Variations in the TNF-α Gene (TNF-α -308G→A) Affect Attention and Action Selection Mechanisms in a Dissociated Fashion

Association of inflammation cytokines with cognitive function in first-episode major depressive disorder

Objective

Abnormal cognitive functioning is a core symptom of Major Depressive Disorder (MDD) and is strongly correlated with MDD prognosis. Current studies suggest that the occurrence of MDD may be related to oxidative stress-induced inflammation, hypothalamic-pituitary-adrenal axis disorders, diminished monoamine function and microbe-brain-gut axis, among other pathways. In recent years, the relationship between the immune-inflammatory response and MDD has been a hot topic of research, but how the relationship between immunoinflammation and cognitive function is manifested in MDD is still unclear. In this study, we examined cognitive function characteristics, serum inflammatory factors, brain-derived neurotrophic factor, and their correlations before and after pharmacological treatment(paroxetine hydrochloride tablets) in patients with first-episode major depressive disorder, aiming to identify objective biomarkers for cognitive function assessment.

Methods

We included 22 patients with first-episode major depressive disorder and 27 healthy volunteers from the community during the same period. The Hamilton Depression Scale-17 (HAMD-17) assessed the severity of depressive symptoms at baseline and after 8 weeks of treatment. The Repeatable Battery for the Assessment of Neuropsychological Status(RBANS) evaluated cognitive function, and serum samples were collected to determine levels of inflammatory and neurotrophic factors at these two time points. For healthy volunteers, only HAMD-17 scale scores, RBANS scale scores, and serum samples were taken at baseline. Spearman's correlation analyzed the relationship between inflammatory factors, neurotrophic factors, and cognitive function. Multiple linear regression determined factors affecting cognitive function in first-time patients.

Results

Baseline findings indicated that patients' IL-6 and TNF-α levels exceeded those of healthy individuals, while their IFN-α levels were below; their scores in language, attention, delayed memory, and the RBANS scale were also lower than healthy counterparts. Post-treatment, patients' BDNF, IL-6, and TNF-α levels remained higher than those of healthy subjects, and their IFN-α levels were still lower; their language and attention scores were also inferior. Association analyses revealed an association between BDNF and visuospatial/constructional ability scores and language scores in patients with MDD at baseline, and a positive relationship between TNF-α and attention score. Multiple regression analysis indicated an association between TNF-α levels and attention scores in MDD patients at baseline.

Conclusions

Our study concludes that TNF-α and BDNF correlate with cognitive function in MDD at baseline, and furthermore, TNF-α could potentially serve as an objective biomarker to support the assessment of attentional function at baseline.

Melatonin, an Antitumor Necrosis Factor Therapy

Tumor necrosis factor (TNF) is a biomarker of inflammation whose levels are elevated in patients with several diseases associated with dysregulation of the immune response. The main limitations of currently used anti-TNF therapies are the induction of immunodepression, which in many cases leads to serious adverse effects such as infection and cancer, and the inability to cross the blood-brain barrier in neuroinflammatory conditions. Melatonin, in addition to being a chronobiotic compound, is widely known for its antioxidant and immunomodulatory capacity to control inflammatory processes in different pathological contexts. The aim of the present review is to address human-based studies that describe the effect of melatonin on TNF production. The review includes all the articles published in PubMed databases until April 15, 2024. After depuration, 45 studies were finally included in the review, 23 related to the in vitro action of melatonin in human cells and 22 in vivo studies in humans. Most of the data reviewed support the idea that melatonin has an immunosuppressive effect on TNF levels, which, together with its low toxicity profile, low cost, and ability to cross the blood-brain barrier, points to melatonin as a potential anti-TNF therapy. Therefore, improving our knowledge of the action of melatonin in regulating TNF through appropriate clinical trials would reveal the true potential of this molecule as a possible anti-TNF therapy.

Neurophysiological dynamics of metacontrol states: EEG insights into conflict regulation

Understanding the neural mechanisms underlying metacontrol and conflict regulation is crucial for insights into cognitive flexibility and persistence. This study employed electroencephalography (EEG), EEG-beamforming and directed connectivity analyses to explore how varying metacontrol states influence conflict regulation at a neurophysiological level. Metacontrol states were manipulated by altering the frequency of congruent and incongruent trials across experimental blocks in a modified flanker task, and both behavioral and electrophysiological measures were analyzed. Behavioral data confirmed the experimental manipulation's efficacy, showing an increase in persistence bias and a reduction in flexibility bias during increased conflict regulation. Electrophysiologically, theta band activity paralleled the behavioral data, suggesting that theta oscillations reflect the mismatch between expected metacontrol bias and actual task demands. Alpha and beta band dynamics differed across experimental blocks, though these changes did not directly mirror behavioral effects. Post-response alpha and beta activity were more pronounced in persistence-biased states, indicating a neural reset mechanism preparing for future cognitive demands. By using a novel artificial neural networks method, directed connectivity analyses revealed enhanced inter-regional communication during persistence states, suggesting stronger top-down control and sensorimotor integration. Overall, theta band activity was closely tied to metacontrol processes, while alpha and beta bands played a role in resetting the neural system for upcoming tasks. These findings provide a deeper understanding of the neural substrates involved in metacontrol and conflict monitoring, emphasizing the distinct roles of different frequency bands in these cognitive processes.

Elevated CRP and TNF-α levels are associated with blunted neural oscillations serving fluid intelligence

INTRODUCTION

Inflammatory processes help protect the body from potential threats such as bacterial or viral invasions. However, when such inflammatory processes become chronically engaged, synaptic impairments and neuronal cell death may occur. In particular, persistently high levels of C-reactive protein (CRP) and tumor necrosis factor-alpha (TNF-α) have been linked to deficits in cognition and several psychiatric disorders. Higher-order cognitive processes such as fluid intelligence (Gf) are thought to be particularly vulnerable to persistent inflammation. Herein, we investigated the relationship between elevated CRP and TNF-α and the neural oscillatory dynamics serving Gf.

METHODS

Seventy adults between the ages of 20-66 years (Mean = 45.17 years, SD = 16.29, 21.4% female) completed an abstract reasoning task that probes Gf during magnetoencephalography (MEG) and provided a blood sample for inflammatory marker analysis. MEG data were imaged in the time-frequency domain, and whole-brain regressions were conducted using each individual's plasma CRP and TNF-α concentrations per oscillatory response, controlling for age, BMI, and education.

RESULTS

CRP and TNF-α levels were significantly associated with region-specific neural oscillatory responses. In particular, elevated CRP concentrations were associated with altered gamma activity in the right inferior frontal gyrus and right cerebellum. In contrast, elevated TNF-α levels scaled with alpha/beta oscillations in the left anterior cingulate and left middle temporal, and gamma activity in the left intraparietal sulcus.

DISCUSSION

Elevated inflammatory markers such as CRP and TNF-α were associated with aberrant neural oscillations in regions important for Gf. Linking inflammatory markers with regional neural oscillations may hold promise in identifying mechanisms of cognitive and psychiatric disorders.

