Gray matter reduction associated with psychopathology and cognitive dysfunction in unipolar depression: a voxel-based morphometry study

Association between change in brain gray matter volume, cognition, and depression severity: Pre- and post- antidepressant pharmacotherapy for late-life depression

Late-life depression (LLD) is associated with cognitive impairments and reduced gray matter volume (GMV); however the mechanisms underlying this association are not well understood. The goal of this study was to characterize changes in depression severity, cognitive function, and brain structure associated with pharmacologic antidepressant treatment for LLD. We administered a detailed neurocognitive battery and conducted structural magnetic resonance imaging (MRI) on 26 individuals with LLD, pre-/post-a 12-week treatment trial with venlafaxine. After calculating changes in cognitive performance, GMV, and depression severity, we calculated Pearson's correlations, performed permutation testing, and false discovery rate correction. We found that loss of GMV over 12 weeks in the superior orbital frontal gyrus was associated with less improvement in depression severity and that increased GMV in the same was associated with greater improvement in depression severity. We detected no associations between changes in cognitive performance and improvements in either depressive symptoms or changes in GMV.

White matter correlates of impaired attention control in major depressive disorder and healthy volunteers

BACKGROUND

Major depressive disorder (MDD) is associated with impaired attention control and alterations in frontal-subcortical connectivity. We hypothesized that attention control as assessed by Stroop task interference depends on white matter integrity in fronto-cingulate regions and assessed this relationship using diffusion tensor imaging (DTI) in MDD and healthy volunteers (HV).

METHODS

DTI images and Stroop task were acquired in 29 unmedicated MDD patients and 16 HVs, aged 18-65 years. The relationship between Stroop interference and fractional anisotropy (FA) was examined using region-of-interest (ROI) and tract-based spatial statistics (TBSS) analyses.

RESULTS

ROI analysis revealed that Stroop interference correlated positively with FA in left caudal anterior cingulate cortex (cACC) in HVs (r = 0.62, p = 0.01), but not in MDD (r = -0.05, p= 0.79) even after controlling for depression severity. The left cACC was among 4 ROIs in fronto-cingulate network where FA was lower in MDD relative to HVs (F_(1,41) = 8.87, p = 0.005). Additionally, TBSS showed the same group interaction of differences and correlations, although only at a statistical trend level.

LIMITATIONS

The modest sample size limits the generalizability of the findings.

CONCLUSIONS

Structural connectivity of white matter network of cACC correlated with magnitude of Stroop interference in HVs, but not MDD. The cACC-frontal network, sub-serving attention control, may be disrupted in MDD. Less cognitive control may include enhanced effects of salience in HVs, or less effective response inhibition in MDD. Further studies of salience and inhibition components of executive function may better elucidate the relationship between brain white matter changes and executive dysfunction in MDD.

Clinical and demographic predictors of response to rTMS treatment in unipolar and bipolar depressive disorders

OBJECTIVE

Previous studies investigated predictors of repetitive transcranial magnetic stimulation (rTMS) response in depressive disorders but there is still limited knowledge about clinical predictors. Moreover, predictors of rTMS response in bipolar depression (BDD) are less studied than unipolar depression (UDD).

METHODS

We performed a binary logistic regression analysis in 248 patients with depressive disorders (unipolar N=102, bipolar N=146) who received 20 sessions of DLPFC rTMS (High-frequency rTMS, low-frequency rTMS, bilateral rTMS) to investigate significant clinical and demographic predictors of rTMS response. We also investigated effects of depression type, response (yes, no) and time on reducing somatic and cognitive-affective symptoms of patients.

RESULTS

Depression type (unipolar vs. bipolar) did not have a significant effect on rTMS response. 45% of all patients, 51.5% of UDD patients and 41% of BDD patients, responded to rTMS treatment. Age was the only significant demographic predictor of treatment response in all patients. Cognitive-affective symptoms, compared to somatic symptoms were significant predictors for treatment response to rTMS. Common and unique clinical predictor for UDD and BDD were identified.

CONCLUSIONS

Younger patients and those with cognitive-affective rather than somatic symptoms benefit more from DLPFC rTMS treatment. rTMS is effective in UDD and BDD patients. Patients should be selected based on clinical and demographic profile.

SIGNIFICANCE

Findings are based on the largest thus far reported sample of patients with depressive disorders that received DLPFC rTMS.

Microstructural Abnormalities of Basal Ganglia and Thalamus in Bipolar and Unipolar Disorders: A Diffusion Kurtosis and Perfusion Imaging Study

OBJECTIVE

Bipolar disorder (BD) is often misdiagnosed as unipolar depression (UD), leading to mistreatment and poor clinical outcomes. However, little is known about the similarities and differences in subcorticalgray matter regions between BD and UD.

METHODS

Thirty-five BD patients, 30 UD patients and 40 healthy controls underwent diffusional kurtosis imaging (DKI) and three dimensional arterial spin labeling (3D ASL). The parameters including mean kurtosis (MK), axial kurtosis (Ka), radial kurtosis (Kr), fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (Da), radial diffusivity (Dr) and cerebral blood flow (CBF) were measured by using regions-of-interest analysis in the caudate, putamen and thalamus of the subcortical gray matter regions.

RESULTS

UD exhibited differences from controls for DKI measures and CBF in the left putamen and caudate. BD showed differences from controls for DKI measures in the left caudate. Additionally, BD showed lower Ka in right putamen, higher MD in right caudate compared with UD. Receiver operating characteristic analysis revealed the Kr of left caudate had the highest predictive power for distinguishing UD from controls.

CONCLUSION

The two disorders may have overlaps in microstructural abnormality in basal ganglia. The change of caudate may serve as a potential biomarker for UD.

Electroconvulsive therapy changes the regional resting state function measured by regional homogeneity (ReHo) and amplitude of low frequency fluctuations (ALFF) in elderly major depressive disorder patients: An exploratory study

Electroconvulsive therapy (ECT) is the most effective and rapid treatment for severe major depressive disorder (MDD) in elderly patients. The mechanism of ECT is unclear, and studies on ECT in elderly MDD patients by resting-state functional magnetic resonance imaging are rare. Thirteen elderly MDD patients were scanned before and after ECT using a 3.0T MRI scanner. Regional homogeneity (ReHo) and amplitude of low-frequency fluctuations (ALFF) were processed to compare resting-state function before and after treatment. Depression and anxiety symptoms of all patients abated after ECT. Decreased ReHo values in the bilateral superior frontal gyrus (SFG) were observed after ECT, and the values of right SFG significantly correlated with an altered Hamilton depression rating scale score. Increased ALFF values in the left middle frontal gyrus, right middle frontal gyrus, orbital part, and decreased ALFF values in the left midcingulate area, left precentral gyrus, right SFG/middle frontal gyrus after ECT were also observed. These results support the hypothesis that ECT may affect the regional resting state brain function in geriatric MDD patients.

Structural alterations in the prefrontal cortex mediate the relationship between Internet gaming disorder and depressed mood

Adaptive gaming use has positive effects, whereas depression has been reported to be prevalent in Internet gaming disorder (IGD). However, the neural correlates underlying the association between depression and Internet gaming remain unclear. Moreover, the neuroanatomical profile of the striatum in IGD is relatively less clear despite its important role in addiction. We found lower gray matter (GM) density in the left dorsolateral prefrontal cortex (DLPFC) in the IGD group than in the Internet gaming control (IGC) group and non-gaming control (NGC) group, and the GM density was associated with lifetime usage of Internet gaming, depressed mood, craving, and impulsivity in the gaming users. Striatal volumetric analysis detected a significant reduction in the right nucleus accumbens (NAcc) in the IGD group and its association with lifetime usage of gaming and depression. These findings suggest that alterations in the brain structures involved in the reward system are associated with IGD-related behavioral characteristics. Furthermore, the DLPFC, involved in cognitive control, was observed to serve as a mediator in the association between prolonged gaming and depressed mood. This finding may provide insight into an intervention strategy for treating IGD with comorbid depression.

Altered fractional amplitude of low frequency fluctuation associated with cognitive dysfunction in first-episode drug-naïve major depressive disorder patients

BACKGROUND

Previous studies have demonstrated that abnormities of both resting-state brain activity and cognitive dysfunction are frequently observed in patients with major depressive disorder (MDD). However, the underlying relationship between these two aspects is less investigated. In this context, the aim of the present study was to investigate the association between cognitive dysfunction and altered resting-state brain function in first-episode drug-naïve MDD patients.

