Altered neural processes underlying executive function in occupational burnout-Basis for a novel EEG biomarker

Introduction

As burnout has become a global pandemic, there is a call for improved understanding and detection of alterations in brain functions related to it. We have previously reported challenges in executive functions (EFs) in daily life, especially in metacognition, in subjects with occupational burnout, along with alterations in cardiac physiology. In the current study, we focused on the impact of burnout on brain physiology during a task requiring EF.

Methods

Fifty-four volunteers filled in inventories of burnout, depression, and EF in daily life (BBI-15, BDI, and BRIEF-A). Based on the BBI-15 score, subjects were divided into burnout and non-burnout groups. Subjects performed a Go/NoGo test (Executive RT test) engaging several EFs, while their EEG was recorded. The inventory scores, cognitive performance scores, and event-related potential (N2, P3) amplitudes, latencies, and interpeak latencies (IPLs) were compared between the groups.

Results

There were significant differences in the BDI and BRIEF-A scores between the groups, with more symptoms of depression and challenges in daily life in the burnout group. There were no differences in objective performance measures in the EF task between the groups. However, centroparietal P3 amplitude was larger, and while there were no differences in N2 or P3 latencies, N2-P3 IPL was longer in the Go condition in the burnout than in non-burnout group. Both ERP measures correlated significantly with burnout symptoms. A regression model from centroparietal P3 amplitude and N2-P3 IPL predicted significantly both the BBI-15 score and the BRIEF-A metacognition index.

Discussion

We conclude that burnout is linked with challenges in EF in daily life and alterations in the underlying neural processes. While cognitive performance in the task was equal, electrophysiological measures differed between the groups. Prolonged N2-P3 IPL points toward slowed transition from one cognitive process to another. Increased P3 amplitude, on the other hand, reflects increased allocation of neural processing resources. This may be a compensatory mechanism, allowing for equal performance with controls. These electrophysiological measures, obtained during the EF task, show promise as brain physiology-based biomarkers of burnout, contributing to its improved and objective detection. In addition, these results indicate occupational burnout is linked with objective alterations in brain physiology.

The Brain's Glymphatic System: Drawing New Perspectives in Neuroscience

This paper delves into the intricate structure and functionality of the brain's glymphatic system, bringing forth new dimensions in its neuroscientific understanding. This paper commences by exploring the cerebrospinal fluid (CSF)-its localization, production, and pivotal role within the central nervous system, acting as a cushion and vehicle for nutrient distribution and waste elimination. We then transition into an in-depth study of the morphophysiological aspects of the glymphatic system, a recent discovery revolutionizing the perception of waste clearance from the brain, highlighting its lymphatic-like characteristics and remarkable operations. This paper subsequently emphasizes the glymphatic system's potential implications in Alzheimer's disease (AD), discussing the connection between inefficient glymphatic clearance and AD pathogenesis. This review also elucidates the intriguing interplay between the glymphatic system and the circadian rhythm, illustrating the optimal functioning of glymphatic clearance during sleep. Lastly, we underscore the hitherto underappreciated involvement of the glymphatic system in the tumoral microenvironment, potentially impacting tumor growth and progression. This comprehensive paper accentuates the glymphatic system's pivotal role in multiple domains, fostering an understanding of the brain's waste clearance mechanisms and offering avenues for further research into neuropathological conditions.

Physical Exercise Modulates Brain Physiology Through a Network of Long- and Short-Range Cellular Interactions

In the last decades, the effects of sedentary lifestyles have emerged as a critical aspect of modern society. Interestingly, recent evidence demonstrated that physical exercise plays an important role not only in maintaining peripheral health but also in the regulation of central nervous system function. Many studies have shown that physical exercise promotes the release of molecules, involved in neuronal survival, differentiation, plasticity and neurogenesis, from several peripheral organs. Thus, aerobic exercise has emerged as an intriguing tool that, on one hand, could serve as a therapeutic protocol for diseases of the nervous system, and on the other hand, could help to unravel potential molecular targets for pharmacological approaches. In the present review, we will summarize the cellular interactions that mediate the effects of physical exercise on brain health, starting from the factors released in myocytes during muscle contraction to the cellular pathways that regulate higher cognitive functions, in both health and disease.

