Approach/Avoidance Behavior
Conditions
Brief summary
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).
Detailed description
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.
Interventions
DEVICETranscranial 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).
Sponsors
National Institute of Mental Health (NIMH)
University of Minnesota
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
1. Age between 18 and 65 years old. 2. Confident level of English language.
Exclusion criteria
1. Chronic condition that requires pharmacological treatment over the course of study participation. 2. Metallic or electric implant in the head, neck, or chest area or otherwise MRI-noncompatible implants. 3. History or evidence of seizures, head injuries with loss of consciousness, chronic neurological or mental disorder. 4. Pregnancy or breast-feeding. 5. History or evidence of alcohol or drug addiction.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Reaction Times in the Approach/Avoidance Test | 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
| Measure | Time frame | Description |
|---|---|---|
| Amplitude of TMS Evoked Potentials | 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. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| All Participants All 26 participants consented in this study | 26 |
| Total | 26 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Withdrawal by Subject | 2 | 1 |
Baseline characteristics
| Characteristic | All Participants |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 0 Participants |
| Age, Categorical Between 18 and 65 years | 26 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants |
| Race (NIH/OMB) Asian | 5 Participants |
| Race (NIH/OMB) Black or African American | 2 Participants |
| Race (NIH/OMB) More than one race | 2 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) White | 17 Participants |
| Sex: Female, Male Female | 13 Participants |
| Sex: Female, Male Male | 13 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 11 | 0 / 12 |
| other Total, other adverse events | 0 / 11 | 0 / 12 |
| serious Total, serious adverse events | 0 / 11 | 0 / 12 |
Outcome results
Primary
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).
Population: Cross-over study - all participants were in both arms at different timepoints
| Arm | Measure | Value (MEDIAN) | Dispersion |
|---|---|---|---|
| TMS Over the Left Prefrontal Cortex | Reaction Times in the Approach/Avoidance Test | 36.8 milliseconds | Standard Error 16.3 |
| TMS Over the Head Vertex | Reaction Times in the Approach/Avoidance Test | 12.4 milliseconds | Standard Error 21.2 |
Secondary
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).
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| TMS Over the Left Prefrontal Cortex | Amplitude of TMS Evoked Potentials | 1.3 microvolts | Standard Deviation 1.9 |
| TMS Over the Head Vertex | Amplitude of TMS Evoked Potentials | 0.2 microvolts | Standard Deviation 1.1 |