Neurofilaments - Small proteins of physiological significance and predictive power for future neurodegeneration and cognitive decline across the life span

Neurofilaments (NFs) are not only important for axonal integrity and nerve conduction in large myelinated axons but they are also thought to be crucial for receptor and synaptic functioning. Therefore, NFs may play a critical role in cognitive functions, as cognitive processes are known to depend on synaptic integrity and are modulated by dopaminergic signaling. Here, we present a theory-driven interdisciplinary approach that NFs may link inflammation, neurodegeneration, and cognitive functions. We base our hypothesis on a wealth of evidence suggesting a causal link between inflammation and neurodegeneration and between these two and cognitive decline (see Fig. 1), also taking dopaminergic signaling into account. We conclude that NFs may not only serve as biomarkers for inflammatory, neurodegenerative, and cognitive processes but also represent a potential mechanical hinge between them, moreover, they may even have predictive power regarding future cognitive decline. In addition, we advocate the use of both NFs and MRI parameters, as their synthesis offers the opportunity to individualize medical treatment by providing a comprehensive view of underlying disease activity in neurological diseases. Since our society will become significantly older in the upcoming years and decades, maintaining cognitive functions and healthy aging will play an important role. Thanks to technological advances in recent decades, NFs could serve as a rapid, noninvasive, and relatively inexpensive early warning system to identify individuals at increased risk for cognitive decline and could facilitate the management of cognitive dysfunctions across the lifespan.

Post-inflammatory administration of N-acetylcysteine reduces inflammation and alters receptor levels in a cellular model of Parkinson's disease

Parkinson's disease (PD) is a complex, multifactorial neurodegenerative disease with a prevalence of 1% over the age of 55. Neuropathological hallmarks of PD include the loss of dopaminergic neurons in the substantia nigra pars compacta and the accumulation of Lewy bodies that contain a variety of proteins and lipids including alpha-synuclein (α-syn). Although the formation of α-syn occurs intracellularly, it can also be found in the extracellular space where it can be taken up by neighboring cells. Toll-like receptor 2 (TLR2) is an immune system receptor that has been shown to recognize extracellular α-syn and modulate its uptake by other cells. Lymphocyte-activation gene 3 (LAG3), an immune checkpoint receptor, has also been proposed to play a role in extracellular α-syn internalization; however, a recent study has disputed this role. Internalized α-syn can trigger expression and secretion of inflammatory cytokines such as tumor necrosis factor alpha (TNF-α), interleukin (IL)-1β, IL-2, and IL-6 and induce neuroinflammation, apoptosis, and mitophagy that results in cellular death. In this study, we tested if N-acetylcysteine (NAC), an anti-inflammatory and anti-carcinogenic drug, can circumvent the detrimental effects of neuroinflammation and induce an anti-inflammatory response by modulating transcription and expression of TLR2 and LAG3 receptors. Cells overexpressing wild-type α-syn were treated with TNF-α to induce inflammation followed by NAC to inhibit the deleterious effects of TNF-α-induced inflammation and apoptosis. SNCA gene transcription and α-syn protein expression were validated by q-PCR and Western blot (WB), respectively. Cell viability was measured, and apoptosis was evaluated by WB and terminal deoxynucleotidyl transferase nick end labeling methods. Alterations in LAG3 and TLR2 receptor levels were evaluated by immunofluorescent labeling, WB, and q-PCR. TNF-α not only increased inflammation but also increased endogenous and overexpressed α-syn levels. NAC treatment decreased expression of TLR2 and increased transcription of LAG3 receptor and diminished inflammation-mediated toxicity and cell death. Here, we demonstrate that NAC can reduce neuroinflammation that occurs as a result of alpha-synuclein overexpression, via a TLR2-associated pathway, making it a promising candidate for therapeutic intervention. Further studies are needed to elucidate molecular mechanisms and pathways related to neuroinflammation in PD and to develop possible new therapeutic approaches to slow the clinical progression of PD.

Genetic associations with resilience to potentially traumatic events and vantage sensitivity to social support

INTRODUCTION

Stress responses and mental health outcomes greatly vary when individuals are exposed to potentially traumatic events (PTEs). The Differential Susceptibility Model (DSM) (Pluess, 2015) suggests individual differences in stress responses are influenced by gene-environment interactions, with genes conferring reactivity. While individuals can be resilient (or vulnerable) to PTEs, they can also have vantage sensitivity (or resistance) to social support. This study examined whether selected genotypes moderated the effect of PTEs and social support on mental health.

METHODS

This cross-sectional candidate gene study included 450 college students (M age = 20.4, 79.3 % women) who provided buccal cells for genotyping and completed measures of psychosocial variables. DNA was genotyped for 12 genetic variants.

RESULTS

Hierarchical regression revealed that the Mental Health Inventory (MHI) was associated with the Trauma History Questionnaire (THQ), rs1800795 in IL-6, and THQ × rs1800795 [R² = 0.10, F(3, 418) = 15.68, p < .01]. The MHI was associated with the Social Support Survey (SSS), rs4680 in COMT, and SSS × rs4680 [R² = 0.24, F(3, 429) = 44.19, p < .01]. Only THQ and SSS survived multiple testing corrections.

DISCUSSION

Findings partially support the DSM that the G/G genotype of rs1800795 in IL-6 is associated with resilience to PTEs, and the Met/Met genotype of rs4680 in COMT is associated with vantage sensitivity to social support. Limitations include cross-sectional design, limited PTE measurement, small convenience sample, and noncorrection for multiple significance test. Clinicians need to view resilience holistically and understand resilience is associated with psychosocial and genetic factors.

Peripheral blood inflammatory markers in patients with attention deficit/hyperactivity disorder (ADHD): A systematic review and meta-analysis

It has been observed that subclinical inflammation might be involved in the pathophysiology of attention deficit/hyperactivity disorder (ADHD). However, studies investigating peripheral blood levels of immune-inflammatory markers have provided mixed findings. We performed a systematic review and meta-analysis of studies comparing unstimulated serum or plasma levels of C-reactive protein (CRP) and cytokines in subjects with ADHD and healthy controls (the PROSPERO registration number: CRD 42021276869). Online searches covered the publication period until 30th Sep 2021 and random-effects meta-analyses were carried out. Out of 1844 publication records identified, 10 studies were included. The levels of interleukin (IL)-6 were significantly higher in studies of participants up to the age of 18 years (k = 10, g = 0.70, 95%CI: 0.10-1.30, p = 0.023) and after including those above the age of 18 years (k = 10, g = 0.71, 95%CI: 0.12-1.31, p = 0.019). In turn, the levels of tumor necrosis factor-α (TNF-α) were significantly lower in subjects with ADHD compared to healthy controls (k = 7, g = -0.16, 95%CI: -0.30 - -0.03, p = 0.020). Individual studies had a high contribution to the overall effect, since the overall effect was no longer significant after removing single studies. No significant differences were found with respect to the levels of CRP, IL-1β, IL-10 and interferon-γ. The present findings indicate that individuals with ADHD tend to show elevated levels of IL-6 and reduced levels of TNF-α. Larger and longitudinal studies recording potential confounding factors and comorbid psychopathology are needed to confirm our findings.

The Health Hazards of Volcanoes: First Evidence of Neuroinflammation in the Hippocampus of Mice Exposed to Active Volcanic Surroundings

Neuroinflammation is a process related to the onset of neurodegenerative diseases; one of the hallmarks of this process is microglial reactivation and the secretion by these cells of proinflammatory cytokines such as TNFα. Numerous studies report the relationship between neuroinflammatory processes and exposure to anthropogenic air pollutants, but few refer to natural pollutants. Volcanoes are highly inhabited natural sources of environmental pollution that induce changes in the nervous system, such as reactive astrogliosis or the blood-brain barrier breakdown in exposed individuals; however, no neuroinflammatory event has been yet defined. To this purpose, we studied resting microglia, reactive microglia, and TNFα production in the brains of mice chronically exposed to an active volcanic environment on the island of São Miguel (Azores, Portugal). For the first time, we demonstrate a proliferation of microglial cells and an increase in reactive microglia, as well an increase in TNFα secretion, in the central nervous system of individuals exposed to volcanogenic pollutants.

