Cognitive Control & the Functional Organization of the Frontal Cortex

NCT06436209 | Recruiting

• 2 other identifiers: 08029924415R01MH125497
• Study Type: interventional
• Target: 60
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this basic experimental clinical trial is to understand the effect of multitasking practice on the structure of neural representations of tasks in the human lateral prefrontal cortex and control brain regions. The main question it aims to answer is: What changes in neural representational structure predict improvements in multitasking behavior due to multitasking practice? Healthy human participants will learn two independent tasks, each mapping a set of stimuli to motor responses based on different rules. Participants will be randomized to one of two interventions. Participants assigned to the multitask practice intervention (MPI) will practice multitasking the two tasks over multiple days. Those assigned to the single-task practice intervention (SPI) will instead practice each task separately while controlling for the total number of practice opportunities associated with each task across the interventions. Both before and after the practice, the ability of all participants to perform both tasks simultaneously will be behaviorally measured using a well-established psychological refractory period (PRP) paradigm, and their neural representations will be measured using functional MRI while they perform the two tasks. Researchers will then compare improvements in multitasking behavior across the two groups, as well as changes in neural representational geometry of the tasks in the lateral prefrontal cortex and control brain regions, and test whether multitasking training is associated with specific changes in neural representations in the lateral prefrontal cortex.

Conditions

Multitasking Behavior and Neural Representations Associated With Multitasking Ability; Healthy Volunteers; Executive Function

Keywords

psychological refractory period (PRP), behavioral training, neural representational geometry, lateral prefrontal cortex, separability and generalizability

Outcome Measures

Primary Outcomes (3)

• Effect of the practice intervention on change in overall and task-relevant neural separability in lateral prefrontal cortex

  Overall neural separability (also referred to as shattering dimensionality) will be measured by employing cross-validated neural decoding of lateral PFC fMRI BOLD multi-voxel patterns, averaging decoding accuracies across all balanced dichotomies of the task inputs. Task-relevant neural separability will be measured by averaging decoding accuracies across all task-relevant variables.

  through study completion, an average of 1.5 years

• Effect of multitasking practice on behavioral multitasking cost

  Behavioral multitasking cost will be estimated by computing the difference in mean response time on task 2 on long SOAs and short SOAs in the Psychological Refractory Period paradigm. The effect of multitasking practice on behavioral multitasking will be estimated using linear mixed-effects regression, and is defined as the regression weight associated with the interaction effect of time point and intervention on multitasking cost.

  through study completion, an average of 1.5 years

• Contribution of overall and task-relevant neural separability in lateral prefrontal cortex to the effect of multitasking practice on behavioral multitasking cost

  The contribution of prefrontal neural separability change to the effect of multitasking practice on behavioral multitasking will be estimated using linear mixed-effects regression, and is defined as the regression weight associated with the interaction effect of time point, intervention and separability on multitasking cost.

  through study completion, an average of 1.5 years

Secondary Outcomes (2)

• Cross-classification generalization performance of task-relevant variables in lateral prefrontal cortex

  through study completion, an average of 1.5 years

• Coding axis angles between stimulus feature representations in two tasks in lateral prefrontal cortex

  through study completion, an average of 1.5 years

Study Arms (2)

Multitask Practice

EXPERIMENTAL

Behavioral: Multitask Practice Intervention (MPI)

Single Task Practice

ACTIVE COMPARATOR

Behavioral: Single-task Practice Intervention (SPI)

Interventions

Multitask Practice Intervention (MPI) BEHAVIORAL

Multitask practice intervention (MPI) includes multiple behavioral testing sessions during which participants receive practice with multitasking two tasks using the psychological refractory period procedure.

Multitask Practice

Single-task Practice Intervention (SPI) BEHAVIORAL

Single task practice intervention (SPI) includes multiple behavioral testing sessions during which participants receive separate practice on two tasks.

Single Task Practice

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Normal or corrected to normal vision.

You may not qualify if:

• Left handedness
• Presence or history of neurological or psychiatric disorders
• Usage of brain related medications
• Previous head injury and time spent unconscious
• Any implanted medial fragment or device in the body of the participant.
• Tattoos above the neck
• Injury to the eye or other body part involving a metallic object or fragment.
• Welding, grinding, or cutting of metal in lifetime of participant without usage of safety protection glasses.
• injury to the participant by a metallic object or foreign body (e.g., BB, bullet, shrapnel, etc.)
• Pregnancy or possibility of pregnancy
• Implants or devices including:
• Electronic implant or device, Magnetically-activated implant or device, Cardiac pacemaker, Implanted cardioverter defibrillator (ICD), Aneurysm clip(s), Neurostimulation system, Spinal cord stimulator, Internal electrodes or wires, Bone growth/bone fusion stimulator, Cochlear, otologic, or other ear implant, Insulin or infusion pump, Implanted drug infusion device, Any type of prosthesis (eye, penile, etc.), Heart valve prosthesis, Eyelid spring or wire, Artificial or prosthetic limb, Metallic stent, filter, or coil, Shunt (spinal or intraventricular), Vascular access port and/or catheter, Radiation seeds or implants, Swan-Ganz or triple lumen catheter, Medication patch (Nicotine,Nitroglycerine), Any metallic fragment or foreign body, Wire mesh implant, Tissue expander (e.g., breast), Surgical staples, clips, or metallic sutures Joint replacement (hip, knee, etc.) Bone/joint pin, screw, nail, wire, plate, etc. IUD or diaphragm, Dentures or partial plates, Tattoo or permanent makeup above the neck, Body piercing jewelry that can not be removed, Breathing disorder, Motion disorder or tremors, Claustrophobia, Hearing aid

Sponsors & Collaborators

• Brown University: lead
• National Institute of Mental Health (NIMH): collaborator

Study Sites (1)

Metcalf Research Building, Brown University & MRI Research Facility, Brown University

Providence, Rhode Island, 02912, United States

RECRUITING

MeSH Terms

Conditions

Multitasking Behavior

Condition Hierarchy (Ancestors)

Behavior

Study Officials

• David Badre, PhD

  Brown University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

David Badre, PhD

CONTACT

401-863-9563; david_badre@brown.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 17, 2024
• First Posted: May 31, 2024
• Study Start: March 27, 2024
• Primary Completion (Estimated): July 31, 2026
• Study Completion (Estimated): July 31, 2026
• Last Updated: August 15, 2025

Record last verified: 2025-05

Data Sharing

• IPD Sharing: Will share

Locations

US (1)