Reduced focal fiber collinearity in the cingulum bundle in adults with obsessive-compulsive disorder

Abstract

Obsessive-compulsive disorder (OCD) is a disabling condition, often associated with a chronic course. Given its role in attentional control, decision-making, and emotional regulation, the anterior cingulate cortex is considered to have a key role in the pathophysiology of the disorder. Notably, the cingulum bundle, being the major white matter tract connecting to this region, has been historically a target for the surgical treatment of intractable OCD. In this study, we aimed to identify the extent to which focal—more than diffuse—abnormalities in fiber collinearity of the cingulum bundle could distinguish 48 adults with OCD (mean age [SD] = 23.3 [4.5] years; F/M = 30/18) from 45 age- and sex-matched healthy control adults (CONT; mean age [SD] = 23.2 [3.8] years; F/M = 28/17) and further examine if these abnormalities correlated with symptom severity. Use of tract-profiles rather than a conventional diffusion imaging approach allowed us to characterize white matter microstructural properties along (100 segments), as opposed to averaging these measures across, the entire tract. To account for these 100 different segments of the cingulum bundle, a repeated measures analysis of variance revealed a main effect of group (OCD < CONT; F[1,87] = 5.3; P = 0.024) upon fractional anisotropy (FA, a measure of fiber collinearity and/or white matter integrity), in the cingulum bundle, bilaterally. Further analyses revealed that these abnormalities were focal (middle portion) within the left and right cingulum bundle, although did not correlate with symptom severity in OCD. Findings indicate that focal abnormalities in connectivity between the anterior cingulate cortex and other prefrontal cortical regions may represent neural mechanisms of OCD.

White matter microstructure and connectivity in patients with obsessive‐compulsive disorder and their unaffected siblings

“…Compared to HCs, the OCD group showed lower FA and higher RD values in the anterior cingulum, forceps minor, and ATR, which is in line with the classical cortico‐striato‐thalamo‐cortical (CSTC) circuit model of OCD 10,51‐53 and with prior research in this area. Specifically, reduced FA was previously reported in OCD patients within the anterior cingulum bundle, 7,9‐11,13,51,54 the forceps minor, 8,10,11,14,16‐18,20 and the ATR 21,55 . However, we also observed alterations outside the CSTC, including within the IFOF, which connects the frontal lobe to parieto‐occipito‐temporal regions.…”

“…To differentiate myelin‐related pathology from axonal damage, the component measures from which FA is derived can be studied: an increase in radial diffusivity (RD) may signify increased space between fibers suggesting demyelination or dysmyelination, 5 whereas a decrease in axial diffusivity (AD) may suggest axonal injury 6 . Although results are mixed, most previous dMRI studies have reported lower FA in patients with OCD as compared to healthy controls, most consistently in the cingulum bundle 7‐13 and corpus callosum 8,10,11,14‐18 . A small number of previous dMRI studies have also investigated RD and AD in OCD patients, which report higher RD values in the forceps major, 19 corpus callosum 14,20 and in widespread WM, 21 as well as no between‐group difference in AD, suggesting that decreased myelination rather than axonal degeneration may underlie WM pathology in OCD.…”

The Role of Self-Talk in Predicting Death Anxiety, Obsessive-Compulsive Disorder, and Coping Strategies in the Face of Coronavirus Disease (COVID-19)

“…In addition to DA, the death of loved ones and recommendation to wash hands repeatedly may create disturbing thoughts and behaviors related to the disease, which may cause obsessive-compulsive disorder (OCD). OCD is a psychiatric disorder that involves intrusive and persistent thoughts and time-consuming compulsive behaviors (9). The dread of pollution and extreme washing of hands is likely the prevalent symptom of OCD (9,10).…”

“…OCD is a psychiatric disorder that involves intrusive and persistent thoughts and time-consuming compulsive behaviors (9). The dread of pollution and extreme washing of hands is likely the prevalent symptom of OCD (9,10). Studies showed that because of the fear of getting infected with the COVID-19, the individual with OCD attempts to stop these thoughts and behavior but often cannot succeed, which ultimately causes social and functional disturbances in many situations (9)(10)(11).…”

“…The dread of pollution and extreme washing of hands is likely the prevalent symptom of OCD (9,10). Studies showed that because of the fear of getting infected with the COVID-19, the individual with OCD attempts to stop these thoughts and behavior but often cannot succeed, which ultimately causes social and functional disturbances in many situations (9)(10)(11). The stress condition, strong infection, and lethality in severe cases can lead to several mental problems, so people use coping strategies to protect themselves in such a situation.…”