Absence of systematic relationships between REMS duration episodes and spectral power Delta and Ultra-Slow bands in contiguous NREMS episodes in healthy humans

2013 ◽  
Vol 110 (1) ◽  
pp. 162-169 ◽  
Author(s):  
O. Le Bon ◽  
P. Linkowski
Keyword(s):  
Spectral Power ◽  
Sleep Cycle ◽  
Consecutive Series ◽  
Sleep Regulation ◽  
Healthy Human ◽  
Sleep Quantity ◽  
Healthy Humans ◽  
Crucial Component ◽  
Sleep Physiology ◽  
Human Participants

Previous studies in animals and humans have reported correlations between the durations of rapid eye movement sleep (REMS) episodes and immediately preceding or subsequent non-REMS (NREMS) episodes. The relationship between these two types of sleep is a crucial component in understanding the regulation and neurophysiology of ultradian alternations that occur during sleep. Although the present study replicated previous studies, we also measured NREMS in terms of spectral power Delta and Ultra-Slow bands in addition to duration in examining correlations. The spectral power Delta band, also known as slow-wave activity, measures sleep quantity and is believed to reflect sleep physiology better than mere episode durations. The Ultra-Slow spectral power band was analyzed in parallel. Healthy human participants of both sexes ( n = 26, age range 15–45 yr, n = 12 female) were carefully selected to participate in two consecutive series of home polysomnograms performed after 2 nights of habituation to the equipment. In the analyses, REMS episode durations (minutes) were compared with immediately preceding and immediately subsequent NREMS episodes (Delta and Ultra-Slow power) in each sleep cycle. REMS episode duration was more strongly correlated with preceding NREMS episodes than with subsequent NREMS episodes. However, in most cases, no correlations were observed in either direction. One ultradian sleep regulation hypothesis, which is based on stronger correlations between REMS and subsequent NREMS episode durations, holds that the main purpose of REMS is to reactivate NREMS during each sleep cycle. The present results do not support that hypothesis.

scholarly journals (Lack of) Effects of noradrenergic stimulation on human working memory performance

2020 ◽  
Vol 237 (10) ◽  
pp. 3033-3046
Author(s):  
Nadine Wanke ◽  
Jana Christina Müller ◽  
Klaus Wiedemann ◽  
Lars Schwabe
Keyword(s):  
Working Memory ◽  
Spatial Working Memory ◽  
Memory Performance ◽  
Interactive Effect ◽  
Control Group ◽  
Healthy Human ◽  
Double Blind ◽  
Healthy Humans ◽  
Before And After ◽  
Human Participants

Abstract Rationale Working memory depends on prefrontal cortex functioning, which is particularly sensitive to levels of noradrenaline. Studies in non-human primates have shown that modest levels of noradrenaline improve working memory, and that higher levels of noradrenaline impair working memory performance. However, research in humans provided inconsistent findings concerning noradrenergic effects on working memory. Objective The present study aimed at assessing dose-dependent effects of yohimbine, an alpha-2 adrenoceptor antagonist, on working memory performance in healthy humans. We further aimed to explore a potential interactive effect between noradrenergic arousal and lack of control over aversive events on working memory performance. Methods We used a double-blind, fully crossed, placebo-controlled, between-subject design. Participants (N = 121) performed an adaptive n-back task before and after oral administration of either a placebo, 20 mg, or 40 mg yohimbine and a manipulation of controllability, during which participants could either learn to avoid electric shocks (controllability groups), had no instrumental control over shock administration (uncontrollability groups), or did not receive any shocks (no-shock control group). Results While no significant results of noradrenergic stimulation through yohimbine were obtained using conventional frequentist analyses, additional Bayesian analyses provided strong evidence for the absence of an association between pharmacological treatment and working memory performance. We further observed no effect of controllability and no interaction between noradrenergic stimulation and the manipulation of controllability. Conclusions Our results suggest that noradrenergic stimulation through yohimbine does not affect (non-spatial) working memory in healthy human participants.

scholarly journals Testing the effects of Δ9-THC and D-cycloserine on extinction of conditioned fear in humans

