he overarching goal of this dissertation was to assess whether transcutaneous vagus nerve stimulation (tVNS) has beneficial effects over sham stimulation in laboratory models of anxiety.... Show morehe overarching goal of this dissertation was to assess whether transcutaneous vagus nerve stimulation (tVNS) has beneficial effects over sham stimulation in laboratory models of anxiety. Specifically, in Part I, the effects of tVNS were tested in a fear conditioning paradigm to test the utility of tVNS as an add-on treatment for exposure therapy. In Part II, the effects of tVNS as a stand-alone treatment for one of the core symptoms of anxiety – perseverative cognition – was tested within the experimental framework of a Breathing Focus task. Part III deals with working mechanisms: what is the optimal site of the ear to stimulate the auricular branch of the vagus nerve (ABVN) and what is the hypothesized working mechanism underlying the anxiolytic effects of tVNS? Specifically, the effects of tVNS on both physiological as well as behavioral indices of locus coeruleus – noradrenaline (LC-NA) network activity were tested. Show less
Burger, A.M.; Diest, I. van; Does, W. van der; Korbee, J.N.; Waziri, N.; Brosschot, J.F.; Verkuil, B. 2019
Fear overgeneralization is thought to be one of the cardinal processes underlying anxiety disorders, and a determinant of the onset, maintenance and recurrence of these disorders. Animal studies... Show moreFear overgeneralization is thought to be one of the cardinal processes underlying anxiety disorders, and a determinant of the onset, maintenance and recurrence of these disorders. Animal studies have shown that stimulating the vagus nerve (VNS) affects neuronal pathways implicated in pattern separation and completion, suggesting it may reduce the generalization of a fear memory to novel situations. In a one-day study, 58 healthy students were subjected to a fear conditioning, fear generalization, and fear extinction paradigm. Participants were randomly assigned to receive either transcutaneous auricular VNS (tVNS; final N = 29) or sham stimulation (final N = 29) during the generalization and extinction phases. tVNS did not affect fear generalization, as reflected by US expectancy ratings and fear potentiated startle responses. However, participants who received tVNS reported lower US expectancy ratings to the CS + during the extinction phase, possibly reflecting a stronger declarative extinction of fear. No effects of tVNS on fear potentiated startle responses during extinction were found. The pattern of findings regarding extinction of declarative fear suggest a facilitating effect of tVNS. Show less
Burger, A.M.; Does, W. van der; Thayer, J.F.; Brosschot, J.F.; Verkuil, B. 2019
Worrying is a central component of anxiety disorders. We tested whether non-invasive vagus nerve stimulation reduces negative thought intrusions in high worriers. Worry was assessed with a... Show moreWorrying is a central component of anxiety disorders. We tested whether non-invasive vagus nerve stimulation reduces negative thought intrusions in high worriers. Worry was assessed with a Breathing Focus Task, which consists of a pre-worry period, a worry induction, and a post-worry period. Ninety-seven high worriers were randomly allocated to receive transcutaneous electrical stimulation of the auricular branch of the vagus nerve at the concha (tVNS), or of the earlobe (sham stimulation) throughout the lab session. Participants who received tVNS reported significantly fewer negative thought intrusions during the pre-worry period, but the effects of tVNS after the worry induction were mixed. An exploratory analysis indicated that participants in the tVNS condition were more likely to report negative thought intrusions shortly after the worry induction, but became less likely to do so as the post-worry period went on. No effects of tVNS on RMSSD were observed. These findings provide preliminary indications that tVNS may decrease the occurrence of worrisome thoughts. Show less
Burger, A.M.; Dies, I. van; Does, W. van der; Hysaj, M.; Thayer, J.F.; Brosschot, J.F.; Verkuil, B. 2018
