Altered reward-related effective connectivity in obsessive-compulsive disorder: an fMRI study

Abstract

Background: Obsessive-compulsive disorder (OCD) is characterized by anxiety-provoking, obsessive thoughts. Patients usually react to these thoughts with repetitive behaviours that reduce anxiety and are perceived as rewarding. Hence, reward plays a major role in the psychopathology of OCD. Previous studies showed altered activation in frontostriatal networks, among others, in association with the processing of reward in patients with OCD. Potential alterations in connectivity within these networks have, however, barely been explored. Methods: We investigated a sample of patients with OCD and healthy controls using functional MRI and a reward learning task presented in an event-related design. Dynamic causal modelling (DCM) was used to estimate effective connectivity. Results: Our sample included 37 patients with OCD and 39 healthy controls. Analyses of task-related changes in connectivity showed a significantly altered effective connectivity between the ventromedial prefrontal cortex (vmPFC) and the orbitofrontal cortex (OFC), among others, both in terms of endogenous connectivity as well as modulatory effects under positive feedback. Clinical measures of compulsion correlated with the effect of feedback input on visual sensory areas. Limitations: The reported alterations should be interpreted within the context of the task and the a priori-defined network considered in the analysis. Conclusion: This disrupted connectivity in parts of the default mode network and the frontostriatal network may indicate increased rumination and self-related processing impairing the responsiveness toward external rewards. This, in turn, may underlie the general urge for reinforcement accompanying compulsive behaviours.

Dynamic Causal Modeling on the Identification of Interacting Networks in the Brain: A Systematic Review

“…3) FC-OC: We found 27 papers [17], [24], [36], [48], [58][59][60], [66], [70], [78], [87], [95], [97][98], [100][101], [119][120][121][122][123][124][125][126][127][128][129] involved in this connectivity category, spanning eight different task types, of which disease diagnosis had the highest prevalence.…”

“…11) FC-INS: Nine papers, [31], [35], [63], [72], [80], [111], [129], [132], [146], involved in this connectivity category, with a heterogeneous set of task types (please refer to Fig. 2 for more details).…”

Sustained attention induces altered effective connectivity of the ascending thalamo-cortical relay in obsessive-compulsive disorder

“…Effective connectivity studies are beginning to illuminate understanding about casual brain network interactions in OCD. For example, using a reward learning task, Alves-Pinto et al, showed alterations in intrinsic connectivity and contextual modulation of fronto-striatal circuits, mainly from the ventromedial PFC (vmPFC) to the left and right orbitofrontal cortex (OFC) ( 145 ). In another study, Schlösser and colleagues used a Stroop color-word task to elicit aberrant effective connectivity pathways between OCD and HC in the fronto-cingulate system, consistent with an over-active error control system during decision-making observed in OCD ( 13 ).…”

Neuromodulation of OCD: A review of invasive and non-invasive methods

“…Dysregulation of the limbic system has been implicated in a number of models of OCD pathogenesis, including increased classical conditioning of compulsions; reduced modulation of a frontal-based habit system by hippocampal-based memory; and a deficit of implicit learning with compensation by explicit learning ( 22 – 24 ). Indeed, patients with OCD show reduced task-based reward learning, correlated with reduced activity in, and connectivity between, limbic structures such as the NAcc, ventral putamen, vmPFC, OFC, hippocampus, and amygdala ( 15 , 24 – 27 ). During episodes of increased symptomatology there is hyperactivation in limbic structures ( 28 , 29 ).…”