Brain Criticality, Oculomotor Control, and Cognitive Effort Study
This study is looking at how the brain works when healthy young adults do challenging thinking tasks and how it responds to a treatment called transcranial magnetic stimulation (TMS). TMS uses a device to gently stimulate specific areas of the brain. Researchers want to understand how the brain's "critical state dynamics" (its ability to be flexible) are affected by these tasks and by TMS. They are also investigating how the balance of brain activity (excitation to inhibition, or E/I balance) changes. You may be eligible if you are a healthy adult between 18 and 45 years old. The study will measure changes in brain activity immediately after TMS compared to a sham (inactive) stimulation to see if the treatment has an effect.
- Study design
- This is an interventional study planning to enroll 60 healthy participants. It will compare the effects of active transcranial magnetic stimulation (cTBS or iTBS) to a sham (inactive) stimulation.
- What's involved
- You would need to agree to an MRI scan and two study sessions involving transcranial magnetic stimulation. The study does not specify the total duration of participation.
- Compensation
- Not stated in the trial record.
- Follow-up
- The primary outcomes measure immediate effects of the stimulation, so follow-up beyond the stimulation sessions is not specified.
AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.
Brain Criticality, Oculomotor Control, and Cognitive Effort
At a glance
Conditions
Where it's being run
1 sites across 1 statesStudy leadership
- John A Westbrook, PhD · PRINCIPAL_INVESTIGATOR · Rutgers University
Who to contact
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What this trial measures
- Critical dynamics - immediate effects of cTBS versus sham stimulationChange in correlations recorded during rest, immediately after stimulation, for active versus sham stimulation.
Long-range temporal correlations quantified by the scaling exponent, which is derived from EEG data, via detrended fluctuation analysis. Scores range from 0.5 (uncorrelated time series) to 1.0 (correlated time series). Lower scores, indicating weaker correlations, are expected following active continuous theta burst stimulation (cTBS) versus sham stimulation. So, the difference score should be negative, indicating weaker long-range temporal correlations as a result of cTBS, immediately after stimulation.
- Functional E/I balance - immediate effects of cTBS versus sham stimulationChange in the functional E/I balance recorded during rest, immediately after stimulation, for active versus sham stimulation.
The functional E/I ratio, which is derived from a comparison of band-limited amplitude to the fluctuation function, reflects the balance of excitation versus inhibition driving the associated oscillations. Scores range from approximately 0.5 to 1.5 with values below 1.0 indicating inhibition dominance and values above 1.0 indicating excitation dominance. Lower scores, indicating more inhibition dominance, are expected following active continuous theta burst stimulation (cTBS) versus sham stimulation. So, the difference score should be negative, indicating a lower E/I balance as a result of cTBS, immediately after stimulation.
- Avalanche branching ratio - immediate effects of cTBS versus sham stimulationChange in the avalanche branching ratio recorded during rest, immediately after stimulation, for active versus sham stimulation.
The growth rate of neuronal avalanches can be estimated from the clustering of high amplitude events in in electroencephalography (EEG) signal. Faster growing avalanches correspond with tighter clustering of events in time. Scores range from approximately 0.5 to 1.5 with values below 1.0 indicating inhibition dominance and values above 1.0 indicating excitation dominance. Lower scores, indicating more inhibition dominance, are expected following active continuous theta burst stimulation (cTBS) versus sham stimulation. So, the difference score should be negative, indicating a lower E/I balance as a result of cTBS, immediately after stimulation.
- Critical dynamics - immediate effects of iTBS versus sham stimulationChange in correlations recorded during rest, immediately after stimulation, for active versus sham stimulation.
Long-range temporal correlations quantified by the scaling exponent, which is derived from EEG data, via detrended fluctuation analysis. Scores range from 0.5 (uncorrelated time series) to 1.0 (correlated time series). Higher scores, indicating stronger correlations, are expected following active intermittent theta burst stimulation (iTBS) versus sham stimulation. So, the difference score should be positive, indicating stronger long-range temporal correlations as a result of iTBS, immediately after stimulation.
- Functional E/I balance - immediate effects of iTBS versus sham stimulationChange in the functional E/I balance recorded during rest, immediately after stimulation, for active versus sham stimulation.
The functional E/I ratio, which is derived from a comparison of band-limited amplitude to the fluctuation function, reflects the balance of excitation versus inhibition driving the associated oscillations. Scores range from approximately 0.5 to 1.5 with values below 1.0 indicating inhibition dominance and values above 1.0 indicating excitation dominance. Higher scores, indicating more excitation dominance, are expected following active intermittent theta burst stimulation (iTBS) versus sham stimulation. So, the difference score should be positive, indicating a higher E/I balance as a result of iTBS, immediately after stimulation.
- Avalanche branching ratio - immediate effects of iTBS versus sham stimulationChange in the avalanche branching ratio recorded during rest, immediately after stimulation, for active versus sham stimulation.
The growth rate of neuronal avalanches can be estimated from the clustering of high amplitude events in in electroencephalography (EEG) signal. Faster growing avalanches correspond with tighter clustering of events in time. Scores range from approximately 0.5 to 1.5 with values below 1.0 indicating inhibition dominance and values above 1.0 indicating excitation dominance. Higher scores, indicating more excitation dominance, are expected following active intermittent theta burst stimulation (iTBS) versus sham stimulation. So, the difference score should be positive, indicating a higher E/I balance as a result of iTBS, immediately after stimulation.
