Brain Criticality, Oculomotor Control, and Cognitive Effort
Purpose
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.
Condition
- Healthy
Eligibility
- Eligible Ages
- Between 18 Years and 45 Years
- Eligible Sex
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- Provision of signed and dated informed consent form 2. Stated willingness to comply with all study and availability for the duration of the study 3. Males and females; Ages 18-45 4. Healthy, neurologically normal with no diagnosed mental or physical illness 5. Willingness to adhere to the MRI and two session stimulation protocol 6. Fluent in English 7. Normal or corrected to normal vision 8. At least twelve years of education (high school equivalent)
Exclusion Criteria
- Ongoing drug or alcohol abuse 2. Diagnosed psychiatric or mental illness 3. Currently taking psychoactive medication 4. Prior brain injury 5. Metal in body 6. History of seizures or diagnosis of epilepsy 7. Claustrophobia 8. Pregnant or possibly pregnant 9. Younger than 18 or older than 45 10. Use of medications which potentially lower the usage threshold
Study Design
- Phase
- N/A
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover Assignment
- Intervention Model Description
- 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.
- Primary Purpose
- Basic Science
- Masking
- Double (Participant, Investigator)
- Masking Description
- 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.
Arm Groups
| Arm | Description | Assigned Intervention |
|---|---|---|
|
Active Comparator Continuous theta burst stimulation |
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. |
|
|
Active Comparator Intermittent theta burst stimulation |
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. |
|
|
Sham Comparator Sham theta burst stimulation |
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. |
|
Recruiting Locations
Piscataway 5102713, New Jersey 5101760 08854
More Details
- Status
- Recruiting
- Sponsor
- Rutgers, The State University of New Jersey
Detailed Description
The healthy human brain is a complex, dynamical system which is hypothesized to operate, at rest, near a phase transition - at the boundary between order and chaos. Proximity to this critical point is functionally adaptive as it affords maximal flexibility, dynamic range, and information transmission capacity, with implications for short term memory and cognitive control. Divergence from this critical point has become correlated with diverse forms of psychopathology and neuropathy suggesting that distance from a critical point is both a potential biomarker of disorder and also a target for intervention in disordered brains. The Investigators have further hypothesized that task performance depends on how closely brains operate to criticality during task performance and also that subjective cognitive effort is a reflection of divergence from criticality, induced by engagement with demanding tasks. A key control parameter determining distance from criticality in a resting brain is hypothesized to be the balance of cortical excitation to inhibition (the "E/I balance"). Transcranial magnetic stimulation is a widely used experimental and clinical tool for neuromodulation and theta-burst stimulation (TBS) protocols are thought to modulate the E/I balance. Here the Investigators test whether cortical dynamics can be systematically modulated away from the critical point with continuous theta-burst stimulation (cTBS) and intermittent theta-burst stimulation (iTBS), which is thought to decrease and increase E/I balance, respectively. Depending on baseline E/I balance prior to stimulation, this will make people's brains either operate closer to, or farther away from critiality and thereby impact on cognitive control and subjective cognitive effort during performance of control-demanding tasks.