Efficacy of Repetitive Transcranial Magnetic Stimulation Combined With Visual Scanning Treatment on Cognitive-Behavioral Symptoms of Unilateral Spatial Neglect in Patients With Traumatic Brain Injury: Study Protocol for a Randomized Controlled Trial

Left hemispatial neglect (LHSN) is a frequent and disabling condition affecting patients who suffered from traumatic brain injury (TBI). LHSN is a neuropsychological syndrome characterized clinically by difficulties in attending, responding, and consciously representing the right side of space. Despite its frequency, scientific evidence on effective treatments for this condition in TBI patients is still low. According to existing literature, we hypothesize that in TBI, LHSN is caused by an imbalance in inter-hemispheric activity due to hyperactivity of the left hemisphere, as observed in LHSN after right strokes. Thus, by inhibiting this left hyperactivity, repetitive Transcranial Magnetic Stimulation (rTMS) would have a rebalancing effect, reducing LHSN symptoms in TBI patients. We plan to test this hypothesis within a single-blind, randomized SHAM controlled trial in which TBI patients will receive inhibitory i-rTMS followed by cognitive treatment for 15 days. Neurophysiological and clinical measures will be collected before, afterward, and in the follow-up. This study will give the first empirical evidence about the efficacy of a novel approach to treating LHSN in TBI patients.

Clinical Trial Registration:https://www.clinicaltrials.gov/ct2/show/NCT04573413?cond=Neglect%2C+Hemispatial&cntry=IT&city=Bologna&draw=2&rank=2, identifier: NCT04573413.

Age and Dietary Vitamin C Intake Affect Brain Physiology in Genetically Modified Mice Expressing Human Lipoprotein(A) and Unable to Synthesize Vitamin C

AIMS

Lipoprotein (a) deposition in coronary vascular plaques and cerebral vessels is a recognized risk factor for cardiovascular disease, and research supports its role as a "repair factor" in vascular walls weakened by vitamin C deficiency.

BACKGROUND

Humans depend on dietary vitamin C as an important antioxidant, and as a cofactor in collagen synthesis, yet are prone to vitamin C deficiency. The brain is the one with the highest vitamin C content, due to its high oxygen consumption and oxidative stress. It has been shown that brain aging is accompanied by accumulated oxidative damage, which can lead to memory decline and neurological diseases.

OBJECTIVE

Our transgenic mouse, Gulo (-/-); Lp(a)+, presents a unique model for the study of key aspects of human metabolism with respect to a lack of internal vitamin C synthesis and the production of human Lipoprotein(a).

METHOD

This mouse model was used in our study to investigate the effects of prolonged intake of low and high levels of vitamin C, at different ages, on oxidative damage, cholesterol levels and Lipoprotein(a) deposition in the brain.

RESULT

The results show that a long-term high vitamin C intake is important in maintaining brain cholesterol homeostasis and preventing oxidative damage in Gulo(-/-);Lp(a)+ mice as they age. Moreover, we observed that the formation of brain Lipoprotein(a) deposits was negatively correlated with brain level of vitamin C, thereby confirming its role as a stability factor for an impaired extracellular matrix.

CONCLUSION

Our study emphasizes the critical role of vitamin C in protecting brain health as we age. Other: Our findings show that optimal vitamin C intake from early life to old age is important in brain health to prevent oxidative stress damage and to maintain cholesterol homeostasis in the brain. More importantly, negative correlation between brain ascorbic levels and the formation of Lp(a) deposit on the choroid plexus further emphasizes the critical role of vitamin C in protecting brain health throughout the normal aging process.

Epitranscriptomic regulation by m6A RNA methylation in brain development and diseases

Cellular RNAs are pervasively tagged with diverse chemical moieties, collectively called epitranscriptomic modifications. The methylation of adenosine at N6 position generates N6-methyladenosine (m6A), which is the most abundant and reversible epitranscriptomic modification in mammals. The m6A signaling is mediated by a dedicated set of proteins comprised of writers, erasers, and readers. Contrary to the activation-repression binary view of gene regulation, emerging evidence suggests that the m6A methylation controls multiple aspects of mRNA metabolism, such as splicing, export, stability, translation, and degradation, culminating in the fine-tuning of gene expression. Brain shows the highest abundance of m6A methylation in the body, which is developmentally altered. Within the brain, m6A methylation is biased toward neuronal transcripts and sensitive to neuronal activity. In a healthy brain, m6A maintains several developmental and physiological processes such as neurogenesis, axonal growth, synaptic plasticity, circadian rhythm, cognitive function, and stress response. The m6A imbalance contributes to the pathogenesis of acute and chronic CNS insults, brain cancer, and neuropsychiatric disorders. This review discussed the molecular mechanisms of m6A regulation and its implication in the developmental, physiological, and pathological processes of the brain.