METHODS

Twenty-five drug-naïve MDD patients and twenty-six age-, sex-, and education-matched normal controls were recruited in this study. Cognitive function was evaluated by using a series of validated test procedures. The resting-state functional magnetic resonance imaging data were obtained on a Philips 3.0 Tesla scanner and analysed using the fractional amplitude of low frequency fluctuation (fALFF) method. Correlations of fALFF values with cognitive dysfunction were further analysed.

RESULTS

Compared with healthy controls, MDD patients showed significantly fewer completed categories in the Wisconsin Card Sorting Test (WCST) and decreased scores in the first and second subtests of the Continuous Performance Test (CPT). However, the two groups did not differ in their performance on the Stroop Colour Word Test and Trail-making Test. MDD patients exhibited significantly decreased fALFF values in the left superior frontal gyrus (SFG), left middle frontal gyrus, and left inferior frontal gyrus, as well as increased fALFF values in the left inferior temporal gyrus (ITG), bilateral parahippocampal gyrus, and the right caudate. Finally, the correlation analyses revealed that fALFF values in the left SFG and left ITG were associated with the number of WSCT completed categories and scores on the second subtest of the CPT in MDD, respectively.

CONCLUSIONS

The present findings suggest that there is little evidence of an association between regional abnormalities in resting-state brain function and cognitive deficits in MDD.

What is the impact of child abuse on gray matter abnormalities in individuals with major depressive disorder: a case control study

BACKGROUND

Patients with major depressive disorder (MDD) present heterogeneous clinical symptoms, and childhood abuse is associated with deepening of psychopathology. The aim of this study was to identify structural brain abnormalities in MDD and to assess further differences in gray matter density (GMD) associated with childhood abuse in MDD.

METHODS

Differences in regional GMD between 34 MDD patients and 26 healthy controls were assessed using magnetic resonance imaging and optimized voxel-based morphometry. Within the MDD group, further comparisons were performed focusing on the experience of maltreatment during childhood (23 MDD with child abuse vs 11 MDD without child abuse).

RESULTS

Compared with healthy controls, the MDD patient group showed decreased GMD in the bilateral orbitofrontal cortices, right superior frontal gyrus, right posterior cingulate gyrus, bilateral middle occipital gyri, and left cuneus. In addition, the patient group showed increased GMD in bilateral postcentral gyri, parieto-occipital cortices, putamina, thalami, and hippocampi, and left cerebellar declive and tuber of vermis. Within the MDD patient group, the subgroup with abuse showed a tendency of decreased GMD in right orbitofrontal cortex, but showed increased GMD in the left postcentral gyrus compared to the subgroup without abuse.

CONCLUSIONS

Our findings suggest a complicated dysfunction of networks between cortical-subcortical circuits in MDD. In addition, increased GMD in postcentral gyrus and a possible reduction of GMD in the orbitofrontal cortex of MDD patients with abuse subgroup may be associated with abnormalities of body perception and emotional dysregulation.

Different Patterns of Correlation between Grey and White Matter Integrity Account for Behavioral and Psychological Symptoms in Alzheimer's Disease

Behavioral disorders and psychological symptoms (BPSD) in Alzheimer's disease (AD) are known to correlate with grey matter (GM) atrophy and, as shown recently, also with white matter (WM) damage. WM damage and its relationship with GM atrophy are reported in AD, reinforcing the interpretation of the AD pathology in light of a disconnection syndrome. It remains uncertain whether this disconnection might account also for different BPSD observable in AD. Here, we tested the hypothesis of different patterns of association between WM damage of the corpus callosum (CC) and GM atrophy in AD patients exhibiting one of the following BPSD clusters: Mood (i.e., anxiety and depression; ADmood), Frontal (i.e., dishinibition and elation; ADfrontal), and Psychotic (delusions and hallucinations; ADpsychotic) related symptoms, as well as AD patients without BPSD. Overall, this study brings to light the strict relationship between WM alterations in different parts of the CC and GM atrophy in AD patients exhibiting BPSD, supporting the hypothesis that such symptoms are likely to be caused by characteristic patterns of neurodegeneration of WM and GM, rather than being a reactive response to accumulation of cognitive disabilities, and should therefore be regarded as potential markers of diagnostic and prognostic value in AD.

Abnormal cerebellar volume in acute and remitted major depression

Abnormal cortical volume is well-documented in patients with major depressive disorder (MDD), but cerebellar findings have been heterogeneous. It is unclear whether abnormal cerebellar structure relates to disease state or medication. In this study, using structural MRI, we investigated cerebellar volume in clinically acute (with and without psychotropic treatment) and remitted MDD patients. High-resolution structural MRI data at 3T were obtained from acute medicated (n=29), acute unmedicated (n=14) and remitted patients (n=16). Data from 29 healthy controls were used for comparison purposes. Cerebellar volume was investigated using cerebellum-optimized voxel-based analysis methods. Patients with an acute MDD episode showed increased volume of left cerebellar area IX, and this was true for both medicated and unmedicated individuals (p<0.05 cluster-corrected). Remitted patients exhibited bilaterally increased area IX volume. In remitted, but not in acutely ill patients, area IX volume was significantly associated with measures of depression severity, as assessed by the Hamilton Depression Rating Scale (HAMD). In addition, area IX volume in remitted patients was significantly related to the duration of antidepressant treatment. In acutely ill patients, no significant relationships were established using clinical variables, such as HAMD, illness or treatment duration and number of depressive episodes. The data suggest that cerebellar area IX, a non-motor region that belongs to a large-scale brain functional network with known relevance to core depressive symptom expression, exhibits abnormal volume in patients independent of clinical severity or medication. Thus, the data imply a possible trait marker of the disorder. However, given bilaterality and an association with clinical scores at least in remitted patients, the current findings raise the possibility that cerebellar volume may be reflective of successful treatment as well.

Gray matter volumes in symptomatic and asymptomatic offspring of parents diagnosed with bipolar disorder

Children of parents diagnosed with bipolar disorder (BD), termed high-risk offspring (HRO), are at greater risk of developing psychiatric disorders compared to healthy children of healthy parents (HCO). Gray matter volume (GMV) abnormalities have been observed in HRO, however, these reports are inconsistent. We posit that this variability may be attributed to differences in methodology among offspring studies; in particular, the presence of psychiatric symptoms in HRO. Here, we directly compared GMVs between symptomatic and asymptomatic HRO, and HCO. High-resolution T1-weighted MR images were collected from 31 HRO (18 symptomatic and 13 asymptomatic) and 20 age- and sex-matched HCO. HRO had at least one parent diagnosed with BD. Symptomatic HRO were defined as having a psychiatric diagnosis other than BD, while asymptomatic HRO were required to be free of any psychiatric diagnosis. Scans were processed using voxel-based morphometry methods and between group analyses were performed in SPM. Compared to HCO, the HRO group showed decreased GMV in the right inferior orbitofrontal, right middle frontal, and bilateral superior and middle temporal regions. Both symptomatic and asymptomatic HRO groups showed decreased GMV in these regions separately when compared to HCO. When comparing symptomatic and asymptomatic HRO, GMVs were comparable in all regions except the lateral occipital cortex. Our study compared symptomatic and asymptomatic HRO directly. In doing so, we provided further support for the presence of discrete GMV deficits in HRO, and confirmed that these deficits are present irrespective of the presence of symptoms in HRO.

Gray matter increases in fronto-parietal regions of depression patients with aripiprazole monotherapy: An exploratory study

We investigated the treatment effects of aripiprazole monotherapy in first-episode medication-naïve patients with major depressive disorder (MDD). The accompanying changes in the gray matter volume (GMV) were also explored.Fifteen patients completed the trial and received structural scans by 3-Tesla magnetic resonance imaging at baseline and partially responding state (sixth week). To account for the test-retest bias, 27 healthy controls were scanned twice within 6 weeks. We utilized optimized voxel-based morphometry with different comparisons between groups.The partially responding patients with MDD had greater GMV in left middle frontal gyrus and left superior parietal gyrus when compared with baseline. However, they had decreases in the GMV of right orbitofrontal gyrus and right inferior temporal gyrus after response. The partially responding patients with MDD still had residual GMV deficits in right superior frontal gyrus when compared with controls. However, the lack of second patient group without aripiprazole intervention would be a significant limitation to interpret the aripiprazole-specific effects on GMV.The changes in the GMV of fronto-parieto-temporal regions and residual GMV deficits in the superior frontal gyrus might represent "state-dependent brain changes" and "residual-deficit brain regions," respectively, for aripiprzole monotherapy in MDD.

