The Cerebellum Plays More Than One Role in the Dysregulation of Appetite: Review of Structural Evidence from Typical and Eating Disorder Populations

Objective Dysregulated appetite control is characteristic of anorexia nervosa (AN), bulimia nervosa (BN) and obesity (OB). Studies using a broad range of methods suggest the cerebellum plays an important role in aspects of weight and appetite control, and is implicated in both AN and OB by reports of aberrant grey matter volume (GMV) compared to non-clinical populations. As functions of the cerebellum are anatomically segregated, specific localization of aberrant anatomy may indicate the mechanisms of its relationship with weight and appetite in different states. We sought to determine if there were consistencies in regions of cerebellar GMV changes in AN/BN and OB, as well as across normative variation. Method Systematic review and meta-analysis using GingerALE. Results Twenty-six publications were identified as either case-control studies (nOB=277; nAN/BN=510) or regressed weight from normative (NOR) data against brain volume (total n=3,830). AN/BN and OB analyses both showed consistently decreased GMV within Crus I and Lobule VI, but volume reduction was bilateral for AN/BN and unilateral for OB. Analysis of the normative dataset identified a cluster in right posterior lobe which overlapped with AN/BN cerebellar reduction. Sensitivity analyses indicated robust repeatability for NOR and AN/BN cohorts, but found OB-specific heterogeneity. Discussion Findingss: uggest that more than one area of the cerebellum is involved in control of eating behaviour and is differentially affected in normal variation and pathological conditions. Specifically, we hypothesise an association with sensorimotor and emotional learning via Lobule VI in AN/BN, and executive function via Crus I in OB.