Vagus Nerve Stimulation as a Potential Therapy in Early Alzheimer’s Disease: A Review

Frontiers in Human Neuroscience, Journal Year: 2022, Volume and Issue: 16

Published: April 29, 2022

Cognitive dysfunction in Alzheimer’s disease (AD) is caused by disturbances neuronal circuits of the brain underpinned synapse loss, and death. Amyloid beta tau protein cause these pathological changes enhance neuroinflammation, which turn modifies progression severity. Vagal nerve stimulation (VNS), via activation locus coeruleus (LC), results release catecholamines hippocampus neocortex, can synaptic plasticity reduce inflammatory signalling. has shown promise to cognitive ability animal models. Research rodents that VNS have positive effects on basal function plasticity, tune signalling, limit accumulation amyloid plaques. humans with invasive non-invasive devices for modulation cognition. However, direct vagus afforded procedure carries surgical risks. In contrast, potential be a broadly available therapy manage symptoms early AD, however, magnitude specificity its remains elucidated, non-inferiority as compared still needs established. Ongoing clinical trials healthy individuals patients AD will provide valuable information clarify benefits cognition AD. Whether or produce significant improvement memory whether modify require further investigation.

Language: Английский

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Associations among locus coeruleus catecholamines, tau pathology, and memory in aging

Neuropsychopharmacology, Journal Year: 2022, Volume and Issue: 47(5), P. 1106 - 1113

Published: Jan. 15, 2022

Language: Английский

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Vagus nerve stimulation: mechanisms and factors involved in memory enhancement

Frontiers in Human Neuroscience, Journal Year: 2023, Volume and Issue: 17

Published: June 29, 2023

Vagus nerve stimulation (VNS) has been recognized as a useful neuromodulation tool to target the central nervous system by electrical of peripheral nerves. Activation nucleus solitary tract (NTS) in brainstem vagal afferent fibers allows for modulation various higher order brain regions, including limbic and cerebral cortex structures. Along with neurological psychiatric indications, clinical preclinical studies suggest that VNS can improve memory. While underlying mechanisms memory involve areas, such prefrontal processes alertness arousal, here we focus on VNS-induced improvements related hippocampus, main area implicated acquisition. In addition, detail research demonstrating targeted approach modify outcomes delve into molecular associated these changes. These findings indicate greater understanding while also considering parameters, administration site, timing relation training, sex-specific factors, may allow optimal application enhance

Language: Английский

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Neuromodulation of Neural Oscillations in Health and Disease

Biology, Journal Year: 2023, Volume and Issue: 12(3), P. 371 - 371

Published: Feb. 26, 2023

Using EEG and local field potentials (LFPs) as an index of large-scale neural activities, research has been able to associate oscillations in different frequency bands with markers cognitive functions, goal-directed behavior, various neurological disorders. While this gives us a glimpse into how neurons communicate throughout the brain, causality these synchronized network activities remains poorly understood. Moreover, effect major neuromodulatory systems (e.g., noradrenergic, cholinergic, dopaminergic) on brain drawn much attention. More recent studies have suggested that cross-frequency coupling (CFC) is heavily responsible for mediating network-wide communication across subcortical cortical structures, implicating importance neurotransmitters shaping coordinated actions. By bringing light role each system plays regulating brain-wide oscillations, we hope paint clearer picture pivotal play variety functions disorders, neuromodulation techniques can be optimized means controlling dynamics. The aim review showcase important dynamics, informing future pay close attention their involvement specific features associated behaviors.

Language: Английский

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Stress-induced vagal activity influences anxiety-relevant prefrontal and amygdala neuronal oscillations in male mice

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Jan. 9, 2024

Abstract The vagus nerve crucially affects emotions and psychiatric disorders. However, the detailed neurophysiological dynamics of in response to its associated pathological changes remain unclear. In this study, we demonstrated that spike rates cervical change depending on anxiety behavior an elevated plus maze test, these were eradicated stress-susceptible male mice. Furthermore, instantaneous negatively positively correlated with power 2–4 Hz 20–30 oscillations, respectively, prefrontal cortex amygdala. oscillations also underwent dynamic behavioral state maze, no longer observed vagotomized Chronic stimulation restored behavior-relevant neuronal recovery altered states These results suggested physiological vagal-brain communication underlies mood

Language: Английский

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Transcutaneous vagus nerve stimulation: a new strategy for Alzheimer’s disease intervention through the brain-gut-microbiota axis?

Frontiers in Aging Neuroscience, Journal Year: 2024, Volume and Issue: 16

Published: Feb. 27, 2024

Transcutaneous vagus nerve stimulation (tVNS) is an emerging non-invasive technique designed to stimulate branches of the distributed over body surface. Studies suggest a correlation between brain-gut-microbiota (BGM) axis and pathogenesis Alzheimer’s disease (AD). The BGM represents complex bidirectional communication system, with being crucial component. Therefore, electrical might have potential modify—most time probably in non-physiological way—the signal transmission within axis, potentially influencing progression or symptoms AD. This review explores interaction percutaneous emphasizing its effects on It examines various aspects, such as specific brain regions, gut microbiota composition, maintenance intestinal environmental homeostasis, inflammatory responses, plasticity, hypothalamic–pituitary–adrenal (HPA) regulation. suggests that tVNS could serve effective strategy modulate intervene treatment future.

