NCT05368987 · The University of Texas Health Science Center, Houston
Neuromodulation of the Fear Extinction Circuit Using Temporally and Anatomically Specific TMS in Humans
What this study is about
This study aims to explore the mechanisms of how transcranial magnetic stimulation (TMS) impacts fear circuits. The overarching objectives are to understand how varying TMS parameters affect targeted brain regions in order to optimize its impact on enhancing fear extinction memory consolidation in a population with known fear extinction deficiencies: post-traumatic stress disorder (PTSD).
View original scientific description
This study aims to explore the mechanisms of how transcranial magnetic stimulation (TMS) impacts fear circuits. The overarching objectives are to understand how varying TMS parameters affect targeted brain regions in order to optimize its impact on enhancing fear extinction memory consolidation in a population with known fear extinction deficiencies: post-traumatic stress disorder (PTSD). 250 subjects will take part in this research study across UTHealth Houston.
Interventions
DEVICE
Transcranial magnetic stimulation (TMS)
Research subjects will undergo non-invasive TMS, with a frequency of 20Hz and intensity of 120% of their resting motor threshold (rMT) at varying time points and locations.
BEHAVIORAL
Fear Conditioning and Extinction Paradigm
Participants will undergo a 3-day experimental paradigm. On day 1, participants will undergo a resting-state and structural scans in the fMRI scanner. The data from this scan will be used to determine the specific location of the TMS target for each participant. And participants will be aversively conditioned to two cues in the fMRI scanner. Task based and resting-state scans will occur on this day. On day 2, subjects will undergo extinction training outside of the scanner where one of the conditioned cues will be paired with TMS in a temporally and anatomically specific manner. A resting-state scan will occur before and after inside the scanner. On day 3, conditioned cues will be presented during the extinction recall phase of the study. This phase will be conducted in the fMRI scanner. Task-based and resting-state scans will occur on this day.
Primary outcome measures
Skin Conductance Response (SCR)
Time frame: Experimental Day 1
Conductance is measured by placing two electrodes next to the skin and passing a tiny electric charge between the two points. SCR is proportionally related to the number of sweat glands that are activated, meaning in essence that the more emotionally aroused an individual is, the more the SCR amount is increased.
Skin Conductance Response (SCR)
Time frame: Experimental Day 3
Conductance is measured by placing two electrodes next to the skin and passing a tiny electric charge between the two points. SCR is proportionally related to the number of sweat glands that are activated, meaning in essence that the more emotionally aroused an individual is, the more the SCR amount is increased.
Functional MRI (fMRI) blood-oxygen-level-dependent (BOLD) responses
Time frame: Experimental Day 1
fMRI data, including blood-oxygen-level-dependent (BOLD) responses, is used in neuroimaging studies assess neural correlate activations and observe the increase/decrease in activation of a particular brain area in response to a specific cue. When these cells are active, there is an increase in blood oxygen in the surrounding area.
Functional MRI (fMRI) blood-oxygen-level-dependent (BOLD) responses
Time frame: Experimental Day 3
fMRI data, including blood-oxygen-level-dependent (BOLD) responses, is used in neuroimaging studies assess neural correlate activations and observe the increase/decrease in activation of a particular brain area in response to a specific cue. When these cells are active, there is an increase in blood oxygen in the surrounding area.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Willing and able to provide informed consent.
Exclusion criteria
- Lifetime history of seizure or significant head trauma or other significant neurologic disease (e.g., tic disorder)
- History of serious/significant psychiatric diagnoses ("Axis I" diagnoses)
- Current significant suicidal ideation, plan or intent or suicidal behavior in past 6 months based on CSSRS and clinical judgment or Self-injurious behavior that involves suicidal intent, requires medical attention, or occurs daily
- Use of neuroleptics within one year prior to study
- Current substance use
- Pregnancy (to be ruled out by urine β-HCG).
- Metallic implants or devices contraindicating magnetic resonance imaging.
- Currently taking medications that lower the seizure threshold. These include antipsychotics, high dose theophylline or stimulants such as methylphenidate. Patients taking bupropion must be on a stable dose (\*last 3 months) and take less than or equal to 300 mg/day.
- Implanted devices in subject's head (shunts, cochlear implants); metal in subject's head (other than dental implants).
- High risk of adverse emotional or behavioral reaction, and/or an inability to understand study procedures or the informed consent process
- Additional exclusion criteria for Healthy controls (HC) group: Current psychiatric diagnosis ("Axis I" diagnosis)
Where
- Houston, Texas
Collaborators
National Institute of Mental Health (NIMH)
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced May 5, 2026 · Source of record for eligibility and locations