Brain imaging correlates of cognitive impairment in depression

Amygdala biomarkers of treatment response in major depressive disorder: An fMRI systematic review of SSRI antidepressants

Functional neuroimaging studies have demonstrated abnormal activity and functional connectivity (FC) of the amygdala among individuals with major depressive disorder (MDD), which may be rectified with selective serotonin reuptake inhibitor (SSRI) treatment. This systematic review aimed to identify changes in the amygdala on functional magnetic resonance imaging (fMRI) scans among individuals with MDD who received SSRIs. A search for fMRI studies examining amygdala correlates of SSRI response via fMRI was conducted through OVID (MEDLINE, PsycINFO, and Embase). The end date was April 4th, 2023. In total, 623 records were screened, and 16 studies were included in this review. While the search pertained to SSRIs broadly, the included studies were escitalopram-, citalopram-, fluoxetine-, sertraline-, and paroxetine-specific. Decreases in event-related amygdala activity were found following 6-to-12-week SSRI treatment, particularly in response to negative stimuli. Eight-week courses of SSRI pharmacotherapy were associated with increased event-related amygdala FC (i.e., with the prefrontal [PFC] and anterior cingulate cortices, insula, thalamus, caudate nucleus, and putamen) and decreased resting-state effective connectivity (i.e., amygdala-PFC). Preliminary evidence suggests that SSRIs may alter amygdala activity and FC in MDD. Additional studies are needed to corroborate findings. Future research should employ long-term follow-ups to determine whether effects persist after treatment termination.

The functional role of the pulvinar in discriminating between objective and subjective cognitive impairment in major depressive disorder

INTRODUCTION

Emotionally driven cognitive complaints represent a major diagnostic challenge for clinicians and indicate the importance of objective confirmation of the accuracy of depressive patients' descriptions of their cognitive symptoms.

METHODS

We compared cognitive status and structural and functional brain connectivity changes in the pulvinar and hippocampus between patients with total depression and healthy controls. The depressive group was also classified as "amnestic" or "nonamnestic," based on the members' subjective reports concerning their forgetfulness. We then sought to determine whether these patients would differ in terms of objective neuroimaging and cognitive findings.

RESULTS

The right pulvinar exhibited altered connectivity in individuals with depression with objective cognitive impairment, a finding which was not apparent in depressive patients with subjective cognitive impairment.

DISCUSSION

The pulvinar may play a role in depression-related cognitive impairments. Connectivity network changes may differ between objective and subjective cognitive impairment in depression and may play a role in the increased risk of dementia in patients with depression.

Effective Connectivity of the Bilateral Amygdala, Dorsomedial Prefrontal, and Subgenual Anterior Cingulate Cortices: Feasibility of Positive Social Emotion Regulation Models for Real-Time Functional Magnetic Resonance Imaging

Effective connectivity based on functional magnetic resonance imaging (fMRI) allows assessing directions of interaction between brain regions. For real-time fMRI, we compared models of positive social emotion regulation based on a network involving the bilateral amygdala, dorsomedial prefrontal, and subgenual anterior cingulate cortex. The top-down regulation model implied modulation of the dorsomedial prefrontal cortex exerted onto other regions, while the bottom-up model implied the inverse modulation. The validity of model calculations was tested using the data from three healthy volunteers who imagined positive interactions with people in presented photos (stimuli). We confirmed the dominance of the top-down model and evaluated the number and duration of iterations required for model estimations. The study shows the applicability of the four-node effective connectivity models for regulation of positive social emotions using real-time fMRI, e.g., for neurofeedback applications.

A detailed description of the distress trajectory from pre- to post-treatment in breast cancer patients receiving neoadjuvant chemotherapy

PURPOSE

To characterize the distress trajectory in patients with newly diagnosed, non-metastatic breast cancer from pre-neoadjuvant chemotherapy until 12 months after onset of treatment and to identify demographic and clinical predictors of distress in these patients.

METHODS

In a retrospective, longitudinal study, chart review data were abstracted for 252 eligible patients treated at a comprehensive cancer care center. The center screens for distress at least monthly with the distress thermometer; the highest distress score per month was included in the analyses. The growth trajectory was established using mixed modeling and predictors were added to the initial growth model in subsequent models.

RESULTS

Distress showed a cubic growth trajectory with highest distress prior to treatment onset followed by a steep decline in the first three months of treatment. A slight increase in distress was apparent over months 6-10. Being Hispanic was associated with a stronger increase in distress in the second half of the year (p = 0.012). NACT was associated with lower distress and surgery with higher distress (both: p < 0.001).

CONCLUSION

Distress is at its peak prior to treatment onset and rapidly decreases once treatment has started. Oncologist should be aware that both completion of NACT and undergoing surgery are associated with increases in distress and Hispanic patients may be more at risk for an increase in distress at these times; this suggests that careful monitoring of distress during the treatment trajectory and in Hispanic patients in particular in order to provide timely support.

Functional MRI in major depressive disorder: A review of findings, limitations, and future prospects

Objective diagnosis and prognosis in major depressive disorder (MDD) remains a challenge due to the absence of biomarkers based on physiological parameters or medical tests. Numerous studies have been conducted to identify functional magnetic resonance imaging‐based biomarkers of depression that either objectively differentiate patients with depression from healthy subjects, predict personalized treatment outcome, or characterize biological subtypes of depression. While there are some findings of consistent functional biomarkers, there is still lack of robust data acquisition and analysis methodology. According to current findings, primarily, the anterior cingulate cortex, prefrontal cortex, and default mode network play a crucial role in MDD. Yet, there are also less consistent results and the involvement of other regions or networks remains ambiguous. We further discuss image acquisition, processing, and analysis limitations that might underlie these inconsistencies. Finally, the current review aims to address and discuss possible remedies and future opportunities that could improve the search for consistent functional imaging biomarkers of depression. Novel acquisition techniques, such as multiband and multiecho imaging, and neural network‐based cleaning approaches can enhance the signal quality in limbic and frontal regions. More comprehensive analyses, such as directed or dynamic functional features or the identification of biological depression subtypes, can improve objective diagnosis or treatment outcome prediction and mitigate the heterogeneity of MDD. Overall, these improvements in functional MRI imaging techniques, processing, and analysis could advance the search for biomarkers and ultimately aid patients with MDD and their treatment course.

