Mingtian Zhong

First-Episode Medication-Naive Major Depressive Disorder Is Associated with Altered Resting Brain Function in the Affective Network

Background Major depressive disorder (MDD) has been associated with abnormal structure and function of the brains affective network, including the amygdala and orbitofrontal cortex (OFC). However, it is unclear if alterations of resting-state function in this affective network are present at the initial onset of MDD. Aims To examine resting-state function of the brains affective network in first-episode, medication-naive patients with MDD compared to healthy controls (HCs). Methods Resting-state functional magnetic resonance imaging (rs-fMRI) was performed on 32 first-episode, medication-naive young adult patients with MDD and 35 matched HCs. The amplitude of low-frequency fluctuations (ALFF) of the blood oxygen level-dependent (BOLD) signal and amygdala-seeded functional connectivity (FC) were investigated. Results Compared to HC, MDD patients showed reduced ALFF in the bilateral OFC and increased ALFF in the bilateral temporal lobe extending to the insular and left fusiform cortices. Enhanced anti-correlation of activity between the left amygdala seed and the left OFC was found in MDD patients but not in HCs. Conclusions Reduced ALFF in the OFC suggests hypo-functioning of emotion regulation in the affective network. Enhanced anti-correlation of activity between the amygdala and OFC may reflect dysfunction of the amygdala-OFC network and additionally represent a pathological process of MDD.

Is impaired response inhibition independent of symptom dimensions in obsessive-compulsive disorder? Evidence from ERPs

Impaired response inhibition has been consistently reported in patients diagnosed with obsessive-compulsive disorder (OCD). This clinically heterogeneous disorder is characterized by several symptom dimensions that may have distinct, but partially overlapping, neural correlates. The present study examined whether alterations in response inhibition may be related to symptom severity and symptom dimensions. Event-related potentials (ERPs) were recorded in a group of 42 medication-free OCD patients as well as 42 healthy controls during a stop-signal task. Symptom dimension scores were obtained using the Yale-Brown Obsessive Compulsive Scale symptom checklist. OCD patients showed longer stop-signal reaction times (SSRT, p < 0.01) and larger stop-N2 amplitudes (p < 0.01) compared to healthy controls. Neither the longer SSRT nor the larger stop-N2 scores were significantly correlated with symptom severity or present or lifetime OCD symptoms in OCD patients. These results indicate that deficient response inhibition is a common occurrence in OCD patients that is independent of global symptom severity and symptom dimensions. These data support the notion that impaired response inhibition may be a general attribute of patients with OCD.

An attentional inhibitory deficit for irrelevant information in obsessive-compulsive disorder: evidence from ERPs.

Previous studies on attentional bias have demonstrated that patients with obsessive-compulsive disorder (OCD) have an overall longer reaction time (RT) for various stimuli. It was hypothesized that this general slowness may indicate the presence of an attentional inhibition deficit in OCD. To test the hypothesis, event-related potentials (ERPs) were recorded in 31 non-medicated OCD patients and 29 age-, handedness- and sex-matched healthy controls while they performed an emotional Stroop task (EST). Relative to the control subjects, the OCD patients had similar interference effects for negative words, but an overall longer RT and larger P2 and P3 amplitudes to all words. These results support the notion that OCD is characterized by an attentional inhibitory dysfunction for irrelevant information.