Subcortical brain alterations in major depressive disorder: findings from the ENIGMA Major Depressive Disorder working group

The pattern of structural brain alterations associated with major depressive disorder (MDD) remains unresolved. This is in part due to small sample sizes of neuroimaging studies resulting in limited statistical power, disease heterogeneity and the complex interactions between clinical characteristics and brain morphology. To address this, we meta-analyzed three-dimensional brain magnetic resonance imaging data from 1728 MDD patients and 7199 controls from 15 research samples worldwide, to identify subcortical brain volumes that robustly discriminate MDD patients from healthy controls. Relative to controls, patients had significantly lower hippocampal volumes (Cohen's d=-0.14, % difference=-1.24). This effect was driven by patients with recurrent MDD (Cohen's d=-0.17, % difference=-1.44), and we detected no differences between first episode patients and controls. Age of onset ⩽21 was associated with a smaller hippocampus (Cohen's d=-0.20, % difference=-1.85) and a trend toward smaller amygdala (Cohen's d=-0.11, % difference=-1.23) and larger lateral ventricles (Cohen's d=0.12, % difference=5.11). Symptom severity at study inclusion was not associated with any regional brain volumes. Sample characteristics such as mean age, proportion of antidepressant users and proportion of remitted patients, and methodological characteristics did not significantly moderate alterations in brain volumes in MDD. Samples with a higher proportion of antipsychotic medication users showed larger caudate volumes in MDD patients compared with controls. This currently largest worldwide effort to identify subcortical brain alterations showed robust smaller hippocampal volumes in MDD patients, moderated by age of onset and first episode versus recurrent episode status.

The impact of metabotropic glutamate receptors into active neurodegenerative processes: A "dark side" in the development of new symptomatic treatments for neurologic and psychiatric disorders

Metabotropic glutamate (mGlu) receptor ligands are under clinical development for the treatment of CNS disorders with high social and economic burden, such as schizophrenia, major depressive disorder (MDD), and Parkinson's disease (PD), and are promising drug candidates for the treatment of Alzheimer's disease (AD). So far, clinical studies have shown symptomatic effects of mGlu receptor ligands, but it is unknown whether these drugs act as disease modifiers or, at the opposite end, they accelerate disease progression by enhancing neurodegeneration. This is a fundamental issue in the treatment of PD and AD, and is also an emerging theme in the treatment of schizophrenia and MDD, in which neurodegeneration is also present and contribute to disease progression. Moving from in vitro data and preclinical studies, we discuss the potential impact of drugs targeting mGlu2, mGlu3, mGlu4 and mGlu5 receptor ligands on active neurodegeneration associated with AD, PD, schizophrenia, and MDD. We wish to highlight that our final comments on the best drug candidates are not influenced by commercial interests or by previous or ongoing collaborations with drug companies. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.

Cognitive Dysfunction in Major Depressive Disorder: Assessment, Impact, and Management

Cognitive dysfunction is increasingly being recognized as an important clinical dimension in major depressive disorder. This review summarizes the existing data on the epidemiology, assessment, and treatment of cognitive dysfunction among nonelderly adults with the disorder. Overall, cognitive dysfunction is prevalent, persists through periods of symptom remission, and may be independently associated with functional outcomes. However, although the evidence increasingly suggests that clinicians should be heedful of their patients' cognitive functioning, there is as yet no consensus on how best to monitor cognition clinically. In addition, although most studies have reported improved cognition with antidepressant medications, psychotherapy, and neuromodulation, the clinical significance of these improvements is unclear, and high-level evidence to guide decision making is limited. Nonetheless, given the important functional implications, clinicians should assess and monitor cognition and optimize both medication and psychological treatments to mitigate cognitive dysfunction among patients with major depressive disorder.

Brain-derived neurotrophic factor promoter methylation and cortical thickness in recurrent major depressive disorder

Recent studies have reported that methylation of the brain-derived neurotrophic factor (BDNF) gene promoter is associated with major depressive disorder (MDD). This study aimed to investigate the association between cortical thickness and methylation of BDNF promoters as well as serum BDNF levels in MDD. The participants consisted of 65 patients with recurrent MDD and 65 age- and gender-matched healthy controls. Methylation of BDNF promoters and cortical thickness were compared between the groups. The right medial orbitofrontal, right lingual, right lateral occipital, left lateral orbitofrontal, left pars triangularis, and left lingual cortices were thinner in patients with MDD than in healthy controls. Among the MDD group, right pericalcarine, right medical orbitofrontal, right rostral middle frontal, right postcentral, right inferior temporal, right cuneus, right precuneus, left frontal pole, left superior frontal, left superior temporal, left rostral middle frontal and left lingual cortices had inverse correlations with methylation of BDNF promoters. Higher levels of BDNF promoter methylation may be closely associated with the reduced cortical thickness among patients with MDD. Serum BDNF levels were significantly lower in MDD, and showed an inverse relationship with BDNF methylation only in healthy controls. Particularly the prefrontal and occipital cortices seem to indicate key regions in which BDNF methylation has a significant effect on structure.

Computational meta-analysis of statistical parametric maps in major depression

OBJECTIVE

Several neuroimaging meta-analyses have summarized structural brain changes in major depression using coordinate-based methods. These methods might be biased toward brain regions where significant differences were found in the original studies. In this study, a novel voxel-based technique is implemented that estimates and meta-analyses between-group differences in grey matter from individual MRI studies, which are then applied to the study of major depression.

METHODS

A systematic review and meta-analysis of voxel-based morphometry studies were conducted comparing participants with major depression and healthy controls by using statistical parametric maps. Summary effect sizes were computed correcting for multiple comparisons at the voxel level. Publication bias and heterogeneity were also estimated and the excess of heterogeneity was investigated with metaregression analyses.

RESULTS

Patients with major depression were characterized by diffuse bilateral grey matter loss in ventrolateral and ventromedial frontal systems extending into temporal gyri compared to healthy controls. Grey matter reduction was also detected in the right parahippocampal and fusiform gyri, hippocampus, and bilateral thalamus. Other areas included parietal lobes and cerebellum. There was no evidence of statistically significant publication bias or heterogeneity.

CONCLUSIONS

The novel computational meta-analytic approach used in this study identified extensive grey matter loss in key brain regions implicated in emotion generation and regulation. Results are not biased toward the findings of the original studies because they include all available imaging data, irrespective of statistically significant regions, resulting in enhanced detection of additional areas of grey matter loss.

Regional cortical thinning of the orbitofrontal cortex in medication-naïve female patients with major depressive disorder is not associated with MAOA-uVNTR polymorphism

BACKGROUND

Orbitofrontal cortex alterations have been suggested to underlie the impaired mood regulation in depression. MAOA-uVNTR (monoamine oxidase A-upstream variable number of tandem repeats) polymorphism has been reported to be associated with major depressive disorder by various studies. The influence of MAOA-uVNTR genotype on function and structure of the orbitofrontal cortex has previously been reported. In this study, we investigated the difference in orbitofrontal cortex thickness between medication-naïve female patients with major depressive disorder and healthy controls, and the influence of MAOA-uVNTR genotype on orbitofrontal cortex thickness in depression.

METHODS

Thirty-one patients with major depressive disorder and 43 healthy controls were included. All participants were subjected to T1-weighted structural magnetic resonance imaging and genotyped for MAOA-uVNTR polymorphism. An automated procedure of FreeSurfer was used to analyze difference in orbitofrontal cortex thickness.