Depressive Symptoms Differentially Predict Neurocognition in Latinx and Non-Hispanic White People Living with HIV

OBJECTIVES

Depression is common in people living with HIV (PLWH) and can contribute to neurocognitive dysfunction. Depressive symptoms in PLWH are often measured by assessing only cognitive/affective symptoms. Latinx adults, however, often express depressive symptoms in a somatic/functional manner, which is not typically captured in assessments of depression among PLWH. Given the disproportionate burden of HIV that Latinx adults face, examining whether variations in expressed depressive symptoms differentially predict neurocognitive outcomes between Latinx and non-Hispanic white PLWH is essential.

METHODS

This cross-sectional study included 140 PLWH (71% Latinx; 72% male; mean (M) age = 47.1 ± 8.5 years; M education = 12.6 ± 2.9 years) who completed a comprehensive neurocognitive battery, Wechsler Test of Adult Reading (WTAR), and Beck Depression Inventory-II (BDI-II). Neurocognitive performance was measured using demographically adjusted T-scores. BDI-II domain scores were computed for the Fast-Screen (cognitive/affective items) score (BDI-FS) and non-FS score (BDI-NFS; somatic/functional items).

RESULTS

Linear regressions revealed that the BDI-NFS significantly predicted global neurocognitive function and processing speed in the Latinx group (p < .05), such that higher physical/functional symptoms predicted worse performance. In the non-Hispanic white group, the cognitive/affective symptoms significantly predicted processing speed (p = .02), with more symptoms predicting better performance. Interaction terms of ethnicity and each BDI sub-score indicated that Latinx participants with higher cognitive/affective symptoms performed worse on executive functioning.

CONCLUSIONS

Depressive symptoms differentially predict neurocognitive performance in Latinx and non-Hispanic white PLWH. These differences should be considered when conducting research and intervention among the increasingly culturally and ethnically diverse population of PLWH.

HIV, Depression, and Cognitive Impairment in the Era of Effective Antiretroviral Therapy

PURPOSE OF REVIEW

Mental health disorders, especially depression, are prevalent among people living with HIV (PLWH) and are associated with cognitive impairment (CI) among HIV-uninfected (HIV-) individuals. We conducted a comprehensive review of the link between depression and cognition among PLWH.

RECENT FINDINGS

Studies examining depression and cognition in PLWH report high rates of current (median = 24%) and lifetime depression (42%). There is reliable evidence that depression is associated with overall CI among PLWH, and in the cognitive domains of processing speed, executive function, learning and memory, and motor function. Although few studies have examined the interaction between HIV serostatus and depression on CI, there is no evidence of a stronger association between CI and depression in PLWH compared with HIV- controls. Depression is prevalent and reliably associated with CI in PLWH, with an overall pattern of domain-specific associations similar to that of HIV- individuals.

Elevated Depressive Symptoms Are a Stronger Predictor of Executive Dysfunction in HIV-Infected Women Than in Men

BACKGROUND

HIV-infected (HIV+) women seem to be more vulnerable to neurocognitive impairment (NCI) than HIV+ men, perhaps in part due to mental health factors. We assessed the association between elevated depressive symptoms and NCI among HIV+ and HIV-uninfected (HIV-) women and men.

SETTING

Women's Interagency HIV Study and Multicenter AIDS Cohort Study.

METHODS

Eight hundred fifty-eight HIV+ (429 women; 429 men) and 562 HIV- (281 women; 281 men) completed the Center for Epidemiologic Studies Depression (16 cutoff) Scale and measures of psychomotor speed/attention, executive, and motor function over multiple visits (or time points). Women's Interagency HIV Study and Multicenter AIDS Cohort Study participants were matched according to HIV status, age, race/ethnicity, and education. Generalized linear mixed models were used to examine interactions between biological sex, HIV serostatus, and depression on impairment (T-scores <40) after covariate adjustment.

RESULTS

Despite a higher frequency of depression among men, the association between depression and executive function differed by sex and HIV serostatus. HIV+ women with depression had 5 times the odds of impairment on a measure of executive control and inhibition versus HIV- depressed women and 3 times the odds of impairment on that measure versus HIV+ depressed men. Regardless of group status, depression was associated with greater impairment on processing speed, executive (mental flexibility), and motor function (P's < 0.05).

CONCLUSIONS

Depression contributes to NCI across a broad range of cognitive domains in HIV+ and HIV- individuals, but HIV+ depressed women show greater vulnerabilities in executive function. Treating depression may help to improve cognition in patients with HIV infection.

Characterizing neurocognitive markers of familial risk for depression using multi-modal imaging, behavioral and self-report measures

BACKGROUND

Major depressive disorder (MDD) is associated with poorer behavioral performance in domains of working memory and associated cognitive systems for cognitive control and attention. Functional neuroimaging studies show altered functioning in MDD in frontal executive control circuits implicated in these cognitive processes. It is not yet known whether poor cognitive performance involving these circuits is part of the familial risk for MDD, and we addressed this issue using a multi-modal imaging, behavioral and self-report approach in unaffected first-degree relatives of parent probands with MDD.

METHODS

72 unaffected adult first-degree relatives of probands with MDD (mean age 30.5 ± 13.4 years) with and 66 case-wise matched non-relative controls underwent functional magnetic resonance imaging during performance of 'n-back' working memory task, a Go/No-go task assessing cognitive control and an Auditory Oddball test of selective attention. Groups were compared on imaging data analyzed voxel wise with a focus on dorsolateral prefrontal cortex, anterior cingulate cortex and insula regions of interest, and on corresponding behavioral accuracy and reaction time data. Symptoms were assessed using self-report scales.

