Abstract

IntroductionObsessive compulsive disorder (OCD) affects 2-3% of the general population. The neurobiology of OCD has been linked to dysfunction of cortico-striatal circuits connecting the orbitofrontal (OFC) to the striatum. Recently, this loop has become an approved target for non-invasive neuromodulatory treatment of OCD.ObjectivesTo explore structural and functional connectivity of the OFC in OCD subjects and healthy controls.Methods14 OCD patients and 12 age/sex-matched controls underwent magnetic resonance imaging (MRI) (3T-Philips scanner) for diffusion tensor imaging (DTI) and resting state functional connectivity (rsFC). DTI images were brain extracted and corrected for movement and eddy currents. A diffusion tensor model was fitted to each voxel and used to generate Fractional Anisotropy (FA) maps. Voxel-wise statistical analysis of FA was performed using Tract-Based Spatial Statistics. RsFC images were preprocessed and seed-based correlation (SBC) analysis was performed using Data Processing Assistant for Resting-State fMRI.ResultsWe found decreased values of FA in the body of the Corpus Callosum bilaterally (MNI_coordinates: x= 16, y= -16, z= 33 and x= -19, y= -16, z= 42) and left superior longitudinal fasciculus in OCD patients (fig 1, left), as well as decreased rsFC of the right superior orbitofrontal seed with the left inferior frontal gyrus and left middle occipital gyrus (fig 2, right).ConclusionsUsing an exploratory multimodal approach we found evidence of abnormal structural and functional long-range connectivity of the OFC in OCD. If confirmed in a larger sample these connectivity abnormalities could be explored as potential predictors of response to OFC-targeted non-invasive neuromodulatory interventions.DisclosureNo significant relationships.

Highlights

  • Literature showed that patients suffering from disorders belonging to the schizophrenic (SZ) and bipolar (DB) spectrum have a qualitatively similar but quantitatively different neurocognitive impairment that correlates with the outcomes

  • Executive functions were measured with Tower of London (ToL) and Modified Wisconsin Card Sorting Test (MCST), attention with Attentive Matrices (MA) and Stroop Test (ST), non-verbal logic skills with Colored Matrices by Raven (PM47)

  • The logistic regression analysis showed that the scores obtained at the MCST and MA positively correlate with the efficacy of the treatment for both groups

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Summary

Introduction

Altered fear learning processes could be mechanistically linked to the development and/or maintenance of obsessive-compulsive disorder (OCD). Methods: We assessed 18 patients with OCD and 18 healthy participants during a 2-day experimental protocol where brain activation and skin conductance responses (SCR) where assessed during fear conditioning, extinction learning, and extinction recall within the fMRI scanner. Our analyses revealed a significant negative association between clinical improvement after CBT and activity at the right insula during fear conditioning (x = 39, y = 12, z = -11; t = 5.64; p

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