Testing the Contribution of Orbitofrontal Cortex Networks to Decision-making

Study Overview
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Brief Summary
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This research study examines the contribution of orbitofrontal cortex (OFC) networks to decision-making.

Detailed Description
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This study will combine functional magnetic resonance imaging (fMRI), non-invasive transcranial magnetic stimulation (TMS), olfactory stimuli, and a devaluation task to define the specific contributions of orbitofrontal cortex (OFC) networks in outcome-guided behavior. We will use network-targeted TMS to modulate activity within anterior OFC and posterior OFC networks, examining if they have different contributions to decision-making. This is a randomized, between-subjects design.

Official Title
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Testing the Contribution of Orbitofrontal Cortex Networks to Decision-making

Conditions
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Healthy

Intervention / Treatment
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* Device: Real transcranial magnetic stimulation (TMS) before conditioning
* Device: Real transcranial magnetic stimulation (TMS) before devaluation test
* Device: Sham transcranial magnetic stimulation (TMS)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age between 18 and 40 years old Right-handed Fluent English speakers Exclusion Criteria: History of significant neurological conditions (e.g., epilepsy, dementia, multiple sclerosis, brain tumors, etc.) History of major psychiatric conditions (e.g., general anxiety disorder, depression, schizophrenia, obsessive-compulsive disorder, post-traumatic stress disorder, attention deficit hyperactivity disorder, substance use disorder, etc.) Significant medical illnesses (e.g., cancer, meningitis, chronic obstructive pulmonary disease, cardiovascular disease, etc.) Significant cerebrovascular risk factors (e.g., hypertension, diabetes, elevated cholesterol, etc.) Current use of psychoactive medications (e.g., barbiturates, benzodiazepines, chloral hydrate, haloperidol, lithium, carbamazepine, phenytoin, citalopram, escitalopram, fluoxetine, diazepam, etc.) Smell or taste dysfunction History of significant allergies requiring hospitalization for treatment History of severe asthma requiring hospitalization for treatment Habitual smoking History of eating disorders (e.g., anorexia nervosa, bulimia nervosa, binge-eating disorder, etc.) Dieting or fasting Magnetic implants (e.g., shunts or stents, aneurysm clips, surgical clips, cochlear implants, metal bone/joint pins, plates and screws, eyelid spring or wires, etc.) Electronic devices (e.g., implanted cardiac defibrillator, cardiac pacemaker, deep brain/spinal cord or nerve stimulator, internal electrodes/wires, medication infusion devices, etc.) History of metal working without proper eye protection, or injury with metal shrapnel or metal slivers Claustrophobia Pregnancy Predisposition to seizures (e.g., personal history of seizures, family history of seizures epilepsy, pregnancy, alcoholism, etc.) Use of medications that increase the likelihood of seizures (e.g., bupropion SR, citalopram, duloxetine, ketamine, gamma-hydroxybutyrate, etc.) History of surgical procedures performed on the brain or spinal cord History of severe head trauma followed by loss of consciousness History of fainting spells or syncope Hearing problems or tinnitus

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 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: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: TMS targeting anterior OFC networks<br>Participants will receive TMS and sham targeting the anterior OFC network. | Device: Real transcranial magnetic stimulation (TMS) before conditioning<br>* Real TMS will be applied using the MagVenture MagPro X100 stimulator with the active side of the Cool-B65 A/P coil before the conditioning phase of the task.<br>Device: Real transcranial magnetic stimulation (TMS) before devaluation test<br>* Real TMS will be applied using the MagVenture MagPro X100 stimulator with the active side of the Cool-B65 A/P coil before the devaluation test phase of the task.<br>Device: Sham transcranial magnetic stimulation (TMS)<br>* Sham TMS will be applied using the MagVenture MagPro X100 stimulator with the placebo side of the Cool-B65 A/P coil.<br>|
| Experimental: TMS targeting posterior OFC networks<br>Participants will receive TMS and sham targeting the posterior OFC network. | Device: Real transcranial magnetic stimulation (TMS) before conditioning<br>* Real TMS will be applied using the MagVenture MagPro X100 stimulator with the active side of the Cool-B65 A/P coil before the conditioning phase of the task.<br>Device: Real transcranial magnetic stimulation (TMS) before devaluation test<br>* Real TMS will be applied using the MagVenture MagPro X100 stimulator with the active side of the Cool-B65 A/P coil before the devaluation test phase of the task.<br>Device: Sham transcranial magnetic stimulation (TMS)<br>* Sham TMS will be applied using the MagVenture MagPro X100 stimulator with the placebo side of the Cool-B65 A/P coil.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Behavior on devaluation task | Percentage of cues predicting non-devalued vs devalued odors chosen during the devaluation task. | 1 hour after intervention | 
| Resting-state functional magnetic resonance imaging | Resting-state activity determined by functional magnetic resonance imaging. | 1 hour after intervention |