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Completed

NCT Number: NCT05416138

Theta Phase-specific TMS to Modulate Prefrontal Activity

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).

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Key information

Conditions

Approach/Avoidance Behavior

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Minnesota

Minneapolis, Minnesota, 55455, United States

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age between 18 and 65 years old.
  • Confident level of English language.

Exclusion criteria

  • Chronic condition that requires pharmacological treatment over the course of study participation.
  • Metallic or electric implant in the head, neck, or chest area or otherwise MRI-noncompatible implants.
  • History or evidence of seizures, head injuries with loss of consciousness, chronic neurological or mental disorder.
  • Pregnancy or breast-feeding.
  • History or evidence of alcohol or drug addiction.

Treatment and study plan

Transcranial Magnetic Stimulation (TMS)

Device

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).

Primary outcomes

  1. Reaction Times in the Approach/Avoidance Test

    Time frame: During the stimulation/task for each condition (approximately 6 minutes per run, 4 runs per condition).

    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.

Secondary outcomes

  1. Amplitude of TMS Evoked Potentials

    Time frame: During the stimulation/task for each condition (approximately 6 minutes per run, 4 runs per condition).

    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.

Sponsors and collaborators

Lead sponsor

University of Minnesota

Other

Collaborators

  • National Institute of Mental Health (NIMH)

Registry information

Official study title

The Effects of Closed-loop TMS-EEG on Immediate Prefrontal Activity and Approach/Avoidance Behavior

Important dates

Study start
2022
Primary completion
2024
Study completion
2024
First posted
Jun 13, 2022
Registry last updated
Dec 10, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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