Neuroprotective Potential of Ellagic Acid: A Critical Review

Ellagic acid (EA) is a dietary polyphenol present in various fruits, vegetables, herbs, and nuts. It exists either independently or as part of complex structures, such as ellagitannins, which release EA and several other metabolites including urolithins following absorption. During the past few decades, EA has drawn considerable attention because of its vast range of biological activities as well as its numerous molecular targets. Several studies have reported that the oxidative stress-lowering potential of EA accounts for its broad-spectrum pharmacological attributes. At the biochemical level, several mechanisms have also been associated with its therapeutic action, including its efficacy in normalizing lipid metabolism and lipidemic profile, regulating proinflammatory mediators, such as IL-6, IL-1β, and TNF-α, upregulating nuclear factor erythroid 2-related factor 2 and inhibiting NF-κB action. EA exerts appreciable neuroprotective activity by its free radical-scavenging action, iron chelation, initiation of several cell signaling pathways, and alleviation of mitochondrial dysfunction. Numerous in vivo studies have also explored the neuroprotective attribute of EA against various neurotoxins in animal models. Despite the increasing number of publications with experimental evidence, a critical analysis of available literature to understand the full neuroprotective potential of EA has not been performed. The present review provides up-to-date, comprehensive, and critical information regarding the natural sources of EA, its bioavailability, metabolism, neuroprotective activities, and underlying mechanisms of action in order to encourage further studies to define the clinical usefulness of EA for the management of neurological disorders.

Neurophysiological mechanisms underlying motor feature binding processes and representations

Coherent, voluntary action requires an integrated representation of these actions and their defining features. Although theories delineate how action integration requiring binding between different action features may be accomplished, the underlying neurophysiological mechanisms are largely elusive. The present study examined the neurophysiological mechanisms underlying binding processes in actions. To this end, we conducted EEG recordings and applied standard event-related potential analyses, temporal EEG signal decomposition and multivariate pattern analyses (MVPA). According to the code occupation account, an overlap between a planned and a to-be-performed action impairs performance. The level, to which performance is attenuated depends on the strength of binding of action features. This binding process then determines the representation of them, the so-called action files. We show that code occupation and bindings between action features specifically modulate processes preceding motor execution as showed by the stimulus-locked lateralized readiness potential (LRP). Conversely, motor execution processes reflected by the response-locked LRP were not modulated by action file binding. The temporal decomposition of the EEG signal, further distinguished between action file related processes: the planned response determining code occupation was reflected in general (voluntary) response selection but not in involuntary (response priming-related) activation. Moreover, MVPA on temporally decomposed neural signals indicated that action files are represented as a continuous chain of activations. Within this chain, inhibitory and response re-activation patterns can be distinguished. Taken together, the neurophysiological correlates of action file binding suggest that parallel, stimulus- and response-related pre-motor processes are responsible for the code occupation in the human motor system.

Tourette syndrome as a motor disorder revisited - Evidence from action coding

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Feature Binding/integration in the motor domain in Tourette Syndrome (TS) is examined.

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Motor binding processes and interleaved action are intact in TS.

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Binding processes are differentially modulated in the motor domain and sensori-motor processes.

Because tics are the defining clinical feature of Tourette syndrome, it is conceptualized predominantly as a motor disorder. There is some evidence though suggesting that the neural basis of Tourette syndrome is related to perception–action processing and binding between perception and action. However, binding processes have not been examined in the motor domain in these patients. If it is particularly perception–action binding but not binding processes within the motor system, this would further corroborate that Tourette syndrome it is not predominantly, or solely, a motor disorder.

Here, we studied N = 22 Tourette patients and N = 24 healthy controls using an established action coding paradigm derived from the Theory of Event Coding framework and concomitant EEG-recording addressing binding between a planned but postponed, and an interleaved immediate reaction with different levels of overlap of action elements. Behavioral performance during interleaved action coding was normal in Tourette syndrome. Response locked lateralized readiness potentials reflecting processes related to motor execution were larger in Tourette syndrome, but only in simple conditions. However, pre-motor processes including response preparation and configuration reflected by stimulus-locked lateralized readiness potentials were normal. This was supported by a Bayesian data analysis providing evidence for the null hypothesis. The finding that processes integrating different action-related elements prior to motor execution are normal in Tourette syndrome suggests that Tourette it is not solely a motor disorder. Considering other recent evidence, the data show that changes in “binding” in Tourette syndrome are specific for perception–action integration but not for action coding.

Association between TNFA, IL10 and IL18 promoter gene variants and cognitive functions in patients with relapsing-remitting multiple sclerosis

OBJECTIVES

To investigate the relationship between TNFA-308G > A, IL10-1082A > G, IL18-607C > A, and cognitive functioning in relapsing-remitting multiple sclerosis (RRMS).

RESULTS

In the patients' group: AG genotype of TNFA-308G > A was associated with higher serum tumor necrosis factor-alpha (TNF-alpha) than GG genotype, and higher TNF-alpha levels correlated with poorer results on Symbol Digit Modalities Test; CC genotype of IL18-607C > A was related to lower score on Isaacs test, compared to AC variant; AA genotype of IL10-1082A > G was associated with abnormally low results on Paced Auditory Series Addition Test.

CONCLUSIONS

TNFA-308G > A, IL10-1082A > G and IL18-607C > A gene variants may be associated with impaired cognitive functions in RRMS patients.

Intact Context-Dependent Modulation of Conflict Monitoring in Childhood ADHD

Objective: Conflict monitoring is well known to be modulated by context. This is known as the Gratton effect, meaning that the degree of interference is smaller when a stimulus-response conflict had been encountered previously. It is unclear to what extent these processes are changed in ADHD. Method: Children with ADHD (combined subtype) and healthy controls performed a modified version of the sequence flanker task. Results: Patients with ADHD made significantly more errors than healthy controls, indicating general performance deficits. However, there were no differences regarding reaction times, indicating an intact Gratton effect in ADHD. These results were supported by Bayesian statistics. Conclusion: The results suggest that the ability to take contextual information into account during conflict monitoring is preserved in patients with ADHD despite this disorder being associated with changes in executive control functions overall. These findings are discussed in light of different theoretical accounts on contextual modulations of conflict monitoring.

Applying deep learning to single-trial EEG data provides evidence for complementary theories on action control

Efficient action control is indispensable for goal-directed behaviour. Different theories have stressed the importance of either attention or response selection sub-processes for action control. Yet, it is unclear to what extent these processes can be identified in the dynamics of neurophysiological (EEG) processes at the single-trial level and be used to predict the presence of conflicts in a given moment. Applying deep learning, which was blind to cognitive theory, on single-trial EEG data allowed to predict the presence of conflict in ~95% of subjects ~33% above chance level. Neurophysiological features related to attentional and motor response selection processes in the occipital cortex and the superior frontal gyrus contributed most to prediction accuracy. Importantly, deep learning was able to identify predictive neurophysiological processes in single-trial neural dynamics. Hence, mathematical (artificial intelligence) approaches may be used to foster the validation and development of links between cognitive theory and neurophysiology of human behavior.

Vahid et al. use a deep-learning approach to analyze single-trial EEG data to examine theories on action control. Their approach enables the identification of spatial and temporal neurophysiological features that are predictive of the response control during the Simon task. The results confirm cognitive theory-driven approaches on the relationship between neurophysiology and human behavior.

