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Ferstl M, Kühnel A, Klaus J, Lin WM, Kroemer NB. Non-invasive vagus nerve stimulation conditions increased invigoration and wanting in depression. Compr Psychiatry 2024; 132:152488. [PMID: 38657358 DOI: 10.1016/j.comppsych.2024.152488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 04/02/2024] [Accepted: 04/13/2024] [Indexed: 04/26/2024] Open
Abstract
BACKGROUND Major depressive disorder (MDD) is often marked by impaired motivation and reward processing, known as anhedonia. Many patients do not respond to first-line treatments, and improvements in motivation can be slow, creating an urgent need for rapid interventions. Recently, we demonstrated that transcutaneous auricular vagus nerve stimulation (taVNS) acutely boosts effort invigoration in healthy participants, but its effects on depression remain unclear. OBJECTIVE To assess the impact of taVNS on effort invigoration and maintenance in a sample that includes patients with MDD, evaluating the generalizability of our findings. METHODS We used a single-blind, randomized crossover design in 30 patients with MDD and 29 matched (age, sex, and BMI) healthy control participants (HCP). RESULTS Consistent with prior findings, taVNS increased effort invigoration for rewards in both groups during Session 1 (p = .040), particularly for less wanted rewards in HCP (pboot < 0.001). However, invigoration remained elevated in all participants, and no acute changes were observed in Session 2 (Δinvigoration = 3.3, p = .12). Crucially, throughout Session 1, we found taVNS-induced increases in effort invigoration (pboot = 0.008) and wanting (pboot = 0.010) in patients with MDD, with gains in wanting maintained across sessions (Δwanting = 0.06, p = .97). CONCLUSIONS Our study replicates the invigorating effects of taVNS in Session 1 and reveals its generalizability to depression. Furthermore, we expand upon previous research by showing taVNS-induced conditioning effects on invigoration and wanting within Session 1 in patients that were largely sustained. While enduring motivational improvements present challenges for crossover designs, they are highly desirable in interventions and warrant further follow-up research.
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Affiliation(s)
- Magdalena Ferstl
- Department of Psychiatry and Psychotherapy, Tübingen Center for Mental Health, University of Tübingen, Tübingen, Germany
| | - Anne Kühnel
- Section of Medical Psychology, Department of Psychiatry and Psychotherapy, Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Johannes Klaus
- Department of Psychiatry and Psychotherapy, Tübingen Center for Mental Health, University of Tübingen, Tübingen, Germany
| | - Wy Ming Lin
- Department of Psychiatry and Psychotherapy, Tübingen Center for Mental Health, University of Tübingen, Tübingen, Germany; Hector Research Institute for Education Science and Psychology, University of Tübingen, Tübingen, Germany
| | - Nils B Kroemer
- Department of Psychiatry and Psychotherapy, Tübingen Center for Mental Health, University of Tübingen, Tübingen, Germany; Section of Medical Psychology, Department of Psychiatry and Psychotherapy, Faculty of Medicine, University of Bonn, Bonn, Germany; German Center for Mental Health (DZPG), Germany.
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Lucchi F, Lloyd B, Nieuwenhuis S. Non-invasive vagus nerve stimulation and the motivation to work for rewards: A replication of Neuser et al. (2020, Nature Communications). Psychophysiology 2024; 61:e14484. [PMID: 37942809 DOI: 10.1111/psyp.14484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 10/20/2023] [Accepted: 10/20/2023] [Indexed: 11/10/2023]
Abstract
The vagus nerve is thought to be involved in the allostatic regulation of motivation and energy metabolism via gut-brain interactions. A recent study by Neuser and colleagues (2020) provided novel evidence for this process in humans, by reporting a positive effect of transcutaneous auricular vagus nerve stimulation (taVNS) on the invigoration of reward-seeking behaviors, especially for food rewards. We conducted an independent direct replication of Neuser et al. (2020), to assess the robustness of their findings. Following the original study, we used a single-blind, sham-controlled, randomized cross-over design. We applied left-sided taVNS in healthy human volunteers (n = 40), while they performed an effort allocation task in which they had to work for monetary and food rewards. The replication study was purely confirmatory in that it strictly followed the analysis plans and scripts used by Neuser et al. Although, in line with Neuser et al., we found strong effects of task variables on effort invigoration and effort maintenance, we failed to replicate their key finding: taVNS did not increase the strength of invigoration (p = .62); the data were five times more likely (BF10 = 0.19) under the null hypothesis. We also found substantial evidence against an effect of taVNS on effort maintenance (p = .50; BF10 = 0.20). Our results provide evidence against the idea that left-sided taVNS boosts the motivational drive to work for rewards. Our study also highlights the need for direct replications of influential taVNS studies.