Language: Английский

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Transcutaneous Auricular Vagus Nerve Stimulation Does Not Accelerate Fear Extinction: A Randomized, Sham‐Controlled Study

Psychophysiology, Journal Year: 2025, Volume and Issue: 62(1)

Published: Jan. 1, 2025

ABSTRACT Transcutaneous auricular vagus nerve stimulation (taVNS) has been tested as a strategy to facilitate fear extinction learning based on the hypothesis that taVNS increases central noradrenergic activity. Four studies out of six found enhance especially at beginning extinction. Facilitatory effects were mainly observed in US expectancy, less fear‐potentiated startle (FPS), and not skin conductance response (SCR). Suboptimal parameters may explain reported mixed results. Also, variability selected conditioning paradigms statistical power impedes comparability between studies. This study sought further test whether accelerates indexed by FPS, SCR. Similar most previous studies, we employed differential paradigm. The left ear 79 healthy participants was stimulated with either sham (earlobe) or (cymba concha) during learning. To maximize beneficial taVNS, cymba concha administered continuously maximum level below pain threshold. Results pre‐registered frequentist exploratory Bayesian analyses indicate did accelerate any outcomes. null results commonly used does reliably optimize More research is needed if protocol determines efficacy optimizing

Language: Английский

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Non‐Invasive Auricular Vagus Nerve Stimulation Decreases Heart Rate Variability Independent of Caloric Load

Psychophysiology, Journal Year: 2025, Volume and Issue: 62(2)

Published: Feb. 1, 2025

ABSTRACT The vagus nerve is crucial in regulating physiological functions, including the cardiovascular system. While heart rate (HR) and its variability (HRV) may provide non‐invasive proxies of cardiac vagal activity, transcutaneous auricular stimulation (taVNS) has yielded mixed effects, with limited research on right branch stimulation. In a randomized crossover study 36 healthy participants, we investigated taVNS effects HR HRV indexed by SDRR, RMSSD, HF‐HRV, LF/HF ratio. To assess impact side (left vs. ear) indices interaction state, recorded electrocardiograms four sessions per person, covering three session phases: baseline, during (taVNS sham), post‐milkshake consumption First, found moderate evidence against affecting (BF 10 = 0.21). Second, decreased (multivariate p 0.004) independent strong for RMSSD 15.11) HF‐HRV 11.80). Third, taVNS‐induced changes were comparable across sides stronger than sham, indicating consistent side. We conclude that reduces as SDRR without altering HR, contradicting assumption se increases cardiovagal activity increased due to stimulating afferents. Instead, our results support role afferent activation arousal. Crucially, both can safely modulate system increasing risk bradycardia or causing adverse events offering new treatment possibilities.

Language: Английский

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Vagus nerve stimulation increases stomach-brain coupling via a vagal afferent pathway

Brain stimulation, Journal Year: 2022, Volume and Issue: 15(5), P. 1279 - 1289

Published: Sept. 1, 2022

BackgroundMaintaining energy homeostasis is vital and supported by vagal signaling between digestive organs the brain. Previous research has established a gastric network in brain that phase synchronized with rhythm of stomach, but tools to perturb its function were lacking.ObjectiveTo evaluate whether stomach-brain coupling can be acutely increased non-invasively stimulating afferent projections brain.MethodsUsing single-blind randomized crossover design, we investigated effect acute right-sided transcutaneous auricular vagus nerve stimulation (taVNS) versus sham on coupling.ResultsIn line preclinical research, taVNS nucleus solitary tract (NTS) midbrain while boosting across Crucially, cortex, taVNS-induced changes occurred primarily transmodal regions associated hunger ratings as indicators subjective metabolic state.ConclusionstaVNS increases via an NTS-midbrain pathway signals gut-induced reward, indicating communication body effectively modulated vago-vagal signaling. Such insights may help us better understand role afferents orchestrating recruitment which could pave way for novel neuromodulatory treatments.

Language: Английский

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Alpha EEG Activity and Pupil Diameter Coupling during Inactive Wakefulness in Humans

eNeuro, Journal Year: 2022, Volume and Issue: 9(2), P. ENEURO.0060 - 21.2022

Published: March 1, 2022

Variations in human behavior correspond to the adaptation of nervous system different internal and environmental demands. Attention, a cognitive process for weighing demands, changes over time. Pupillary activity, which is affected by fluctuating levels processing, appears identify neural dynamics that relate states attention. In mice, example, pupil directly correlate with brain state fluctuations. Although, humans, alpha-band activity associated inhibitory processes cortical networks during visual its amplitude modulated attention, conclusive evidence linking this narrowband time remains sparse. We hypothesize that, as alpha diameter indicate attentional variations time, these two measures should be comodulated. work, we recorded electroencephalographic (EEG) pupillary 16 subjects who had their eyes fixed on gray screen 1 min. Our study revealed high-frequency component covariate spontaneously. Specifically, maximum was observed occur ∼300 ms before peak diameter. contrast, minimum noted ∼350 trough The consistent temporal coincidence measurements strongly suggests subject's indicated EEG amplitude, changing moment can monitored measuring together pupil.

Language: Английский

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