Deep Learning Based on Event-Related EEG Differentiates Children with ADHD from Healthy Controls

Attention Deficit Hyperactivity Disorder (ADHD) is one of the most prevalent neuropsychiatric disorders in childhood and adolescence and its diagnosis is based on clinical interviews, symptom questionnaires, and neuropsychological testing. Much research effort has been undertaken to evaluate the usefulness of neurophysiological (EEG) data to aid this diagnostic process. In the current study, we applied deep learning methods on event-related EEG data to examine whether it is possible to distinguish ADHD patients from healthy controls using purely neurophysiological measures. The same was done to distinguish between ADHD subtypes. The results show that the applied deep learning model (“EEGNet”) was able to distinguish between both ADHD subtypes and healthy controls with an accuracy of up to 83%. However, a significant fraction of individuals could not be classified correctly. It is shown that neurophysiological processes indicating attentional selection associated with superior parietal cortical areas were the most important for that. Using the applied deep learning method, it was not possible to distinguish ADHD subtypes from each other. This is the first study showing that deep learning methods applied to EEG data are able to dissociate between ADHD patients and healthy controls. The results show that the applied method reflects a promising means to support clinical diagnosis in ADHD. However, more work needs to be done to increase the reliability of the taken approach.

RETRACTED: Neurophysiological mechanisms underlying the modulation of cognitive control by simultaneous conflicts

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal) This article has been retracted at the request of the Editor-in-Chief with the agreement of the authors. In a previous version of the paper reviewed in another journal, the reviewer suggested changing the filter settings because the setting used (reported hp 0.5) can produce serious artifactual effects on the ERP components (N200, N400 and P300) that the authors were interested in. In this published version of the article a different filter (0.2Hz HP) setting is reported in the methods. However, the results sections are identical. A change in filter setting should have led to different results. There is reasonable doubt that the reported filter settings were indeed applied on the reported data. However, there is consensus that this was due to an error, acknowledged by the authors who fully co-operated with the investigation and agreed with the decision. There is no indication of any fraudulent motivation.

Methamphetamine-associated difficulties in cognitive control allocation may normalize after prolonged abstinence

Chronic heavy methamphetamine use likely causes dopaminergic neurotoxicity, which is commonly thought to result in cognitive control deficits. Both of these alterations may persist even after the use is discontinued, but tend to (partly) improve with increasing duration of abstinence. While several studies have demonstrated that the reinstatement of comparatively normal dopaminergic signaling may take months, if not years, the amelioration of cognitive deficits has predominantly been investigated in much shorter intervals of several weeks to less than half a year. Against this background, we set out to investigate the effects on prolonged abstinence in n = 27 abstinent former methamphetamine users in a cross-sectional design using behavioral and neurophysiological measures of cognitive control. Our behavioral results suggest that former users struggled to identify and adapt to different degrees of cognitive control requirements, which made their behavioral performance less expedient than that of healthy controls. On the neurophysiological level, this was reflected by reduced modulations of the N2-N450 amplitude in response to high vs. low cognitive control requirements. Yet, those effects could only be observed in methamphetamine users who had been abstinent for a relatively short time (mean 9.9; max. 18 months), but not in former users who had been abstinent two years or longer. While this finding alone does not allow for causal inferences, it suggests that the amelioration of control deficits may take longer than what is commonly investigated (1-6 months). Hence, some of the statements about permanent/irreversible dopamine-dependent executive dysfunctions in former methamphetamine users should be interpreted with caution.

Catecholaminergic Modulation of Conflict Control Depends on the Source of Conflicts

Background

To display goal-directed behavior, we must be able to resolve response conflicts that arise from processing various distractors. Such conflicts may be triggered by different kinds of distractor stimuli (e.g., priming and flanker stimuli), but it has remained largely unclear whether the functional and neurobiological underpinnings of both conflict types differ. We therefore investigated the functional relevance of the catecholamines dopamine and norepinephrine, which have been shown to increase the signal-to-noise ratio in neuronal processing and should therefore modulate response conflicts.

Methods

In a double-blind, randomized, placebo-controlled study design, we examined the effect of methylphenidate (0.5 mg/kg) on both flanker-induced and priming-induced response conflicts in a group of n=25 healthy young adults. We used EEG recordings to examine event-related potentials in combination with source localization analyses to identify the cognitive-neurophysiological subprocesses and functional neuroanatomical structures modulated by methylphenidate.

Results

Compared with placebo, methylphenidate decreased flanker conflicts. This was matched by increased congruency effects in the fronto-central N2/P3 event-related potential complex and associated with modulations in the right inferior frontal gyrus. In contrast to this, methylphenidate did not modulate the size of prime-evoked conflicts.

Conclusions

Our results suggest that catecholamine-driven increases in signal-to-noise ratio and neural gain control do not equally benefit differently evoked conflicts. This supports the hypothesis of an at least partly different neurobiological basis for flanker- and prime-evoked response conflicts. As the right inferior frontal gyrus plays an important role in inhibition, the catecholaminergic system may reduce flanker conflicts by supporting the inhibition of distracting information.

Working memory load affects repetitive behaviour but not cognitive flexibility in adolescent autism spectrum disorder

OBJECTIVES

Autism spectrum disorder (ASD) is associated with repetitive and stereotyped behaviour, suggesting that cognitive flexibility may be deficient in ASD. A central, yet not examined aspect to understand possible deficits in flexible behaviour in ASD relates (i) to the role of working memory and (ii) to neurophysiological mechanisms underlying behavioural modulations.

METHODS

We analysed behavioural and neurophysiological (EEG) correlates of cognitive flexibility using a task-switching paradigm with and without working memory load in adolescents with ASD and typically developing controls (TD).

RESULTS

Adolescents with ASD versus TD show similar performance in task switching with no memory load, indicating that 'pure' cognitive flexibility is not in deficit in adolescent ASD. However performance during task repetition decreases with increasing memory load. Neurophysiological data reflect the pattern of behavioural effects, showing modulations in P2 and P3 event-related potentials.

CONCLUSIONS

Working memory demands affect repetitive behaviour while processes of cognitive flexibility are unaffected. Effects emerge due to deficits in preparatory attentional processes and deficits in task rule activation, organisation and implementation of task sets when repetitive behaviour is concerned. It may be speculated that the habitual response mode in ASD (i.e. repetitive behaviour) is particularly vulnerable to additional demands on executive control processes.

The neurophysiological basis of developmental changes during sequential cognitive flexibility between adolescents and adults

Cognitive flexibility is a major facet of executive functions and often refers to sequential task control; that is, it is very likely that one may re-encounter a task that has previously been abandoned to carry out a different task. In the context of sequential cognitive flexibility, the "backward inhibition (BI) effect" has been studied quite extensively. Here we ask whether there are age-related differences between adolescents and adults to overcome BI and what system-neurophysiological mechanisms underlie these modulations. This was examined using a system neurophysiological study procedure combining event-related potentials data with source localization and EEG signal decomposition methods. We show that sequential cognitive flexibility, and the ability overcome backward inhibition, is inferior in adolescents compared with adults. Accounting for intra-individual variability in the neurophysiological data, this data suggest that two partly inter-related processes underlie the differences between adolescents than adults to overcome backward inhibition: One process refers to the suppression of the inhibitory effect of the n-1 trial on the n-2 trial during perceptual categorization of incoming information that is associated with right inferior frontal regions. The other process refers to immature response selection and conflict monitoring mechanisms associated with regions in the medial frontal cortex.