RESULTS

Relatives were distinguished by comparatively decreased activation in the left dorsolateral prefrontal cortex (DLPFC) during updating of working memory. Behaviorally, relatives also showed more errors of omission during working memory updating. DLPFC hypo-activation was associated with greater depressive symptom severity.

CONCLUSIONS

Deficits in cognitive processing may be part of the profile of familial risk for depression, preceding illness onset, specifically in the domain of working memory.

Meta-analyses of the neural mechanisms and predictors of response to psychotherapy in depression and anxiety

Understanding the neural mechanisms underlying psychological therapy could aid understanding of recovery processes and help target treatments. The dual-process model hypothesises that psychological therapy is associated with increased emotional-regulation in prefrontal brain regions and decreased implicit emotional-reactivity in limbic regions; however, research has yielded inconsistent findings. Meta-analyses of brain activity changes accompanying psychological therapy (22 studies, n = 352) and neural predictors of symptomatic improvement (11 studies, n = 293) in depression and anxiety were conducted using seed-based d mapping. Both resting-state and task-based studies were included, and analysed together and separately. The most robust findings were significant decreases in anterior cingulate/paracingulate gyrus, inferior frontal gyrus and insula activation after therapy. Cuneus activation was predictive of subsequent symptom change. The results are in agreement with neural models of improved emotional-reactivity following therapy as evidenced by decreased activity within the anterior cingulate and insula. We propose compensatory as well as corrective neural mechanisms of action underlie therapeutic efficacy, and suggest the dual-process model may be too simplistic to account fully for treatment mechanisms. More research on predictors of psychotherapeutic response is required to provide reliable predictors of response.

Mutual Information-Based Brain Network Analysis in Post-stroke Patients With Different Levels of Depression

Post-stroke depression (PSD) is the most common stroke-related emotional disorder, and it severely affects the recovery process. However, more than half cases are not correctly diagnosed. This study was designed to develop a new method to assess PSD using EEG signal to analyze the specificity of PSD patients' brain network. We have 107 subjects attended in this study (72 stabilized stroke survivors and 35 non-depressed healthy subjects). A Hamilton Depression Rating Scale (HDRS) score was determined for all subjects before EEG data collection. According to HDRS score, the 72 patients were divided into 3 groups: post-stroke non-depression (PSND), post-stroke mild depression (PSMD) and post-stroke depression (PSD). Mutual information (MI)-based graph theory was used to analyze brain network connectivity. Statistical analysis of brain network characteristics was made with a threshold of 10-30% of the strongest MIs. The results showed significant weakened interhemispheric connections and lower clustering coefficient in post-stroke depressed patients compared to those in healthy controls. Stroke patients showed a decreasing trend in the connection between the parietal-occipital and the frontal area as the severity of the depression increased. PSD subjects showed abnormal brain network connectivity and network features based on EEG, suggesting that MI-based brain network may have the potential to assess the severity of depression post stroke.

From Serotonin to Neuroplasticity: Evolvement of Theories for Major Depressive Disorder

The serotonin (5-HT) hypothesis of depression has played an important role in the history of psychiatry, yet it has also been criticized for the delayed onset and inadequate efficacy of selective serotonin reuptake inhibitors (SSRIs). With evolvement of neuroscience, the neuroplasticity hypothesis of major depressive disorder (MDD) has been proposed and may provide a better framework for clarification the pathogenesis of MDD and antidepressant efficacy. In this article, we first summarized the evidence challenging the monoamine hypothesis and proposed that the antidepressant efficacy of SSRIs is not derived from elevated monoamine (5-HT, noradrenaline (NE), or dopamine (DA)) concentration or monoamine neurotransmission. Second, we reviewed the role of stress in the pathogenesis of MDD and gave a brief introduction to the neuroplasticity hypothesis of MDD. Third, we explored the possible mechanisms underlying the antidepressant efficacy of typical antidepressants in the context of neuroplasticity theory. Fourth, we tried to provide an explanatory framework for the significant difference in onset of efficacy between typical antidepressants and ketamine. Finally, we provided a brief summarization about this review article and some perspectives for future studies.

Predictors of response in the treatment of moderate depression

Objective:

To identify neurocognitive and sociodemographic variables that could be associated with clinical response to three modalities of treatment for depression, as well as variables that predicted superior response to one treatment over the others.

Method:

The present study derives from a research project in which depressed patients (n=272) received one of three treatments – long-term psychodynamic psychotherapy (n=90), fluoxetine therapy (n=91), or a combination thereof (n=91) – over a 24-month period.

Results:

Sociodemographic variables were not found to be predictive. Six predictive neurocognitive variables were identified: three prognostic variables related to working memory and abstract reasoning; one prescriptive variable related to working memory; and two variables found to be moderators.

Conclusions:

The results of this study indicate subgroups of patients who might benefit from specific therapeutic strategies and subgroups that seem to respond well to long-term psychodynamic psychotherapy and combined therapy. The moderators found suggest that abstract reasoning and processing speed may influence the magnitude and/or direction of clinical improvement.

Brain network reorganization differs in response to stress in rats genetically predisposed to depression and stress-resilient rats

Treatment-resistant depression (TRD) remains a pressing clinical problem. Optimizing treatment requires better definition of the specificity of the involved brain circuits. The rat strain bred for negative cognitive state (NC) represents a genetic animal model of TRD with high face, construct and predictive validity. Vice versa, the positive cognitive state (PC) strain represents a stress-resilient phenotype. Although NC rats show depressive-like behavior, some symptoms such as anhedonia require an external trigger, i.e. a stressful event, which is similar to humans when stressful event induces a depressive episode in genetically predisposed individuals (gene-environment interaction). We aimed to distinguish neurobiological predisposition from the depressogenic pathology at the level of brain-network reorganization. For this purpose, resting-state functional magnetic resonance imaging time series were acquired at 9.4 Tesla scanner in NC (N=11) and PC (N=7) rats before and after stressful event. We used a graph theory analytical approach to calculate the brain-network global and local properties. There was no difference in the global characteristics between the strains. At the local level, the response in the risk strain was characterized with an increased internodal role and reduced local clustering and efficiency of the anterior cingulate cortex (ACC) and prelimbic cortex compared to the stress-resilient strain. We suggest that the increased internodal role of these prefrontal regions could be due to the enhancement of some of their long-range connections, given their connectivity with the amygdala and other default-mode-like network hubs, which could create a bias to attend to negative information characteristic for depression.