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Affiliation(s)
- Federica Lucchi
- Institute of Psychology, Leiden University, Leiden, the Netherlands
| | - Beth Lloyd
- Institute of Psychology, Leiden University, Leiden, the Netherlands
- Leiden Institute for Brain and Cognition, Leiden University, Leiden, the Netherlands
| | - Sander Nieuwenhuis
- Institute of Psychology, Leiden University, Leiden, the Netherlands
- Leiden Institute for Brain and Cognition, Leiden University, Leiden, the Netherlands
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Décarie-Spain L, Hayes AMR, Lauer LT, Kanoski SE. The gut-brain axis and cognitive control: A role for the vagus nerve. Semin Cell Dev Biol 2024; 156:201-209. [PMID: 36803834 PMCID: PMC10427741 DOI: 10.1016/j.semcdb.2023.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 02/07/2023] [Indexed: 02/18/2023]
Abstract
Survival requires the integration of external information and interoceptive cues to effectively guide advantageous behaviors, particularly foraging and other behaviors that promote energy acquisition and consumption. The vagus nerve acts as a critical relay between the abdominal viscera and the brain to convey metabolic signals. This review synthesizes recent findings from rodent models and humans revealing the impact of vagus nerve signaling from the gut on the control of higher-order neurocognitive domains, including anxiety, depression, reward motivation, and learning and memory. We propose a framework where meal consumption engages gastrointestinal tract-originating vagal afferent signaling that functions to alleviate anxiety and depressive-like states, while also promoting motivational and memory functions. These concurrent processes serve to favor the encoding of meal-relevant information into memory storage, thus facilitating future foraging behaviors. Modulation of these neurocognitive domains by vagal tone is also discussed in the context of pathological conditions, including the use of transcutaneous vagus nerve stimulation for the treatment of anxiety disorders, major depressive disorder, and dementia-associated memory impairments. Collectively, these findings highlight the contributions of gastrointestinal vagus nerve signaling to the regulation of neurocognitive processes that shape various adaptive behavioral responses.
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Affiliation(s)
- Léa Décarie-Spain
- Human and Evolutionary Biology Section, Department of Biological Sciences, Dornsife College of Letters, Arts and Sciences, University of Southern California, 3616 Trousdale Pkwy, Los Angeles, CA 90089, USA
| | - Anna M R Hayes
- Human and Evolutionary Biology Section, Department of Biological Sciences, Dornsife College of Letters, Arts and Sciences, University of Southern California, 3616 Trousdale Pkwy, Los Angeles, CA 90089, USA
| | - Logan Tierno Lauer
- Human and Evolutionary Biology Section, Department of Biological Sciences, Dornsife College of Letters, Arts and Sciences, University of Southern California, 3616 Trousdale Pkwy, Los Angeles, CA 90089, USA
| | - Scott E Kanoski
- Human and Evolutionary Biology Section, Department of Biological Sciences, Dornsife College of Letters, Arts and Sciences, University of Southern California, 3616 Trousdale Pkwy, Los Angeles, CA 90089, USA; Neuroscience Graduate Program, University of Southern California, 3641Watt Way, Los Angeles, CA 90089, USA.
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Teckentrup V, Kroemer NB. Mechanisms for survival: vagal control of goal-directed behavior. Trends Cogn Sci 2024; 28:237-251. [PMID: 38036309 DOI: 10.1016/j.tics.2023.11.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 11/01/2023] [Accepted: 11/02/2023] [Indexed: 12/02/2023]
Abstract
Survival is a fundamental physiological drive, and neural circuits have evolved to prioritize actions that meet the energy demands of the body. This fine-tuning of goal-directed actions based on metabolic states ('allostasis') is deeply rooted in our brain, and hindbrain nuclei orchestrate the vital communication between the brain and body through the vagus nerve. Despite mounting evidence for vagal control of allostatic behavior in animals, its broader function in humans is still contested. Based on stimulation studies, we propose that the vagal afferent pathway supports transitions between survival modes by gating the integration of ascending bodily signals, thereby regulating reward-seeking. By reconceptualizing vagal signals as catalysts for goal-directed behavior, our perspective opens new avenues for theory-driven translational work in mental disorders.
