The when, where and how of cognitive and emotional disturbances in anorexia nervosa

Proposal details

Title: The when, where and how of cognitive and emotional disturbances in anorexia nervosa
Research Area(s): Emotion and Self Regulation
Background: Anorexia Nervosa is a debilitating and chronic illness defined by extreme food restriction, weight loss, and emotional disturbances. It is typically developed in adolescence, and has the highest mortality rate of any psychiatric disorder, with up to 22% of anorexic sufferers dying because of illness-related factors. Given the seriousness of this disorder, it is important to understand more about the psychological and biological factors that cause it. Identifying these factors is also necessary for effective screening and treatment evaluation. Recent evidence suggests that anorexia nervosa is associated with disturbances in the brain regions responsible for emotional functioning. This project will be the first to use brain imaging measures to examine both ‘when’ and ‘where’ these disturbances occur in individuals with anorexia nervosa, and their comparison with cognitive disturbances. We will test females with anorexia nervosa at admission to hospital, and again once they have gained weight (before the end of their inpatient admission) to determine whether these disturbances are a marker of anorexia nervosa, and not just a reflection of weight loss. This research will provide important new insights into understanding anorexia nervosa as a disorder of cognitive and emotional function. In this study, we address the question of whether anorexia nervosa is due to impairments in the emotional brain systems in two important ways: 1. by using universal signals of basic emotions (fear, anger, disgust, sadness) shown in previous studies to elicit our core emotional brain systems, rather than food or body-specific stimuli which may only elicit components of these systems during states of hunger and malnourishment and 2. by testing individuals with anorexia nervosa during the acute phase of the illness (when starvation and malnourishment are present) and again during the weight-recovered phase (when these factors are not present) to determine whether emotional brain disturbances are more akin to trait-like disturbances independent of state-based illness changes. Emotional brain responses will be measured using both high temporal resolution (‘when’) as well as high spatial resolution (‘where’) brain imaging techniques, to ensure disturbances are not specific to a particular methodology. In addition, by recording concurrent body arousal (with skin conductance responses, SCRs), we can examine ‘how’ the changes in brain activity interact with body arousal changes. We will examine emotion-related disturbances in the context of general cognitive disturbances (with a specific focus on auditory oddball paradigm), and investigate potential vulnerability factors for these dysfunctions, including genetic disposition (polymorphisms) and personality temperament. Thus, the primary focus of the proposed research is to investigate whether a) anorexia nervosa is a manifestation of a breakdown in the core emotion networks of the brain, which leads to a dysregulation in emotional functioning seen in the symptoms of this disorder and b) whether these disturbances are distinct from more general breakdowns in cognitive functioning.
Aims: Aims of Project 1. To examine the temporal aspects (‘when’) of emotion and cognitive processing in anorexia nervosa using psychological tasks and a high temporal resolution measure of brain activity (event-related potentials, ERPs). 2. To examine the spatial location (‘where’) emotion and cognitive processing breaks down in the brain in anorexia nervosa, using psychological tasks and a high spatial resolution measure of brain function (functional magnetic resonance imaging, fMRI). 3. To investigate ‘how’ these ‘when’ and ‘where’ disturbances relate to changes in body arousal, by using our novel technique for simultaneous recording of ERPs and fMRI with skin conductance arousal. 4. To determine whether emotion disturbances are an objective marker of anorexia nervosa, independent of degree of weight loss and cognitive disturbances, by testing ERPs, fMRI and arousal at admission to hospital (when weight loss and malnutrition are severe) and again after weight gain. 5. To examine the role of potential predisposing factors such as genotype and personality temperament in the expression of the above disturbances.
Method: 1. ERP's/SCR's recorded during a facial emotion perception task and auditory oddball task. 2. fMRI/SCR's recorded during a facial emotion perception task and auditory oddball task. 3. Neuropsychological functioning across a number of domains (i.e. sensory-motor, language, attention, memory, and executive functions etc). 4. A cheek swab will provide saliva to inform on DNA correlates (polymorphisms) of the brain and behavioural functions measured.