Mood disorders in the elderly: prevalence, functional impact, and management challenges

Despite the lower prevalence of severe mood disorders in the elderly as compared to younger adults, late-life depression and bipolar disorder (BD) are more strongly associated with negative outcomes related to the presence of medical comorbidities, cognitive deficits, and increased suicide risk and overall mortality. The mechanisms that contribute to these associations are probably multifactorial, involving pathological factors related directly and indirectly to the disease itself, ranging from biological to psychosocial factors. Most of the accumulated knowledge on the nature of these associations derives from naturalistic and observational studies, and controlled data are still scarce. Nonetheless, there has clearly been a recent growth of the scientific interest on late-life BD and geriatric depression. In the present study, we review the most relevant studies on prevalence, clinical presentation, and cognitive/functional impact of mood disorders in elderly. Several clinical-epidemiological studies were dedicated to the study of the prevalence of mood disorders in old age in distinct settings; however, fewer studies investigated the underlying neurobiological findings and treatment specificities in late-life depression and BD. In the present study, we further discuss the implications of these findings on the management of mood disorders in older adults.

Source analysis of P3a and P3b components to investigate interaction of depression and anxiety in attentional systems

This study examined the impact of depressive disorders, anxiety disorders and the comorbidity of these disorders on the regional electrophysiological features of brain activity. Sixty-four-channel event-related potentials (ERP) were acquired during a visual oddball task in patients with depressive disorder, patients with anxiety disorders, patients with comorbid depressive and anxiety disorders and healthy subjects. An fMRI-constrained source model was applied to ERP to identify different cortical activities in the patient and control groups. Comorbid patients showed an abnormal frontal-greater-than-parietal P3b topography in the right hemisphere and the highest P3a amplitude at frontal and central sites at the scalp midline. For P3b, depressed patients showed decreased right-lateralized activity in the precentral sulcus (PrCS) and posterior parietal cortex (PPC). Anxious patients demonstrated hyperactive prefrontal cortices (PFC). Comorbid patients presented decreased activity in the cingulate gyrus, right PrCS and right PPC and increased activity in the left PFC and left insular (INS). For P3a, hyperactive left PrCS was found in comorbid patients. Comorbid patients showed both anxiety-related and depression-related activity. A superimposition effect of depression and anxiety was identified with (1) aggravated hypo-function of the right-lateralized dorsal attention and salience networks and (2) complicated anxiety-related hyper-function of the left-lateralized ventral attention and salience networks.

Changes in brain connectivity related to the treatment of depression measured through fMRI: a systematic review

Depression is a mental illness that presents alterations in brain connectivity in the Default Mode Network (DMN), the Affective Network (AN) and other cortical-limbic networks, and the Cognitive Control Network (CCN), among others. In recent years the interest in the possible effect of the different antidepressant treatments on functional connectivity has increased substantially. The goal of this paper is to conduct a systematic review of the studies on the relationship between the treatment of depression and brain connectivity. Nineteen studies were found in a systematic review on this topic. In all of them, there was improvement of the clinical symptoms after antidepressant treatment. In 18 out of the 19 studies, clinical improvement was associated to changes in brain connectivity. It seems that both DMN and the connectivity between cortical and limbic structures consistently changes after antidepressant treatment. However, the current evidence does not allow us to assure that the treatment of depression leads to changes in the CCN. In this regard, some papers report a positive correlation between changes in brain connectivity and improvement of depressive symptomatology, particularly when they measure cortical-limbic connectivity, whereas the changes in DMN do not significantly correlate with clinical improvement. Finally, some papers suggest that changes in connectivity after antidepressant treatment might be partly related to the mechanisms of action of the treatment administered. This effect has been observed in two studies with stimulation treatment (one with rTMS and one with ECT), and in two papers that administered three different pharmacological treatments. Our review allows us to make a series of recommendations that might guide future researchers exploring the effect of anti-depression treatments on brain connectivity.

Clinical, cognitive, and functional connectivity correlations of resting-state intrinsic brain activity alterations in unmedicated depression

The pervasive and persistent nature of depressive symptoms has made resting-state functional magnetic resonance imaging (rs-fMRI) an appropriate approach for understanding the underlying mechanisms of major depressive disorder. The majority of rs-fMRI research has focused on depression-related alterations in the interregional coordination of brain baseline low frequency oscillations (LFOs). However, alteration of the regional amplitude of LFOs in depression, particularly its clinical, cognitive and network implications, has not been examined comprehensively yet. rs-fMRI amplitudes of low-frequency fluctuation (ALFF/fALFF) mediated by two LFO bands of 0.01-0.08 Hz (LF-ALFF/fALFF) and 0.1-0.25 Hz (HF-ALFF/fALFF) were measured in unmedicated subjects with major depressive disorder (n=20) and a healthy control group (n=25). A novel method of "ALFF-based functional connectivity" analysis was developed to test regional/network interaction abnormalities in depression. Our results revealed abnormal alterations in ALFF for both lower and higher frequency bands of LFOs in regions that participate in affective networks, corticostriatal circuits and motor/somatosensory networks. A strong positive correlation was detected between depressive symptom severity and fALFF in the anterior cingulate cortex. Functional connectivity of the thalamus and postcentral area with altered ALFF were found to be decreased with other interacting regions of their involved networks. Major depressive disorder relates to the alterations of regional properties of intrinsic neural activity with meaningful clinical and cognitive correlations. This study also proposes an integrating regional/network dysfunction in MDD.