2012 ◽  
Vol 26 (4) ◽  
pp. 471-478 ◽  
Author(s):  
Floris Klumpers ◽  
Damiaan Denys ◽  
J Leon Kenemans ◽  
Christian Grillon ◽  
Jasper van der Aart ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Receptor Agonist ◽  
Cannabinoid Receptor ◽  
Human Subjects ◽  
Conditioned Fear ◽  
Healthy Human ◽  
Healthy Humans ◽  
Fear Potentiated Startle ◽  
Human Participants ◽  
Carry Over

Preclinical evidence implicates several neurotransmitter systems in the extinction of conditioned fear. These results are of great interest, because the reduction of acquired fear associations is critical in therapies for anxiety disorders. We tested whether findings with respect to the N-methyl-D-aspartate (NMDA) and cannabinoid receptor (CB) systems in animals carry over to healthy human subjects. To that end, we administered selected doses of D-cycloserine (partial NMDA receptor agonist, 250 mg), delta-9-tetrahydrocannabinol (THC, CB1 receptor agonist, 10 mg), or placebo prior to the extinction session of a 3-day conditioning protocol. D-cycloserine did not affect within-session extinction, or the retention of extinction in healthy human participants, in contrast with patient data but in line with previous reports in healthy volunteers. During extinction training, Δ9-THC reduced conditioned skin conductance responses, but not fear-potentiated startle. This effect was not retained at the retention test 2 days later, suggesting it was dependent on acute effects of the drug. Our findings implicate that facilitation of the CB1 or NMDA system with the substances used in this study does not affect conditioned fear extinction lastingly in healthy humans. The apparent discrepancy between these findings and the results from (pre-)clinical trials is discussed in terms of room for improvement in these systems in healthy volunteers, and the lack of specificity of THC as a CB1 agonist.

scholarly journals An Analysis of the External Validity of EEG Spectral Power in an Uncontrolled Outdoor Environment during Default and Complex Neurocognitive States

2021 ◽  
Vol 11 (3) ◽  
pp. 330
Author(s):  
Dalton J. Edwards ◽  
Logan T. Trujillo
Keyword(s):  
External Validity ◽  
Spectral Power ◽  
Brain Activity ◽  
Outdoor Environment ◽  
Oscillatory Activity ◽  
Brain State ◽  
Beta Band ◽  
Eeg Spectral Power ◽  
Eeg Power ◽  
Human Participants

Traditionally, quantitative electroencephalography (QEEG) studies collect data within controlled laboratory environments that limit the external validity of scientific conclusions. To probe these validity limits, we used a mobile EEG system to record electrophysiological signals from human participants while they were located within a controlled laboratory environment and an uncontrolled outdoor environment exhibiting several moderate background influences. Participants performed two tasks during these recordings, one engaging brain activity related to several complex cognitive functions (number sense, attention, memory, executive function) and the other engaging two default brain states. We computed EEG spectral power over three frequency bands (theta: 4–7 Hz, alpha: 8–13 Hz, low beta: 14–20 Hz) where EEG oscillatory activity is known to correlate with the neurocognitive states engaged by these tasks. Null hypothesis significance testing yielded significant EEG power effects typical of the neurocognitive states engaged by each task, but only a beta-band power difference between the two background recording environments during the default brain state. Bayesian analysis showed that the remaining environment null effects were unlikely to reflect measurement insensitivities. This overall pattern of results supports the external validity of laboratory EEG power findings for complex and default neurocognitive states engaged within moderately uncontrolled environments.

scholarly journals Sex-related differences in response to masseteric injections of glutamate and nerve growth factor in healthy human participants

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abdelrahman M. Alhilou ◽  
Akiko Shimada ◽  
Camilla I. Svensson ◽  
Peter Svensson ◽  
Malin Ernberg ◽  
...  
Keyword(s):  
Nmda Receptors ◽  
Nerve Fiber ◽  
Masseter Muscle ◽  
Pain Sensitivity ◽  
Nerve Fibers ◽  
Receptor Expression ◽  
Healthy Human ◽  
Neurophysiological Mechanisms ◽  
Human Participants ◽  
Positive Correlations

