Impact of transcutaneous vagus nerve stimulation on healthy cognitive and brain aging

Abstract

Evidence for clinically meaningful benefits of transcutaneous vagus nerve stimulation (VNS) has been rapidly accumulating over the past 15 years. This relatively novel non-invasive brain stimulation technique has been applied to a wide range of neuropsychiatric disorders including schizophrenia, obsessive compulsive disorder, panic disorder, post-traumatic stress disorder, bipolar disorder, and Alzheimer’s disease. More recently, non-invasive forms of VNS have allowed for investigations within healthy aging populations. These results offer insight into protocol considerations specific to older adults and how to translate those results into effective clinical trials and, ultimately, effective clinical care. In this review, we characterize the possible mechanisms by which non-invasive VNS may promote healthy aging (e.g., neurotransmitter effects, inflammation regulation, functional connectivity changes), special considerations for applying non-invasive VNS in an older adult population (e.g., vagus nerve changes with age), and how non-invasive VNS may be used in conjunction with existing behavioral interventions (e.g., cognitive behavioral therapy, cognitive training) to promote healthy emotional and cognitive aging.

Influence of 2-week auricular transcutaneous vagus nerve stimulation on memory: findings from a randomized trial in community-dwelling adults

“…Additionally, neurotransmitters like acetylcholine, serotonin, dopamine, brain-derived neurotrophic factor (BDNF), and gamma-aminobutyric acid (GABA), as con rmed in neurophysiological studies [38] , might contribute to atVNS's mechanism of action. It is possible that atVNS reduces neuroin ammation through the cholinergic anti-in ammatory pathway [39] , enhances blood ow to speci c brain regions, in uences peripheral hemodynamics [4] and modulates parasympathetic activity [40] . Furthermore, our previous study showed that two weeks of atVNS improved sleep scores, which could be linked to the activation of the ascending reticular activating system [41] known for its role in regulating the sleep-wake cycle.…”

Transcutaneous auricular vagus nerve stimulation can modulate fronto-parietal brain networks

“…This network is involved in sustained attention, novelty detection, problem-solving, working memory, and decision-making ( Vincent et al, 2008 ; Marek and Dosenbach, 2018 ; De Ridder et al, 2022 ). Considering the function of the fronto-parietal network, tVNS may have an effect on improving cognitive function and may serve as a treatment strategy for cognitive impairment ( Naparstek et al, 2023 ; Trifilio et al, 2023 ).…”

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

“…These fibers modulate functions in organs such as the heart, lungs, and gastrointestinal tract, regulating anti-inflammatory reflexes, secretion, and peristalsis in the gastrointestinal tract ( Bonaz et al, 2018 ). Anatomical studies have shown that the VN projects centrally to subcortical brain structures including the cerebellum, thalamus, and hippocampus ( Yakunina et al, 2018 ; Trifilio et al, 2023 ), exerting excitatory effects on these neurons ( Rutecki, 1990 ). The VN transmits signals through four nuclei in the CNS, namely the nucleus tractus solitarius (NTS), the spinal trigeminal nucleus, the solitary nucleus and the dorsomedial nucleus (DMN; Berthoud and Neuhuber, 2000 ).…”