RLS patients show better nocturnal performance in the Simon task due to diminished visuo-motor priming

OBJECTIVE

The restless legs syndrome (RLS) is characterized by sensory-motor symptoms which usually occur predominantly at rest in the evening and at night. It is assumed that this circadian rhythm is caused by low dopamine levels in the evening. Yet, it has never been investigated whether RLS patients show diurnal variations in cognitive functions modulated by dopamine and what neurophysiological and functional neuroanatomical processes underlie such modulations.

METHODS

We used a Simon task combined with EEG and source localization to investigate whether top-down response selection and/or automatic visuo-motor priming are subject to diurnal changes in RLS patients, as compared to matched healthy controls.

RESULTS

We found that RLS patients showed better task performance due to reduced visuo-motor priming in the evening, as reflected by smaller early lateralized readiness potential (e-LRP) amplitudes and decreased activation of the superior parietal cortex and premotor cortex. Top-down response selection and early attentional processing were unaffected by RLS.

CONCLUSIONS

Counterintuitively, RLS patients show enhanced task performance in the evening, i.e. when experiencing dopaminergic deficiency. Yet, this may be explained by deficits in visuo-motor priming that lead to reduced false response tendencies.

SIGNIFICANCE

This study reveals a counterintuitive circadian variation of cognitive functions in RLS patients.

Specific neurophysiological mechanisms underlie cognitive inflexibility in inflammatory bowel disease

Inflammatory bowel disease (IBD) is highly prevalent. While the pathophysiological mechanisms of IBD are increasingly understood, there is a lack of knowledge concerning cognitive dysfunctions in IBD. This is all the more the case concerning the underlying neurophysiological mechanisms. In the current study we focus on possible dysfunctions of cognitive flexibility (task switching) processes in IBD patients using a system neurophysiological approach combining event-related potential (ERP) recordings with source localization analyses. We show that there are task switching deficits (i.e. increased switch costs) in IBD patients. The neurophysiological data show that even though the pathophysiology of IBD is diverse and wide-spread, only specific cognitive subprocesses are altered: There was a selective dysfunction at the response selection level (N2 ERP) associated with functional alterations in the anterior cingulate cortex and the right inferior frontal gyrus. Attentional selection processes (N1 ERP), perceptual categorization processes (P1 ERP), or mechanisms related to the flexible implementation of task sets and related working memory processes (P3 ERP) do not contribute to cognitive inflexibility in IBD patients and were unchanged. It seems that pathophysiological processes in IBD strongly compromise cognitive-neurophysiological subprocesses related to fronto-striatal networks. These circuits may become overstrained in IBD when cognitive flexibility is required.

Self-Regulatory Capacities Are Depleted in a Domain-Specific Manner

Performing an act of self-regulation such as making decisions has been suggested to deplete a common limited resource, which impairs all subsequent self-regulatory actions (ego depletion theory). It has however remained unclear whether self-referred decisions truly impair behavioral control even in seemingly unrelated cognitive domains, and which neurophysiological mechanisms are affected by these potential depletion effects. In the current study, we therefore used an inter-individual design to compare two kinds of depletion, namely a self-referred choice-based depletion and a categorization-based switching depletion, to a non-depleted control group. We used a backward inhibition (BI) paradigm to assess the effects of depletion on task switching and associated inhibition processes. It was combined with EEG and source localization techniques to assess both behavioral and neurophysiological depletion effects. The results challenge the ego depletion theory in its current form: Opposing the theory’s prediction of a general limited resource, which should have yielded comparable effects in both depletion groups, or maybe even a larger depletion in the self-referred choice group, there were stronger performance impairments following a task domain-specific depletion (i.e., the switching-based depletion) than following a depletion based on self-referred choices. This suggests at least partly separate and independent resources for various cognitive control processes rather than just one joint resource for all self-regulation activities. The implications are crucial to consider for people making frequent far-reaching decisions e.g., in law or economy.

Humans with latent toxoplasmosis display altered reward modulation of cognitive control

Latent infection with Toxoplasma gondii has repeatedly been shown to be associated with behavioral changes that are commonly attributed to a presumed increase in dopaminergic signaling. Yet, virtually nothing is known about its effects on dopamine-driven reward processing. We therefore assessed behavior and event-related potentials in individuals with vs. without latent toxoplasmosis performing a rewarded control task. The data show that otherwise healthy young adults with latent toxoplasmosis show a greatly diminished response to monetary rewards as compared to their non-infected counterparts. While this selective effect eliminated a toxoplasmosis-induced speed advantage previously observed for non-rewarded behavior, Toxo-positive subjects could still be demonstrated to be superior to Toxo-negative subjects with respect to response accuracy. Event-related potential (ERP) and source localization analyses revealed that this advantage during rewarded behavior was based on increased allocation of processing resources reflected by larger visual late positive component (LPC) amplitudes and associated activity changes in the right temporo-parietal junction (BA40) and left auditory cortex (BA41). Taken together, individuals with latent toxoplasmosis show superior behavioral performance in challenging cognitive control situations but may at the same time have a reduced sensitivity towards motivational effects of rewards, which might be explained by the presumed increase in dopamine.

Inflammation, Self-Regulation, and Health: An Immunologic Model of Self-Regulatory Failure

Self-regulation is a fundamental human process that refers to multiple complex methods by which individuals pursue goals in the face of distractions. Whereas superior self-regulation predicts better academic achievement, relationship quality, financial and career success, and lifespan health, poor self-regulation increases a person's risk for negative outcomes in each of these domains and can ultimately presage early mortality. Given its centrality to understanding the human condition, a large body of research has examined cognitive, emotional, and behavioral aspects of self-regulation. In contrast, relatively little attention has been paid to specific biologic processes that may underlie self-regulation. We address this latter issue in the present review by examining the growing body of research showing that components of the immune system involved in inflammation can alter neural, cognitive, and motivational processes that lead to impaired self-regulation and poor health. Based on these findings, we propose an integrated, multilevel model that describes how inflammation may cause widespread biobehavioral alterations that promote self-regulatory failure. This immunologic model of self-regulatory failure has implications for understanding how biological and behavioral factors interact to influence self-regulation. The model also suggests new ways of reducing disease risk and enhancing human potential by targeting inflammatory processes that affect self-regulation.

ADHD patients fail to maintain task goals in face of subliminally and consciously induced cognitive conflicts

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) patients have been reported to display deficits in action control processes. While it is known that subliminally and consciously induced conflicts interact and conjointly modulate action control in healthy subjects, this has never been investigated for ADHD.

METHOD

We investigated the (potential) interaction of subliminally and consciously triggered response conflicts in children with ADHD and matched healthy controls using neuropsychological methods (event-related potentials; ERPs) to identify the involved cognitive sub-processes.

RESULTS

Unlike healthy controls, ADHD patients showed no interaction of subliminally and consciously triggered response conflicts. Instead, they only showed additive effects as their behavioural performance (accuracy) was equally impaired by each conflict and they showed no signs of task-goal shielding even in cases of low conflict load. Of note, this difference between ADHD and controls was not rooted in early bottom-up attentional stimulus processing as reflected by the P1 and N1 ERPs. Instead, ADHD showed either no or reversed modulations of conflict-related processes and response selection as reflected by the N2 and P3 ERPs.