AbstractThe neurophysiological mechanisms underlying NGF-induced masseter muscle sensitization and sex-related differences in its effect are not well understood in humans. Therefore, this longitudinal cohort study aimed to investigate the effect of NGF injection on the density and expression of substance P, NMDA-receptors and NGF by the nerve fibers in the human masseter muscle, to correlate expression with pain characteristics, and to determine any possible sex-related differences in these effects of NGF. The magnitude of NGF-induced mechanical sensitization and pain during oral function was significantly greater in women than in men (P < 0.050). Significant positive correlations were found between nerve fiber expression of NMDA-receptors and peak pain intensity (rs = 0.620, P = 0.048), and expression of NMDA-receptors by putative nociceptors and change in temporal summation pain after glutamate injection (rs = 0.561, P = 0.003). In women, there was a significant inverse relationship between the degree of NGF-induced mechanical sensitization and the change in nerve fiber expression of NMDA-receptors alone (rs = − 0.659, P = 0.013), and in combination with NGF (rs = − 0.764, P = 0.001). In conclusion, women displayed a greater magnitude of NGF-induced mechanical sensitization that also was associated with nerve fibers expression of NMDA-receptors, when compared to men. The present findings suggest that, in women, increased peripheral NMDA-receptor expression could be associated with masseter muscle pain sensitivity.

Decoupling countermands nonselective response inhibition during selective stopping

2021 ◽  
Author(s):  
Corey George Wadsley ◽  
John Cirillo ◽  
Arne Nieuwenhuys ◽  
Winston D Byblow
Keyword(s):  
Response Inhibition ◽  
Interference Effect ◽  
Complex Form ◽  
Functional Coupling ◽  
Response Preparation ◽  
Response Delay ◽  
Healthy Human ◽  
Human Participants ◽  
Goal Directed Behavior ◽  
Effector Response

Response inhibition is essential for goal-directed behavior within dynamic environments. Selective stopping is a complex form of response inhibition where only part of a multi-effector response must be cancelled. A substantial response delay emerges on unstopped effectors when a cued effector is successfully stopped. This stopping-interference effect is indicative of nonselective response inhibition during selective stopping which may, in-part, be a consequence of functional coupling. The present study examined selective stopping of (de)coupled bimanual responses in healthy human participants of either sex. Participants performed synchronous and asynchronous versions of an anticipatory stop-signal paradigm across two sessions while mu (µ) and beta (β) rhythm were measured with electroencephalography. Results showed that responses were behaviorally decoupled during asynchronous go trials and the extent of response asynchrony was associated with lateralized sensorimotor µ and β desynchronization during response preparation. Selective stopping produced a stopping-interference effect and was marked by a nonselective increase and subsequent rebound in prefrontal and sensorimotor β. In support of the coupling account, stopping-interference was smaller during selective stopping of asynchronous responses, and negatively associated with the magnitude of decoupling. However, the increase in sensorimotor β during selective stopping was equivalent between the stopped and unstopped hand irrespective of response synchrony. Overall, the findings demonstrate that decoupling facilitates selective stopping after a global pause process and emphasizes the importance of considering the influence of both the go and stop context when investigating response inhibition.

scholarly journals Genotypic and Phenotypic Traits That Distinguish Neonatal Meningitis-Associated Escherichia coli from Fecal E. coli Isolates of Healthy Human Hosts

2012 ◽  
Vol 78 (16) ◽  
pp. 5824-5830 ◽  
Author(s):  
Catherine M. Logue ◽  
Curt Doetkott ◽  
Paul Mangiamele ◽  
Yvonne M. Wannemuehler ◽  
Timothy J. Johnson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Phylogenetic Group ◽  
Neonatal Meningitis ◽  
Phenotypic Traits ◽  
Healthy Human ◽  
Content Type ◽  
Plasmid Content ◽  
E Coli ◽  
Healthy Humans ◽  
Definition Of

ABSTRACTNeonatal meningitisEscherichia coli(NMEC) is one of the top causes of neonatal meningitis worldwide. Here, 85 NMEC and 204 fecalE. coliisolates from healthy humans (HFEC) were compared for possession of traits related to virulence, antimicrobial resistance, and plasmid content. This comparison was done to identify traits that typify NMEC and distinguish it from commensal strains to refine the definition of the NMEC subpathotype, identify traits that might contribute to NMEC pathogenesis, and facilitate choices of NMEC strains for future study. A large number ofE. colistrains from both groups were untypeable, with the most common serogroups occurring among NMEC being O18, followed by O83, O7, O12, and O1. NMEC strains were more likely than HFEC strains to be assigned to the B2 phylogenetic group. Few NMEC or HFEC strains were resistant to antimicrobials. Genes that best discriminated between NMEC and HFEC strains and that were present in more than 50% of NMEC isolates were mainly from extraintestinal pathogenicE. coligenomic and plasmid pathogenicity islands. Several of these defining traits had not previously been associated with NMEC pathogenesis, are of unknown function, and are plasmid located. Several genes that had been previously associated with NMEC virulence did not dominate among the NMEC isolates. These data suggest that there is much about NMEC virulence that is unknown and that there are pitfalls to studying single NMEC isolates to represent the entire subpathotype.