RESULTS

Patients showed a significantly thinner left orbitofrontal cortex (F_(1,71) = 7.941, p = 0.006) and right orbitofrontal cortex (F_(1,71) = 17.447, p < 0.001). For the orbitofrontal cortex sub-region analysis, patients showed a significantly thinner left medial orbitofrontal cortex (F_(1,71) = 8.117, p = 0.006), right medial orbitofrontal cortex (F_(1,71) = 21.795, p < 0.001) and right lateral orbitofrontal cortex (F_(1,71) = 9.932, p = 0.002) compared to healthy controls. No significant interaction of diagnosis and MAOA-uVNTR genotype on orbitofrontal cortex thickness was revealed.

CONCLUSIONS

Our results suggest that structural alterations of the orbitofrontal cortex may be associated with the pathophysiology of major depressive disorder. Future studies with larger sample sizes are needed to detect a possible association between MAOA-uVNTR genotype and orbitofrontal cortex thickness in depression.

Neuromodulation of Attentional Control in Major Depression: A Pilot DeepTMS Study

While Major Depressive Disorder (MDD) is primarily characterized by mood disturbances, impaired attentional control is increasingly identified as a critical feature of depression. Deep transcranial magnetic stimulation (deepTMS), a noninvasive neuromodulatory technique, can modulate neural activity and induce neuroplasticity changes in brain regions recruited by attentional processes. This study examined whether acute and long-term high-frequency repetitive deepTMS to the dorsolateral prefrontal cortex (DLPFC) can attenuate attentional deficits associated with MDD. Twenty-one MDD patients and 26 matched control subjects (CS) were administered the Beck Depression Inventory and the Sustained Attention to Response Task (SART) at baseline. MDD patients were readministered the SART and depressive assessments following a single session (n = 21) and after 4 weeks (n = 13) of high-frequency (20 Hz) repetitive deepTMS applied to the DLPFC. To control for the practice effect, CS (n = 26) were readministered the SART a further two times. The MDD group exhibited deficits in sustained attention and cognitive inhibition. Both acute and long-term high-frequency repetitive frontal deepTMS ameliorated sustained attention deficits in the MDD group. Improvement after acute deepTMS was related to attentional recovery after long-term deepTMS. Longer-term improvement in sustained attention was not related to antidepressant effects of deepTMS treatment.

Baseline brain perfusion and brain structure in patients with major depression: a multimodal magnetic resonance imaging study

BACKGROUND

Abnormal regional cerebral blood flow (rCBF) and grey matter volume have been frequently reported in patients with major depressive disorder (MDD). However, it is unclear to what extent structural and functional change co-occurs in patients with MDD and whether markers of neural activity, such as rCBF, can be predicted by structural change.

METHODS

Using MRI, we investigated resting-state rCBF and brain structure in patients with MDD and healthy controls between July 2008 and January 2013. We acquired perfusion images obtained with continuous arterial spin labelling, used voxel-based morphometry to assess grey matter volume and integrated biological parametric mapping analyses to investigate the impact of brain atrophy on rCBF.

RESULTS

We included 43 patients and 29 controls in our study. Frontotemporal grey matter volume was reduced in patients compared with controls. In patients, rCBF was reduced in the anterior cingulate and bilateral parahippocampal areas and increased in frontoparietal and striatal regions. These abnormalities were confirmed by analyses with brain volume as a covariate. In patients with MDD there were significant negative correlations between the extent of depressive symptoms and bilateral parahippocampal rCBF. We found a positive correlation between depressive symptoms and rCBF for right middle frontal cortical blood flow.

LIMITATIONS

Medication use in patients has to be considered as a limitation of our study.

CONCLUSION

Our data suggest that while changes of cerebral blood flow and brain volume co-occur in patients with MDD, structural change is not sufficient to explain altered neural activity in patients at rest. Abnormal brain structure and function in patients with MDD appear to reflect distinct levels of neuropathology.

Gray matter volume abnormalities were associated with sustained attention in unmedicated major depression

BACKGROUND

Impaired sustained attention seems to be a core feature of depression while the anatomical alteration of brain was widely reported in depression patients. The authors aimed to identify the relationship between anatomical brain changes and sustained attention deficits in unmedicated patients with major depressive disorder (MDD).

METHODS

A total of 51 medication-free MDD patients and 51 matched healthy controls (HC) underwent high-resolution structural magnetic resonance imaging scanning, and optimized voxel-based morphometry method was performed to analyze the changes of gray matter volume (GMV). We employed a computerized neurocognitive task from the Cambridge Neuropsychological Tests Automated Battery (CANTAB)--Rapid Visual Information Processing (RVP) task--as a measurement of sustained attention. Based on clinical symptoms, 40 patients who had completed CANTAB-RVP test were divided into MDDa (mild depression patients) and MDDb (severe depression patients) groups. Then the relationships among sustained attention, GMV of different regions and clinical symptoms were explored separately.

RESULTS

MDD patients showed significant GMV increase in left posterior cingulate cortex (PCC) and inferior frontal gyrus (IFG) (p<0.001, uncorrected), and significant GMV decrease in medial/superior frontal gyrus (MFG/SFG) and lingual gyrus (p<0.001, uncorrected). Structure-cognition correlation analyses revealed that in MDD patients, GMV alterations of the IFG were significantly correlated with sustained attention as measured by the CANTAB-RVP.

CONCLUSIONS

Increased GMV values of IFG were associated with sustained attention which may underlie the pathophysiology of MDD or be part of the cognition circuit. In the severe depression patients, sustained attention deficits were positively correlated with clinical symptoms.

The gray matter alterations in major depressive disorder and panic disorder: Putative differences in the pathogenesis

OBJECTIVE

This is a comprehensive study to establish a diagnosis-specific gray matter deficit model for major depressive disorder (MDD) and panic disorder (PD).

METHOD

We enrolled 53 patients with first-episode medication-naïve PD, 54 healthy controls and 53 patients with first-episode medication-naïve MDD in this study. They were age, handedness and gender matched. All participating subjects all received baseline structural scanning by the 3-Tesla magnetic resonance scanner. The optimized voxel-based morphometry was performed on the 3 groups of subjects and the ANOVA analysis was used to estimate the inter-group gray matter differences between each group.

RESULTS

The PD group had higher gray matter volume than MDD group in the right medial frontal cortex and right temporal gyrus. The PD group had gray matter reductions in the right inferior frontal gyrus and right insula. The MDD group had gray matter reductions in bilateral medial frontal cortex, right superior frontal gyrus, right superior temporal gyrus and bilateral cerebellums.

CONCLUSION

The gray matter alterations of fronto-insula and fronto-temporo-cerebellum regions probably would be specific for PD and MDD respectively. In addition, the differences of gray matter volume in the fronto-temporal regions would be helpful to differentiate MDD from PD.

Neuroanatomical correlates of late-life depression and associated cognitive changes

We compared cortical thickness between patients with late-life depression (LLD) and healthy controls and between patients with early-onset (EOD) and late-onset (LOD) depression. We also tested age effects on cortical thickness in LLD and controls and if cortical thickness and hippocampal volumes were associated with cognitive performance in LLD. Three-dimensional T1-weighted magnetic resonance images were obtained in 49 LLD and 49 matched hospital controls and processed using FreeSurfer. General linear model analysis was used as a statistical approach. LLD group had thinning in the left parahippocampal, fusiform, and inferior-parietal cortex compared with controls. Age correlated with cortical thinning in controls but not in LLD. Women in the LOD groups had extensive cortical thinning in the lateral prefrontal cortex bilaterally compared with EOD women. Absence of statistically significant changes observed in men should however be treated with caution because of the low number of men in the study. Mini-Mental Status Examination score correlated with lateral prefrontal cortical thickness bilaterally and hippocampal volume in the total group of LLD and in LOD but not EOD. LLD is associated with cortical thinning, which is associated with age at depression onset, gender, and level of cognitive functioning.