A Voxel-Based Morphometric MRI Study in Young Adults with Borderline Personality Disorder

Background Increasing evidence has documented subtle changes in brain morphology and function in patients with borderline personality disorder (BPD). However, results of magnetic resonance imaging volumetry in patients with BPD are inconsistent. In addition, few researchers using voxel-based morphometry (VBM) have focused on attachment and childhood trauma in BPD. This preliminary study was performed to investigate structural brain changes and their relationships to attachment and childhood trauma in a homogenous sample of young adults with BPD. Method We examined 34 young adults with BPD and 34 healthy controls (HCs) to assess regionally specific differences in gray matter volume (GMV) and gray matter concentration (GMC). Multiple regressions between brain volumes measured by VBM and attachment style questionnaire (ASQ) and childhood trauma questionnaire (CTQ) scores were performed. Results Compared with HCs, subjects with BPD showed significant bilateral increases in GMV in the middle cingulate cortex (MCC)/posterior cingulate cortex (PCC)/precuneus. GMC did not differ significantly between groups. In multiple regression models, ASQ insecure attachment scores were correlated negatively with GMV in the precuneus/MCC and middle occipital gyrus in HCs, HCs with more severe insecure attachment showed smaller volumes in precuneus/MCC and middle occipital gyrus, whereas no negative correlations between insecure attachment and GMV in any region were found in BPD group. In addition, CTQ total scores were not correlated with GMV in any region in the two groups respectively. Conclusions Our findings fit with those of previous reports of larger precuneus GMV in patients with BPD, and suggest that GMV in the precuneus/MCC and middle occipital gyrus is associated inversely with insecure attachment style in HCs. Our finding of increased GMV in the MCC and PCC in patients with BPD compared with HCs has not been reported in previous VBM studies.

Abnormal white matter structural connectivity in adults with obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a complex and severe psychiatric disorder whose pathogenesis is not fully understood. Recent studies have shown white matter (WM) alterations in adults with OCD, but the results have been inconsistent. The present study investigated WM structure in OCD patients with the hypothesis that large-scale brain networks may be disrupted in OCD. A total of 24 patients with OCD and 23 healthy controls (HCs) were scanned with diffusion tensor imaging. A tract-based spatial statistics (TBSS) approach was used to detect differences across the whole brain in patients with OCD vs HCs; post hoc fiber tractography was applied to characterize developmental differences between the two groups. Relative to HCs, patients with OCD had lower fractional anisotropy (FA) values in the corpus callosum (CC), left anterior corona radiata (ACR), left superior corona radiata (SCR) and left superior longitudinal fasciculus (SLF), and higher radial diffusivity in the genu and body of CC. Among the TBSS de-projected region of interest results, compared with HCs, patients with OCD showed lower of the mean FA values of fiber bundles passing though the SLF, and shorter lengths of ACR, SCR and CC. In conclusion, this study provides novel evidence of widespread microstructural alterations in OCD and suggests that OCD may involve abnormalities affecting a broader network of regions than commonly believed.

Components of inhibition in autogenous- and reactive-type obsessive-compulsive disorder: Dissociation of interference control

Obsessive-compulsive disorder (OCD) is characterized by unwanted, intrusive thoughts (obsessions) and/or repetitive, ritualistic behaviors (compulsions). Findings related to the two components of inhibition, namely interference control and behavioral inhibition, among OCD patients have been inconsistent. It might be that this inconsistency is due to the heterogeneity among OCD cases representing multiple subtypes of OCD, such as autogenous obsessions and reactive obsessions types (AOs vs. ROs). AOs and ROs are distinguished by the category of their most disturbing obsessions. The purpose of this study was to systematically examine whether inhibition functions differ between AO and RO patients. We assessed interference control and behavioral inhibition with the emotional Stroop task (EST) and stop-signal task (SST), respectively, in 42 AOs, 55 ROs and 62 healthy controls (HCs) and event-related potentials (ERPs) were recorded in a random subset of these subjects (25 AOs, 25 ROs, and 31HCs). Results showed that in the EST, AOs exhibited longer reaction times (RTs) for color-naming positive-, negative-, and neutral-valence word stimulus than both ROs and HCs, and demonstrated larger P2 and less negative N450 amplitudes than HCs and larger P3 amplitudes than ROs and HCs. In the SST, both AOs and ROs showed lengthened stop signal reaction time (SSRT) and reduced Stop-P3 amplitudes in successful inhibition (SI) trials compared to the HC group. These present findings suggest that behavioral inhibition impairment may reflect a common pathology in both the autogenous- and reactive-type OCD patients, whereas interference inhibition impairment appears to be specific to patients with autogenous obsessions. These findings strengthened the insight into the clinical heterogeneity and pathophysiology of OCD.

