scholarly journals Brain preparedness: The proactive role of the cortisol awakening response

2020 ◽  
Author(s):  
Bingsen Xiong ◽  
Changming Chen ◽  
Yanqiu Tian ◽  
Shouwen Zhang ◽  
Chao Liu ◽  
...  
Keyword(s):  
Memory Performance ◽  
Blood Oxygen Level Dependent ◽  
Causal Link ◽  
Causal Modeling ◽  
Cortisol Awakening Response ◽  
Functional Coupling ◽  
Double Blind ◽  
Randomized Design ◽  
Proactive Effects ◽  
Proactive Role

AbstractUpon awakening from nighttime sleep, the stress hormone cortisol exhibits a burst in the morning within 30-minutes in humans. This cortisol awakening response (CAR) is thought to prepare the brain for upcoming challenges. Yet, the neurobiological mechanisms underlying the CAR-mediated ‘preparation’ function remains unknown. Using blood-oxygen-level-dependent functional magnetic resonance imaging (BOLD-fMRI) with a dedicated prospective design and pharmacological manipulation, we investigated this proactive mechanism in humans across two fMRI studies. In Study 1, we found that a robust CAR was predictive of less hippocampal and prefrontal activity, though enhanced functional coupling between those regions and facilitated working memory performance, during a demanding task later in the afternoon. These results implicate the CAR in proactively promoting brain preparedness based on improved neural efficiency. To address the causality of this proactive effect, we conducted a second study (Study 2) in which we suppressed the CAR with a double blind, placebo controlled, randomized design using Dexamethasone. We found that pharmacological suppression of CAR mirrored the proactive effects from Study 1. Dynamic causal modeling analyses further revealed a reduction of prefrontal top-down modulation over hippocampal activity when performing a cognitively demanding task in the afternoon. These findings establish a causal link between the CAR and its proactive role in optimizing brain functional networks involved in neuroendocrine control and memory.

scholarly journals Effects of transcranial static magnetic stimulation over the primary motor cortex on local and network spontaneous electroencephalogram oscillations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sumiya Shibata ◽  
Tatsunori Watanabe ◽  
Yoshihiro Yukawa ◽  
Masatoshi Minakuchi ◽  
Ryota Shimomura ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Power Spectrum ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Controlled Study ◽  
Functional Coupling ◽  
Phase Lag ◽  
Theta Band ◽  
Double Blind

AbstractTranscranial static magnetic stimulation (tSMS) is a novel non-invasive brain stimulation technique that reduces cortical excitability at the stimulation site. We investigated the effects of tSMS over the left primary motor cortex (M1) for 20 min on the local electroencephalogram (EEG) power spectrum and interregional EEG coupling. Twelve right-handed healthy subjects participated in this crossover, double-blind, sham-controlled study. Resting-state EEG data were recorded for 3 min before the intervention and 17 min after the beginning of the intervention. The power spectrum at the left central electrode (C3) and the weighted phase lag index (wPLI) between C3 and the other electrodes was calculated for theta (4–8 Hz), alpha (8–12 Hz), and beta (12–30 Hz) frequencies. The tSMS significantly increased theta power at C3 and the functional coupling in the theta band between C3 and the parietal midline electrodes. The tSMS over the left M1 for 20 min exhibited modulatory effects on local cortical activity and interregional functional coupling in the theta band. The neural oscillations in the theta band may have an important role in the neurophysiological effects induced by tSMS over the frontal cortex.

Cholinergic Influences on Use-Dependent Plasticity

2002 ◽  
Vol 87 (1) ◽  
pp. 166-171 ◽  
Author(s):  
L. Sawaki ◽  
B. Boroojerdi ◽  
A. Kaelin-Lang ◽  
A. H. Burstein ◽  
C. M. Bütefisch ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Motor System ◽  
Global Changes ◽  
Double Blind ◽  
Double Blind Placebo ◽  
Corticomotor Excitability ◽  
Dependent Plasticity ◽  
Motor Practice ◽  
Randomized Design ◽  
Human Motor

Motor practice elicits use-dependent plasticity in humans as well as in animals. Given the influence of cholinergic neurotransmission on learning and memory processes, we evaluated the effects of scopolamine (a muscarinic receptor antagonist) on use-dependent plasticity and corticomotor excitability in a double-blind placebo-controlled randomized design study. Use-dependent plasticity was substantially attenuated by scopolamine in the absence of global changes in corticomotor excitability. These results identify a facilitatory role for cholinergic influences in use-dependent plasticity in the human motor system.