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Affiliation(s)
- Vanessa Teckentrup
- Department of Psychiatry and Psychotherapy, Tübingen Center for Mental Health, University of Tübingen, 72076 Tübingen, Germany; School of Psychology and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
| | - Nils B Kroemer
- Department of Psychiatry and Psychotherapy, Tübingen Center for Mental Health, University of Tübingen, 72076 Tübingen, Germany; Section of Medical Psychology, Department of Psychiatry and Psychotherapy, Faculty of Medicine, University of Bonn, 53127 Bonn, Germany; German Center for Mental Health (DZPG), 72076 Tübingen, Germany.
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Altınkaya Z, Öztürk L, Büyükgüdük İ, Yanık H, Yılmaz DD, Yar B, Değirmenci E, Dal U, Veldhuizen MG. Non-invasive vagus nerve stimulation in a hungry state decreases heart rate variability. Physiol Behav 2023; 258:114016. [PMID: 36334796 DOI: 10.1016/j.physbeh.2022.114016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 10/21/2022] [Accepted: 10/30/2022] [Indexed: 11/15/2022]
Abstract
Vagus nerve signals from the gut to brain carry information about nutrients and drive food reward. Such signals are disrupted by consuming large amounts of high-calorie foods, necessitating greater food intake to elicit a similar neural response. Non-invasive vagus nerve stimulation (nVNS) via a branch innervating the ear is a candidate treatment for obesity in humans. There is disagreement on the optimal location of nVNS in the ear for experimental and clinical studies. There are also no studies comparing nVNS in hungry and post-prandial states. We aimed to compare ear position(s) for nVNS and explore the effects of nVNS during hungry and post-prandial states on proxies for autonomic outflow (heart-rate variability) and efferent metabolism (gastric wave frequency and resting energy expenditure). In a within-subject design, 14 participants (10 women, on average 29.4 +/- 6.7 years old) received nVNS in four different locations (cymba conchae, tragus, earlobe, or tragus AND cymba conchae) on separate days. In each session, participants were asked to consume a palatable chocolate flavored milk. With electrography on the abdomen and indirect calorimetry in a canopy, we measured electro-cardiogram, electro-gastrogram and resting energy expenditure for 15 min before and at least 35 min after consumption of the palatable drink. We also collected ratings of the palatable drink and internal and other states. Pre-drink consumption (in a hungry state) we observed no differences in the effect of location of acute nVNS on resting energy expenditure and gastric wave measures. However, nVNS in cymba conchae decreases heart-rate variability (relative to sham) and ratings of how much participants want to consume the drink (relative to tragus AND cymba conchae and a trend relative to sham). After drink consumption and with continued nVNS, gastric wave frequency is unchanged, and resting energy expenditure increases regardless of stimulation location. Heart-rate variability decreases in all locations, except cymba conchae. We also observe a trend for an increase in gastric wave amplitude in late post-drink consumption time-points in cymba conchae. We observe no support for the combined stimulation of tragus AND cymba conchae being more effective than either of the individual locations. These results suggest that nVNS in the cymba conchae in a hungry state has a similar acute effect on vagal tone as food consumption: to decrease heart rate variability. This effect then negates the usual postprandial effects of a decrease in heart rate variability as seen in the other nVNS locations. These preliminary observations suggest that nVNS in cymba conchae may act primarily on vagal afferent autonomic (and only modestly on metabolic output) in a similar way as food consumption does.
