Date of Degree
PhD (Doctor of Philosophy)
Decision makers flexibly deploy decision-making strategies based on the specific features of the problems they face (Ford, Schmitt, Schechtman, Hults, & Doherty, 1989; Payne, Bettman, & Johnson, 1993). However, research on the neuroscience of decision making has focused on a "policy capture" approach that utilizes static decision problems to study the relationships between input (the problem presented), output (the choices made), and the brain. Since the decision problems are prepackaged, this approach does not provide information about the neural bases of predecisional processes critical for flexible decision making, such as selecting an appropriate decision-making strategy and dynamically acquiring and integrating the information needed to progress toward choice. The aim of the current project is to use the lesion method to explore the neural bases of predecisional processes. The fronto-limbic information acquisition network (FLIAN) is proposed as a neural framework critical for predecisional processes in flexible decision making. According to the FLIAN model, the ventromedial prefrontal cortex (vmPFC) represents the decision problem as currently perceived (i.e., the decision space), which is the basis for selecting a decision strategy via interactions with limbic structures. The vmPFC implements the strategy through the coordination of attribute-based information acquisition induced by the amygdala and relational, option-based acquisition induced by the hippocampus. In Chapter 1, the literature pertinent to FLIAN structures is reviewed, including the neuroanatomical and functional backgrounds of those structures, their roles in decision making, and their potential roles in predecisional processes. Chapter 2 provides a review of the behavioral literature on predecisional processes and outlines the FLIAN model in detail. Chapters 3 and 4 present studies that test, and provide partial support for, the FLIAN model using the lesion method and information board tasks. As predicted, the hippocampus is shown to be critical for relational, option-based information acquisition. The vmPFC is shown to be critical for determining how attributes are weighted in the decision space representation and for organizing predecisional behavior. The amygdala was not found to play its role in attribute-based acquisition, but previous studies do support this function and further research is warranted on the role of the amygdala, as well as the hippocampus and vmPFC, in predecisional processes. Future research should also explore the consequences of abnormal predecisional functioning for social behavior, memory, and emotion processing.
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Copyright 2011 Bradley Charles Taber-Thomas
Taber-Thomas, Bradley Charles. "A model of the neural basis of predecisional processes: the fronto-limbic information acquisition network." dissertation, University of Iowa, 2011.