Failure to segregate emotional processing from cognitive and sensorimotor processing in major depression

The False Recognition Test, a new tool for the assessment of false memories, with normative data from an Italian sample

INTRODUCTION

False memory can be defined as remembering something that did not happen. To a certain extent it is a normal phenomenon, but its occurrence seems to increase in healthy and pathological aging, possibly providing relevant clues on some clinical conditions in the spectrum of dementia. We adapted a well-established Deed-Roediger-McDermott paradigm, frequently used in experimental contexts, to devise a new neuropsychological assessment tool, the False Recognition Test (FRT), that can investigate classical facets of episodic memory performance (i.e. free recall and recognition), and assess proneness to produce semantically related and non-semantic false memories. Here we describe the FRT and provide normative data and correction grids to consider the possible effects of age, gender, and education on the FRT scores.

METHOD

Two-hundred and thirty-two Italian healthy individuals (99 male) aged 18-91 years, with different educational levels (from primary to university) underwent the FRT, together with validated tests for cognitive screening and episodic memory assessment and one scale for depression.

RESULTS

Multiple linear regression analysis revealed that age and education significantly influenced performance on FRT. From the derived linear equations, we provide correction grids for the raw scores of the FRT, and equivalent scores estimated using a nonparametric method. Correlational analysis showed significant associations between FRT subscores and cognitive, executive and memory functions, and depression.

CONCLUSION

The FRT may constitute a useful instrument for both clinical and research purposes.

One size does not fit all: notable individual variation in brain activity correlates of antidepressant treatment response

Introduction

To date, no robust electroencephalography (EEG) markers of antidepressant treatment response have been identified. Variable findings may arise from the use of group analyses, which neglect individual variation. Using a combination of group and single-participant analyses, we explored individual variability in EEG characteristics of treatment response.

Methods

Resting-state EEG data and Montgomery-Åsberg Depression Rating Scale (MADRS) symptom scores were collected from 43 patients with depression before, at 1 and 12 weeks of pharmacotherapy. Partial least squares (PLS) was used to: 1) identify group differences in EEG connectivity (weighted phase lag index) and complexity (multiscale entropy) between eventual medication responders and non-responders, and 2) determine whether group patterns could be identified in individual patients.

Results

Responders showed decreased alpha and increased beta connectivity, and early, widespread decreases in complexity over treatment. Non-responders showed an opposite connectivity pattern, and later, spatially confined decreases in complexity. Thus, as in previous studies, our group analyses identified significant differences between groups of patients with different treatment outcomes. These group-level EEG characteristics were only identified in ~40-60% of individual patients, as assessed quantitatively by correlating the spatiotemporal brain patterns between groups and individual results, and by independent raters through visualization.

Discussion

Our single-participant analyses suggest that substantial individual variation exists, and needs to be considered when investigating characteristics of antidepressant treatment response for potential clinical applicability.

Clinical trial registration

https://clinicaltrials.gov, identifier NCT00519428.

Characteristic patterns of functional connectivity-mediated cerebral small vessel disease-related cognitive impairment and depression

Cerebral small vessel disease is common in most individuals aged 60 years or older, and it is associated with cognitive dysfunction, depression, anxiety disorder, and mobility problems. Currently, many cerebral small vessel disease patients have both cognitive impairment and depressive symptoms, but the relationship between the 2 is unclear. The present research combined static and dynamic functional network connectivity methods to explore the patterns of functional networks in cerebral small vessel disease individuals with cognitive impairment and depression (cerebral small vessel disease-mild cognitive impairment with depression) and their relationship. We found specific functional network patterns in the cerebral small vessel disease-mild cognitive impairment with depression individuals (P < 0.05). The cerebral small vessel disease individuals with depression exhibited unstable dynamic functional network connectivity states (transitions likelihood: P = 0.040). In addition, we found that the connections within the lateral visual network between the sensorimotor network and ventral attention network could mediate white matter hyperintensity-related cognitive impairment (indirect effect: 0.064; 95% CI: 0.003, 0.170) and depression (indirect effect: -0.415; 95% CI: -1.080, -0.011). Cognitive function can negatively regulate white matter hyperintensity-related depression. These findings elucidate the association between cognitive impairment and depression and provide new insights into the underlying mechanism of cerebral small vessel disease-related cognitive dysfunction and depression.

