TMS Alteration of the Reward Positivity

Study Overview
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Brief Summary
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The aim of this proposal is to demonstrate that stimulation of different brain regions differently affects the electroencephalographic feature known as the Reward Positivity (RewP).

Detailed Description
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The aim of this proposal is to demonstrate that stimulation of different brain regions differently affects the electroencephalographic feature known as the Reward Positivity (RewP). The RewP is a sensitive and specific biomarker of reward receipt. This proposal will advance a causal test of the hypothesis that there are two major sources of variance that contribute to this brain response: a dorsal midline contribution to information encoding and a ventral midline contribution that is modulated by affect. Together, these findings will reveal how the RewP acts to blend multiple aspects of value together in the service of motivated learning. The objective of this proposal is to gather pilot data to demonstrate the feasibility of using transcranial magnetic stimulation (TMS) to perturb idiosyncratically-defined (fMRI-based) dorsal or ventral targets in order to causally test the hypothesis that these different sources contribute different types of variance to the RewP. TMS double cone deep coil stimulation should diminish +RPE encoding in the RewP when compared to sham. TMS Figure-8 coil stimulation should diminish affective modulation of RewP amplitude when compared to sham.

Official Title
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Causal Dissociation of Value Contributions to the Reward Positivity

Conditions
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Anhedonia

Intervention / Treatment
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* Device: Transcranial Magnetic Stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: • Men or women aged 18-30 Exclusion Criteria: Participants unwilling or unable to give informed consent Presence of other known medical or psychiatric comorbidity that in the investigator's opinion would compromise participation in the study MEG/MRI contraindications History of psychosis Not fluent in English

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 30 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Two separate arms of study
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Theta Stim<br>To stimulate fMRI-informed individualized targets in dlPFC to diminish affective modulation of the RewP. Based on our working hypothesis, TMS Figure-8 coil stimulation should diminish affective modulation of RewP amplitude when compared to sham. | Device: Transcranial Magnetic Stimulation<br>* Figure 8 coil stimulation<br>|
| Sham Comparator: Sham Stim<br>Sham stimulation. The Reward Positivity should be unaffected. | Device: Transcranial Magnetic Stimulation<br>* Figure 8 coil stimulation<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Reward Positivity | EEG Amplitude 200-400 ms following reward receipt | During intervention |