Top-Down Control of Serotonin Systems by the Prefrontal Cortex: A Path toward Restored Socioemotional Function in Depression

Social withdrawal, increased threat perception, and exaggerated reassurance seeking behaviors are prominent interpersonal symptoms in major depressive disorder (MDD). Altered serotonin (5-HT) systems and corticolimbic dysconnectivity have long been suspected to contribute to these symptomatic facets; however, the underlying circuits and intrinsic cellular mechanisms that control 5-HT output during socioemotional interactions remain poorly understood. We review literature that implicates a direct pathway between the ventromedial prefrontal cortex (vmPFC) and dorsal raphe nucleus (DRN) in the adaptive and pathological control of social approach-avoidance behaviors. Imaging and neuromodulation during approach-avoidance tasks in humans point to the cortical control of brainstem circuits as an essential regulator of socioemotional decisions and actions. Parallel rodent studies using viral-based connectomics and optogenetics are beginning to provide a cellular blueprint of the underlying circuitry. In these studies, manipulations of vmPFC synaptic inputs to the DRN have revealed bidirectional influences on socioaffective behaviors via direct monosynaptic excitation and indirect disynaptic inhibition of 5-HT neurons. Additionally, adverse social experiences that result in permanent avoidance biases, such as social defeat, drive long-lasting plasticity in this microcircuit, potentiating the indirect inhibition of 5-HT output. Conversely, neuromodulation of the vmPFC via deep brain stimulation (DBS) attenuates avoidance biases by restoring the direct excitatory drive of 5-HT neurons and strengthening a key subset of forebrain 5-HT projections. Better understanding the cellular organization of the vmPFC-DRN pathway and identifying molecular determinants of its neuroplasticity can open fundamentally novel avenues for the treatment of affective disorders.

Decreased insular connectivity in drug-naive major depressive disorder at rest

BACKGROUND

The insula has extensive links to the fronto-limbic circuit and associated regions, which is involved in the neurobiology of major depressive disorder (MDD). However, few studies are designed to examine the insular connectivity in MDD. This study was performed to examine the insular connectivity in drug-naive MDD directly by using the insular cortices as seeds.

METHODS

Functional magnetic resonance imaging data were obtained from 44 drug-naive MDD patients and 44 healthy controls at rest. The functional connectivity (FC) method was used to analyze the images.

RESULTS

Significantly decreased FCs were found between the right insula and the left middle frontal gyrus (MFG, orbital part), left superior temporal gyrus (STG), right putamen, and right middle occipital gyrus (MOG), and between the left insula and the left superior temporal pole and right MOG in the patients compared with the controls. There were significantly negative correlations between the z values of the left insula-left superior temporal pole connectivity and the current episode duration (r=-0.332, p=0.028), between the z values of the right insula-left STG connectivity and the episode number (r=-0.343, p=0.023), and between the z values of the right insula-left MFG (orbital part) connectivity and the Automatic Thoughts Questionnaire scores (r=-0.359, p=0.017) in the patients.

CONCLUSIONS

The findings reveal that depressed patients have decreased insular connectivity with the fronto-limbic circuit, hate circuit, and visual regions, and suggest that the insula may act as an integration center of emotional processing which is disrupted in the depressed patients.

Abnormal Anterior Cingulate N-Acetylaspartate and Executive Functioning in Treatment-Resistant Depression After rTMS Therapy

BACKGROUND

Cognitive impairment is a key feature of treatment-resistant depression (TRD) and can be related to the anterior cingulate cortex (ACC) function. Repetitive transcranial magnetic stimulation (rTMS) as an antidepressant intervention has increasingly been investigated in the last two decades. However, no studies to date have investigated the association between neurobiochemical changes within the anterior cingulate and executive dysfunction measured in TRD being treated with rTMS.

METHODS

Thirty-two young depressed patients with treatment-resistant unipolar depression were enrolled in a double-blind, randomized study [active (n=18) vs. sham (n=14)]. ACC metabolism was investigated before and after high-frequency (15 Hz) rTMS using 3-tesla proton magnetic resonance spectroscopy (1H-MRS). The results were compared with 28 age- and gender-matched healthy controls. Executive functioning was measured with the Wisconsin Card Sorting Test (WCST) among 34 subjects with TRD and 28 healthy subjects.

RESULTS

Significant reductions in N-acetylaspartate (NAA) and choline-containing Compound levels in the left ACC were found in subjects with TRD pre-rTMS when compared with healthy controls. After successful treatment, NAA levels increased significantly in the left ACC of subjects and were not different from those of age-matched controls. In the WCST, more perseverative errors and fewer correct numbers were observed in TRD subjects at baseline. Improvements in both perseverative errors and correct numbers occurred after active rTMS. In addition, improvement of perseverative errors was positively correlated with enhancement of NAA levels in the left ACC in the active rTMS group.

CONCLUSIONS

Our results suggest that the NAA concentration in the left ACC is associated with an improvement in cognitive functioning among subjects with TRD response to active rTMS.

Increased cognition connectivity network in major depression disorder: a FMRI study

OBJECTIVE

Evidence of the brain network involved in cognitive dysfunction has been inconsistent for major depressive disorder (MDD), especially during early stage of MDD. This study seeks to examine abnormal cognition connectivity network (CCN) in MDD within the whole brain.

METHODS

Sixteen patients with MDD and 16 health controls were scanned during resting-state using 3.0 T functional magnetic resonance imaging (fMRI). All patients were first episode without any history of antidepressant treatment. Both the left and right dorsolateral prefrontal cortex (DLPFC) were used as individual seeds to identify CCN by the seed-target correlation analysis. Two sample t test was used to calculate between-group differences in CCN using fisher z-transformed correlation maps.

RESULTS

The CCN was constructed by bilateral seed DLPFC in two groups separately. Depressed subjects exhibited significantly increased functional connectivity (FC) by left DLPFC in one cluster, overlapping middle frontal gyrus, BA7, BA43, precuneus, BA6, BA40, superior temporal gyrus, BA22, inferior parietal lobule, precentral gyrus, BA4 and cingulate gyrus in left cerebrum. Health controls did not show any cluster with significantly greater FC compared to depressed subjects in left DLPFC network. There was no significant difference of FC in right DLPFC network between depressed subjects and the health controls.

CONCLUSION

There are differences in CCN during early stage of MDD, as identified by increased FCs among part of frontal gyrus, parietal cortex, cingulate cortex, and BA43, BA22, BA4 with left DLPFC. These brain areas might be involved in the underlying mechanisms of cognitive dysfunction in MDD.

Specificity of abnormal brain volume in major depressive disorder: a comparison with borderline personality disorder

BACKGROUND

Abnormal brain volume has been frequently demonstrated in major depressive disorder (MDD). It is unclear if these findings are specific for MDD since aberrant brain structure is also present in disorders with depressive comorbidity and affective dysregulation, such as borderline personality disorder (BPD). In this transdiagnostic study, we aimed to investigate if regional brain volume loss differentiates between MDD and BPD. Further, we tested for associations between brain volume and clinical variables within and between diagnostic groups.

METHODS

22 Females with a DSM-IV diagnosis of MDD, 17 females with a DSM-IV diagnosis of BPD and without comorbid posttraumatic stress disorder, and 22 age-matched female healthy controls (HC) were investigated using magnetic resonance imaging. High-resolution structural data were analyzed using voxel-based morphometry.

RESULTS

A significant (p<0.05, cluster-corrected) volume decrease of the anterior cingulate cortex (ACC) was found in MDD compared to HC, as opposed to volume decreases of the amygdala in BPD compared to both HC and MDD. Sensitivity and specificity of regional gray matter volume for a diagnosis of MDD were modest to fair. Amygdala volume was related to depressive symptoms across the entire patient sample.

LIMITATIONS

Potential limitations of this study include the modest sample size and the heterogeneous psychotropic drug treatment.

CONCLUSIONS

ACC volume reduction is more pronounced in MDD with an intermediate degree of volume loss in BPD compared to HC. In contrast, amygdala volume loss is more pronounced in BPD compared to MDD, yet amygdala volume is associated with affective symptom expression in both disorders.

Attentional Set-Shifting Across Species

Attentional set-shifting, as a measure of executive flexibility, has been a staple of investigations into human cognition for over six decades. Mediated by the frontal cortex in mammals, the cognitive processes involved in forming, maintaining and shifting an attentional set are vulnerable to dysfunction arising from a number of human neurodegenerative diseases (such as Alzheimer's, Parkinson's and Huntington's diseases) and other neurological disorders (such as schizophrenia, depression, and attention deficit/hyperactivity disorder). Our understanding of these diseases and disorders, and the cognitive impairments induced by them, continues to advance, in tandem with an increasing number of tools at our disposal. In this chapter, we review and compare commonly used attentional set-shifting tasks (the Wisconsin Card Sorting Task and Intradimensional/Extradimensional tasks) and their applicability across species. In addition to humans, attentional set-shifting has been observed in a number of other animals, with a substantial body of literature describing performance in monkeys and rodents. We consider the task designs used to investigate attentional set-shifting in these species and the methods used to model human diseases and disorders, and ultimately the comparisons and differences between species-specific tasks, and between performance across species.

