Exploring the Brain’s Response to Food Stimuli in Anorexia Nervosa: A Comprehensive Meta-Analysis of Neuroimaging Studies

Abstract

Despite the increased interest in understanding the neural underpinnings of Anorexia Nervosa (AN), its neurobiology is poorly understood. This activation likelihood estimation (ALE) meta-analysis aimed to explore brain activity during food stimuli processing among individuals with AN and those who have recovered (REC). Following the PRISMA guidelines, we searched throughout PubMed and PsycInfo, until the 28th of June 2023. Twenty-six publications were included, encompassing data from 403 AN, 141 REC, and 472 HC. The findings indicated significant convergence in the left Inferior Parietal Lobule (IPL) in the HC > AN + REC contrast, whereas the AN + REC > HC contrast did not yield any significant cluster. From the sensitivity analyses confined to studies encompassing solely visual stimuli, the same significant cluster (left IPL) emerged for the HC > AN + REC contrast and no significant convergence was found for the reverse contrast, showing that the stimulation employed (visual, taste-based or olfactory cues) does not affect the food stimuli processing. Furthermore, when limited to studies involving only AN participants, the sensitivity analyses found no significant convergence for either the HC > AN or the reverse contrast. The fact that no significant cluster emerged when excluding REC participants from the analyses, together with a qualitative analysis of the results from the merged sample (i.e., HC > AN + REC contrast), suggests that REC individuals maintain the dysfunctional pattern. The hypoactivation of the left IPL supports its role in body image disturbance, diminished somatosensory-gustatory processing related to fasting, and fear with weight gain, three core symptoms of AN.