Reasoning with linear orders: differential parietal cortex activation in sub-clinical depression. An FMRI investigation in sub-clinical depression and controls

The capacity to learn new information and manipulate it for efficient retrieval has long been studied through reasoning paradigms, which also has applicability to the study of social behavior. Humans can learn about the linear order within groups using reasoning, and the success of such reasoning may vary according to affective state, such as depression. We investigated the neural basis of these latter findings using functional neuroimaging. Using BDI-II criteria, 14 non-depressed (ND) and 12 mildly depressed volunteers took part in a linear-order reasoning task during functional magnetic resonance imaging. The hippocampus, parietal, and prefrontal cortices were activated during the task, in accordance with previous studies. In the learning phase and in the test phase, greater activation of the parietal cortex was found in the depressed group, which may be a compensatory mechanism in order to reach the same behavioral performance as the ND group, or evidence for a different reasoning strategy in the depressed group.

Neural correlates during working memory processing in major depressive disorder

BACKGROUND

Functional magnetic resonance imaging (fMRI) studies in major depressive disorder (MDD) have revealed cortical-limbic-subcortical dysfunctions during working memory (WM) processing, but the results are inconsistent and it is unclear to what extent these findings are influenced by demographic, clinical characteristics and task performance of patients. The present study conducted a quantitative coordinate-based meta-analysis of fMRI data to investigate the hypothesized dysfunction in the neural correlates during WM processing in MDD.

METHODS

A systematic research was conducted for fMRI studies during WM processing comparing MDD patients with healthy controls (HC). Meta-analysis was performed using effect size signed differential mapping (ES-SDM). Meta-regression analyses with age, sex and medication as factors were performed in MDD group.

RESULTS

Functional MRI data of 160 MDD patients and 203 HC from 13 WM experiments across 11 studies were included in this meta-analysis. In the pooled meta-analysis of all included studies, significant increased activation during WM in the left lateral prefrontal cortex, left precentral gyrus, left insula, right superior temporal and right supramarginal areas, and significant decreased activity in the right precentral gyrus, right precuneus and right insula were observed in MDD compared with controls. In the subgroup analysis of the studies with matched task performance, MDD subgroup showed hyperactivation only in the left prefrontal cortex and hypoactivation in the regions similar to the pooled analysis. The meta-regression with age, sex and medication showed no significance in MDD group.

CONCLUSIONS

Regardless of differences in task performance between groups, patients with MDD showed consistent functional abnormalities in the cortical-limbic-subcortical circuitry during WM processing. Distinct patterns of neural engagement may reflect compensatory neural strategies to potential dysfunction in MDD.

Neurocognitive changes in depressed patients in psychodynamic psychotherapy, therapy with fluoxetine and combination therapy

BACKGROUND

Randomized controlled trials (RCTs) examining the efficacy of different forms of therapy for depression are relatively common. However, there are not many RCTs comparing neurocognitive effects of these treatments. Neurocognitive changes across three types of treatment for depression were compared. Long-term psychodynamic psychotherapy (LTPP) was compared with fluoxetine treatment, and their combination, in the treatment of moderate depression.

METHODS

A 272 adult patients with beck depression inventory (BDI) scores 20-35 were randomized to receive LTPP, fluoxetine monotherapy or their combination for a 24 months period. The Wechsler adult intelligence scale version III (WAIS-III) was the primary neuropsychological measure.

RESULT

Multilevel mixed model analyses indicated that there were neurocognitive changes within and between treatments, with statistically significant differences over time (p>.01). LTPP and combined treatment seemed to be more efficacious in modifying specific areas of cognition than fluoxetine alone.

LIMITATIONS

Sample very homogenous, threatening external validity.

CONCLUSIONS

LTPP and its combination with fluoxetine demonstrated to be effective for specific neurocognitive increasing in patients with moderate depression. This study suggests marked differences over time in the neurocognitive effects between the three treatment forms compared. Results found here may be of clinical relevance for building bridges between pharmacotherapy and psychodynamic psychotherapy.

Emotion regulation, attention to emotion, and the ventral attentional network

Accounts of the effect of emotional information on behavioral response and current models of emotion regulation are based on two opposed but interacting processes: automatic bottom-up processes (triggered by emotionally arousing stimuli) and top-down control processes (mapped to prefrontal cortical areas). Data on the existence of a third attentional network operating without recourse to limited-capacity processes but influencing response raise the issue of how it is integrated in emotion regulation. We summarize here data from attention to emotion, voluntary emotion regulation, and on the origin of biases against negative content suggesting that the ventral network is modulated by exposure to emotional stimuli when the task does not constrain the handling of emotional content. In the parietal lobes, preferential activation of ventral areas associated with “bottom-up” attention by ventral network theorists is strongest in studies of cognitive reappraisal. In conditions when no explicit instruction is given to change one's response to emotional stimuli, control of emotionally arousing stimuli is observed without concomitant activation of the dorsal attentional network, replaced by a shift of activation toward ventral areas. In contrast, in studies where emotional stimuli are placed in the role of distracter, the observed deactivation of these ventral semantic association areas is consistent with the existence of proactive control on the role emotional representations are allowed to take in generating response. It is here argued that attentional orienting mechanisms located in the ventral network constitute an intermediate kind of process, with features only partially in common with effortful and automatic processes, which plays an important role in handling emotion by conveying the influence of semantic networks, with which the ventral network is co-localized. Current neuroimaging work in emotion regulation has neglected this system by focusing on a bottom-up/top-down dichotomy of attentional control.

