TY - GEN A1 - Ventura-Bort, Carlos A1 - Wirkner, Janine A1 - Genheimer, Hannah A1 - Wendt, Julia A1 - Hamm, Alfons O. A1 - Weymar, Mathias T1 - Effects of Transcutaneous Vagus Nerve Stimulation (tVNS) on the P300 and Alpha-Amylase Level BT - A Pilot Study T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Recent research suggests that the P3b may be closely related to the activation of the locus coeruleus-norepinephrine (LC-NE) system. To further study the potential association, we applied a novel technique, the non-invasive transcutaneous vagus nerve stimulation (tVNS), which is speculated to increase noradrenaline levels. Using a within-subject cross-over design, 20 healthy participants received continuous tVNS and sham stimulation on two consecutive days (stimulation counterbalanced across participants) while performing a visual oddball task. During stimulation, oval non-targets (standard), normal-head (easy) and rotated-head (difficult) targets, as well as novel stimuli (scenes) were presented. As an indirect marker of noradrenergic activation we also collected salivary alpha-amylase (sAA) before and after stimulation. Results showed larger P3b amplitudes for target, relative to standard stimuli, irrespective of stimulation condition. Exploratory post hoc analyses, however, revealed that, in comparison to standard stimuli, easy (but not difficult) targets produced larger P3b (but not P3a) amplitudes during active tVNS, compared to sham stimulation. For sAA levels, although main analyses did not show differential effects of stimulation, direct testing revealed that tVNS (but not sham stimulation) increased sAA levels after stimulation. Additionally, larger differences between tVNS and sham stimulation in P3b magnitudes for easy targets were associated with larger increase in sAA levels after tVNS, but not after sham stimulation. Despite preliminary evidence for a modulatory influence of tVNS on the P3b, which may be partly mediated by activation of the noradrenergic system, additional research in this field is clearly warranted. Future studies need to clarify whether tVNS also facilitates other processes, such as learning and memory, and whether tVNS can be used as therapeutic tool. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 473 KW - EEG KW - P300 KW - tVNS KW - norepinephrine KW - locus coeruleus KW - salivary alpha-amylase Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-419259 IS - 473 ER - TY - JOUR A1 - Ventura-Bort, Carlos A1 - Wirkner, Janine A1 - Genheimer, Hannah A1 - Wendt, Julia A1 - Hamm, Alfons O. A1 - Weymar, Mathias T1 - Effects of Transcutaneous Vagus Nerve Stimulation (tVNS) on the P300 and Alpha-Amylase Level BT - A Pilot Study JF - Frontiers in Human Neuroscience N2 - Recent research suggests that the P3b may be closely related to the activation of the locus coeruleus-norepinephrine (LC-NE) system. To further study the potential association, we applied a novel technique, the non-invasive transcutaneous vagus nerve stimulation (tVNS), which is speculated to increase noradrenaline levels. Using a within-subject cross-over design, 20 healthy participants received continuous tVNS and sham stimulation on two consecutive days (stimulation counterbalanced across participants) while performing a visual oddball task. During stimulation, oval non-targets (standard), normal-head (easy) and rotated-head (difficult) targets, as well as novel stimuli (scenes) were presented. As an indirect marker of noradrenergic activation we also collected salivary alpha-amylase (sAA) before and after stimulation. Results showed larger P3b amplitudes for target, relative to standard stimuli, irrespective of stimulation condition. Exploratory post hoc analyses, however, revealed that, in comparison to standard stimuli, easy (but not difficult) targets produced larger P3b (but not P3a) amplitudes during active tVNS, compared to sham stimulation. For sAA levels, although main analyses did not show differential effects of stimulation, direct testing revealed that tVNS (but not sham stimulation) increased sAA levels after stimulation. Additionally, larger differences between tVNS and sham stimulation in P3b magnitudes for easy targets were associated with larger increase in sAA levels after tVNS, but not after sham stimulation. Despite preliminary evidence for a modulatory influence of tVNS on the P3b, which may be partly mediated by activation of the noradrenergic system, additional research in this field is clearly warranted. Future studies need to clarify whether tVNS also facilitates other processes, such as learning and memory, and whether tVNS can be used as therapeutic tool. KW - EEG KW - P300 KW - tVNS KW - norepinephrine KW - locus coeruleus KW - salivary alpha-amylase Y1 - 2018 U6 - https://doi.org/10.3389/fnhum.2018.00202 SN - 1662-5161 VL - 12 SP - 1 EP - 12 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Ventura-Bort, Carlos A1 - Wirkner, Janine A1 - Dolcos, Florin A1 - Wendt, Julia A1 - Hamm, Alfons O. A1 - Weymar, Mathias T1 - Enhanced spontaneous retrieval of cues from emotional events: an ERP study JF - Biological psychology N2 - Recent evidence points to enhanced episodic memory retrieval not only for emotional items but also for neutral information encoded in emotional contexts. However, prior research only tested instructed explicit recognition, and hence here we investigated whether memory retrieval is also heightened for cues from emotional contexts when retrieval is not explicitly probed. During the first session of a two-session experiment, neutral objects were presented on different background scenes varying in emotional and neutral contents. One week later, objects were presented again (with no background) intermixed with novel objects. In both sessions, participants were instructed to attentively watch the stimuli (free viewing procedure), and during the second session, ERPs were also collected to measure the ERP Old/New effect, an electrophysiological correlate of episodic memory retrieval. Analyses were performed using cluster-based permutation tests in order to identify reliable spatiotemporal ERP differences. Based on this approach, old relative to new objects, were associated with larger ERP positivity in an early (364-744 ms) and late time window (760-1148 ms) over distinct central electrode clusters. Interestingly, significant late ERP Old/New differences were only observed for objects previously encoded with emotional, but not neutral scenes (504 to 1144 ms). Because these ERP differences were observed in a non-instructed retrieval context, our results indicate that long-term, spontaneous retrieval for neutral objects, is particularly heightened if encoded within emotionally salient contextual information. These findings may assist in understanding mechanisms underlying spontaneous retrieval of emotional associates and the utility of ERPs to study maladaptive involuntary memories in trauma- and stress-related disorders. KW - Event-related potentials KW - ERP KW - Emotion KW - Retrieval KW - Spontaneous memory KW - Old/New effect Y1 - 2019 U6 - https://doi.org/10.1016/j.biopsycho.2019.107742 SN - 0301-0511 SN - 1873-6246 VL - 148 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Ventura-Bort, Carlos A1 - Wirkner, Janine A1 - Wendt, Julia A1 - Hamm, Alfons O. A1 - Weymar, Mathias T1 - Establishment of emotional memories is mediated by vagal nerve activation BT - evidence from noninvasive taVNS JF - The journal of neuroscience : the official journal of the Society for Neuroscience N2 - Emotional memories are better remembered than neutral ones, but the mechanisms leading to this memory bias are not well under-stood in humans yet. Based on animal research, it is suggested that the memory-enhancing effect of emotion is based on central nor-adrenergic release, which is triggered by afferent vagal nerve activation. To test the causal link between vagus nerve activation and emotional memory in humans, we applied continuous noninvasive transcutaneous auricular vagus nerve stimulation (taVNS) during exposure to emotional arousing and neutral scenes and tested subsequent, long-term recognition memory after 1 week. We found that taVNS, compared with sham, increased recollection-based memory performance for emotional, but not neutral, material. These findings were complemented by larger recollection-related brain potentials (parietal ERP Old/New effect) during retrieval of emotional scenes encoded under taVNS, compared with sham. Furthermore, brain potentials recorded during encoding also revealed that taVNS facilitated early attentional discrimination between emotional and neutral scenes. Extending animal research, our behavioral and neu-ral findings confirm a modulatory influence of the vagus nerve in emotional memory formation in humans. KW - emotion KW - ERPs KW - memory KW - Old KW - New effect KW - LPP KW - vagus nerve KW - tVNS Y1 - 2021 U6 - https://doi.org/10.1523/JNEUROSCI.2329-20.2021 SN - 1529-2401 VL - 41 IS - 36 SP - 7636 EP - 7648 PB - Society for Neuroscience CY - Washington, DC ER - TY - GEN A1 - Weymar, Mathias A1 - Ventura-Bort, Carlos A1 - Wirkner, Janine A1 - Genheimer, Hannah A1 - Wendt, Julia A1 - Hamm, Alfons O. T1 - Effects of Transcutaneous Vagus Vagus Nerve Stimulation (TVNS) on selective attentions and emotional episodic memory : findings from ERP research T2 - Psychophysiology : journal of the Society for Psychophysiological Research N2 - Recent research indicates that non- invasive stimulation of the afferent auricular vagal nerve (tVNS) may modulate various cognitive and affec-tive functions, likely via activation of the locus coeruleus- norepinephrine (LC- NE) system. In a series of ERP studies we found that the attention- related P300 component is enhanced during continuous vagal stimula-tion, compared to sham, which is also related to increased salivary alpha amylase levels (a putative indirect marker for central NE activation). In another study, we investigated the effect of continuous tVNS on the late positive potential (LPP), an electrophysiological index for motivated atten-tion toward emotionally evocative cues, and the effects of tVNS on later recognition memory (1- week delay). Here, vagal stimulation prompted earlier LPP differences (300- 500 ms) between unpleasant and neutral scenes. During retrieval, vagal stimulation significantly improved memory performance for unpleasant, but not neutral pictures, compared to sham stimulation, which was also related to enhanced salivary alpha amylase levels. In line, unpleasant images encoded under tVNS compared to sham stimulation also produced enhanced ERP old/new differences (500- 800 ms) during retrieval indicating better recollection. Taken together, our studies suggest that tVNS facilitates attention, learning and episodic memory, likely via afferent projections to the arousal- modulated LC- NE system. We will, however, also show data that point to critical stimulation parameters (likely duration and frequency) that need to be considered when applying tVNS Y1 - 2019 U6 - https://doi.org/10.1111/psyp.13501 SN - 0048-5772 SN - 1469-8986 VL - 56 SP - S12 EP - S12 PB - Wiley CY - Hoboken ER - TY - GEN A1 - Weymar, Mathias A1 - Ventura-Bort, Carlos A1 - Wirkner, Janine A1 - Wendt, Julia A1 - Hamm, Alfons T1 - Effects of Transcutaneous Vagus Nerve Stimulation (TVNS) on unpleasant picture processing and long-term memory T2 - Psychophysiology : journal of the Society for Psychophysiological Research Y1 - 2018 SN - 0048-5772 SN - 1469-8986 VL - 55 SP - S18 EP - S18 PB - Wiley CY - Hoboken ER - TY - GEN A1 - Weymar, Mathias A1 - Ventura-Bort, Carlos A1 - Genheimer, Hannah A1 - Wirkner, Janine A1 - Wendt, Julia A1 - Hamm, Alfons O. T1 - THE P300 AND THE LC-NE SYSTEM: NEW INSIGHTS FROM TRANSCUTANEOUS VAGUS NERVE STIMULATION (TVNS) T2 - Psychophysiology : journal of the Society for Psychophysiological Research KW - P300 KW - norepinephrine KW - transcutaneous vagus nerve stimulation Y1 - 2017 SN - 0048-5772 SN - 1469-8986 VL - 54 SP - S145 EP - S145 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Ventura-Bort, Carlos A1 - Dolcos, Florin A1 - Wendt, Julia A1 - Wirkner, Janine A1 - Hamm, Alfons O. A1 - Weymar, Mathias T1 - Item and source memory for emotional associates is mediated by different retrieval processes JF - Neuropsychologia : an international journal in behavioural and cognitive neuroscience N2 - Recent event-related potential (ERP) data showed that neutral objects encoded in emotional background pictures were better remembered than objects encoded in neutral contexts, when recognition memory was tested one week later. In the present study, we investigated whether this long-term memory advantage for items is also associated with correct memory for contextual source details. Furthermore, we were interested in the possibly dissociable contribution of familiarity and recollection processes (using a Remember/Know procedure). The results revealed that item memory performance was mainly driven by the subjective experience of familiarity, irrespective of whether the objects were previously encoded in emotional or neutral contexts. Correct source memory for the associated background picture, however, was driven by recollection and enhanced when the content was emotional. In ERPs, correctly recognized old objects evoked frontal ERP Old/New effects (300-500 ms), irrespective of context category. As in our previous study (Ventura-Bort et al., 2016b), retrieval for objects from emotional contexts was associated with larger parietal Old/New differences (600-800 ms), indicating stronger involvement of recollection. Thus, the results suggest a stronger contribution of recollection-based retrieval to item and contextual background source memory for neutral information associated with an emotional event. KW - event-related potentials KW - emotion KW - source memory KW - remember/know KW - old/new KW - effect Y1 - 2017 U6 - https://doi.org/10.1016/j.neuropsychologia.2017.12.015 SN - 0028-3932 SN - 1873-3514 VL - 145 PB - Elsevier CY - Oxford ER -