Wake EEG and Sleep Hypoxemia Predicts Poor Driving and Vigilance Following Extended Wakefulness in People With OSA.

Obstructive sleep apnoea (OSA) is a highly prevalent but heterogeneous condition which makes identifying patients at risk of vigilance and driving impairment clinically challenging. Resting wake electroencephalography (EEG) is associated with vigilance performance in healthy participants. We examined if rested wake EEG predicted vigilance and driving impairment in OSA following extended wakefulness.

The Acute Effects of Non-concussive Head Impacts on Brain Microstructure, Chemistry and Function in Male Soccer Players: A Pilot Randomised Controlled Trial.

Background: Head impacts, particularly, non-concussive impacts, are common in sport. Yet, their effects on the brain remain poorly understood. Here, we investigated the acute effects of non-concussive impacts on brain microstructure, chemistry, and function using magnetic resonance imaging (MRI) and other techniques.

Aspartate in the Brain: A Review.

L-Aspartate (aspartic acid; CHNO; 2-aminobutanedoic acid) is a non-essential α-amino acid found ubiquitously throughout the body, including in the brain. Aspartate is one of the protein-forming amino acids and the formation of tRNA-aspartate complex is catalysed by aspartyl tRNA synthetase. Free aspartate, which is the main subject of this review, plays key roles in metabolism, as an amino donor and acceptor.

Glutamine transport via amino acid transporter NTT4 (SLC6A17) maintains presynaptic glutamate supply at excitatory synapses in the CNS.

The glutamate-glutamine cycle is thought to be the principle metabolic pathway that recycles glutamate at synapses. In this cycle, synaptically released glutamate is sequestered by astrocytes and forms glutamine, before being returned to the presynaptic terminal for conversion back into glutamate to replenish the neurotransmitter pool. While many aspects of this cycle are established, a key component remains unknown: the nature of the transporter responsible for the presynaptic uptake of glutamine.

Childhood muscle growth: Reference curves for lower leg muscle volumes and their clinical application in cerebral palsy.

Skeletal muscles grow substantially during childhood. However, quantitative information about the size of typically developing children's muscles is sparse. Here, the objective was to construct muscle-specific reference curves for lower leg muscle volumes in children aged 5 to 15 y.

The Effect of Cranial Sutures Should Be Considered in Transcranial Electrical Stimulation.

Background: Computational modeling is used to optimize transcranial electrical stimulation (tES) approaches, and the precision of these models is dependent on their anatomical accuracy. We are unaware of any computational modeling of tES that has included cranial sutures.

Objectives: The aims of the study were to review the literature on the timing of closure of the coronal and squamous sutures, which are situated under electrode placements used in tES; to review the literature regarding differences in skull and suture conductivity and to determine a more accurate conductivity for sutures; and to identify magnetic resonance image (MRI) techniques that could be used to detect cranial sutures.

Glutamate concentrations and cognitive deficits in ultra-treatment-resistant schizophrenia: An exploratory and comparative H-MRS study.

Background And Aims: Glutamate plays a crucial role in cognition, learning, and mood regulation, with studies suggesting glutamatergic dysfunction in chronic schizophrenia. This study explored glutamate levels in the occipital cortex (OCC) and cognitive function in ultra-treatment resistant schizophrenia (uTRS) compared to healthy controls.

Methods: Fifteen uTRS participants and 19 healthy controls underwent 3T proton magnetic resonance spectroscopy (H-MRS) to measure glutamate levels in the OCC.

L-Proline Alters Energy Metabolism in Brain Cortical Tissue Slices.

L-Proline (L-Pro) is a non-essential amino acid which, in high concentrations, can cause neurological problems including seizures, although the causative mechanism for this is unclear. Here, we studied the impact of physiological levels of proline on brain energy metabolism and investigated the metabolism of L-Pro itself, using the cortical brain tissue slice and stable isotope labelling from [1- C]glucose and [1,2- C]acetate detected by NMR spectroscopy and LCMS. L-Pro was actively taken up by the slices and significantly reduced the total metabolic pools of all measured metabolites with glutamine the least affected, while reducing net flux of C into glycolytic byproducts (lactate and alanine).