Neural correlates of psychotherapy in anxiety and depression: a meta-analysis

Several studies have used neuroimaging methods to identify neural change in brain networks associated to emotion regulation after psychotherapy of depression and anxiety. In the present work we adopted a meta-analytic technique specific to neuroimaging data to evaluate the consistence of empirical findings and assess models of therapy that have been proposed in the literature. Meta-analyses were conducted with the Activation Likelihood Estimation technique, which evaluates the overlap between foci of activation across studies. The analysis included 16 studies found in Pubmed (200 foci of activation and 193 patients). Separate meta-analyses were conducted on studies of 1) depression, post-traumatic stress disorder and panic disorder investigated with rest state metabolism (6 studies, 70 patients); 2) depression, post-traumatic stress disorder and panic disorder investigated with task-related activation studies (5 studies, 65 patients); 3) the previous studies considered jointly; and 4) phobias investigated with studies on exposure-related activation (5 studies, 57 patients). Studies on anxiety and depression gave partially consistent results for changes in the dorsomedial prefrontal cortex and in the posterior cingulated gyrus/precuneus. Several areas of change in the temporal lobes were also observed. Studies on the therapy of phobia were consistent with a reduction of activity in medial temporal areas. The cluster of change in the prefrontal cortex may refer to increased recruitment of control processes, as hypothesized by influential models of emotion regulation changes due to psychotherapy. However, not all areas associated with controlled emotion regulation were detected in the meta-analysis, while involvement of midline structures suggested changes in self-related information processing. Changes in phobia were consistent with reduced reactivity to phobic stimuli.

One ring to rule them all?--Temporospatial specificity of deep brain stimulation for treatment-resistant depression

Deep brain stimulation (DBS) for intractable cases of depression has emerged as a valuable therapeutic option during the last decade. While several locations have been intensely investigated in recent years, the literature is lacking an all-encompassing perspective thereupon asking if and how these stimulation sites relate to each other and what this may imply for the underlying mechanisms of action of this treatment modality. We aim at proposing a model of DBS mechanism of action with particular focus on several puzzling aspects regarding an apparent temporo-spatial specificity of antidepressant action, i.e. the discrepancy between protracted response after initiation of stimulation and rapid relapse upon discontinuation, as well as differential effects on psychopathology. We suggest that the pre-treatment depressive state is determined by the interaction of individual traits with dysfunctional adaptive processes as responses to stress, resulting in a disease-associated, overtly dysfunctional, equilibrium. The antidepressant action of DBS is thought to modify and re-set this equilibrium in a temporospatially distinct manner by influencing the activity states of two different brain circuitries. The idea of sequential and temporospatially distinct mechanisms of action bears implications for the assessment of psychopathology and behavior in clinical and preclinical studies as well as investigations into brain circuit activity states.

Using standardized fMRI protocols to identify patterns of prefrontal circuit dysregulation that are common and specific to cognitive and emotional tasks in major depressive disorder: first wave results from the iSPOT-D study

Functional neuroimaging studies have implicated dysregulation of prefrontal circuits in major depressive disorder (MDD), and these circuits are a viable target for predicting treatment outcomes. However, because of the heterogeneity of tasks and samples used in studies to date, it is unclear whether the central dysfunction is one of prefrontal hyperreactivity or hyporeactivity. We used a standardized battery of tasks and protocols for functional magnetic resonance imaging, to identify the common vs the specific prefrontal circuits engaged by these tasks in the same 30 outpatients with MDD compared with 30 matched, healthy control participants, recruited as part of the International Study to Predict Optimized Treatment in Depression (iSPOT-D). Reflecting cognitive neuroscience theory and established evidence, the battery included cognitive tasks designed to assess functions of selective attention, sustained attention-working memory and response inhibition, and emotion tasks to assess explicit conscious and implicit nonconscious viewing of facial emotion. MDD participants were distinguished by a distinctive biosignature of: hypoactivation of the dorsolateral prefrontal cortex during working memory updating and during conscious negative emotion processing; hyperactivation of the dorsomedial prefrontal cortex during working memory and response inhibition cognitive tasks and hypoactivation of the dorsomedial prefrontal during conscious processing of positive emotion. These results show that the use of standardized tasks in the same participants provides a way to tease out prefrontal circuitry dysfunction related to cognitive and emotional functions, and not to methodological or sample variations. These findings provide the frame of reference for identifying prefrontal biomarker predictors of treatment outcomes in MDD.

Amplitude of low-frequency oscillations in first-episode, treatment-naive patients with major depressive disorder: a resting-state functional MRI study

Background

Resting-state fMRI is a novel approach to measure spontaneous brain activity in patients with major depressive disorder (MDD). Although most resting-state fMRI studies have focused on the examination of temporal correlations between low-frequency oscillations (LFOs), few studies have explored the amplitude of these LFOs in MDD. In this study, we applied the approaches of amplitude of low-frequency fluctuation (ALFF) and fractional ALFF to examine the amplitude of LFOs in MDD.

Methodology/Principal Findings

A total of 36 subjects, 18 first-episode, treatment-naive patients with MDD matched with 18 healthy controls (HCs) completed the fMRI scans. Compared with HCs, MDD patients showed increased ALFF in the right fusiform gyrus and the right anterior and posterior lobes of the cerebellum but decreased ALFF in the left inferior temporal gyrus, bilateral inferior parietal lobule, and right lingual gyrus. The fALFF in patients was significantly increased in the right precentral gyrus, right inferior temporal gyrus, bilateral fusiform gyrus, and bilateral anterior and posterior lobes of the cerebellum but was decreased in the left dorsolateral prefrontal cortex, bilateral medial orbitofrontal cortex, bilateral middle temporal gyrus, left inferior temporal gyrus, and right inferior parietal lobule. After taking gray matter (GM) volume as a covariate, the results still remained.

Conclusions/Significance

These findings indicate that MDD patients have altered LFO amplitude in a number of regions distributed over the frontal, temporal, parietal, and occipital cortices and the cerebellum. These aberrant regions may be related to the disturbances of multiple emotion- and cognition-related networks observed in MDD and the apparent heterogeneity in depressive symptom domains. Such brain functional alteration of MDD may contribute to further understanding of MDD-related network imbalances demonstrated in previous fMRI studies.