Features of Psychomotor Coordination in Adolescents with Neuropsychiatric Pathology Enrolled in a Standard Educational Program

The imbalance between the speed and accuracy of cognitive-motor operations can lead to the formation of abnormal behavioral programs fraught with serious negative consequences for the individual. For successful correction and prevention of social disadaptation in adolescents with nervous and mental diseases and functional disorders in mental sphere in general education schools, the peculiarities of their psychomotor activity should be taken into account. We measured some parameters of visual-motor coordination and sensorimotor reaction in adolescents with mental disorders with (n = 36) or without (n = 27) organic brain damage. Adolescents from both groups showed higher speed, but poorer accuracy and smoothness, of movements than typically developing students (n = 70). The visual and acoustic reaction times were longer in adolescents with mental disorders without organic brain damage than in reference groups.

Sexual Dimorphism in the Brain Correlates of Adult-Onset Depression: A Pilot Structural and Functional 3T MRI Study

Major Depressive Disorder (MDD) is a disabling illness affecting more than 5% of the elderly population. Higher female prevalence and sex-specific symptomatology have been observed, suggesting that biologically-determined dimensions might affect the disease onset and outcome. Rumination and executive dysfunction characterize adult-onset MDD, but sex differences in these domains and in the related brain mechanisms are still largely unexplored. The present pilot study aimed to explore any interactions between adult-onset MDD and sex on brain morphology and brain function during a Go/No-Go paradigm. We hypothesized to detect diagnosis by sex effects on brain regions involved in self-referential processes and cognitive control. Twenty-four subjects, 12 healthy (HC) (mean age 68.7 y, 7 females and 5 males) and 12 affected by adult-onset MDD (mean age 66.5 y, 5 females and 7 males), underwent clinical evaluations and a 3T magnetic resonance imaging (MRI) session. Diagnosis and diagnosis by sex effects were assessed on regional gray matter (GM) volumes and task-related functional MRI (fMRI) activations. The GM volume analyses showed diagnosis effects in left mid frontal cortex (p < 0.01), and diagnosis by sex effects in orbitofrontal, olfactory, and calcarine regions (p < 0.05). The Go/No-Go fMRI analyses showed MDD effects on fMRI activations in left precuneus and right lingual gyrus, and diagnosis by sex effects on fMRI activations in right parahippocampal gyrus and right calcarine cortex (p < 0.001, ≥ 40 voxels). Our exploratory results suggest the presence of sex-specific brain correlates of adult-onset MDD-especially in regions involved in attention processing and in the brain default mode-potentially supporting cognitive and symptom differences between sexes.

Handedness and depression: A meta-analysis across 87 studies

Alterations in functional brain lateralization, often indicated by an increased prevalence of left- and/or mixed-handedness, have been demonstrated in several psychiatric and neurodevelopmental disorders like schizophrenia or autism spectrum disorder. For depression, however, this relationship is largely unclear. While a few studies found evidence that handedness and depression are associated, both the effect size and the direction of this association remain elusive. Here, we collected data from 87 studies totaling 35,501 individuals to provide a precise estimate of differences in left-, mixed- and non-right-handedness between depressed and healthy samples and computed odds ratios (ORs) between these groups. Here, an OR > 1 signifies higher rates of atypical handedness in depressed compared to healthy samples. We found no differences in left- (OR = 1.04, 95% CI = [0.95, 1.15], p = .384), mixed- (OR = 1.64, 95% CI = [0.98, 2.74], p = .060) or non-right-handedness (OR = 1.05, 95% CI = [0.96, 1.15], p = .309) between the two groups. We could thus find no link between handedness and depression on the meta-analytical level.

Trace amine-associated receptor 1 (TAAR1): Potential application in mood disorders: A systematic review

There is a need for innovation with respect to therapeutics in psychiatry. Available evidence indicates that the trace amine-associated receptor 1 (TAAR1) agonist SEP-363856 is promising, as it improves measures of cognitive and reward function in schizophrenia. Hedonic and cognitive impairments are transdiagnostic and constitute major burdens in mood disorders. Herein, we systematically review the behavioural and genetic literature documenting the role of TAAR1 in reward and cognitive function, and propose a mechanistic model of TAAR1's functions in the brain. Notably, TAAR1 activity confers antidepressant-like effects, enhances attention and response inhibition, and reduces compulsive reward seeking without impairing normal function. Further characterization of the responsible mechanisms suggests ion-homeostatic, metabolic, neurotrophic, and anti-inflammatory enhancements in the limbic system. Multiple lines of evidence establish the viability of TAAR1 as a biological target for the treatment of mood disorders. Furthermore, the evidence suggests a role for TAAR1 in reward and cognitive function, which is attributed to a cascade of events that are relevant to the cellular integrity and function of the central nervous system.

