The impulsive brain: new insights into the neural correlates of binge eating in normal weight population
Year: 2018
Type: dissertation
Abstract: Despite humans are known to embody a unique ability to self-regulate, sometimes they act impulsively (Hofmann et al., 2009). Generally, impulsive behaviors may derive from the co-occurrence of dysfunctional inhibitory processes and strong urges to act (Bari and Robbins, 2013). In more detail, our impulses, if not appropriate to the situation, are usually kept under control by inhibitory mechanisms; however, when inhibition fails, impulsive acts may stem (Bari and Robbins, 2013). Researchers and mental health experts agree that impulsivity can boost the risk for a range of maladaptive behaviors, such as substance abuse (Kale et al., 2018; Loxton, 2018). Recently, drawing upon the surmised similarities between addiction and overeating (Gearhardt et al., 2009), some authors have hypothesized that the same impulsivity aspects that lead people to abuse alcohol or drugs may also lead to dysregulated eating. In support of this theory, recent studies have shown that individuals with eating disorders and obesity are more impulsive than healthy people, especially when binge eating behavior is present (Waxman, 2008). However, given that most of these investigations focused on people with full-blown eating or weight disorders, it is still unclear whether high impulsivity characterized these individuals also before the dysregulated eating began or if it developed as a result of it. Thus, little is known about the role of impulsivity as a potential risk and predisposing factor for binge eating within the general population. Based on these premises, the aim of the present thesis is to shed some new light on the role of impulsivity at the roots of binge eating behavior. Starting from the contemporary state of the art, Chapter 1 provides an overview of the definitions of the various facets of impulsivity and their neural correlates. Subsequently, Chapter 2 reviews some of the behavioral and neuroimaging studies exploring the relationship between impulsivity and eating behavior. From the existing state of knowledge, I emphasize the need for an in-depth exploration of the role of different impulsivity-related aspects in normal-weight individuals with binge eating. Hence, I outline the primary purposes of this project. First, given the well-established impact of eating and weight disorders on cognitive and neurobiological processes (Horstmann et al., 2015; Smith et al., 2011; van den Akker et al., 2014), I decided to focus on a non-clinical population of normal-weight individuals with binge eating, to provide a clearer account of the role of impulsivity as a hallmark of this behavior, regardless of weight status. Second, given that impulsivity comprises several related forms that depend on distinct neuropsychological processes and neural systems (Dalley and Robbins, 2017), I chose to assess this construct multi-modally, with self-reported, behavioral and neuroimaging measures, in the same study population, to disentangle the relative contribution of each component in the characterization of binge eating (Filbey and Yezhuvath, 2017). The second part of the thesis cover four experiments, in which, by comparing two groups of normal-weight individuals with and without binge eating, I aimed to explore: • General trait impulsivity, as assessed by self-reported questionnaires (Chapter 3); • Response inhibition abilities toward food, measured with food-specific Go/No-Go, GNG (Chapter 4) and Stop Signal Task, SST (Chapter 5); • Task-related brain activity during the execution of both tasks (Task-based functional MRI studies; Chapters 4 - 5); • Functional brain connectivity at rest (Resting-state functional MRI study; Chapter 6); • Brain morphometry (Voxel-based morphometry study; Chapter 7). In conclusion, the last chapter (Chapter 8) will draw upon the entire thesis, tying up the various theoretical and empirical strands in order to discuss the main findings of the experiments and their implication to future studies into this area. \n \n\t \n
Author: Rossella Oliva
Language: English
Subfield: Clinical Psychology
Field: Psychology
Domain: Social Sciences
Open Access status: green
OpenAlex ID: W3137017136