Functional conductivity imaging: quantitative mapping of brain activity.

Theory and modelling suggest that detection of neuronal activity may be feasible using phase sensitive MRI methods. Successful detection of neuronal activity both in vitro and in vivo has been described while others have reported negative results. Magnetic resonance electrical properties tomography may be a route by which signal changes can be identified.

Effect of Ethanol on Brain Electrical Tissue Conductivity in Social Drinkers.

Background: How the biophysics of electrical conductivity measures relate to brain activity is poorly understood. The sedative, ethanol, reduces metabolic activity but its impact on brain electrical conductivity is unknown.

Purpose: To investigate whether ethanol reduces brain electrical tissue conductivity.

Brain energy metabolism: A roadmap for future research.

Although we have learned much about how the brain fuels its functions over the last decades, there remains much still to discover in an organ that is so complex. This article lays out major gaps in our knowledge of interrelationships between brain metabolism and brain function, including biochemical, cellular, and subcellular aspects of functional metabolism and its imaging in adult brain, as well as during development, aging, and disease. The focus is on unknowns in metabolism of major brain substrates and associated transporters, the roles of insulin and of lipid droplets, the emerging role of metabolism in microglia, mysteries about the major brain cofactor and signaling molecule NAD, as well as unsolved problems underlying brain metabolism in pathologies such as traumatic brain injury, epilepsy, and metabolic downregulation during hibernation.

AMP-activated protein kinase activators have compound and concentration-specific effects on brain metabolism.

AMP-activated protein kinase (AMPK) is a key sensor of energy balance playing important roles in the balancing of anabolic and catabolic activities. The high energy demands of the brain and its limited capacity to store energy indicate that AMPK may play a significant role in brain metabolism. Here, we activated AMPK in guinea pig cortical tissue slices, both directly with A769662 and PF 06409577 and indirectly with AICAR and metformin.

Details matter in quality science. Adopting a checklist for magnetic resonance spectroscopy can help you get them right.

The ISMRM study group on magnetic resonance spectroscopy has produced recommendations for reporting methods. The Journal of Neurochemistry has decided to encourage the use of the checklist for these standards by authors and reviewers in order to improve reproducibility and reliability of the science, make it easier for reviewers and to help educate the scientific community. Here, we explain why getting the details right is important.

Elevation of cell-associated HIV-1 transcripts in CSF CD4+ T cells, despite effective antiretroviral therapy, is linked to brain injury.

Antiretroviral therapy (ART) can attain prolonged undetectable HIV-1 in plasma and cerebrospinal fluid (CSF), but brain injury remains prevalent in people living with HIV-1 infection (PLHIV). We investigated cell-associated (CA)-HIV-1 RNA transcripts in cells in CSF and blood, using the highly sensitive Double-R assay, together with proton Magnetic Resonance Spectroscopy (H MRS) of major brain metabolites, in sixteen PLHIV. 14/16 CSF cell samples had quantifiable CA-HIV-1 RNA, at levels significantly higher than in their PBMCs (median 9,266 vs 185 copies /106 CD4+ T-cells; p<0.

Motor cortical excitability and pre-supplementary motor area neurochemistry in healthy adults with substantia nigra hyperechogenicity.

Substantia nigra (SN) hyperechogenicity, viewed with transcranial ultrasound, is a risk marker for Parkinson's disease. We hypothesized that SN hyperechogenicity in healthy adults aged 50-70 years is associated with reduced short-interval intracortical inhibition in primary motor cortex, and that the reduced intracortical inhibition is associated with neurochemical markers of activity in the pre-supplementary motor area (pre-SMA). Short-interval intracortical inhibition and intracortical facilitation in primary motor cortex was assessed with paired-pulse transcranial magnetic stimulation in 23 healthy adults with normal (n = 14; 61 ± 7 yrs) or abnormally enlarged (hyperechogenic; n = 9; 60 ± 6 yrs) area of SN echogenicity.