Anatomical and functional brain abnormalities in unmedicated major depressive disorder

BACKGROUND

Using magnetic resonance imaging (MRI) and resting-state functional magnetic resonance imaging (rsfMRI) to explore the mechanism of brain structure and function in unmedicated patients with major depressive disorder (MDD).

PATIENTS AND METHODS

Fifty patients with MDD and 50 matched healthy control participants free of psychotropic medication underwent high-resolution structural and rsfMRI scanning. Optimized diffeomorphic anatomical registration through exponentiated lie algebra and the Data Processing Assistant for rsfMRI were used to find potential differences in gray-matter volume (GMV) and regional homogeneity (ReHo) between the two groups. A Pearson correlation model was used to analyze associations of morphometric and functional changes with clinical symptoms.

RESULTS

Compared to healthy controls, patients with MDD showed significant GMV increase in the left posterior cingulate gyrus and GMV decrease in the left lingual gyrus (P<0.001, uncorrected). In ReHo analysis, values were significantly increased in the left precuneus and decreased in the left putamen (P<0.001, uncorrected) in patients with MDD compared to healthy controls. There was no overlap between anatomical and functional changes. Linear correlation suggested no significant correlation between mean GMV values within regions with anatomical abnormality and ReHo values in regions with functional abnormality in the patient group. These changes were not significantly correlated with symptom severity.

CONCLUSION

Our study suggests a dissociation pattern of brain regions with anatomical and functional alterations in unmedicated patients with MDD, especially with regard to GMV and ReHo.

Influence of age of onset on limbic and paralimbic structures in depression

AIM

Major depressive disorder (MDD) onset during childhood/adolescence is associated with a greater illness burden and distinct clinical profile. However, limited research exists on the effect of age of MDD onset on volumetric abnormalities in para/limbic structures during adulthood.

METHODS

Subgenual anterior cingulate cortex (sgACC), hippocampus and caudate nucleus volumes were measured by manual tracing in depressed individuals (n = 45) and healthy controls (HC; n = 19). Volumetric comparisons were carried out between HC and MDD patients divided into those with pediatric (≤ 18 years; n = 17) and adult onset (≥ 19 years; n = 28).

RESULTS

The adult MDD-onset group had smaller sgACC volumes than the pediatric-onset and HC groups (age, sex controlled). No differences in caudate and hippocampus volumes existed. sgACC and hippocampal volumes were inversely correlated with depression severity.

CONCLUSIONS

Surprisingly, pediatric MDD-onset was not associated with more pronounced sgACC, hippocampus and caudate volume reductions. Nevertheless, age of illness onset appears to be a meaningful dimension of study in efforts to understand the neurobiological heterogeneity of MDD.

Impact of lingual gyrus volume on antidepressant response and neurocognitive functions in Major Depressive Disorder: a voxel-based morphometry study

BACKGROUND

Voxel-based morphometry (VBM) has demonstrated structural brain changes between patients with Major Depressive Disorder (MDD) and healthy individuals. The initial response to antidepressants is crucial to predict prognosis in the treatment of MDD. The aim of the present study was to investigate gray matter abnormalities predicting antidepressant responsiveness and the relationships between volumetric differences and clinical/cognitive traits in MDD patients.

METHODS

Fifty MDD patients who received 8 week period antidepressant treatment and 29 healthy controls participated in this study. VBM was applied to assess structural changes between MDD groups and control group. Neuropsychological tests were conducted on all participants.

RESULTS

Both treatment responsive and non-responsive patients showed a significant volume reduction of the left insular, but only non-responsive patients had decreased volume in the right superior frontal gyrus compared to healthy controls. The comparison between treatment responsive and non-responsive patient groups demonstrated a significant difference in gray matter volume in the lingual gyrus. The larger volume of lingual gryus predicted early antidepressant response, which was attributable to better performance in neuropsychological tests.

LIMITATION

This study included a small sample size and the patients received various antidepressants and benzodiazepines.

CONCLUSION

Our findings suggest that the patients who responded poorly to antidepressants were morphologically and cognitively impaired, whereas the treatment responsive patients showed less structural changes and relatively preserved cognitive functions. The lingual gyrus may be a possible candidate region to predict antidepressant responsiveness and maintained cognition in MDD.

Fusion analysis of first episode depression: where brain shape deformations meet local composition of tissue

Computational neuroanatomical techniques that are used to evaluate the structural correlates of disorders in the brain typically measure regional differences in gray matter or white matter, or measure regional differences in the deformation fields required to warp individual datasets to a standard space. Our aim in this study was to combine measurements of regional tissue composition and of deformations in order to characterize a particular brain disorder (here, major depressive disorder). We use structural Magnetic Resonance Imaging (MRI) data from young adults in a first episode of depression, and from an age- and sex-matched group of non-depressed individuals, and create population gray matter (GM) and white matter (WM) tissue average templates using DARTEL groupwise registration. We obtained GM and WM tissue maps in the template space, along with the deformation fields required to co-register the DARTEL template and the GM and WM maps in the population. These three features, reflecting tissue composition and shape of the brain, were used within a joint independent-components analysis (jICA) to extract spatially independent joint sources and their corresponding modulation profiles. Coefficients of the modulation profiles were used to capture differences between depressed and non-depressed groups. The combination of hippocampal shape deformations and local composition of tissue (but neither shape nor local composition of tissue alone) was shown to discriminate reliably between individuals in a first episode of depression and healthy controls, suggesting that brain structural differences between depressed and non-depressed individuals do not simply reflect chronicity of the disorder but are there from the very outset.

•

We combine measurements of regional tissue composition and of deformations to characterize major depressive disorder.

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We use structural MRI data from young adults in a first episode of depression.

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The combination of hippocampal shape deformations and tissue composition was shown to discriminate between individuals.

A systematic review of the clinical relevance of repetitive transcranial magnetic stimulation

OBJECTIVE

Repetitive transcranial magnetic stimulation (rTMS) is an approved treatment for depression. The clinical relevance of its efficacy is unclear. The clinical relevance of findings in the rTMS literature was assessed by translating Hamilton Depression Rating Scale (HAMD) data into Clinical Global Impression-Improvement scale (CGI-I) scores.

METHOD

We performed electronic searches of MEDLINE, Embase, PsycINFO, PubMed and Cochrane Central Register of Controlled Trials for RCTs and non-RCT trials on rTMS using Hamilton Depression Rating Scale (HAMD). Articles were included if published in English before January 2014. We translated HAMD scores into nominal CGI-I scores for rTMS for depression and for treatment-resistant depression (TRD).

RESULTS

About 960 abstracts were retrieved. Sixty-three studies were included, yielding 130 study arms. For depression, the mean percentage change in HAMD scores in all sham-controlled rTMS treatment arms was 35.63 (SD 16.35) and for sham-rTMS 23.33 (SD 16.51). For TRD, active rTMS in sham-controlled studies showed a mean HAMD percentage reduction of 45.21 (SD 10.94) versus 25.04 (SD 17.55) for sham-rTMS. When aggregated scores were translated into notional CGI-I scores, for the treatment of depression, the notional CGI-I score difference between rTMS and sham-rTMS was 0.5 in favour of rTMS; for TRD, it was 0.75 in favour of rTMS. Differences between rTMS and sham-rTMS were bigger when all study arms were combined.

CONCLUSION

Whilst rTMS appears to be efficacious for both non-refractory and treatment-resistant depression, the clinical relevance of its efficacy is doubtful.

The neuroscience of depression: implications for assessment and intervention

Major Depressive Disorder (MDD) is among the most prevalent of all psychiatric disorders and is the single most burdensome disease worldwide. In attempting to understand the profound deficits that characterize MDD across multiple domains of functioning, researchers have identified aberrations in brain structure and function in individuals diagnosed with this disorder. In this review we synthesize recent data from human neuroimaging studies in presenting an integrated neural network framework for understanding the impairments experienced by individuals with MDD. We discuss the implications of these findings for assessment of and intervention for MDD. We conclude by offering directions for future research that we believe will advance our understanding of neural factors that contribute to the etiology and course of depression, and to recovery from this debilitating disorder.