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Affiliation(s)
| | - Lina Öztürk
- Mersin University, Faculty of Medicine, Mersin, Turkey
| | - İlkim Büyükgüdük
- Department of Psychology, Faculty of Science and Letters, Mersin University, Mersin, Turkey
| | - Hüseyin Yanık
- Department of Electrical and Electronics Engineering, Faculty of Engineering, Mersin University, Mersin, Turkey
| | - Dilan Deniz Yılmaz
- Department of Physiology, Faculty of Medicine, Mersin University, Mersin, Turkey
| | - Berçem Yar
- Department of Psychology, Faculty of Science and Letters, Mersin University, Mersin, Turkey
| | - Evren Değirmenci
- Department of Electrical and Electronics Engineering, Faculty of Engineering, Mersin University, Mersin, Turkey; Biotechnology Research and Applications Center, Mersin University, Mersin, Turkey
| | - Uğur Dal
- Department of Physiology, Faculty of Medicine, Mersin University, Mersin, Turkey
| | - Maria Geraldine Veldhuizen
- Department of Psychology, Faculty of Science and Letters, Mersin University, Mersin, Turkey; Biotechnology Research and Applications Center, Mersin University, Mersin, Turkey; Department of Anatomy, Faculty of Medicine, Mersin University, Mersin, Turkey.
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Brougher J, Aziz U, Adari N, Chaturvedi M, Jules A, Shah I, Syed S, Thorn CA. Self-Administration of Right Vagus Nerve Stimulation Activates Midbrain Dopaminergic Nuclei. Front Neurosci 2022; 15:782786. [PMID: 34975384 PMCID: PMC8716493 DOI: 10.3389/fnins.2021.782786] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/29/2021] [Indexed: 12/12/2022] Open
Abstract
Background: Left cervical vagus nerve stimulation (l-VNS) is an FDA-approved treatment for neurological disorders including epilepsy, major depressive disorder, and stroke, and l-VNS is increasingly under investigation for a range of other neurological indications. Traditional l-VNS is thought to induce therapeutic neuroplasticity in part through the coordinated activation of multiple broadly projecting neuromodulatory systems in the brain. Recently, it has been reported that striking lateralization exists in the anatomical and functional connectivity between the vagus nerves and the dopaminergic midbrain. These emerging findings suggest that VNS-driven activation of this important plasticity-promoting neuromodulatory system may be preferentially driven by targeting the right, rather than the left, cervical nerve. Objective: To compare the effects of right cervical VNS (r-VNS) vs. traditional l-VNS on self-administration behavior and midbrain dopaminergic activation in rats. Methods: Rats were implanted with a stimulating cuff electrode targeting either the right or left cervical vagus nerve. After surgical recovery, rats underwent a VNS self-administration assay in which lever pressing was paired with r-VNS or l-VNS delivery. Self-administration was followed by extinction, cue-only reinstatement, and stimulation reinstatement sessions. Rats were sacrificed 90 min after completion of behavioral training, and brains were removed for immunohistochemical analysis of c-Fos expression in the dopaminergic ventral tegmental area (VTA) and substantia nigra pars compacta (SNc), as well as in the noradrenergic locus coeruleus (LC). Results: Rats in the r-VNS cohort performed significantly more lever presses throughout self-administration and reinstatement sessions than did rats in the l-VNS cohort. Moreover, this appetitive behavioral responding was associated with significantly greater c-Fos expression among neuronal populations within the VTA, SNc, and LC. Differential c-Fos expression following r-VNS vs. l-VNS was particularly prominent within dopaminergic midbrain neurons. Conclusion: Our results support the existence of strong lateralization within vagal-mesencephalic signaling pathways, and suggest that VNS targeted to the right, rather than left, cervical nerve preferentially activates the midbrain dopaminergic system. These findings raise the possibility that r-VNS could provide a promising strategy for enhancing dopamine-dependent neuroplasticity, opening broad avenues for future research into the efficacy and safety of r-VNS in the treatment of neurological disease.
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Affiliation(s)
- Jackson Brougher
- Department of Neuroscience, University of Texas at Dallas, Richardson, TX, United States
| | - Umaymah Aziz
- Department of Neuroscience, University of Texas at Dallas, Richardson, TX, United States
| | - Nikitha Adari
- Department of Neuroscience, University of Texas at Dallas, Richardson, TX, United States
| | - Muskaan Chaturvedi
- Department of Neuroscience, University of Texas at Dallas, Richardson, TX, United States
| | - Aryela Jules
- Department of Neuroscience, University of Texas at Dallas, Richardson, TX, United States
| | - Iqra Shah
- Department of Neuroscience, University of Texas at Dallas, Richardson, TX, United States
| | - Saba Syed
- Department of Neuroscience, University of Texas at Dallas, Richardson, TX, United States
| | - Catherine A Thorn
- Department of Neuroscience, University of Texas at Dallas, Richardson, TX, United States
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