Respiratory-related brain pulsations are increased in epilepsy-a two-centre functional MRI study

Resting-state functional MRI has shown potential for detecting changes in cerebral blood oxygen level-dependent signal in patients with epilepsy, even in the absence of epileptiform activity. Furthermore, it has been suggested that coefficient of variation mapping of fast functional MRI signal may provide a powerful tool for the identification of intrinsic brain pulsations in neurological diseases such as dementia, stroke and epilepsy. In this study, we used fast functional MRI sequence (magnetic resonance encephalography) to acquire ten whole-brain images per second. We used the functional MRI data to compare physiological brain pulsations between healthy controls (n = 102) and patients with epilepsy (n = 33) and furthermore to drug-naive seizure patients (n = 9). Analyses were performed by calculating coefficient of variation and spectral power in full band and filtered sub-bands. Brain pulsations in the respiratory-related frequency sub-band (0.11-0.51 Hz) were significantly (P < 0.05) increased in patients with epilepsy, with an increase in both signal variance and power. At the individual level, over 80% of medicated and drug-naive seizure patients exhibited areas of abnormal brain signal power that correlated well with the known clinical diagnosis, while none of the controls showed signs of abnormality with the same threshold. The differences were most apparent in the basal brain structures, respiratory centres of brain stem, midbrain and temporal lobes. Notably, full-band, very low frequency (0.01-0.1 Hz) and cardiovascular (0.8-1.76 Hz) brain pulses showed no differences between groups. This study extends and confirms our previous results of abnormal fast functional MRI signal variance in epilepsy patients. Only respiratory-related brain pulsations were clearly increased with no changes in either physiological cardiorespiratory rates or head motion between the subjects. The regional alterations in brain pulsations suggest that mechanisms driving the cerebrospinal fluid homeostasis may be altered in epilepsy. Magnetic resonance encephalography has both increased sensitivity and high specificity for detecting the increased brain pulsations, particularly in times when other tools for locating epileptogenic areas remain inconclusive.

Depressive Symptomatology, Racial Discrimination Experience, and Brain Tissue Volumes Observed on Magnetic Resonance Imaging

Not much is known about brain structural change in younger populations and minorities. The cross-sectional relationship between depressive symptomatology and racial discrimination with structural measures of brain tissue volume was investigated using magnetic resonance images of 710 participants in the Coronary Artery Risk Development in Young Adults CARDIA Study in 2010. Those reporting depressive symptoms and racial discrimination had lower total brain matter volume compared with those who reported neither (-8.8 mL, 95% confidence interval (CI): -16.4, -1.2), those who reported depressive symptoms only (-10.9 mL, 95% CI: -20.4, -1.4), and those who reported racial discrimination only (-8.6 mL, 95% CI: -16.5, -0.8). Results were similar for total normal white matter. There were 103% higher odds (odds ratio = 2.03, 95% CI: 1.32, 3.14) of being in the highest quartile of white matter hyperintensities in those with depressive symptoms only compared to those without. Although tests for interaction by race were not statistically significant, sensitivity analyses stratified by race revealed inverse associations with total brain matter and total white matter volumes only among black participants with combined depressive symptomatology and experience of racial discrimination, and positive associations only among white participants with depressive symptoms with presence of white matter hyperintensities, suggesting future studies may focus on race.

Altered physiological brain variation in drug-resistant epilepsy

INTRODUCTION

Functional magnetic resonance imaging (fMRI) combined with simultaneous electroencephalography (EEG-fMRI) has become a major tool in mapping epilepsy sources. In the absence of detectable epileptiform activity, the resting state fMRI may still detect changes in the blood oxygen level-dependent signal, suggesting intrinsic alterations in the underlying brain physiology.

METHODS

In this study, we used coefficient of variation (CV) of critically sampled 10 Hz ultra-fast fMRI (magnetoencephalography, MREG) signal to compare physiological variance between healthy controls (n = 10) and patients (n = 10) with drug-resistant epilepsy (DRE).

RESULTS

We showed highly significant voxel-level (p < 0.01, TFCE-corrected) increase in the physiological variance in DRE patients. At individual level, the elevations range over three standard deviations (σ) above the control mean (μ) CV_MREG values solely in DRE patients, enabling patient-specific mapping of elevated physiological variance. The most apparent differences in group-level analysis are found on white matter, brainstem, and cerebellum. Respiratory (0.12-0.4 Hz) and very-low-frequency (VLF = 0.009-0.1 Hz) signal variances were most affected.

CONCLUSIONS

The CV_MREG increase was not explained by head motion or physiological cardiorespiratory activity, that is, it seems to be linked to intrinsic physiological pulsations. We suggest that intrinsic brain pulsations play a role in DRE and that critically sampled fMRI may provide a powerful tool for their identification.

