Effects of non‐invasive vagus nerve stimulation on cognitive and autonomic correlates of perseverative cognition

Abstract

Perseverative cognitions can provoke psychophysiological stress in the absence of an actual stressor and are considered important transdiagnostic vulnerability factors for several (mental) health issues. These stress-related cognitive processes are reflected by both cognitive (assessed by self-reports) and autonomic inflexibility (assessed by heart rate variability; HRV), with a key role attributed to the vagus nerve. Interestingly, modulation of the afferent branches of the vagus can be achieved with transcutaneous auricular vagus nerve stimulation (taVNS), a non-invasive technique that employs a low-intensity electrical current applied to the ear. In a sample of healthy individuals, we investigated the effects of taVNS of the left concha, compared to sham (earlobe) stimulation, on the cognitive and autonomic correlates of perseverative cognition following a psychosocial stress task.Interestingly, taVNS significantly reduced cognitive rigidity, reflected by reduced subjective perseverative thinking after psychosocial stress. Although there were no direct effects on autonomic correlates of perseverative cognition, individual differences in perseverative thinking after the stressor significantly affected the effects of taVNS on HRV. Specifically, more autonomic inflexibility during the stress task (i.e., reduced HRV) was associated with increases in perseverative thinking afterward for the sham condition, but not the active taVNS condition. Additional exploratory analyses revealed no significant moderation of stimulation intensity. Overall, the study findings endorse the association between perseverative cognitions and vagus nerve functioning.

Transcutaneous Auricular Vagus Nerve Stimulation to Improve Emotional State

“…taVNS is a noninvasive brain stimulation technique [57] where electrodes apply electrical impulses to the skin of specific areas of the ear [58,59] (see Figure 2) to stimulate the auricular branch of the vagus nerve, also known as Alderman's or Arnold's nerve [60,61]. The location of the auricular vagus nerve was revealed by dissecting the ear of human cadavers [62,63] and mapping the areas of the ear.…”

Putative role of non‐invasive vagus nerve stimulation in cancer pathology and immunotherapy: Can this be a hidden treasure, especially for the elderly?

“…57 So far, several reports have shown the effects of noninvasive VNS at improving functions such as motor function following stroke, control of seizures in epilepsy, cognitive function, and acute respiratory distress syndrome in Covid-19. 52,53,[65][66][67][68][69] The aim of this article is to present the putative role of non-invasive VNS in cancer pathology and immunotherapy.…”

Cognitive Functions following Trigeminal Neuromodulation

“…However, the external ear is also innervated by trigeminal nerve fibers, partially overlapping with the vagus territory [ 100 , 101 ]; therefore, an appropriate electrode positioning easily results in the stimulation of both trigeminal and vagal afferents [ 6 , 102 ]. The study of auricular tVNS has seen great development in recent years, especially with regard to improved cognitive performance, not only in the clinical population but also in healthy subjects [ 103 , 104 , 105 , 106 , 107 ]. While the neurobiological mechanisms are still unclear, the available literature mostly seek to explain the positive effects of tVNS on cognitive performance in terms of a change in brain NE levels [ 64 , 108 ].…”