# Patterns and predictors of orbitofrontal sulcogyral morphology in a nonclinical population

## TL;DR

This study examines how orbitofrontal cortex patterns relate to health and demographic factors in a nonclinical population.

## Contribution

It is the first to evaluate the influence of health and socioeconomic factors on OFC sulcogyral patterns in a neurotypical sample.

## Key findings

- Demographic and socioeconomic factors showed no significant association with OFC sulcogyral patterns.
- Obesity and smoking history were linked to increased odds of specific OFC pattern types.
- Results confirm prior assumptions about demographic neutrality in OFC patterns but suggest health factors may play a role.

## Abstract

Less common orbitofrontal cortex (OFC) sucogyral patterns are observed at higher rates among those witth psychopathology. Previous work has assumed demographic characteristics have no influence on OFC sulcogyral patterns. However, the influence of sociodemographic and health-related characteristics on OFC patterns within a neurotypical population has not been formally evaluated. We used structural brain magnetic resonance imaging (MRI) from a cohort from the Human Connectome Project (HCP) with existing OFC sulcogyral characterizations (n = 238); none of the participants had psychiatric diagnoses. We evaluated distributions of participant demographics (i.e., age), socioeconomic factors (i.e., employment), and health history-related factors (i.e., smoking history) by OFC sulcogyral pattern within each hemisphere. We then used logistic regression to estimate the odds of OFC sulcogyral pattern by participant characteristics. Distributions of study sample characteristics did not vary substantially by OFC sulcogyral pattern type within either hemisphere. Findings from logistic regression analyses suggest no association between OFC sulcogyral pattern and any of the demographic or socioeconomic characteristics. Two health history-related characteristics, body mass index (BMI) and smoking history, were associated with increased odds of having specific OFC pattern types. For example, individuals with obesity had 2.65 increased odds (95% CI: 1.17, 6.65) of having OFC sulcogyral pattern Type II, III, or IV, compared with Type I in the left hemisphere with normal BMIs. We did not observe substantial influence of demographic or socioeconomic characteristics on OFC sulcogyral patterns. These results confirm assumptions made in previous work that demographic and socioeconomic characteristics do not seem to impact OFC patterns. We do show some evidence for an influence of health history-related factors (obesity and smoking history); future work should evaluate whether these and other phenotypic risk factors interact to modify the relationship between psychiatric diagnoses and OFC sulcogyral patterns.