Greater Occipital Nerve Stimulation Boosts Associative Memory in Older Individuals: A Randomized Trial

2020 ◽  
Vol 34 (11) ◽  
pp. 1020-1029
Author(s):  
Alison M. Luckey ◽  
S. Lauren McLeod ◽  
Ian H. Robertson ◽  
Wing Ting To ◽  
Sven Vanneste
Keyword(s):  
The Other ◽  
Transcutaneous Electrical Stimulation ◽  
Older Individuals ◽  
Occipital Nerve Stimulation ◽  
Double Blind ◽  
New Approach ◽  
Occipital Nerve ◽  
Randomized Design ◽  
Greater Occipital Nerve ◽  
The Brain

Transcutaneous electrical stimulation (tES) is a new approach that aims to stimulate the brain. Recently, we have developed tES approaches to enhance plasticity that modulate cortical activity via the greater occipital nerve (ON) in a “bottom-up” way. Thirty subjects between the ages of 55 and 70 years were enrolled and tested using a double-blind, sham-controlled, and randomized design. Half of the participants received active stimulation, while the other half received sham stimulation. Our results demonstrate that ON-tES can enhance memory in older individuals after one session, with effects persisting up to 28 days after stimulation. The hypothesized mechanism by which ON-tES enhances memory is activation of the locus coeruleus–noradrenaline (LC-NA) pathway. It is likely that this pathway was activated after ON-tES, as supported by observed changes in α-amylase concentrations, a biomarker for noradrenaline. There were no significant or long-lasting side effects observed during stimulation. Clinicaltrial.gov (NCT03467698).

Effects of repetitive paired associative stimulation on brain plasticity and working memory in Alzheimer’s disease: a pilot randomized double-blind-controlled trial

2020 ◽  
pp. 1-13
Author(s):  
Sanjeev Kumar ◽  
Reza Zomorrodi ◽  
Zaid Ghazala ◽  
Michelle S. Goodman ◽  
Daniel M. Blumberger ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Working Memory ◽  
Brain Plasticity ◽  
Controlled Trial ◽  
Memory Performance ◽  
Double Blind ◽  
Paired Associative Stimulation ◽  
Post Hoc ◽  
The Impact

ABSTRACT Design: Pilot randomized double-blind-controlled trial of repetitive paired associative stimulation (rPAS), a paradigm that combines transcranial magnetic stimulation (TMS) of the dorsolateral prefrontal cortex (DLPFC) with peripheral median nerve stimulation. Objectives: To study the impact of rPAS on DLPFC plasticity and working memory performance in Alzheimer’s disease (AD). Methods: Thirty-two patients with AD (females = 16), mean (SD) age = 76.4 (6.3) years were randomized 1:1 to receive a 2-week (5 days/week) course of active or control rPAS. DLPFC plasticity was assessed using single session PAS combined with electroencephalography (EEG) at baseline and on days 1, 7, and 14 post-rPAS. Working memory and theta–gamma coupling were assessed at the same time points using the N-back task and EEG. Results: There were no significant differences between the active and control rPAS groups on DLPFC plasticity or working memory performance after the rPAS intervention. There were significant main effects of time on DLPFC plasticity, working memory, and theta–gamma coupling, only for the active rPAS group. Further, on post hoc within-group analyses done to generate hypotheses for future research, as compared to baseline, only the rPAS group improved on post-rPAS day 1 on all three indices. Finally, there was a positive correlation between working memory performance and theta–gamma coupling. Conclusions: This study did not show a beneficial effect of rPAS for DLPFC plasticity or working memory in AD. However, post hoc analyses showed promising results favoring rPAS and supporting further research on this topic. (Clinicaltrials.gov-NCT01847586)

scholarly journals Prevenzione primaria della malattia cardiovascolare: c’è bisogno di un’aspirina?

2019 ◽  
Vol 31 (3) ◽  
pp. 167-170
Author(s):  
Fulvio Floccari ◽  
Fulvio Marrocco ◽  
Rodolfo Rivera ◽  
Luca Di Lullo
Keyword(s):  
Primary Prevention ◽  
Major Bleeding ◽  
Cardiovascular Events ◽  
Geographical Location ◽  
Double Blind ◽  
Intention To Treat ◽  
Major Cardiovascular Events ◽  
Hemorrhagic Event ◽  
Randomized Design ◽  
Increased Risk

The efficacy of antiplatelet treatment with aspirin in the primary prevention of major cardiovascular events was questioned during 2018, following a new series of trials that we summarize here in a quick synoptic overview. The three studies involved are the ASPREE trial, the ASCEND study and the ARRIVE trial. These studies all have a double-blind randomized design, and 100 mg/day aspirin was administered with an intention-to-treat approach and against placebo. Age of the enrolled patients, prevalence of diabetes mellitus and geographical location of other studies are just some of the elements analyzed here, in addition to the different problems of cardiovascular events. The ASPREE study observed a marginal reduction of cardiovascular events with the use of aspirin, by approximately 5% with a confidence interval at risk of insignificancy. On the other hand, the increased risk of a hemorrhagic event appeared to be rather robust, resulting between 18% and 62%. The ASCEND study observed a reduction in cardiovascular events of around 12%, offset by an increase in the risk of major bleeding between 9% and 52%. The ARRIVE study did not detect any incidence of major cardiovascular events, while the risk of major bleeding appeared to even double. The evidences of the current literature push us to review a widespread conviction among professionals who fight the war against cardiovascular disease every day: the prescription of aspirin in the primary prevention can no longer happen systematically, and every single prescription need care between benefits and dangers connected to the treatment.

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