scholarly journals Capsule Formulation of Ethanolic Extract of Pasak Bumi (Eurycoma Longifolia Jack.,) and its Effect on Human Health Vital Signs

2017 ◽  
Vol 22 (2) ◽  
pp. 91
Author(s):  
Laela Hayu Nurani ◽  
Eka Kumalasari ◽  
Abdul Rohman ◽  
Sitarina Widyarini
Keyword(s):  
Bitter Taste ◽  
Vital Signs ◽  
Ethanolic Extract ◽  
Ethanol Extract ◽  
Inclusion Criteria ◽  
Capsule Formulation ◽  
Healthy Human ◽  
Eurycoma Longifolia ◽  
Healthy Humans ◽  
Eurycoma Longifolia Jack

Pasak bumi (Eurycoma longifolia) has the potential to be developed as antihypertensive, antipyretic, aphrodisiacs and health supplements. The use of E. longifolia as a traditional medicine needs to be pursued in the form of more effective and appropriate formulation. The capsule preparations are easy to make and cancover the bitter taste of E. longifolia. Clinical trials in this study use design pre-post treatment in healthy humans. Subjects used were male - healthy men and healthy women who met inclusion criteria and were subjected with formulated capsule for 14 days. The study resulted capsule formula comprising of the ethanolic extract of E. longifolia 300 mg, vivapur 101 300 mg, 58 mg maydis starch, aerosil 3%, talc 2%, and Mg stearate 1%. The results showed that the capsule of E. longifolia did not affect the value of heart rate, respiration rate, body temperature and weight (P > 0.05), based on paired t-test, but they causes a decrease in blood pressure of healthy human. The ethanol extract of E. longifolia caused vasodilation of blood vessels that can be used in antihypertensive therapy.

scholarly journals Antioxidant Activity with Increased Endogenous Levels of Vitamin C, E and A Following Dietary Supplementation with a Combination of Glutathione and Resveratrol Precursors

Nutrients ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3224 ◽  
Author(s):  
Priscilla Biswas ◽  
Cinzia Dellanoce ◽  
Alessandra Vezzoli ◽  
Simona Mrakic-Sposta ◽  
Mauro Malnati ◽  
...  
Keyword(s):  
Dietary Supplements ◽  
Immune Status ◽  
Inflammatory Marker ◽  
Dietary Supplementation ◽  
Positive Outcome ◽  
Redox Status ◽  
Healthy Human ◽  
Treatment Groups ◽  
Human Participants ◽  
Endogenous Synthesis

The effects of two different dietary supplements on the redox status of healthy human participants were evaluated. The first supplement (GluS, Glutathione Synthesis) contains the precursors for the endogenous synthesis of glutathione and the second (GluReS, Glutathione and Resveratrol Synthesis) contains in addition polydatin, a precursor of resveratrol. To assess the influence of GluS and GluReS on the redox status, ten thiol species and three vitamins were measured before (t0) and after 8 weeks (t1) of dietary supplementation. An inflammatory marker, neopterin, was also assessed at the same time points. Both supplements were highly effective in improving the redox status by significantly increasing the reduced-glutathione (GSH) content and other reduced thiol species while significantly decreasing the oxidized species. The positive outcome of the redox status was most significant in the GluRes treatment group which also experienced a significant reduction in neopterin levels. Of note, the endogenous levels of vitamins C, E and A were significantly increased in both treatment groups, with best results in the GluReS group. While both dietary supplements significantly contributed to recognized antioxidant and anti-inflammatory outcomes, the effects of GluReS, the combination of glutathione and resveratrol precursors, were more pronounced. Thus, dietary supplementation with GluReS may represent a valuable strategy for maintaining a competent immune status and a healthy lifespan.

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