Posterior orbitofrontal sulcogyral pattern associated with orbitofrontal cortex volume reduction and anxiety trait in panic disorder

Aims: The posterior region of the orbitofrontal cortex (OFC), which forms its sulcogyral pattern during neurodevelopment, receives multisensory inputs. The purpose of the present study was to assess the relationship between posterior OFC sulcogyral pattern and OFC volume difference in patients with panic disorder. Methods: The anatomical pattern of the posterior orbital sulcus (POS) was classified into three subtypes (absent POS, single POS, double POS) using 3-D high-spatial resolution magnetic resonance images obtained from 28 patients with panic disorder and 28 age- and gender-matched healthy controls. Optimized voxel-based morphometry (VBM) was performed to assess OFC volume differences between the two groups by subtype. Categorical regression analysis was applied to examine the association of POS subtypes with State-Trait Anxiety Inventory and Revised Neuroticism-Extraversion-Openness Personality Inventory scores. Results: No significant difference was found in POS subtype distribution between control subjects and patients with panic disorder. VBM, however, indicated volume reduction in the right posterior-medial OFC region in panic disorder patients with absent POS and single POS. Single POS was positively associated with Trait-Anxiety (β = 0.446, F = 6.409, P = 0.020), and absent POS was negatively associated with Trait-Anxiety (β = -0.394, F = 5.341, P = 0.032) and Neuroticism trait (β = -0.492, F = 6.989, P = 0.017). Conclusions: POS subtypes may be relevant to volume reduction in OFC and the anxiety trait in patients with panic disorder. These findings suggest that volume reduction in OFC in panic disorder may be associated with neurodevelopment.