Reduced gray matter volume in the anterior cingulate, orbitofrontal cortex and thalamus as a function of mild depressive symptoms: a voxel-based morphometric analysis

BACKGROUND

Studies investigating structural brain abnormalities in depression have typically employed a categorical rather than dimensional approach to depression [i.e., comparing subjects with Diagnostic and Statistical Manual of Mental Disorders (DSM)-defined major depressive disorder (MDD) v. healthy controls]. The National Institute of Mental Health, through their Research Domain Criteria initiative, has encouraged a dimensional approach to the study of psychopathology as opposed to an over-reliance on categorical (e.g., DSM-based) diagnostic approaches. Moreover, subthreshold levels of depressive symptoms (i.e., severity levels below DSM criteria) have been found to be associated with a range of negative outcomes, yet have been relatively neglected in neuroimaging research.

METHOD

To examine the extent to which depressive symptoms--even at subclinical levels--are linearly related to gray matter volume reductions in theoretically important brain regions, we employed whole-brain voxel-based morphometry in a sample of 54 participants.

RESULTS

The severity of mild depressive symptoms, even in a subclinical population, was associated with reduced gray matter volume in the orbitofrontal cortex, anterior cingulate, thalamus, superior temporal gyrus/temporal pole and superior frontal gyrus. A conjunction analysis revealed concordance across two separate measures of depression.

CONCLUSIONS

Reduced gray matter volume in theoretically important brain regions can be observed even in a sample that does not meet DSM criteria for MDD, but who nevertheless report relatively elevated levels of depressive symptoms. Overall, these findings highlight the need for additional research using dimensional conceptual and analytic approaches, as well as further investigation of subclinical populations.

A combined study of GSK3β polymorphisms and brain network topological metrics in major depressive disorder

GSK3β genotypes may interact with major depressive disorder (MDD) and may have a role in determining regional gray matter volume differences from healthy comparison subjects. However, any associations of GSK3β genotypes with MDD related to abnormal functional brain activity have yet to be elucidated. In the present study, resting state functional brain networks were constructed by thresholding partial correlation matrices of 90 regions. Differences in the network features of GSK3β-rs6438552 genotypes were tested, and a 2×2 analysis of variance was performed to identify the main effects of genotypes, disease status, and their interactions in MDD. Compared with CC carriers, T+ carriers with MDD showed increased nodal centralities in many brain regions-mainly the limbic system, thalamus and parts of the parietal, temporal, occipital, and frontal regions. Decreased nodal centralities predominantly occurred in the sensorimotor area and parts of the frontal, occipital, and temporal lobes. Significant interactions between genotypes and disease status were found in the left thalamus, left superior occipital gyrus, and left inferior parietal lobe. Only altered nodal centrality in the left angular gyrus was negatively correlated with scores on the Hamilton Depression Rating Scale. Our results suggest the GSK3β genotypic effect of rs6438552 and its interaction with disease status may contribute to the altered topological organization of resting state functional brain networks in MDD patients.

Temporal-lobe morphology differs between healthy adolescents and those with early-onset of depression

Major depressive disorder (MDD) has previously been linked to structural changes in several brain regions, particularly in the medial temporal lobes (Bellani, Baiano, Brambilla, 2010; Bellani, Baiano, Brambilla, 2011). This has been determined using voxel-based morphometry, segmentation algorithms, and analysis of shape deformations (Bell-McGinty et al., 2002; Bergouignan et al., 2009; Posener et al., 2003; Vasic et al., 2008; Zhao et al., 2008): these are methods in which information related to the shape and the pose (the size, and anatomical position and orientation) of structures is lost. Here, we incorporate information about shape and pose to measure structural deformation in adolescents and young adults with and without depression (as measured using the Beck Depression Inventory and Diagnostic and Statistical Manual of Mental Disorders criteria). As a hypothesis-generating study, a significance level of p < 0.05, uncorrected for multiple comparisons, was used, so that subtle morphological differences in brain structures between adolescent depressed individuals and control participants could be identified. We focus on changes in cortical and subcortical temporal structures, and use a multi-object statistical pose and shape model to analyze imaging data from 16 females (aged 16-21) and 3 males (aged 18) with early-onset MDD, and 25 female and 1 male normal control participants, drawn from the same age range. The hippocampus, parahippocampal gyrus, putamen, and superior, inferior and middle temporal gyri in both hemispheres of the brain were automatically segmented using the LONI Probabilistic Brain Atlas (Shattuck et al., 2008) in MNI space. Points on the surface of each structure in the atlas were extracted and warped to each participant's structural MRI. These surface points were analyzed to extract the pose and shape features. Pose differences were detected between the two groups, particularly in the left and right putamina, right hippocampus, and left and right inferior temporal gyri. Shape differences were detected between the two groups, particularly in the left hippocampus and in the left and right parahippocampal gyri. Furthermore, pose measures were significantly correlated with BDI score across the whole (clinical and control) sample. Since the clinical participants were experiencing their very first episodes of MDD, morphological alteration in the medial temporal lobe appears to be an early sign of MDD, and is unlikely to result from treatment with antidepressants. Pose and shape measures of morphology, which are not usually analyzed in neuromorphometric studies, appear to be sensitive to depressive symptomatology.

Insular and hippocampal gray matter volume reductions in patients with major depressive disorder

Background

Major depressive disorder is a serious psychiatric illness with a highly variable and heterogeneous clinical course. Due to the lack of consistent data from previous studies, the study of morphometric changes in major depressive disorder is still a major point of research requiring additional studies. The aim of the study presented here was to characterize and quantify regional gray matter abnormalities in a large sample of clinically well-characterized patients with major depressive disorder.

Methods

For this study one-hundred thirty two patients with major depressive disorder and 132 age- and gender-matched healthy control participants were included, 35 with their first episode and 97 with recurrent depression. To analyse gray matter abnormalities, voxel-based morphometry (VBM8) was employed on T1 weighted MRI data. We performed whole-brain analyses as well as a region-of-interest approach on the hippocampal formation, anterior cingulate cortex and amygdala, correlating the number of depressive episodes.

Results

Compared to healthy control persons, patients showed a strong gray-matter reduction in the right anterior insula. In addition, region-of-interest analyses revealed significant gray-matter reductions in the hippocampal formation. The observed alterations were more severe in patients with recurrent depressive episodes than in patients with a first episode. The number of depressive episodes was negatively correlated with gray-matter volume in the right hippocampus and right amygdala.

Conclusions

The anterior insula gray matter structure appears to be strongly affected in major depressive disorder and might play an important role in the neurobiology of depression. The hippocampal and amygdala volume loss cumulating with the number of episodes might be explained either by repeated neurotoxic stress or alternatively by higher relapse rates in patients showing hippocampal atrophy.

Does body shaping influence brain shape? Habitual physical activity is linked to brain morphology independent of age

OBJECTIVES

Physical activity (PA) was found to influence human brain morphology. However, the impact of PA on brain morphology was mainly demonstrated in seniors. We investigated healthy individuals across a broad age range for the relation between habitual PA and brain morphology.

METHODS

Ninety-five participants (19-82 years) were assessed for self-reported habitual PA with the "Baecke habitual physical activity questionnaire", and T1-weighted magnetic resonance images were evaluated with whole brain voxel based morphometry for gray and white matter volumes and densities.

RESULTS

Regression analyses revealed a positive relation between the extent of physical activity and gray matter volume bilaterally in the anterior hippocampal and parahippocampal gyrus independent of age and gender. Age as well as leisure and locomotion activities were linked to enhanced white matter volumes in the posterior cingulate gyrus and precuneus, suggesting a positive interaction especially in seniors.

CONCLUSIONS

Habitual physical activity is associated with regional volumetric gray and white matter alterations. The positive relation of hippocampal volume and physical activity seems not to be restricted to seniors. Thus, habitual physical activity should be generally considered as an influencing factor in studies investigating medial temporal lobe volume and associated cognitive functions (memory), especially in psychiatric research.