Spontaneous brain state oscillation is associated with self-reported anxiety in a non-clinical sample

The anti-correlation relationship between the default-mode network (DMN) and task-positive network (TPN) may provide valuable information on cognitive functions and mental disorders. Moreover, maintaining a specific brain state and efficaciously switching between different states are considered important for self-regulation and adaptation to changing environments. However, it is currently unclear whether competitions between the DMN and TPN are associated with negative affect (here, anxiety and depression) in non-clinical samples. We measured the average dwell time of DMN dominance over the TPN (i.e., the average state duration before transition to another state, indicating persistent DMN dominance) with a sample of 302 non-clinical young adults. Subsequently, we explored individual differences in this persistent DMN dominance by examining its correlations with subjective depression and anxiety feelings. Moreover, we linked state transition between DMN/TPN dominance with right fronto-insular cortex (RFIC) blood oxygen-level dependent signal variability. We found that the average dwell time of DMN dominance was positively associated with self-reported anxiety. Furthermore, state transition between DMN or TPN dominance was positively linked to RFIC activity. These findings highlight the importance of investigating the complex and dynamic reciprocal inhibition patterns of the DMN and TPN and the important role of the RFIC in the association between these networks.

Relationship between cerebellar structure and emotional memory in depression

BACKGROUND

A few studies have been conducted on the relationship between cerebellar volume and emotional memory or clinical severity in major depressive disorder (MDD). In this study, we aimed to compare the volume and density of the cerebellar gray matter (GM) in patients with MDD and in healthy controls (HCs) and explore the association between these cerebellar parameters and measurements of emotional memory and clinical severity.

METHOD

Voxel-based morphometry (VBM) and Individual Brain Atlases using Statistical Parametric Mapping (IBASPM) were used to assess GM density and volume in the cerebellum, respectively, in patients with MDD and the HCs. Indicators of emotional memory performance were measured, including the hit rate (HR), rate of false alarm (FA), precision (Pr = HR - FA) and emotional memory enhancement [∆Pr = Pr(emotion) - Pr(neutral)] values. Beck Depression Inventory (BDI) scores were used to measure the severity of depression.

RESULTS

In the patients with MDD, the GM density was decreased in three cerebellar cortical regions and increased in three cerebellar cortical regions (p < .005). The GM volumes in eight cerebellar cortical regions were significantly smaller in the patients with MDD than in the HC subjects (p < .05). In the patients with MDD, the GM volume was correlated with the ∆Pr (p < .05) in two cerebellar cortical regions. The BDI scores were significantly correlated with the relative GM densities (p < .05) in 5 cerebellar cortical regions, and the GM volumes in 13 cerebellar cortical regions were correlated with the BDI scores in patients with MDD.

CONCLUSIONS

Emotional memory and the severity of depressive symptoms are associated with structural changes in both the posterior and anterior GM regions in the cerebellum in patients with MDD. These findings could be useful for improving our understanding of the neurobiological mechanisms underlying emotional memory and explaining the abnormalities of the neural correlates that are associated with MDD.

Cognition-related brain networks underpin the symptoms of unipolar depression: Evidence from a systematic review

This systematic review sources the latest neuroimaging evidence for the role of cognition-related brain networks in depression, and relates their abnormal functioning to symptoms of the disorder. Using theoretically informed and rigorous inclusion criteria, we integrate findings from 59 functional neuroimaging studies of adults with unipolar depression using a narrative approach. Results demonstrate that two distinct neurocognitive networks, the autobiographic memory network (AMN) and the cognitive control network (CCN), are central to the symptomatology of depression. Specifically, hyperactivity of the introspective AMN is linked to pathological brooding, self-blame, rumination. Anticorrelated under-engagement of the CCN is associated with indecisiveness, negative automatic thoughts, poor concentration, distorted cognitive processing. Downstream effects of this imbalance include reduced regulation of networks linked to the vegetative and affective symptoms of depression. The configurations of these networks can change between individuals and over time, plausibly accounting for both the variable presentation of depressive disorders and their fluctuating course. Framing depression as a disorder of neurocognitive networks directly links neurobiology to psychiatric practice, aiding researchers and clinicians alike.

A proposed solution to integrating cognitive-affective neuroscience and neuropsychiatry in psychiatry residency training: The time is now

Despite increasing recognition of the importance of a strong neuroscience and neuropsychiatry education in the training of psychiatry residents, achieving this competency has proven challenging. In this perspective article, we selectively discuss the current state of these educational efforts and outline how using brain-symptom relationships from a systems-level neural circuit approach in clinical formulations may help residents value, understand, and apply cognitive-affective neuroscience based principles towards the care of psychiatric patients. To demonstrate the utility of this model, we present a case of major depressive disorder and discuss suspected abnormal neural circuits and therapeutic implications. A clinical neural systems-level, symptom-based approach to conceptualize mental illness can complement and expand residents' existing psychiatric knowledge.

