Brain Criticality, Oculomotor Control, and Cognitive Effort

NCT06344559 | Recruiting FDA Device

• 1 other identifier: 2023001006
• Study Type: interventional
• Target: 60
• Locations: 1 country
• Sites: 1

Brief Summary

The project examines electroencephalography, MRI, and behavioral measures indexing flexibility (critical state dynamics) in the brain when healthy young adults do demanding cognitive tasks, and in response to transcranial magnetic stimulation.

Conditions

Healthy

Outcome Measures

Primary Outcomes (14)

• Critical dynamics - immediate effects of cTBS 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.

  Change in correlations recorded during rest, immediately after stimulation, for active versus sham stimulation.

• Functional E/I balance - immediate effects of cTBS 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.

  Change in the functional E/I balance recorded during rest, immediately after stimulation, for active versus sham stimulation.

• Avalanche branching ratio - immediate effects of cTBS 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.

  Change in the avalanche branching ratio recorded during rest, immediately after stimulation, for active versus sham stimulation.

• Critical dynamics - immediate effects of iTBS 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.

  Change in correlations recorded during rest, immediately after stimulation, for active versus sham stimulation.

• Functional E/I balance - immediate effects of iTBS 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.

  Change in the functional E/I balance recorded during rest, immediately after stimulation, for active versus sham stimulation.

• Avalanche branching ratio - immediate effects of iTBS 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.

  Change in the avalanche branching ratio recorded during rest, immediately after stimulation, for active versus sham stimulation.

• Memory-guided saccade accuracy - effects of 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.

  Change in degrees of visual angle error estimated 44 minutes after stimulation, for cTBS versus sham stimulation.

• Memory-guided saccade accuracy - effects of 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.

  Change in degrees of visual angle error estimated 44 minutes after stimulation, for iTBS versus sham stimulation.

• Anti-saccade accuracy - effects of 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.

  Change in percent accuracy estimated 12 minutes after stimulation, for cTBS versus sham stimulation.

• Anti-saccade accuracy - effects of 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.

  Change in percent accuracy estimated 12 minutes after stimulation, for iTBS versus sham stimulation.

• Subjective effort discounting - 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.

  Change in subjective value estimated 72 minutes after stimulation, for cTBS versus sham stimulation.

• Subjective effort discounting - 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.

  Change in subjective value estimated 72 minutes after stimulation, for iTBS versus sham stimulation.

• Subjective effort rating - 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.

  Change in subjective value estimated 70 minutes after stimulation, for cTBS versus sham stimulation.

• Subjective effort rating - 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.

  Change in subjective value estimated 70 minutes after stimulation, for iTBS versus sham stimulation.

Study Arms (3)

Continuous theta burst stimulation

ACTIVE COMPARATOR

In a cross-over design, all participants will, in one session, receive continuous theta burst stimulation, to the right frontal eye field. Session order will be counter-balanced across participants, and stimulation protocol will be blinded to participants and the Investigator until after data collection is complete.

Device: transcranial magnetic stimulation

Intermittent theta burst stimulation

ACTIVE COMPARATOR

In a cross-over design, all participants will, in one session, receive intermittent theta burst stimulation, to the right frontal eye field. Session order will be counter-balanced across participants, and stimulation protocol will be blinded to participants and the Investigator until after data collection is complete.

Device: transcranial magnetic stimulation

Sham theta burst stimulation

SHAM COMPARATOR

In a cross-over design, all participants will, in one session, receive sham theta burst stimulation, to the right frontal eye field. Session order will be counter-balanced across participants, and stimulation protocol will be blinded to participants and the Investigator until after data collection is complete.

Device: transcranial magnetic stimulation

Interventions

transcranial magnetic stimulation DEVICE

The study intervention involves modulation of cortical excitation to inhibition (E/I) balance in the right frontal eye field (FEF) by means of 2 trains of spaced continuous or intermittent theta burst stimulation (cTBS, iTBS, respectively) using a transcranial magnetic stimulation device. The endpoint of this stimulation will be a decrease (cTBS) or increase (iTBS) in the local E/I ratio that should last at least 60 minutes post-stimulation (Chung et al., 2016). In separate sessions, all participants will receive either active or stimulation to the FEF. The Investigators will contrast the effects of both iTBS and cTBS to sham stimulation and to each other.

Continuous theta burst stimulation; Intermittent theta burst stimulation; Sham theta burst stimulation

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Provision of signed and dated informed consent form
• Stated willingness to comply with all study and availability for the duration of the study
• Males and females; Ages 18-45
• Healthy, neurologically normal with no diagnosed mental or physical illness
• Willingness to adhere to the MRI and two session stimulation protocol
• Fluent in English
• Normal or corrected to normal vision
• At least twelve years of education (high school equivalent)

You may not qualify if:

• Ongoing drug or alcohol abuse
• Diagnosed psychiatric or mental illness
• Currently taking psychoactive medication
• Prior brain injury
• Metal in body
• History of seizures or diagnosis of epilepsy
• Claustrophobia
• Pregnant or possibly pregnant
• Younger than 18 or older than 45
• Use of medications which potentially lower the usage threshold

Sponsors & Collaborators

• Rutgers, The State University of New Jersey: lead

Study Sites (1)

Center for Advanced Human Brain Imaging Research

Piscataway, New Jersey, 08854, United States

RECRUITING

Related Publications (2)

• Huang YZ, Edwards MJ, Rounis E, Bhatia KP, Rothwell JC. Theta burst stimulation of the human motor cortex. Neuron. 2005 Jan 20;45(2):201-6. doi: 10.1016/j.neuron.2004.12.033.

  PMID: 15664172 BACKGROUND

• Chung SW, Hill AT, Rogasch NC, Hoy KE, Fitzgerald PB. Use of theta-burst stimulation in changing excitability of motor cortex: A systematic review and meta-analysis. Neurosci Biobehav Rev. 2016 Apr;63:43-64. doi: 10.1016/j.neubiorev.2016.01.008. Epub 2016 Feb 3.

  PMID: 26850210 BACKGROUND

MeSH Terms

Interventions

Transcranial Magnetic Stimulation

Intervention Hierarchy (Ancestors)

Magnetic Field Therapy; Therapeutics

Study Officials

• John A Westbrook, PhD

  Rutgers University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

John A Westbrook, PhD

CONTACT

9193605399; andrew.westbrook@rutgers.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Masking Details: Participants numbers will be assigned three blinded codes which are linked with either sham, active continuous, or active intermittent theta burst stimulation in the stimulator protocol. The investigator will enter the code to initiate the corresponding stimulator protocol, but will not know which protocol is active. Half of participants will be assigned a sham code corresponding to sham continuous theta burst stimulation and half will be assigned a sham code corresponding to sham intermittent theta burst stimulation. So, for any given session, either continuous or intermittent theta burst stimulation will be used, but it will be unclear whether the stimulation is active or sham.
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor

Model Details: The study will involve three sessions of within-subject, crossover, double-blind transcranial magnetic stimulation with either 1) active intermittent theta burst stimulation, 2) active continuous theta burst stimulation or 3) sham intermittent or continuous theta burst stimulation.

Study Record Dates

• First Submitted: March 27, 2024
• First Posted: April 3, 2024
• Study Start: August 1, 2024
• Primary Completion (Estimated): June 1, 2026
• Study Completion (Estimated): June 1, 2026
• Last Updated: August 7, 2024

Record last verified: 2024-08

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)