A Pilot fMRI Study of Decision-Making Under Uncertainty in Anorexia Nervosa

Objective: Anorexia nervosa is characterized by decision-making that demonstrates an intolerance of uncertainty focused on food of unknown caloric content. This pilot study tested whether this intolerance of uncertainty involved distinct neural networks that process two conditions of uncertainty – risk and ambiguity. Method: Nine female adults with anorexia nervosa (mean age = 27.1 ± 6.7 years) and nine female adult controls (mean age = 27.5 ± 5.8 years) performed a validated lottery test of uncertainty during functional magnetic resonance imaging. Neuroeconomic models that predicted choice on each risk and ambiguity lottery based on the subjective value of the uncertain option versus the standard option were entered as parametric modulators of the neural response to the two types of lotteries. Results: Adult females with anorexia nervosa showed significantly greater activation of an extended network of cingulo-opercular-frontoparietal regions than controls despite similar choices of the ambiguous lottery tickets (T-value ≥ 2.57, p 50 voxels). In contrast, participants with anorexia nervosa were more risk averse and showed significantly reduced activation of prefrontal and temporoparietal regions than controls (T-value ≥ 2.57, p 50 voxels). Discussion: The preliminary findings of functional abnormalities in two distinct neural networks for decision-making under conditions of uncertainty in adult females with anorexia nervosa suggest that the intolerance of uncertainty that biases toward food avoidance may reflect aversions to both risk or probability-based decisions, and even more prominently, ambiguity or decisions based on uncertain outcomes.