Altered threat and safety neural processing linked to persecutory delusions in schizophrenia: a two-task fMRI study

Persecutory delusions are a clinically important symptom in schizophrenia associated with social avoidance and increased violence. Few studies have investigated the neurobiology of persecutory delusions, which is a prerequisite for developing novel treatments. The aim of this two-paradigm functional magnetic resonance imaging (fMRI) study is to characterize social "real world" and linguistic threat brain activations linked to persecutory delusions in schizophrenia (n=26) using instructed-fear/safety and emotional word paradigms. Instructed-fear/safety activations correlated to persecutory delusion severity demonstrated significant increased lateral orbitofrontal cortex and visual association cortex activations for the instructed-fear vs. safety and instructed-fear vs. baseline contrasts; decreased lateral orbitofrontal cortex and ventral occipital-temporal cortex activations were observed for the instructed-safety stimuli vs. baseline contrast. The salience network also showed divergent fear and safety cued activations correlated to persecutory delusions. Emotional word paradigm analyses showed positive correlations between persecutory delusion severity and left-lateralized linguistic and hippocampal-parahippocampal activations for the threat vs. neutral word contrast. Visual word form area activations correlated positively with persecutory delusions for both threat and neutral word vs. baseline contrasts. This study links persecutory delusions to enhanced neural processing of threatening stimuli and decreased processing of safety cues, and helps elucidate systems-level activations associated with persecutory delusions in schizophrenia.

Decreased Resting-State Connectivity between Neurocognitive Networks in Treatment Resistant Depression

Approximately one-third of patients with major depressive disorder (MDD) do not achieve remission after various treatment options and develop treatment resistant depression (TRD). So far, little is known about the pathophysiology of TRD. Studies in MDD patients showed aberrant functional connectivity (FC) of three "core" neurocognitive networks: the salience network (SN), cognitive control network (CCN), and default mode network (DMN). We used a cross-sectional design and performed resting-state FC MRI to assess connectivity of the SN, CCN, and both anterior and posterior DMN in 17 severe TRD, 18 non-TRD, and 18 healthy control (HC) subjects. Relative to both non-TRD and HC subjects, TRD patients showed decreased FC between the dorsolateral prefrontal cortex and angular gyrus, which suggests reduced FC between the CCN and DMN, and reduced FC between the medial prefrontal cortex and precuneus/cuneus, which suggests reduced FC between the anterior and posterior DMN. No significant differences in SN FC were observed. Our results suggest that TRD is characterized by a disturbance in neurocognitive networks relative to non-TRD and HC.

Affective state-dependent changes in the brain functional network in major depressive disorder

In major depressive disorder (MDD), as a network-level disease, the pathophysiology would be displayed to a wide extent over the brain. Moreover, the network-wide changes could be dependent on the context of affective processing. In this study, we sought affective state-dependent changes of the brain functional network by applying a graph-theoretical approach to functional magnetic resonance imaging data acquired in 13 patients with MDD and 12 healthy controls who were exposed to video clips inducing the negative, neutral or positive affective state. For each affective condition, a group-wise brain functional network was constructed based on partial correlation of mean activity across subjects between brain areas. Network parameters, global and local efficiencies, were measured from the brain functional network. Compared with controls', patients' brain functional network shifted to the regular network in the topological architecture, showing decreased global efficiency and increased local efficiency, during negative and neutral affective processing. Further, the shift to the regular network in patients was most evident during negative affective processing. MDD is proposed to provoke widespread changes across the whole brain in an affective state-dependent manner, specifically in the negative affective state.

The relationship between brain oscillatory activity and therapeutic effectiveness of transcranial magnetic stimulation in the treatment of major depressive disorder

Major depressive disorder (MDD) is marked by disturbances in brain functional connectivity. This connectivity is modulated by rhythmic oscillations of brain electrical activity, which enable coordinated functions across brain regions. Oscillatory activity plays a central role in regulating thinking and memory, mood, cerebral blood flow, and neurotransmitter levels, and restoration of normal oscillatory patterns is associated with effective treatment of MDD. Repetitive transcranial magnetic stimulation (rTMS) is a robust treatment for MDD, but the mechanism of action (MOA) of its benefits for mood disorders remains incompletely understood. Benefits of rTMS have been tied to enhanced neuroplasticity in specific brain pathways. We summarize here the evidence that rTMS entrains and resets thalamocortical oscillators, normalizes regulation and facilitates reemergence of intrinsic cerebral rhythms, and through this mechanism restores normal brain function. This entrainment and resetting may be a critical step in engendering neuroplastic changes and the antidepressant effects of rTMS. It may be possible to modify the method of rTMS administration to enhance this MOA and achieve better antidepressant effectiveness. We propose that rTMS can be administered: (1) synchronized to a patient's individual alpha frequency (IAF), or synchronized rTMS (sTMS); (2) as a low magnetic field strength sinusoidal waveform; and, (3) broadly to multiple brain areas simultaneously. We present here the theory and evidence indicating that these modifications could enhance the therapeutic effectiveness of rTMS for the treatment of MDD.

