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| Name | Class |
|---|---|
| Universität Tübingen | OTHER |
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Attaining goals or rewards commonly entails response costs. In light of cost and benefits, how do participants decide what effort should be put in to give it a shot? Figuratively, you may "go with your gut", but the literal contribution of the gut-brain axis in allocating effort is poorly understood to date. Here, the investigators propose to investigate non-invasive transcutaneous vagal nerve stimulation (tVNS) as a potential modulator of energy metabolism and response vigor. Since the neural mechanisms causing the diverse cognitive and behavioral effects of the stimulation remain largely elusive, the investigators will use computational modeling of instrumental behavior and determine the primary metabolic effects of the stimulation. The investigators hypothesize that tVNS will lead to activation of afferent targets in the brain. In turn, the elicited brain activation is expected to mediate the cognitive effects of the stimulation. This may affect both sides of the utility equation because anti-depressive effects may correspond to boosting the benefit of effort whereas anti-nociceptive effects may reduce perceived costs of effort. Collectively, dissecting the cognitive effects of non-invasive tVNS in healthy individuals may facilitate the more widespread use as a treatment in mental disorders that are characterized by metabolic alterations such as depression.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Non-depressed control participants: sham first, active taVNS second | Experimental | Non-depressed control participants receive sham stimulation in the first session (biphasic stimulation with a frequenyc of 25 Hz, 30s OFF/30s ON at the earlobe (sham) for 1.5 h). In a second identical session, they receive active stimulation with the same parameters (at the cymba conchae). |
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| Patients with major depressive disorders: sham first, active taVNS second | Experimental | participants with depression receive sham stimulation in the first session (biphasic stimulation with a frequenyc of 25 Hz, 30s OFF/30s ON at the earlobe (sham) for 1.5 h). In a second identical session, they receive active stimulation with the same parameters (at the cymba conchae). |
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| Patients with major depressive disorders: active taVNS first, sham second | Experimental | participants with depression receive active stimulation in the first session (biphasic stimulation with a frequenyc of 25 Hz, 30s OFF/30s ON at the cymba conchae (active) for 1.5 h). In a second identical session, they receive sham stimulation with the same parameters (at the earlobe). |
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| Non-depressed control participants: active taVNS first, sham second | Experimental | Non-depressed control participants receive active stimulation in the first session (biphasic stimulation with a frequenyc of 25 Hz, 30s OFF/30s ON at the cymba conchae (active) for 1.5 h). In a second identical session, they receive sham stimulation with the same parameters (at the earlobe). |
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| transcutaneous vagus nerve stimulation | Device | Non-invasive brain stimulation technique that is used to stimulate vagal afferent projections to the nucleus of the solitary tract. Invasive VNS has been approved for the treatment of treatment-resistant depression. |
| Measure | Description | Time Frame |
|---|---|---|
| Food reward ratings | Operationalized via visual analogue scale ratings of liking [-100 - 100] and wanting [0-100] in a food cue reactivity task | during stimulation (compared to sham) |
| Motivation to work for rewards: frequency of button presses to gain food an monetary rewards | Operationalized via the relative frequency of button presses on an Xbox controller in an effort allocation task during either the first seconds of each trial (invigoration) or each complete trial (maintenance) | during stimulation (compared to sham) |
| Reward learning: correct choices | Operationalized via number of correct value-based choices in a valenced go/no-go learning task | during stimulation (compared to sham) |
| Positive and negative mood | Operationalized via visual analogue ratings (0-100) of positive and negative affect schedule mood items | Pre stimulation and 20 minutes post stimulation (compared to sham) |
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Inclusion Criteria:
Exclusion Criteria:
lifetime
brain injury
coronary heart disease and occurred apoplexy
schizophrenia
bipolar disorder
implants (e.g., cochlea implant)
asthma
12 month
severe substance use disorders (DSM-V), except tobacco
obessive compulsive disorder
somatic symptom disorder
eating disorder
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| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Department of Psychiatry & Psychotherapy, University of Tübingen | Tübingen | Baden-Wurttemberg | 72076 | Germany |
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| ID | Term |
|---|---|
| D003865 | Depressive Disorder, Major |
| D059445 | Anhedonia |
| ID | Term |
|---|---|
| D003866 | Depressive Disorder |
| D019964 | Mood Disorders |
| D001523 | Mental Disorders |
| D019954 | Neurobehavioral Manifestations |
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| sham stimulation | Device | Sham procedure for active transcutaneous vagus nerve stimulation |
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| D009461 |
| Neurologic Manifestations |
| D009422 | Nervous System Diseases |
| D012816 | Signs and Symptoms |
| D013568 | Pathological Conditions, Signs and Symptoms |