[Show abstract][Hide abstract] ABSTRACT: 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.
[Show abstract][Hide abstract] ABSTRACT: Objective. To investigate the effects of a functional polymorphism of the monoamine oxidase A (MAOA) gene on spontaneous brain activity in healthy male adolescents. Methods. Thirty-one healthy male adolescents with the low-activity MAOA genotype (MAOA-L) and 25 healthy male adolescents with the high-activity MAOA genotype (MAOA-H) completed the 11-item Barratt Impulsiveness Scale (BIS-11) questionnaire and were subjected to resting-state functional magnetic resonance imaging (rs-fMRI) scans. The amplitude of low-frequency fluctuation (ALFF) of the blood oxygen level-dependent (BOLD) signal was calculated using REST software. ALFF data were related to BIS scores and compared between genotype groups. Results. Compared with the MAOA-H group, the MAOA-L group showed significantly lower ALFFs in the pons. There was a significant correlation between the BIS scores and the ALFF values in the pons for MAOA-L group, but not for the MAOA-H group. Further regression analysis showed a significant genotype by ALFF values interaction effect on BIS scores. Conclusions. Lower spontaneous brain activity in the pons of the MAOA-L male adolescents may provide a neural mechanism by which boys with the MAOA-L genotype confers risk for impulsivity and aggression.
BioMed Research International 05/2014; DOI:10.1155/2014/243280 · 2.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to examine cognitive emotion regulation strategies in adult outpatients with major depressive disorder (MDD). A clinical sample of 191 MDD outpatients and a non-clinical sample of 267 general adults were recruited. Nine cognitive emotion regulation strategies were assessed in all participants (aged 21-65 years). Results showed that MDD participants had significantly higher scores on the following strategies: self-blame, acceptance, rumination, catastrophizing, and blaming others, but lower scores on positive refocusing, refocus on planning, positive reappraisal, and putting in perspective strategies than general populations. In addition, self-blame, acceptance, and catastrophizing positively correlated and positive reappraisal negatively correlated with depressive symptoms in MDD populations. Further logistic regression analyses indicated that five strategies have significant and independent contributions to the prediction of MDD group membership (a higher reported use of self-blame, catastrophizing, and acceptance, and a lower reported use of positive refocusing, and putting in perspective). The results suggest that cognitive emotion regulation strategies may be a useful target for psychological assessment and treatment in patients with MDD.
[Show abstract][Hide abstract] ABSTRACT: Major depressive disorder (MDD) has been associated with abnormal structure and function of the brain's 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.
To examine resting-state function of the brain's affective network in first-episode, medication-naive patients with MDD compared to healthy controls (HCs).
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.
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.
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.
PLoS ONE 01/2014; 9(1):e85241. DOI:10.1371/journal.pone.0085241 · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: 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.
[Show abstract][Hide abstract] ABSTRACT: The hopelessness theory of depression posits that individuals with negative cognitive styles are at an increased risk for depression following negative life events. In neuroimaging studies, brain gray matter volume abnormalities correlate with the presence of depressive disorders. However, it is unknown whether changes in gray matter volume also appear in healthy individuals with cognitive vulnerability to depression (CVD).
30 subjects diagnosed with CVD, 33 first-episode patients with major depressive disorder (MDD), and 32 healthy controls were examined using voxel-based morphometry following magnetic resonance imaging (MRI).
We found significant volumetric differences between three groups in the left precentral gyrus, right fusiform gyrus and the right thalamus. In these regions, compared to controls, CVD subjects showed reduced gray matter volumes in the left precentral gyrus and right fusiform gyrus. MDD patients demonstrated reduced gray matter volume in the left precentral gyrus and increased gray matter volume in the right thalamus. Additionally, CVD individuals had significantly smaller right fusiform gyrus and right thalamus than MDD patients. The weakest-link scores on CSQ were negatively correlated with gray matter volumes in the left precentral gyrus.
Reductions in brain gray matter volume exist widely in individuals with CVD. In addition, there exist similar abnormalities in gray matter volume in both CVD subjects and MDD patients. Reductions of gray matter volume in the left precentral gyrus might be correlated to the negative cognitive styles, as well as an increased risk for depression.