C-terminal processing of the teneurin proteins: independent actions of a teneurin C-terminal associated peptide in hippocampal cells

Many neuropsychiatric conditions have a common set of neurological substrates associated with the integration of sensorimotor processing. The teneurins are a recently described family of proteins that play a significant role in visual and auditory development. Encoded on the terminal exon of the teneurin genes is a family of bioactive peptides, termed teneurin C-terminal associated peptides (TCAP), which regulate mood-disorder associated behaviors. Thus, the teneurin-TCAP system could represent a novel neurological system underlying the origins of a number of complex neuropsychiatric conditions. However, it is not known if TCAP-1 exerts its effects as part of a direct teneurin function, whereby TCAP represents a functional region of the larger teneurin protein, or if it has an independent role, either as a splice variant or post-translational proteolytic cleavage product of teneurin. In this study, we show that TCAP-1 can be transcribed as a smaller mRNA transcript. After translation, further processing yields a smaller 15 kDa protein containing the TCAP-1 region. In the mouse hippocampus, immunoreactive (ir) TCAP-1 is exclusively localized to the pyramidal layers of the CA1, CA2 and CA3 regions. Although the localization of TCAP and teneurin in hippocampal regions is similar, they are distinct within the cell as most ir-teneurin is found at the plasma membrane, whereas ir-TCAP-1 is predominantly found in the cytosol. Moreover, in mouse embryonic hippocampal cell culture, FITC-labeled TCAP-1 binds to the plasma membrane and is taken up into the cytosol via dynamin-dependent caveolae-mediated endocytosis. Our data provides novel evidence that TCAP-1 is structurally and functionally distinct from the larger teneurins.

The default mode network and recurrent depression: a neurobiological model of cognitive risk factors

A neurobiological account of cognitive vulnerability for recurrent depression is presented based on recent developments of resting state neural networks. We propose that alterations in the interplay between task positive (TP) and task negative (TN) elements of the Default Mode Network (DMN) act as a neurobiological risk factor for recurrent depression mediated by cognitive mechanisms. In the framework, depression is characterized by an imbalance between TN-TP components leading to an overpowering of TP by TN activity. The TN-TP imbalance is associated with a dysfunctional internally-focused cognitive style as well as a failure to attenuate TN activity in the transition from rest to task. Thus we propose the TN-TP imbalance as overarching neural mechanism involved in crucial cognitive risk factors for recurrent depression, namely rumination, impaired attentional control, and cognitive reactivity. During remission the TN-TP imbalance persists predisposing to vulnerability of recurrent depression. Empirical data to support this model is reviewed. Finally, we specify how this framework can guide future research efforts.

Resting-state quantitative electroencephalography reveals increased neurophysiologic connectivity in depression

Symptoms of Major Depressive Disorder (MDD) are hypothesized to arise from dysfunction in brain networks linking the limbic system and cortical regions. Alterations in brain functional cortical connectivity in resting-state networks have been detected with functional imaging techniques, but neurophysiologic connectivity measures have not been systematically examined. We used weighted network analysis to examine resting state functional connectivity as measured by quantitative electroencephalographic (qEEG) coherence in 121 unmedicated subjects with MDD and 37 healthy controls. Subjects with MDD had significantly higher overall coherence as compared to controls in the delta (0.5-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), and beta (12-20 Hz) frequency bands. The frontopolar region contained the greatest number of "hub nodes" (surface recording locations) with high connectivity. MDD subjects expressed higher theta and alpha coherence primarily in longer distance connections between frontopolar and temporal or parietooccipital regions, and higher beta coherence primarily in connections within and between electrodes overlying the dorsolateral prefrontal cortical (DLPFC) or temporal regions. Nearest centroid analysis indicated that MDD subjects were best characterized by six alpha band connections primarily involving the prefrontal region. The present findings indicate a loss of selectivity in resting functional connectivity in MDD. The overall greater coherence observed in depressed subjects establishes a new context for the interpretation of previous studies showing differences in frontal alpha power and synchrony between subjects with MDD and normal controls. These results can inform the development of qEEG state and trait biomarkers for MDD.