Inhibitory deficit in semantic conflict in obsessive–compulsive disorder: An event-related potential study

The present study examines the inhibitory function of patients with obsessive-compulsive disorder (OCD) involved in semantic conflict using event-related potentials (ERPs). EPRs were recorded in a group of 18 medicine-free OCD patients and 18 normal controls using a modified Stroop paradigm in which the participants were asked to make a judgment of congruent or incongruent stimuli. The reaction time to color-word incongruent stimuli in the OCD group was significantly longer than the reaction time to congruent stimuli. In the OCD group, a significant negativity shift was discovered in P350 amplitude and N450 amplitude in response to incongruent stimuli, a shift not present in the control group. The amplitude of difference waveform was significantly higher for OCD than for control subjects. The findings probably revealed an inhibitory deficit in patients with OCD when performing semantic conflict tasks. The results suggest that this type of inhibitory deficit may be the cause of increased Stroop effects in patients with OCD, and one of contributors to the pathophysiology of OCD.

Abnormal white matter structural connectivity in treatment-naïve young adults with borderline personality disorder.

The pathogenesis of borderline personality disorder (BPD) is not well understood. We examined the microstructure of white matter in patients with BPD.

Spontaneous neural activity in the right superior temporal gyrus and left middle temporal gyrus is associated with insight level in obsessive-compulsive disorder

BACKGROUND Insight into illness is an important issue for psychiatry disorder. Although the existence of a poor insight subtype of obsessive-compulsive disorder (OCD) was recognized in the DSM-IV, and the insight level in OCD was specified further in DSM-V, the neural underpinnings of insight in OCD have been rarely explored. The present study was designed to bridge this research gap by using resting-state functional magnetic resonance imaging (fMRI). METHODS Spontaneous neural activity were examined in 19 OCD patients with good insight (OCD-GI), 18 OCD patients with poor insight (OCD-PI), and 25 healthy controls (HC) by analyzing the amplitude of low-frequency fluctuation (ALFF) in the resting state. Pearson correlation analysis was performed between regional ALFFs and insight levels among OCD patients. RESULTS OCD-GI and OCD-PI demonstrated overlapping and distinct brain alterations. Notably, compared with OCD-GI, tOCD-PI had reduced ALFF in left middle temporal gyrus (MTG) and right superior temporal gyrus (STG), as well as increased ALFF in right middle occipital gyrus. Further analysis revealed that ALFF values for the left MTG and right STG were correlated negatively with insight level in patients with OCD. LIMITATIONS Relatively small sample size and not all patients were un-medicated are our major limitations. CONCLUSIONS Spontaneous brain activity in left MTG and right STG may be neural underpinnings of insight in OCD. Our results suggest the great role of human temporal brain regions in understanding insight, and further underscore the importance of considering insight presentation in understanding the clinical heterogeneity of OCD.

Age at symptom onset is not associated with reduced action cancelation in adults with obsessive-compulsive disorder

The aim of the current study was to examine the association between age at symptom onset and action cancelation in adults with obsessive-compulsive disorder (OCD). Performance on the stop-signal task was compared among adult patients with early-onset OCD (n=63, onset age ≤19), late-onset OCD (n=33, onset age ≥20), and healthy controls (n=51). Stop-signal reaction time (SSRT) was significantly longer in both OCD groups compared to the control group. However, no significant differences were found between the two OCD groups. In addition, age at symptom onset was not associated with response inhibition performance in adults with OCD. The study findings support the existence of reduced performance on action cancelation in patients with OCD compared to healthy controls with no difference between early- and late-onset OCD subtypes.