CONCLUSION

There are fundamental differences in the architecture of cognitive control which might be of use for future diagnostic procedures. Unlike healthy controls, ADHD patients do not seem to be endowed with a threshold which allows them to maintain high behavioural performance in the face of low conflict load. ADHD patients seem to lack sufficient top-down attentional resources to maintain correct response selection in the face of conflicts by shielding the response selection process from response tendencies evoked by any kind of distractor.

Increased Oxidative Parameters and Decreased Cytokine Levels in an Animal Model of Attention-Deficit/Hyperactivity Disorder

Attention-deficit/hyperactivity disorder (ADHD) is a highly heterogeneous disorder characterized by impairing levels of hyperactivity, impulsivity and inattention. Oxidative and inflammatory parameters have been recognized among its multiple predisposing pathways, and clinical studies indicate that ADHD patients have increased oxidative stress. In this study, we aimed to evaluate oxidative (DCFH oxidation, glutathione levels, glutathione peroxidase, catalase and superoxide dismutase activities) and inflammatory (TNF-α, IL-1β and IL-10) parameters in the most widely accepted animal model of ADHD, the spontaneously hypertensive rats (SHR). Prefrontal cortex, cortex (remaining regions), striatum and hippocampus of adult male SHR and Wistar Kyoto rats were studied. SHR presented increased reactive oxygen species (ROS) production in the cortex, striatum and hippocampus. In SHR, glutathione peroxidase activity was decreased in the prefrontal cortex and hippocampus. TNF-α levels were reduced in the prefrontal cortex, cortex (remaining regions), hippocampus and striatum of SHR. Besides, IL-1β and IL-10 levels were decreased in the cortex of the ADHD model. Results indicate that SHR presented an oxidative profile that is characterized by an increase in ROS production without an effective antioxidant counterbalance. In addition, this strain showed a decrease in cytokine levels, mainly TNF-α, indicating a basal deficit. These results may present a new approach to the cognitive disturbances seen in the SHR.

Neurophysiological mechanisms of circadian cognitive control in RLS patients - an EEG source localization study

The circadian variation of sensory and motor symptoms with increasing severity in the evening and at night is a key diagnostic feature/symptom of the restless legs syndrome (RLS). Even though many neurological diseases have shown a strong nexus between motor and cognitive symptoms, it has remained unclear whether cognitive performance of RLS patients declines in the evening and which neurophysiological mechanisms are affected by the circadian variation. In the current study, we examined daytime effects (morning vs. evening) on cognitive performance in RLS patients (n = 33) compared to healthy controls (n = 29) by analyzing flanker interference effects in combination with EEG and source localization techniques. RLS patients showed larger flanker interference effects in the evening than in the morning (p = .023), while healthy controls did not display a comparable circadian variation. In line with this, the neurophysiological data showed smaller N1 amplitudes in RLS patients compared to controls in the interfering task condition in the evening (p = .042), but not in the morning. The results demonstrate diurnal cognitive changes in RLS patients with intensified impairments in the evening. It seems that not all dopamine-regulated cognitive processes are altered in RLS and thus show daytime-dependent impairments. Instead, the daytime-related cognitive impairment emerges from attentional selection processes within the extra-striate visual cortex, but not from later cognitive processes such as conflict monitoring and response selection.

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RLS patients have larger flanker interference effect in the evening.

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RLS patients have enhanced impairment of attentional selection in the evening.

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Nocturnal attentional impairment relies on the extra-striate visual cortex.

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Conflict monitoring and response selection are not affected by RLS.

Therapeutic effects of ellagic acid on memory, hippocampus electrophysiology deficits, and elevated TNF-α level in brain due to experimental traumatic brain injury

OBJECTIVES

Cognitive defects such as learning and memory impairment are amongst the most repetitious sequelae after sever and moderate traumatic brain injury (TBI). It was suggested that ellagic acid (EA), an innate phenol product, display neuroprotective properties against oxidative and inflammatory damages after brain injury. The object of the current study was therapeutic properties of EA on blood-brain barrier (BBB) interruption and elevated content of TNF-α in brain tissue followed by neurologic aftereffects, cognitive and brain electrophysiology deficits as outcomes of diffuse TBI in rat.

MATERIALS AND METHODS

TBI was induced by a 200 g weight falling by a 2-m height through a free-falling tube onto the head of anesthetized rat. TBI rats treated immediately after trauma with EA (100 mg/kg, IP) once every 8 hr until 48 hr later. Neurologic outcomes, passive avoidance task (PAT), hippocampal long-term potentiation (LTP), BBB permeability and content of TNF-α in brain tissue were evaluated.

RESULTS

TBI induced significant impairments in neurological score, BBB function, PAT and hippocampal LTP in TBI+Veh group in compare with Sham+Veh (P<0.001). EA treatment decreased neurologic severity score (NSS), restored increased BBB permeability, cognitive and hippocampal LTP abnormalities, and elevated brain content of TNF-α due to TBI significantly (P<0.001).

CONCLUSION

Our findings propose that EA can restore NSS, cognitive and LTP deficits and prevent brain inflammation may by restore BBB permeability as well as lowering brain content of TNF-α following TBI.

Response inhibition in Attention deficit disorder and neurofibromatosis type 1 - clinically similar, neurophysiologically different

There are large overlaps in cognitive deficits occurring in attention deficit disorder (ADD) and neurodevelopmental disorders like neurofibromatosis type 1 (NF1). This overlap is mostly based on clinical measures and not on in-depth analyses of neuronal mechanisms. However, the consideration of such neuronal underpinnings is crucial when aiming to integrate measures that can lead to a better understanding of the underlying mechanisms. Inhibitory control deficits, for example, are a hallmark in ADD, but it is unclear how far there are similar deficits in NF1. We thus compared adolescent ADD and NF1 patients to healthy controls in a Go/Nogo task using behavioural and neurophysiological measures. Clinical measures of ADD-symptoms were not different between ADD and NF1. Only patients with ADD showed increased Nogo errors and reductions in components reflecting response inhibition (i.e. Nogo-P3). Early perceptual processes (P1) were changed in ADD and NF1. Clinically, patients with ADD and NF1 thus show strong similarities. This is not the case in regard to underlying cognitive control processes. This shows that in-depth analyses of neurophysiological processes are needed to determine whether the overlap between ADD and NF1 is as strong as assumed and to develop appropriate treatment strategies.

The norepinephrine system shows information-content specific properties during cognitive control - Evidence from EEG and pupillary responses

The ability to exert cognitive control is a major function of the prefrontal cortex, the efficiency of which depends on the phasic release of norepinephrine (NE) at particular time points. However, different aspects of information are simultaneously processed at any given moment. This raises the question of whether the norepinephrine system is also capable of specifically modulating selected aspects of all ongoing information processing, especially when several of those processes are carried out by the same functional neuroanatomical structure at the same time. We examine this question in humans using a flanker paradigm by integrating neurophysiological (EEG) and pupil diameter data using novel signal processing techniques including Residue Iteration Decomposition (RIDE) and source localization. We show that during conflict monitoring, motor response-related processes are more strongly modulated by the NE system than stimulus-related processes or central decision processes between stimulus and response. This was the case even though these processes occurred at the same time point and were mediated by overlapping medial frontal cortical structures. The results indicate that the NE system exerts specific modulatory effects for different informational contents that are simultaneously processed in the medial frontal cortex.