Cognitive impairment in major depression and the mGlu2 receptor as a therapeutic target

Cognitive impairment, in particular of attention and memory, is often reported by patients suffering from major depressive disorder (MDD) and deficits in attention are part of the current diagnostic criteria of MDD. Objectively measured cognitive deficits associated with MDD have been described in many studies. They have been conceptualized as an integral facet and epiphenomenon of MDD. However, evidence accumulated in recent years has challenged this notion and demonstrated that in a subset of patients the degree of cognitive deficits cannot be accounted for by the severity of depression. In addition, in some patients cognitive deficits persist despite resolution of depressive symptomatology. It is plausible to assume that cognitive deficits contribute to functional impairment even though supportive data for such a relationship are lacking. However, the exact association between cognitive deficits and major depression and the clinical and neurobiological characteristics of patients with MDD in whom cognitive deficits seem partially or fully independent of the clinical manifestation of depressive symptoms remain poorly understood. This review focuses on objective measures of non-emotional cognitive deficits in MDD and discusses the presence of a subgroup of patients in whom these symptoms can be defined independently and in dissociation from the rest of the depressive symptomatology. The current understanding of brain circuits and molecular events implicated in cognitive impairment in MDD are discussed with an emphasis on the missing elements that could further define the specificity of cognitive impairment in MDD and lead to new therapeutics. Furthermore, this article presents in detail observations made in behavioral studies in rodents with potential novel therapeutic agents, such as negative allosteric modulators at the metabotropic glutamate receptor type 2/3 (mGlu2/3 NAM) which exhibit both cognitive enhancing and antidepressant properties. Such a compound, RO4432717, was tested in tests of short term memory (delayed match to position), cognitive flexibility (Morris water maze, reversal protocol), impulsivity and compulsivity (5-choice serial reaction time) and spontaneous object recognition in rodents, providing first evidence of a profile potentially relevant to address cognitive impairment in MDD. This article is part of a Special Issue entitled 'Cognitive Enhancers'.

Functional network dysfunction in anxiety and anxiety disorders

A recent paradigm shift in systems neuroscience is the division of the human brain into functional networks. Functional networks are collections of brain regions with strongly correlated activity both at rest and during cognitive tasks, and each network is believed to implement a different aspect of cognition. We propose here that anxiety disorders and high trait anxiety are associated with a particular pattern of functional network dysfunction: increased functioning of the cingulo-opercular and ventral attention networks as well as decreased functioning of the fronto-parietal and default mode networks. This functional network model can be used to differentiate the pathology of anxiety disorders from other psychiatric illnesses such as major depression and provides targets for novel treatment strategies.

Neurobiological circuits regulating attention, cognitive control, motivation, and emotion: disruptions in neurodevelopmental psychiatric disorders

OBJECTIVE

This article aims to review basic and clinical studies outlining the roles of prefrontal cortical (PFC) networks in the behavior and cognitive functions that are compromised in childhood neurodevelopmental disorders and how these map into the neuroimaging evidence of circuit abnormalities in these disorders.

METHOD

Studies of animals, normally developing children, and patients with neurodevelopmental disorders were reviewed, with focus on neuroimaging studies.

RESULTS

The PFC provides "top-down" regulation of attention, inhibition/cognitive control, motivation, and emotion through connections with posterior cortical and subcortical structures. Dorsolateral and inferior PFC regulate attention and cognitive/inhibitory control, whereas orbital and ventromedial structures regulate motivation and affect. PFC circuitries are very sensitive to their neurochemical environment, and small changes in the underlying neurotransmitter systems, e.g. by medications, can produce large effects on mediated function. Neuroimaging studies of children with neurodevelopmental disorders show altered brain structure and function in distinctive circuits respecting this organization. Children with attention-deficit/hyperactivity disorder show prominent abnormalities in the inferior PFC and its connections to striatal, cerebellar, and parietal regions, whereas children with conduct disorder show alterations in the paralimbic system, comprising ventromedial, lateral orbitofrontal, and superior temporal cortices together with specific underlying limbic regions, regulating motivation and emotion control. Children with major depressive disorder show alterations in ventral orbital and limbic activity, particularly in the left hemisphere, mediating emotions. Finally, children with obsessive-compulsive disorder appear to have a dysregulation in orbito-fronto-striatal inhibitory control pathways, but also deficits in dorsolateral fronto-parietal systems of attention.

CONCLUSIONS

Altogether, there is a good correspondence between anatomical circuitry mediating compromised functions and patterns of brain structure and function changes in children with neuropsychiatric disorders. Medications may optimize the neurochemical environment in PFC and associated circuitries, and improve structure and function.

Changes in prefrontal-limbic function in major depression after 15 months of long-term psychotherapy

Neuroimaging studies of depression have demonstrated treatment-specific changes involving the limbic system and regulatory regions in the prefrontal cortex. While these studies have examined the effect of short-term, interpersonal or cognitive-behavioural psychotherapy, the effect of long-term, psychodynamic intervention has never been assessed. Here, we investigated recurrently depressed (DSM-IV) unmedicated outpatients (N = 16) and control participants matched for sex, age, and education (N = 17) before and after 15 months of psychodynamic psychotherapy. Participants were scanned at two time points, during which presentations of attachment-related scenes with neutral descriptions alternated with descriptions containing personal core sentences previously extracted from an attachment interview. Outcome measure was the interaction of the signal difference between personal and neutral presentations with group and time, and its association with symptom improvement during therapy. Signal associated with processing personalized attachment material varied in patients from baseline to endpoint, but not in healthy controls. Patients showed a higher activation in the left anterior hippocampus/amygdala, subgenual cingulate, and medial prefrontal cortex before treatment and a reduction in these areas after 15 months. This reduction was associated with improvement in depressiveness specifically, and in the medial prefrontal cortex with symptom improvement more generally. This is the first study documenting neurobiological changes in circuits implicated in emotional reactivity and control after long-term psychodynamic psychotherapy.

