Cognitive Control & the Functional Organization of the Frontal Cortex
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 入组人数
- 60
- 试验地点
- 2
- 主要终点
- Effect of the practice intervention on change in overall and task-relevant neural separability in lateral prefrontal cortex
研究概览
简要总结
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.
详细描述
Background and Study Rationale:
Human performance on a task deteriorates when it is performed concurrently with another task. This multitasking cost has been attributed to competition for shared computational or biological resources and there is considerable debate in the field about the specific nature of these putative resources. Extensive multitasking practice is known to reduce, and sometimes, abolish these costs. These practice-related gains have been attributed to changes in central processing, more efficient task scheduling, or the learning of specialized task representations. The human prefrontal cortex is critical to flexible cognitive control of behavior, and is involved in representing tasks. However, it remains unknown what effect multitasking practice has on prefrontal task representations. In this study, we will directly address a gap in our knowledge by testing the link between multitasking costs and the geometry of neural manifolds representing task inputs in the lateral PFC.
Study Design:
Overview:
This study is a single-center, randomized controlled trial designed to examine the effect of multitask practice on multitasking behavior, the geometry of neural representations of tasks in the lateral prefrontal cortex and the relationship between these effects. A total of 60 healthy subjects are planned, 30 subjects being randomized to each, the multitask practice group (MPG), and the single task practice group (SPG). Baseline and endline assessments of multitasking behavior and neural representations in lateral PFC with fMRI will be conducted in all subjects.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Basic Science
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 35 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Normal or corrected to normal vision.
排除标准
- •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
结局指标
主要结局
Effect of the practice intervention on change in overall and task-relevant neural separability in lateral prefrontal cortex
时间窗: through study completion, an average of 1.5 years
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.
Contribution of overall and task-relevant neural separability in lateral prefrontal cortex to the effect of multitasking practice on behavioral multitasking cost
时间窗: through study completion, an average of 1.5 years
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.
Effect of multitasking practice on behavioral multitasking cost
时间窗: through study completion, an average of 1.5 years
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.
次要结局
- Coding axis angles between stimulus feature representations in two tasks in lateral prefrontal cortex(through study completion, an average of 1.5 years)
- Cross-classification generalization performance of task-relevant variables in lateral prefrontal cortex(through study completion, an average of 1.5 years)