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Previous research suggests that the medial prefrontal cortex (mPFC), and the Anterior Cingulate Cortex (ACC), in particular, is functionally segregated as a cognitive/affective gradient with caudal mPFC associated with cognitive processing, and rostral mPFC associated with affective processing (Bush et al., 2000). However, recent reviews have shown that the ACC is less functionally distinct than was originally thought (Etkin et al., 2011) and a recent meta-analysis has pointed out significant regions of overlap in the ACC in response to negative affect, pain, and cognitive control (Shackman et al., 2011). In light of these findings, one important hypothesis to test is whether the ACC shows a similar functional homogeneity in response to violations of expectation across different domains of potentially aversive or cognitively demanding stimuli. T his dissertation proposes an experiment to test this distinction be tween cognitive and affective components of the ACC and is motivated by a recent unifying computational model of ACC function, the Prediction of Response Outcomes (PRO) model (Alexander & Brown, 2011). Different theories of ACC function can then be compare d to a current model of ACC function attempting to reconcile all of these experimental findings within a framework of the ACC serving as an action-outcome predictor (Alexander and Brown, 2011). According to this model, prediction signals are generated with in the ACC which are then compared and evaluated against the actual outcome that is received, a framework that accounts for a wide variety of error-related and reinforcement learning effects found in the literature. Here we will explore whether and how the mPFC, and in particular the ACC, is involved in the generation of prediction signals across qualitatively different levels of aversion, as there has not yet been a study that has combined both violations of expectation of a predicted level of pain as compared to the violation of a predicted level of required cognitive control. The studies reported here provide a background for possible hypotheses for how the ACC may respond to prediction of different levels of aversive outcomes. |
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