[Depressive recurrence: cognitive alterations and neuroplasticity]

The risk of recurrence in depression is high. It increases with the number of previous episodes while the triggering role of stressful life events progressively decreases. According to the scar hypothesis each episode leaves a long-lasting mark that increases the vulnerability for future episodes. Studies examining scars in depression have explored different domains (psychological, social, neurobiological) but they remain largely inconclusive. We were here interested in studies, still scarce, examining this issue at a neurocognitive level, particularly in those using structural and functional brain imaging techniques. Since depression is essentially a disease of emotion, the neural circuits involved in treating and regulating emotional information are of particular interest. Results indicate the persistence of structural and functional neural abnormalities even in remitted untreated subjects. They also suggest that abnormalities may increase with the number of episodes. However a causal link is difficult to establish and abnormalities may precede the first episode. Longitudinal studies are needed. At a cognitive level, neural abnormalities underlie abnormalities in the way subjects treat and regulate emotional information that may increase their vulnerability to develop new episodes. At a neurobiological level, disturbances in neuroplasticity appear as a possible mechanism. Depression should be considered as a continuous rather than an episodic process, and present data offer interesting perspectives concerning the prevention and the treatment of depressive episodes and their recurrence.

[Neuroimaging of psychiatric and pedopsychiatric disorders]

Over the last two decades, imaging techniques have allowed to establish the cerebral neurophysiologic correlates of psychiatric disorders and have highlighted the impact of psychopathologic events, therapeutic drugs, addictions, on the growth and plasticity of brain. In this review, we intend to illustrate how neuroimaging has improved our knowledge of such alterations in brain maturation (schizophrenia, autistic disorders), fronto-limbic (depressive syndromes) or fronto-striatal (compulsive disorders) regions in psychiatric illnesses, but also in psychopharmacology, or pedopsychiatry. Statistically significant alterations in the structure and/or function of brain are detected in all psychiatric disorders and these are often detectable already during childhood or teenage. Furthermore, neuroimaging has allowed to underline the importance of cerebral networks specific to each disorder, but also to uncover those which are common to different diseases provided that they share common clinical or cognitive features. Besides their value in basic research, neuroimaging findings have been key in changing the perception that society has of these diseases which contributed to their therapeutic approach.

Cognitive and neural correlates of depression-like behaviour in socially defeated mice: an animal model of depression with cognitive dysfunction

Human depression is associated with cognitive deficits. It is critical to have valid animal models in order to investigate mechanisms and treatment strategies for these associated conditions. The goal of this study was to determine the association of cognitive dysfunction with depression-like behaviour in an animal model of depression and investigate the neural circuits underlying the behaviour. Mice that were exposed to social defeat for 14 d developed depression-like behaviour, i.e. anhedonia and social avoidance as indicated by reduced sucrose preference and decreased social interaction. The assessment of cognitive performance of defeated mice demonstrated impaired working memory in the T-maze continuous alternation task and enhanced fear memory in the contextual and cued fear-conditioning tests. In contrast, reference learning and memory in the Morris water maze test were intact in defeated mice. Neuronal activation following chronic social defeat was investigated by c-fosin-situ hybridization. Defeated mice exhibited preferential neural activity in the prefrontal cortex, cingulate cortex, hippocampal formation, septum, amygdala, and hypothalamic nuclei. Taken together, our results suggest that the chronic social defeat mouse model could serve as a valid animal model to study depression with cognitive impairments. The patterns of neuronal activation provide a neural basis for social defeat-induced changes in behaviour.

Association of childhood trauma with cognitive function in healthy adults: a pilot study

BACKGROUND

Animal and human studies suggest that stress experienced early in life has detrimental consequences on brain development, including brain regions involved in cognitive function. Cognitive changes are cardinal features of depression and posttraumatic stress disorder. Early-life trauma is a major risk factor for these disorders. Only few studies have measured the long-term consequences of childhood trauma on cognitive function in healthy adults.

METHODS

In this pilot study, we investigated the relationship between childhood trauma exposure and cognitive function in 47 healthy adults, who were identified as part of a larger study from the general population in Wichita, KS. We used the Cambridge Neuropsychological Test Automated Battery (CANTAB) and the Wide-Range-Achievement-Test (WRAT-3) to examine cognitive function and individual achievement. Type and severity of childhood trauma was assessed by the Childhood Trauma Questionnaire (CTQ). Data were analyzed using multiple linear regression on CANTAB measures with primary predictors (CTQ scales) and potential confounders (age, sex, education, income).

RESULTS

Specific CTQ scales were significantly associated with measures of cognitive function. Emotional abuse was associated with impaired spatial working memory performance. Physical neglect correlated with impaired spatial working memory and pattern recognition memory. Sexual abuse and physical neglect were negatively associated with WRAT-3 scores. However, the association did not reach the significance level of p < 0.01.

CONCLUSIONS

Our results suggest that physical neglect and emotional abuse might be associated with memory deficits in adulthood, which in turn might pose a risk factor for the development of psychopathology.

The effects of perceived emotional distress on language performance in intractable epilepsy

We evaluated the potential moderating effect of emotional distress (Minnesota Multiphasic Personality Inventory 2, scales D and Pt) on language functioning (i.e., Boston Naming Test, phonemic paraphasic error production on the Boston Naming Test, Controlled Oral Word Association Task, Animal Naming, Token Test) in patients with left (N=43) and right (N=34) mesial temporal lobe epilepsy (MTLE) and frontal lobe epilepsy (FLE) (N=30). Video/EEG and brain imaging results confirmed localization. Logistic regression models revealed that perceived emotional distress moderated language performance. Performance of patients with left MTLE and that of patients with FLE were equally poor across language measures. Performance of patients with right MTLE was intact. Depression and anxiety differentially moderated performance. Anxiety was associated with better performance in patients with FLE on classically temporal lobe-mediated tasks (Boston Naming Test). Depression was associated with worse language performance on measures for which impaired performance was traditionally intrinsic to the underlying epileptogenic lesion (word fluency in FLE). Emotional distress influences language performance. Adequate treatment of mood should be considered when managing pharmacoresistant epilepsy.