Functional connectivity in obsessive-compulsive disorder and its subtypes

Abstract

BackgroundObsessive-compulsive disorder (OCD) is an anxiety disorder with significant morbidity whose pathophysiology is not fully understood. Neuroimaging studies have characterized OCD in terms of elevated striatal and prefrontal reactivity to emotion provocation. This neural model may be informed by investigation of functional connectivity in OCD, identifying alterations in how sensory information is integrated into frontostriatal regions.MethodsThe current study employed functional magnetic resonance imaging (fMRI) to compare neural activity and connectivity in 31 OCD patients (12 washing and 19 checking subtypes) and 17 healthy volunteers in an emotion provocation paradigm using visual stimuli.ResultsOCD status was associated with hyper-activation of the posterior cingulate (PCg) in response to emotion provocation. Additionally, OCD patients demonstrated elevated PCg functional connectivity with the visual cortices and frontostriatal regions. Exploratory analyses suggested that stimulus-provoked activity and connectivity was elevated for checking subtypes in motor cortices, and elevated in washing subtypes in the anterior insula and orbitofrontal cortex.ConclusionsThe PCg's role in moderating connectivity between the visual cortex and frontolimbic regions is muted in OCD, consistent with the PCg's suggested role in regulating attention towards emotional stimuli. Exploratory analyses suggest distinct PCg connectivity profiles in OCD subtypes, with checking linked to motor activation, but washing linked to a network supporting emotional salience. The study was not powered to fully investigate the effects of medication, patients often endorsed secondary symptom subtypes that muddied washing/checking distinctions, and the emotion provocation paradigm was of limited intensity compared to life stressors.

Altered Functional Connectivity Strength at Rest in Medication-Free Obsessive-Compulsive Disorder

“…Consistent with the previous research, the present study discovered altered degree values within the CSTC circuit (i.e., left DLPFC and left thalamus) but failed to discover altered degree values in the emotional modulation network at rest in OCD. Different sample sizes, clinical symptoms, medication status, data analysis, and different OCD subtypes may account for these inconsistencies [59][60][61][62]. Moreover, inconsistent with our hypothesis, the current study did not find any relationship between degree values showing betweengroup differences and clinical variables in OCD.…”

Functional connectivity alterations between default mode network and occipital cortex in patients with obsessive-compulsive disorder (OCD)

“… Reggente et al (2018) found in pre-treatment rsfMRI that the DMN and; in second place; the visual network (out of eight investigated networks) best predicted post-CBT treatment OCD severity (explaining 67% of the variance in posttreatment Y-BOCS). Tasked-based imaging studies in OCD patients by Stern et al (2017) ; as well as ( Ravindran et al, 2020 ); also involved visual areas and connectivity between DMN regions and occipital areas, similar to our findings. ( Ravindran et al, 2020 ) stimulated stress using OCD-related images and observed hyperactivation of the posterior cingulate gyrus (PCg), which is part of the DMN.…”

“…Tasked-based imaging studies in OCD patients by Stern et al (2017) ; as well as ( Ravindran et al, 2020 ); also involved visual areas and connectivity between DMN regions and occipital areas, similar to our findings. ( Ravindran et al, 2020 ) stimulated stress using OCD-related images and observed hyperactivation of the posterior cingulate gyrus (PCg), which is part of the DMN. Interestingly, this DMN region was hypoconnected with SN-related regions and hyperconnected with the left primary visual cortex.…”

Altered Global Brain Functional Connectivity in Drug-Naive Patients With Obsessive-Compulsive Disorder

“…Thirdly, OCD samples were not divided into different subtypes based on different clinical symptoms due to the sample characteristics (i.e., most patients (32/40) are mixed with both obsession and compulsion) and relatively small sample size. Different OCD subtypes may have different GFC patterns at rest (53). Future studies should consider these issues.…”