Altered orbitofrontal sulcogyral patterns in gambling disorder: a multicenter study

Abstract

Gambling disorder is a serious psychiatric condition characterized by decision-making and reward processing impairments that are associated with dysfunctional brain activity in the orbitofrontal cortex (OFC). However, it remains unclear whether OFC functional abnormalities in gambling disorder are accompanied by structural abnormalities. We addressed this question by examining the organization of sulci and gyri in the OFC. This organization is in place very early and stable across life, such that OFC sulcogyral patterns (classified into Types I, II, and III) can be regarded as potential pre-morbid markers of pathological conditions. We gathered structural brain data from nine existing studies, reaching a total of 165 individuals with gambling disorder and 159 healthy controls. Our results, supported by both frequentist and Bayesian statistics, show that the distribution of OFC sulcogyral patterns is skewed in individuals with gambling disorder, with an increased prevalence of Type II pattern compared with healthy controls. Examination of gambling severity did not reveal any significant relationship between OFC sulcogyral patterns and disease severity. Altogether, our results provide evidence for a skewed distribution of OFC sulcogyral patterns in gambling disorder and suggest that pattern Type II might represent a pre-morbid structural brain marker of the disease. It will be important to investigate more closely the functional implications of these structural abnormalities in future work.

Fig. 1. Classification of the orbitofrontal cortex sulcogyral patterns with magnetic resonance imaging.

Examples of the four major sulcogyral patterns from four different participants. Patterns were classified into four subtypes (Types I–IV) according to the continuity of the lateral and medial orbital sulci (LOS and MOS, respectively) in the rostrocaudal direction (r rostral, c caudal). Type I refers to continuous LOS and discontinuous MOS (a), Type II refers to continuous LOS and MOS (b), Type III refers to discontinuous LOS and MOS (c), and Type IV refers to continuous MOS and discontinuous LOS (d). Sulcal continuities of the MOS and LOS were determined by evaluating several consecutive axial slices rather than just a single slice. TOS transverse orbital sulcus

Fig. 2. Distribution of the orbitofrontal cortex sulcogyral patterns in the left hemisphere, right hemisphere, and across both hemispheres, in both pathological gamblers (N = 165) and healthy controls (N = 159).

**p < 0.005