Optimistic update bias increases in older age

BACKGROUND

Healthy older adults report greater well-being and life satisfaction than their younger counterparts. One potential explanation for this is enhanced optimism. We tested the influence of age on optimistic and pessimistic beliefs about the future and the associated structural neural correlates.

METHOD

Eighteen young and 18 healthy older adults performed a belief updating paradigm, measuring differences in updating beliefs for desirable and undesirable information about future negative events. These measures were related to regional brain volume, focusing on the anterior cingulate cortex (ACC) because this region is strongly linked to a positivity bias in older age.

RESULTS

We demonstrate an age-related reduction in updating beliefs when older adults are faced with undesirable, but not desirable, information about negative events. This greater 'update bias' in older age persisted even after controlling for a variety of variables including subjective rating scales and poorer overall memory. A structural brain correlate of this greater 'update bias' was evident in greater grey matter volume in the dorsal ACC in older but not in young adults.

CONCLUSIONS

We show a greater update bias in healthy older age. The link between this bias and relative volume of the ACC suggests a shared mechanism with an age-related positivity bias. Older adults frequently have to make important decisions relating to personal, health and financial issues. Our findings have wider behavioural implications in these contexts because an enhanced optimistic update bias may skew such real-world decision making.

Frontal-insula gray matter deficits in first-episode medication-naïve patients with major depressive disorder

OBJECTIVE

This study is designed to investigate the gray matter volume (GMV) deficits in patients with first-episode medication-naïve major depressive disorder (MDD).

METHODS

We enrolled 38 patients with first-episode medication-naïve MDD and 27 controls in this project. Voxel-based morphometry was used to compare GMV differences between two groups. Besides, the relationship between GMV of patients and the severity of clinical symptoms was estimated to confirm the role of GMV deficits in clinical symptoms. The correlation between total GMV and illness duration was also performed to elucidate the impacts of untreated duration on the GMV.

RESULTS

We found that first-episode medication-naïve MDD patients had significant GMV deficits in bilateral superior frontal gyri, left middle frontal gyrus, left medial frontal gyrus and left insula. The GMV of patient group was negatively correlated with the severity of clinical symptoms and the illness duration.

CONCLUSION

A pattern of GMV deficits in fronto-insula might represent the biomarker for first-episode medication-naïve MDD.

Volumetric differences in the anterior cingulate cortex prospectively predict alcohol-related problems in adolescence

RATIONALE

Individual differences in brain structure and function are suggested to exist prior to the onset of alcohol abuse. Cross-sectional studies have demonstrated abnormalities in brain regions underlying affective processes that may form a pathway to the emergence of later alcohol abuse and dependence in vulnerable individuals. However, no prospective studies have examined whether these abnormalities predict later problems with alcohol.

OBJECTIVE

This study aims to examine whether individual differences in affect and brain volume prospectively predict alcohol-related problems in adolescence.

METHOD

Adolescent drinkers (n = 98) were recruited from an ongoing prospective, longitudinal study examining adolescent emotional development. At age 12, participants underwent structural magnetic resonance imaging to obtain volumetric data on the amygdala, hippocampus, orbitofrontal cortex, and anterior cingulate cortex (ACC), and completed a self-report measure of affective temperament. At age 16, participants completed a questionnaire measuring alcohol use, with 39 % reporting alcohol-related problems in the past year.

RESULTS

Pre-existing differences in the left ACC predicted problem drinking. Alcohol-related problems were associated with higher levels of temperamental negative affectivity; however, these were not correlated with anterior cingulate volumes.

CONCLUSIONS

These findings indicate that individual differences in the structural morphology of the anterior cingulate, a region implicated in affective processes, self-control, and drug addiction, predict later alcohol-related problems. Although this finding remained significant after controlling for other substance use and psychopathology, future research is required to test its specificity for alcohol use disorders.

Regional increases of cortical thickness in untreated, first-episode major depressive disorder

The large majority of structural MRI studies of major depressive disorder (MDD) investigated volumetric changes in chronic medicated patients in whom course of illness and treatment effects may impact anatomic measurements. Further, in few studies, separate measurements of cortical thickness and surface area have been performed that reflect different neurobiological processes regulated by different genetic mechanisms. In the present study, we investigated both cortical thickness and surface area in first-episode, treatment-naïve, mid-life MDD to elucidate the core pathophysiology of this disease and its early impact on the brain. We observed increased cortical thickness in the right hemisphere, including medial orbitofrontal gyrus, pars opercularis, rostral middle frontal gyrus and supramarginal gyrus. Increased thickness of rostral middle frontal gyrus was negatively related with depression severity on the Hamilton Depression Rating Scale. Furthermore, MDD patients showed significantly increased associations in cortical thickness measurements among areas where increased cortical thickness was observed. Analysis of pial area revealed a trend toward increased surface area in the left parahippocampal gyrus in MDD. To permit comparison of our data with those of previous gray matter volume studies, voxel-based morphometry was performed. That analysis revealed significantly increased gray matter volume in left paracentral lobule, left superior frontal gyrus, bilateral cuneus and thalamus which form limbic-cortico-striato-pallido-thalamic loops. These changes in first-episode, treatment-naïve, mid-life MDD patients may reflect an active illness-related cortical change close to illness onset, and thus potentially provide important new insight into the early neurobiology of the disorder.

Individual differences in regional prefrontal gray matter morphometry and fractional anisotropy are associated with different constructs of executive function

Although the relationship between structural differences within the prefrontal cortex (PFC) and executive function (EF) has been widely explored in cognitively impaired populations, little is known about this relationship in healthy young adults. Using optimized voxel-based morphometry (VBM), surface-based morphometry (SBM), and fractional anisotropy (FA) we determined the association between regional PFC grey matter (GM) morphometry and white matter tract diffusivity with performance on tasks that tap different aspects of EF as drawn from Miyake et al.'s three-factor model of EF. Reductions in both GM volume (VBM) and cortical folding (SBM) in the ventromedial PFC (vmPFC), ventrolateral PFC (vlPFC), and dorsolateral PFC (dlPFC) predicted better common EF, shifting-specific, and updating-specific performance, respectively. Despite capturing different components of GM morphometry, voxel- and surface-based findings were highly related, exhibiting regionally overlapping relationships with EF. Increased white matter FA in fiber tracts that connect the vmPFC and vlPFC with posterior regions of the brain also predicted better common EF and shifting-specific performance, respectively. These results suggest that the neural mechanisms supporting distinct aspects of EF may differentially rely on distinct regions of the PFC, and at least in healthy young adults, are influenced by regional morphometry of the PFC and the FA of major white matter tracts that connect the PFC with posterior cortical and subcortical regions.

Effects of a novel schizophrenia risk variant rs7914558 at CNNM2 on brain structure and attributional style

BACKGROUND

A single nucleotide polymorphism (rs7914558) within the cyclin M2 (CNNM2) gene was recently identified as a common risk variant for schizophrenia. The mechanism by which CNNM2 confers risk is unknown.

AIMS

To determine the impact of the rs7914558 risk 'G' allele [corrected] on measures of neurocognition, social cognition and brain structure.

METHOD

Patients with schizophrenia (n = 400) and healthy controls (n = 160) completed measures of neuropsychological function and social cognition. Structural magnetic resonance imaging data were also acquired from an overlapping sample of Irish healthy controls (n = 159) and an independent sample of Italian patients (n = 82) and healthy controls (n = 39).

RESULTS

No effects of genotype on neuropsychological test performance were observed. However, a dosage effect of the risk allele was found for an index of social cognition (i.e. attributional style), such that risk status was associated with reduced self-serving bias across groups (GG>AG>AA, P<0.05). Using voxel-based morphometry to investigate neuroanatomical regions putatively supporting social cognition, risk carriers had relatively increased grey matter volume in the right temporal pole and right anterior cingulate cortex (Pcorrected<0.05) in the Irish healthy controls sample; neuroanatomical associations between CNNM2 and grey matter volume in anterior cingulate cortex were also observed in the Italian schizophrenia and healthy controls samples.

CONCLUSIONS

Although the biological role of CNNM2 in schizophrenia remains unknown, these data suggest that this CNNM2 risk variant rs7914558 may have an impact on neural systems relevant to social cognition. How such effects may mediate the relationship between genotype and disease risk remains to be established.