral inhibition, respectively. We also observed that the SFG TMS at theta frequency enhances cognitive control (expectancy of conflict) and modulates theta oscillations in lateral prefrontal regions during the Go Nogo task. In the second research (section 4), we studied how reward sensitivity modulates prediction and choice during value-based decision-making. Two experiments (behavior and fMRI) were performed during a Risk-Learning task to study the effect of reward sensitivity on prediction and choice during value-based decisionmaking. Preliminary results indicated that the rate of learning increases as reward increases, and that with this increased reward there is an increase in ventral striatal activity. The increase in the learning rate indicates that participants are reward-sensitive, as they are guided by rewards when making their decisions and do not incorporate the experience. Taken together, these findings show that theta-band oscillatory activity has a causal role in the expectation of conflict and that reward influences our learning and decision-making.