The system neurophysiological basis of non-adaptive cognitive control: Inhibition of implicit learning mediated by right prefrontal regions

Cognitive control is adaptive in the sense that it inhibits automatic processes to optimize goal-directed behavior, but high levels of control may also have detrimental effects in case they suppress beneficial automatisms. Until now, the system neurophysiological mechanisms and functional neuroanatomy underlying these adverse effects of cognitive control have remained elusive. This question was examined by analyzing the automatic exploitation of a beneficial implicit predictive feature under conditions of high versus low cognitive control demands, combining event-related potentials (ERPs) and source localization. It was found that cognitive control prohibits the beneficial automatic exploitation of additional implicit information when task demands are high. Bottom-up perceptual and attentional selection processes (P1 and N1 ERPs) are not modulated by this, but the automatic exploitation of beneficial predictive information in case of low cognitive control demands was associated with larger response-locked P3 amplitudes and stronger activation of the right inferior frontal gyrus (rIFG, BA47). This suggests that the rIFG plays a key role in the detection of relevant task cues, the exploitation of alternative task sets, and the automatic (bottom-up) implementation and reprogramming of action plans. Moreover, N450 amplitudes were larger under high cognitive control demands, which was associated with activity differences in the right medial frontal gyrus (BA9). This most likely reflects a stronger exploitation of explicit task sets which hinders the exploration of the implicit beneficial information in case of high cognitive control demands. Hum Brain Mapp 37:4511-4522, 2016. © 2016 Wiley Periodicals, Inc.

The neurophysiological basis of reward effects on backward inhibition processes

The ability to flexibly switch between tasks is an important faculty in daily life. One process that has been suggested to be an important aspect of flexible task switching is the inhibition of a recently performed task. This is called backward inhibition. Several studies suggest that task switching performance can be enhanced by rewards. However, it is less clear in how far backward inhibition mechanisms are also affected by rewards, especially when it comes to the neuronal mechanisms underlying reward-related modulations of backward inhibition. We therefore investigated this using a system neurophysiological approach combining EEG recordings with source localization techniques. We demonstrate that rewards reduce the strength of backward inhibition processes. The neurophysiological data shows that these reward-related effects emerge from response and/or conflict monitoring processes within medial frontal cortical structures. Upstream processes of perceptual gating and attentional selection, as well as downstream processes of context updating and stimulus-response mapping are not modulated by reward, even though they also play a role in backward inhibition effects.

The influence of genes on "positive valence systems" constructs: A systematic review

In 2009, the U.S. National Institute of Mental Health (NIMH) proposed an approach toward the deconstruction of psychiatric nosology under the research domain criteria (RDoC) framework. The overarching goal of RDoC is to identify robust, objective measures of behavior, emotion, cognition, and other domains that are more closely related to neurobiology than are diagnoses. A preliminary framework has been constructed, which has connected molecules, genes, brain circuits, behaviors, and other elements to dimensional psychiatric constructs. Although the RDoC framework has salience in emerging studies, foundational literature that pre-dated this framework requires synthesis and translation to the evolving objectives and nomenclature of RDoC. Toward this end, we review the candidate-gene association, linkage, and genome-wide studies that have implicated a variety of loci and genetic polymorphisms in selected Positive Valence Systems (PVS) constructs. Our goal is to review supporting evidence to currently listed genes implicated in this domain and novel candidates. We systematically searched and reviewed literature based on keywords listed under the June, 2011, edition of the PVS matrix on the RDoC website (http://www.nimh.nih.gov/research-priorities/rdoc/positive-valence-systems-workshop-proceedings.shtml), which were supplemented with de novo keywords pertinent to the scope of our review. Several candidate genes linked to the PVS framework were identified from candidate-gene association studies. We also identified novel candidates with loose association to PVS traits from genome-wide studies. There is strong evidence suggesting that PVS constructs, as currently conceptualized under the RDoC initiative, index genetically influenced traits; however, future research, including genetic epidemiological, and psychometric analyses, must be performed.

Interacting sources of interference during sensorimotor integration processes

Every day, a multitude of interfering sensory inputs needs to be integrated and adequately processed using response selection processes. Interference effects are typically investigated using classical paradigms like the Flanker and Simon task. The sources of interference for Flanker and Simon effect are known to be different and according to dual process accounts, two distinct functional pathways are involved in resolving these types of interference. It is an open question how far these sources of interference are related to each other and interact. We investigated this question in a system neurophysiological study utilizing a hybrid paradigm combining both Flanker effect-like and Simon effect-like features. We focus on event-related theta oscillations and use beamforming methods to examine functional neuroanatomical networks. The results show that Simon and Flanker interference interacted in a non-additive fashion by modulating theta band activity, probably reflecting the recruitment of cognitive control processes. Beamforming source reconstruction revealed that theta band activity was related to a broad neuronal network comprising prefrontal and cerebellar regions, including the MFG, SFG, IFG, and SMA. These regions were connected to interference processing and conflict resolution, but differed in the amount of specificity for different sources of interference.

TNFα G308A polymorphism is associated with resilience to sleep deprivation-induced psychomotor vigilance performance impairment in healthy young adults

Cytokines such as TNFα play an integral role in sleep/wake regulation and have recently been hypothesized to be involved in cognitive impairment due to sleep deprivation. We examined the effect of a guanine to adenine substitution at position 308 in the TNFα gene (TNFα G308A) on psychomotor vigilance performance impairment during total sleep deprivation. A total of 88 healthy women and men (ages 22-40) participated in one of five laboratory total sleep deprivation experiments. Performance on a psychomotor vigilance test (PVT) was measured every 2-3h. The TNFα 308A allele, which is less common than the 308G allele, was associated with greater resilience to psychomotor vigilance performance impairment during total sleep deprivation (regardless of time of day), and also provided a small performance benefit at baseline. The effect of genotype on resilience persisted when controlling for between-subjects differences in age, gender, race/ethnicity, and baseline sleep duration. The TNFα G308A polymorphism predicted less than 10% of the overall between-subjects variance in performance impairment during sleep deprivation. Nonetheless, the differential effect of the polymorphism at the peak of performance impairment was more than 50% of median performance impairment at that time, which is sizeable compared to the effects of other genotypes reported in the literature. Our findings provided evidence for a role of TNFα in the effects of sleep deprivation on psychomotor vigilance performance. Furthermore, the TNFα G308A polymorphism may have predictive potential in a biomarker panel for the assessment of resilience to psychomotor vigilance performance impairment due to sleep deprivation.

Ebola: translational science considerations

We are currently in the midst of the most aggressive and fulminating outbreak of Ebola-related disease, commonly referred to as "Ebola", ever recorded. In less than a year, the Ebola virus (EBOV, Zaire ebolavirus species) has infected over 10,000 people, indiscriminately of gender or age, with a fatality rate of about 50%. Whereas at its onset this Ebola outbreak was limited to three countries in West Africa (Guinea, where it was first reported in late March 2014, Liberia, where it has been most rampant in its capital city, Monrovia and other metropolitan cities, and Sierra Leone), cases were later reported in Nigeria, Mali and Senegal, as well as in Western Europe (i.e., Madrid, Spain) and the US (i.e., Dallas, Texas; New York City) by late October 2014. World and US health agencies declared that the current Ebola virus disease (EVD) outbreak has a strong likelihood of growing exponentially across the world before an effective vaccine, treatment or cure can be developed, tested, validated and distributed widely. In the meantime, the spread of the disease may rapidly evolve from an epidemics to a full-blown pandemic. The scientific and healthcare communities actively research and define an emerging kaleidoscope of knowledge about critical translational research parameters, including the virology of EBOV, the molecular biomarkers of the pathological manifestations of EVD, putative central nervous system involvement in EVD, and the cellular immune surveillance to EBOV, patient-centered anthropological and societal parameters of EVD, as well as translational effectiveness about novel putative patient-targeted vaccine and pharmaceutical interventions, which hold strong promise, if not hope, to curb this and future Ebola outbreaks. This work reviews and discusses the principal known facts about EBOV and EVD, and certain among the most interesting ongoing or future avenues of research in the field, including vaccination programs for the wild animal vectors of the virus and the disease from global translational science perspective.