An Ontology Systems Approach on Human Brain Expression and Metaproteomics

Research in the last decade has shown growing evidence of the gut microbiota influence on brain physiology. While many mechanisms of this influence have been proposed in animal models, most studies in humans are the result of a pathology–dysbiosis association and very few have related the presence of certain taxa with brain substructures or molecular pathways. In this paper, we associated the functional ontologies in the differential expression of brain substructures from the Allen Brain Atlas database, with those of the metaproteome from the Human Microbiome Project. Our results showed several coherent clustered ontologies where many taxa could influence brain expression and physiology. A detailed analysis of psychobiotics showed specific slim ontologies functionally associated with substructures in the basal ganglia and cerebellar cortex. Some of the most relevant slim ontology groups are related to Ion transport, Membrane potential, Synapse, DNA and RNA metabolism, and Antigen processing, while the most relevant neuropathology found was Parkinson disease. In some of these cases, new hypothetical gut microbiota-brain interaction pathways are proposed.

The International Multidisciplinary Consensus Conference on Multimodality Monitoring in Neurocritical Care: evidentiary tables: a statement for healthcare professionals from the Neurocritical Care Society and the European Society of Intensive Care Medicine

A variety of technologies have been developed to assist decision-making during the management of patients with acute brain injury who require intensive care. A large body of research has been generated describing these various technologies. The Neurocritical Care Society (NCS) in collaboration with the European Society of Intensive Care Medicine (ESICM), the Society for Critical Care Medicine (SCCM), and the Latin America Brain Injury Consortium (LABIC) organized an international, multidisciplinary consensus conference to perform a systematic review of the published literature to help develop evidence-based practice recommendations on bedside physiologic monitoring. This supplement contains a Consensus Summary Statement with recommendations and individual topic reviews on physiologic processes important in the care of acute brain injury. In this article we provide the evidentiary tables for select topics including systemic hemodynamics, intracranial pressure, brain and systemic oxygenation, EEG, brain metabolism, biomarkers, processes of care and monitoring in emerging economies to provide the clinician ready access to evidence that supports recommendations about neuromonitoring.

Consensus summary statement of the International Multidisciplinary Consensus Conference on Multimodality Monitoring in Neurocritical Care: a statement for healthcare professionals from the Neurocritical Care Society and the European Society of Intensive Care Medicine

Neurocritical care depends, in part, on careful patient monitoring but as yet there are little data on what processes are the most important to monitor, how these should be monitored, and whether monitoring these processes is cost-effective and impacts outcome. At the same time, bioinformatics is a rapidly emerging field in critical care but as yet there is little agreement or standardization on what information is important and how it should be displayed and analyzed. The Neurocritical Care Society in collaboration with the European Society of Intensive Care Medicine, the Society for Critical Care Medicine, and the Latin America Brain Injury Consortium organized an international, multidisciplinary consensus conference to begin to address these needs. International experts from neurosurgery, neurocritical care, neurology, critical care, neuroanesthesiology, nursing, pharmacy, and informatics were recruited on the basis of their research, publication record, and expertise. They undertook a systematic literature review to develop recommendations about specific topics on physiologic processes important to the care of patients with disorders that require neurocritical care. This review does not make recommendations about treatment, imaging, and intraoperative monitoring. A multidisciplinary jury, selected for their expertise in clinical investigation and development of practice guidelines, guided this process. The GRADE system was used to develop recommendations based on literature review, discussion, integrating the literature with the participants' collective experience, and critical review by an impartial jury. Emphasis was placed on the principle that recommendations should be based on both data quality and on trade-offs and translation into clinical practice. Strong consideration was given to providing pragmatic guidance and recommendations for bedside neuromonitoring, even in the absence of high quality data.

Event-related brain potential correlates of two states of conscious awareness in memory

We report an event-related potential (ERP) experiment of human recognition memory that explored the relation between conscious awareness and electrophysiological activity of the brain. We recorded ERPs from healthy adults while they made "remember" and "know" recognition judgments about previously seen words. These two kinds of judgments reflect "autonoetic" and "noetic" awareness, respectively. The ERP effects differed between the two kinds of awareness while they were similar for "true" and "false" recognition. Noetic awareness was associated with a temporoparietal positivity in the N400 range (325-600 ms) and a late (600-1,000 ms) frontocentral negativity, whereas autonoetic awareness was associated with a widespread, late, bifrontal and left parietotemporal (600-1000 ms) positivity. In the very late (1,300-1, 900 ms) time window, a right frontal positivity was observed for both remember and know judgments of both true and false targets. These results provide physiological evidence for two types of conscious awareness in episodic memory retrieval.