Impact of Inhibition of Glutamine and Alanine Transport on Cerebellar Glial and Neuronal Metabolism.

The cerebellum, or "little brain", is often overlooked in studies of brain metabolism in favour of the cortex. Despite this, anomalies in cerebellar amino acid homeostasis in a range of disorders have been reported. Amino acid homeostasis is central to metabolism, providing recycling of carbon backbones and ammonia between cell types.

Corrigendum: Reduced Glutamate in the Medial Prefrontal Cortex Is Associated With Emotional and Cognitive Dysregulation in People With Chronic Pain.

[This corrects the article DOI: 10.3389/fneur.2019.

Brain aging and cardiovascular factors in HIV: a longitudinal volume and shape MRI study.

Objective: We aimed to examine the relative contributions of HIV infection, age, and cardiovascular risk factors to subcortical brain atrophy in people with HIV (PWH).

Design: Longitudinal observational study.

Methods: Virally suppressed PWH with low neuropsychological confounds (n  = 75) and demographically matched HIV-negative controls (n = 31) completed baseline and 18-month follow-up MRI scans, neuropsychological evaluation, cardiovascular assessments, and HIV laboratory tests.

Clinical predictors of working memory performance in obstructive sleep apnea patients before and during extended wakefulness.

Study Objectives: Extended wakefulness (EW) and obstructive sleep apnea (OSA) impair working memory (WM), but their combined effects are unclear. This study examined the impact of EW on WM function in OSA patients and identified clinical predictors of WM impairment.

Methods: Following polysomnography (PSG), 56 OSA patients (mean ± SD, age 49.

Brain mitochondrial dysfunction and driving simulator performance in untreated obstructive sleep apnea.

It is challenging to determine which patients with obstructive sleep apnea (OSA) have impaired driving ability. Vulnerability to this neurobehavioral impairment may be explained by lower brain metabolites levels involved in mitochondrial metabolism. This study compared markers of brain energy metabolism in OSA patients identified as vulnerable vs resistant to driving impairment following extended wakefulness.

Frequency drift in MR spectroscopy at 3T.

Purpose: Heating of gradient coils and passive shim components is a common cause of instability in the B field, especially when gradient intensive sequences are used. The aim of the study was to set a benchmark for typical drift encountered during MR spectroscopy (MRS) to assess the need for real-time field-frequency locking on MRI scanners by comparing field drift data from a large number of sites.

Method: A standardized protocol was developed for 80 participating sites using 99 3T MR scanners from 3 major vendors.

Disruption to normal excitatory and inhibitory function within the medial prefrontal cortex in people with chronic pain.

Background: Growing evidence indicates a link between changes in the medial prefrontal cortex and the pathophysiology of chronic pain. In particular, chronic pain is associated with altered medial prefrontal anatomy and biochemistry. Due to the comorbid affective disorders seen across all pain conditions, the medial prefrontal cortex is a region of significance as it is involved in emotional processing.

Emerging Concepts in Vector Development for Glial Gene Therapy: Implications for Leukodystrophies.

Central Nervous System (CNS) homeostasis and function rely on intercellular synchronization of metabolic pathways. Developmental and neurochemical imbalances arising from mutations are frequently associated with devastating and often intractable neurological dysfunction. In the absence of pharmacological treatment options, but with knowledge of the genetic cause underlying the pathophysiology, gene therapy holds promise for disease control.

Sleep spindle activity correlates with implicit statistical learning consolidation in untreated obstructive sleep apnea patients.

Objective/background: The aim of this study was to examine the relationship between overnight consolidation of implicit statistical learning with spindle frequency EEG activity and slow frequency delta power during non-rapid eye movement (NREM) sleep in obstructive sleep apnea (OSA).

Patients/methods: Forty-seven OSA participants completed the experiment. Prior to sleep, participants performed a reaction time cover task containing hidden patterns of pictures, about which participants were not informed.