- Memory-guided saccade accuracy - effects of cTBS versus sham stimulationChange in degrees of visual angle error estimated 44 minutes after stimulation, for cTBS versus sham stimulation.
Accuracy on the memory-guided saccade task, as quantified by mean degrees of visual angle deviation typically range from \~1.0 to 5.0 degrees, with higher scores indicating higher inaccuracy. Theta burst stimulation to the FEF should modulate cortical excitability making the FEF in some people's brains operate closer to criticality, and in others' brains, operate farther from criticality. Because criticality implies susceptibility and flexibility, stimulation protocols which make the FEF operate closer to criticality, relative to sham stimulation, will show bigger errors in degrees of visual angle.
- Memory-guided saccade accuracy - effects of iTBS versus sham stimulationChange in degrees of visual angle error estimated 44 minutes after stimulation, for iTBS versus sham stimulation.
Accuracy on the memory-guided saccade task, as quantified by mean degrees of visual angle deviation typically range from \~1.0 to 5.0 degrees, with higher scores indicating higher inaccuracy. Theta burst stimulation to the FEF should modulate cortical excitability making the FEF in some people's brains operate closer to criticality, and in others' brains, operate farther from criticality. Because criticality implies susceptibility and flexibility, stimulation protocols which make the FEF operate closer to criticality, relative to sham stimulation, will show bigger errors in degrees of visual angle.
- Anti-saccade accuracy - effects of cTBS versus sham stimulationChange in percent accuracy estimated 12 minutes after stimulation, for cTBS versus sham stimulation.
Accuracy on the anti-saccade task, as quantified by mean percent of correct saccades away from a cue typically ranges between 80% and 100% correct. Theta burst stimulation to the FEF should modulate cortical excitability making the FEF in some people's brains operate closer to criticality, and in others' brains, operate farther from criticality. Because criticality implies greater inter-regional communication between top-down control regions and sensorimotor cortex, stimulation protocols which make the FEF operate closer to criticality, relative to sham stimulation, will a higher perfect increase in accuracy as a result of stimulation.
- Anti-saccade accuracy - effects of iTBS versus sham stimulationChange in percent accuracy estimated 12 minutes after stimulation, for iTBS versus sham stimulation.
Accuracy on the anti-saccade task, as quantified by mean percent of correct saccades away from a cue typically ranges between 80% and 100% correct. Theta burst stimulation to the FEF should modulate cortical excitability making the FEF in some people's brains operate closer to criticality, and in others' brains, operate farther from criticality. Because criticality implies greater inter-regional communication between top-down control regions and sensorimotor cortex, stimulation protocols which make the FEF operate closer to criticality, relative to sham stimulation, will a higher perfect increase in accuracy as a result of stimulation.
- Subjective effort discounting - cTBS versus sham stimulationChange in subjective value estimated 72 minutes after stimulation, for cTBS versus sham stimulation.
Subjective values as estimated from an effort discounting procedure as a discounted offer ranging from 0.0 (full effort discounting) to 1.0 (no effort discounting). Lower values indicate that people find subjective effort to be more costly. Theta burst stimulation to the FEF should modulate cortical excitability making the FEF in some people's brains operate closer to criticality, and in others' brains, operate farther from criticality. We hypothesize that divergence from criticality underlies phenomenological effort. So, we predict that stimulation which makes people's brains operate closer to criticality relative to sham will experience less effort and have a higher subjective value.
- Subjective effort discounting - iTBS versus sham stimulationChange in subjective value estimated 72 minutes after stimulation, for iTBS versus sham stimulation.
Subjective values as estimated from an effort discounting procedure as a discounted offer ranging from 0.0 (full effort discounting) to 1.0 (no effort discounting). Lower values indicate that people find subjective effort to be more costly. Theta burst stimulation to the FEF should modulate cortical excitability making the FEF in some people's brains operate closer to criticality, and in others' brains, operate farther from criticality. We hypothesize that divergence from criticality underlies phenomenological effort. So, we predict that stimulation which makes people's brains operate closer to criticality relative to sham will experience less effort and have a higher subjective value.
- Subjective effort rating - cTBS versus sham stimulationChange in subjective value estimated 70 minutes after stimulation, for cTBS versus sham stimulation.
Likert ratings of subjective effort randing from 1 (low effort) to 10 (high effort). Theta burst stimulation to the FEF should modulate cortical excitability making the FEF in some people's brains operate closer to criticality, and in others' brains, operate farther from criticality. We hypothesize that divergence from criticality underlies phenomenological effort. So, we predict that stimulation which makes people's brains operate closer to criticality relative to sham will experience less effort and have a higher subjective value.
- Subjective effort rating - iTBS versus sham stimulationChange in subjective value estimated 70 minutes after stimulation, for iTBS versus sham stimulation.
Likert ratings of subjective effort randing from 1 (low effort) to 10 (high effort). Theta burst stimulation to the FEF should modulate cortical excitability making the FEF in some people's brains operate closer to criticality, and in others' brains, operate farther from criticality. We hypothesize that divergence from criticality underlies phenomenological effort. So, we predict that stimulation which makes people's brains operate closer to criticality relative to sham will experience less effort and have a higher subjective value.