Viral immune evasion in dengue: toward evidence-based revisions of clinical practice guidelines

Dengue, a leading cause of illness and death in the tropics and subtropics since the 1950׳s, is fast spreading in the Western hemisphere. Over 30% of the world׳s population is at risk for the mosquitoes that transmit any one of four related Dengue viruses (DENV). Infection induces lifetime protection to a particular serotype, but successive exposure to a different DENV increases the likelihood of severe form of dengue fever (DF), dengue hemorrhagic fever (DHF), or dengue shock syndrome (DSS). Prompt supportive treatment lowers the risk of developing the severe spectrum of Dengue-associated physiopathology. Vaccines are not available, and the most effective protective measure is to prevent mosquito bites. Here, we discuss selected aspects of the syndemic nature of Dengue, including its potential for pathologies of the central nervous system (CNS). We examine the fundamental mechanisms of cell-mediated and humoral immunity to viral infection in general, and the specific implications of these processes in the regulatory control of DENV infection, including DENV evasion from immune surveillance. In line with the emerging model of translational science in health care, which integrates translational research (viz., going from the patient to the bench and back to the patient) and translational effectiveness (viz., integrating and utilizing the best available evidence in clinical settings), we examine novel and timely evidence-based revisions of clinical practice guidelines critical in optimizing the management of DENV infection and Dengue pathologies. We examine the role of tele-medicine and stakeholder engagement in the contemporary model of patient centered, effectiveness-focused and evidence-based health care.

ABBREVIATIONS

BBB - blood-brain barrier, CNS - central nervous system, DAMP - damage-associated molecular patterns, DENV - dengue virus, DF - dengue fever, DHF - dengue hemorrhagic fever, DSS - dengue shock syndrome, DALYs - isability adjusted life years, IFN-g - interferon-gamma, ILX - interleukinX, JAK/STAT - janus kinase (JAK) / Signal transducer and activator of transcription (STAT), LT - Escherichia coli heat-labile enterotoxin formulations deficient in GM1 binding by mutation (LT[G33D]), MCP-1 - monocyte chemotactic protein 1, M-CSF - macrophage colony-stimulating fact, MHC - major histocompatibility complex, MIF - macrophage migration inhibitory factor, [MIP-1]-α / -β - macrophage inflammatory protein-1 alpha and beta, mAb - monoclonal antibody, NS1 - non-structural protein 1 of dengue virus, NK - natural killer cells, PAMP - pathogen-associated molecular patterns, PBMC - peripheral blood mononuclear cells, TBF-b - transforming growth factor-beta, TNF-α - tumor necrosis-alpha, VHFs - virus hemorrhagic fevers, WHO - World Health Organization.

Obesity and dementia: adipokines interact with the brain

Obesity is a pandemic and a serious global health concern. Obesity is a risk factor for multiple conditions and contributes to multi-morbidities, resulting in increased health costs and millions of deaths each year. Obesity has been associated with changes in brain structure, cognitive deficits, dementia and Alzheimer׳s disease. Adipokines, defined as hormones, cytokines and peptides secreted by adipose tissue, may have more widespread influence and functionality in the brain than previously thought. In this review, six adipokines, and their actions in the obese and non-obese conditions will be discussed. Included are: plasminogen activator inhibitor-1 (PAI-1), interleukin-6 (IL-6), tumor necrosis factors alpha (TNF-α), angiotensinogen (AGT), adiponectin and leptin. Their functionality in the periphery, their ability to cross the blood brain barrier (BBB) and their influence on dementia processes within the brain will be discussed.

Modulatory effects of proinflammatory cytokines for action cascading processes - evidence from neurosarcoidosis

Neurosarcoidosis is a rare central nervous system manifestation of sarcoidosis. T cell, T-helper cell and macrophage activation via the major histocompatibility complex (MHC) II-mediated pathway causes this disease. Little is known about the possible cognitive disturbances in this disease as most reported instances are case studies. Here, we provide the first in-depth analysis of psychomotor functions in a sample of 30 neurosarcoidosis patients. We investigated action control processes using a paradigm that is able to examine how different tasks are cascaded to achieve the task goal. We integrated electrophysiological (EEG) data with behavioural and neuroimmunological data. Our results show that there was no general cognitive decline in patients with neurosarcoidosis. Patients only presented deficits when two response options have to be prioritized. Patients apply an inefficient processing strategy where they try to processes different response options in parallel. The electrophysiological data show that the deficits are due to dysfunctions at the response selection stage. Behavioural and neurophysiological changes are predictable on the basis of soluble interleukin 2 receptor serum concentrations. The results show that neurosarcoidosis is not associated with nonspecific changes in cognitive functions but does lead to specific alterations in cognitive control that are strongly dependent on immunological parameters.

Tumor necrosis factor alpha: a link between neuroinflammation and excitotoxicity

Tumor necrosis factor alpha (TNF-α) is a proinflammatory cytokine that exerts both homeostatic and pathophysiological roles in the central nervous system. In pathological conditions, microglia release large amounts of TNF-α; this de novo production of TNF-α is an important component of the so-called neuroinflammatory response that is associated with several neurological disorders. In addition, TNF-α can potentiate glutamate-mediated cytotoxicity by two complementary mechanisms: indirectly, by inhibiting glutamate transport on astrocytes, and directly, by rapidly triggering the surface expression of Ca⁺² permeable-AMPA receptors and NMDA receptors, while decreasing inhibitory GABA_A receptors on neurons. Thus, the net effect of TNF-α is to alter the balance of excitation and inhibition resulting in a higher synaptic excitatory/inhibitory ratio. This review summarizes the current knowledge of the cellular and molecular mechanisms by which TNF-α links the neuroinflammatory and excitotoxic processes that occur in several neurodegenerative diseases, but with a special emphasis on amyotrophic lateral sclerosis (ALS). As microglial activation and upregulation of TNF-α expression is a common feature of several CNS diseases, as well as chronic opioid exposure and neuropathic pain, modulating TNF-α signaling may represent a valuable target for intervention.

The functional tumor necrosis factor-α (308A/G) polymorphism modulates attentional selection in elderly individuals

There has been increasing interest in understanding the role of inflammatory processes for cognitive functions in aging using molecular genetic approaches. Though this has mostly been evaluated in pathological aging, little is known about the relevance for cognitive functions in healthy aging in humans. On the basis of behavioral data and neurophysiological data (event-related potentials and time-frequency decomposition) we show that the A-allele of the functional tumor necrosis factor (TNF)-α -308 A/G polymorphism confers dysfunction in a number of cognitive processes: prolonged attentional selection indexed by a delayed P1/N1 complex, an increased P3a, which is interpreted as an enhanced distractibility by nonrelevant stimuli and compromised response selection mechanisms, as indexed by a reduced frontocentral N2. Time-frequency analyses show that allelic variations further exert their effects by modulating alpha and beta frequency oscillations. On a neurobiological level, these effects might be because of the interaction of TNF-α with glutamatergic neural transmission by which TNF-α is known to boost apoptotic mechanisms in elderly individuals.