An interventional study of Transcranial magnetic stimulation (TMS) in Approach/Avoidance Behavior, sponsored by University of Minnesota. Completed at 1 site in United States. Open to participants aged 18 Years to 65 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-12-10.
Sponsored by University of Minnesota · Not applicable, Interventional, and Basic science
The purpose of this study is to evaluate the causal link between the phase of ongoing theta oscillations in the prefrontal cortex and approach/avoidance (Ap/Av) behavior in adults using theta phase-specific transcranial magnetic stimulation (TMS).
Approach/avoidance (Ap/Av) behavior is a reliable marker of the emotional processes in the human brain and a robust predictor of mood disorders. Although existing scientific studies found a correlation between the approach/avoidance behavior and ongoing theta activity (3-7 Hz) in the left dorsolateral prefrontal cortex, the causal evidence of the phase-dependent role and strength of association between the prefrontal theta oscillations and approach/avoidance behavior are still unclear. Here, we will monitor brain oscillations in real-time non-invasively using electroencephalography during the approach/avoidance test and modulate theta peaks or troughs with transcranial magnetic stimulation. These data will provide novel understanding of the mechanisms of emotional processing in human brain.
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Transcranial magnetic stimulation (TMS) will be administrated with a figure-8 coil over the left dorsolateral prefrontal cortex (DLPFC) at the intensity of up to 120% of the individualized resting motor threshold (rMT). Stimulation will be performed during and for the duration of the cognitive test. Up to three TMS pulses will be delivered at the beginning of every test trial (each trial duration is 2-6 seconds). The total duration of the cognitive testing and stimulation per session is approximately 40 minutes (in 4 blocks with breaks in-between).
Device: Transcranial magnetic stimulation (TMS)
Transcranial magnetic stimulation (TMS) will be administrated with a figure-8 coil over the head vertex at the intensity of up to 120% of the individualized resting motor threshold (rMT). Stimulation will be performed during and for the duration of the cognitive test. Up to three TMS pulses will be delivered at the beginning of every test trial (each trial duration is 2-6 seconds). The total duration of the cognitive testing per session is approximately 40 minutes (in 4 blocks with breaks in-between).
Device: Transcranial magnetic stimulation (TMS)
TMS will be performed at either peaks or troughs of ongoing prefrontal theta oscillations (3-7 Hz) concurrently with the cognitive test at the beginning of every test trial. Theta oscillations will be monitored in real-time at the left dorsolateral prefrontal cortex using electroencephalography (EEG).
Reaction Times in the Approach/Avoidance Test
Reaction time (in milliseconds) in the Approach/Avoidance task during transcranial magnetic stimulation (TMS). TMS was synchronized to either the peaks or troughs of the participant's left prefrontal theta waves, in a randomized and counterbalanced order. The preregistered primary outcome measure is the average difference in reaction times between peak- and trough-synchronized stimulation stimuli. This statistical contrast specifically highlights the role of theta phase in phase-aligned stimulation.
Time frame: During the stimulation/task for each condition (approximately 6 minutes per run, 4 runs per condition).
Amplitude of TMS Evoked Potentials
Amplitude of transcranial magnetic stimulation (TMS)-evoked potentials (in microvolts) in ongoing electroencephalography (EEG) in the left prefrontal cortex during the TMS synchronized to either peaks or troughs of the participant's left prefrontal theta waves. The preregistered secondary outcome measure is the average difference in early absolute evoked potentials between peak- and trough-synchronized stimulation epochs. This statistical contrast specifically highlights the phase-specific effect of theta phase-aligned stimulation.
Time frame: During the stimulation/task for each condition (approximately 6 minutes per run, 4 runs per condition).
| Milestone | TMS Over the Prefrontal Cortex Followed by TMS Over the Head Vertex. | TMS Over the Head Vertex Followed by TMS Over the Prefrontal Cortex. |
|---|---|---|
| Started | 13 | 13 |
| Completed | 11 | 12 |
| Not completed | 2 | 1 |
| Withdrew: Withdrawal by subject | 2 | 1 |
Reaction time (in milliseconds) in the Approach/Avoidance task during transcranial magnetic stimulation (TMS). TMS was synchronized to either the peaks or troughs of the participant's left prefrontal theta waves, in a randomized and counterbalanced order. The preregistered primary outcome measure is the average difference in reaction times between peak- and trough-synchronized stimulation stimuli. This statistical contrast specifically highlights the role of theta phase in phase-aligned stimulation.
| milliseconds | TMS Over the Left Prefrontal Cortex | TMS Over the Head Vertex |
|---|---|---|
| Reaction Times in the Approach/Avoidance Test | 36.8 ± 16.3 | 12.4 ± 21.2 |
Amplitude of transcranial magnetic stimulation (TMS)-evoked potentials (in microvolts) in ongoing electroencephalography (EEG) in the left prefrontal cortex during the TMS synchronized to either peaks or troughs of the participant's left prefrontal theta waves. The preregistered secondary outcome measure is the average difference in early absolute evoked potentials between peak- and trough-synchronized stimulation epochs. This statistical contrast specifically highlights the phase-specific effect of theta phase-aligned stimulation.
| microvolts | TMS Over the Left Prefrontal Cortex | TMS Over the Head Vertex |
|---|---|---|
| Amplitude of TMS Evoked Potentials | 1.3 ± 1.9 | 0.2 ± 1.1 |
Collected over During the visit that included TMS procedures (4 hours). Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| TMS Over the Prefrontal Cortex Followed by TMS Over the Head Vertex. | 0/11 (0%) | 0/11 (0%) | 0/11 (0%) |
| TMS Over the Head Vertex Followed by TMS Over the Prefrontal Cortex. | 0/12 (0%) | 0/12 (0%) | 0/12 (0%) |
| Age, Categorical(Participants) | All Participants |
|---|---|
| <=18 years | 0 |
| Between 18 and 65 years | 26 |
| >=65 years | 0 |
| Sex: Female, Male(Participants) | All Participants |
|---|---|
| Female | 13 |
| Male | 13 |
| Race (NIH/OMB)(Participants) | All Participants |
|---|---|
| American Indian or Alaska Native | 0 |
| Asian | 5 |
| Native Hawaiian or Other Pacific Islander | 0 |
| Black or African American | 2 |
| White | 17 |
| More than one race | 2 |
| Unknown or Not Reported | 0 |
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Plan to share: Yes — Full or partial access to the preprocessed data will be provided upon the request to the faculty / research staff of recognized research, medical, and educational institutions for educational and scientific purposes. The request should be sent via an institutional email and will be stored with the study materials. The request should include a short description of the scientific or educational aims.
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