NCT04041154 · Hugo W. Moser Research Institute at Kennedy Krieger, Inc.
Behavioral and Neural Representations of Subjective Effort Cost
What this study is about
The goal of this proposal is to understand the common and distinct behavioral and neural representations of subjective effort valuation, and how these representations are influenced by fatigue and changes in motivation.
View original scientific description
The goal of this proposal is to understand the common and distinct behavioral and neural representations of subjective effort valuation, and how these representations are influenced by fatigue and changes in motivation. It is hypothesized that the brain will use overlapping and distinct neural circuits to represent cognitive and physical effort value, and that fatigue and enhanced motivation will influence the subjective value of effort.
Interventions
BEHAVIORAL
Cognitive Fatigue
Participants will perform a cognitively demanding task (spatial attention task), repeatedly, to induce cognitive fatigue.
BEHAVIORAL
Physical Fatigue
Participants will perform a physically demanding task (grip force exertion task), repeatedly, to induce cognitive fatigue.
BEHAVIORAL
Rewarding Stimuli
Reward-associated stimuli will be used to study how reward-induced changes in motivational state influence effort choices.
Primary outcome measures
Mean of cognitive subjective effort parameters (from behavioral choice data)
Time frame: 1 day
Choice data will be fit to a model of the form u(x) = x\^rho. The parameter rho is indicative of individuals' subjective preferences for effort. We will test if participants cognitive subjective effort parameters will be significantly different than zero. Effort levels will be expressed as a percentage of each individual's maximum exertion capacity. This will ensure that comparisons can be made between participants.
Differences between cognitive subjective effort parameters before and after fatigue (from behavioral choice data)
Time frame: 1 day
Choice data will be fit to a model of the form u(x) = x\^rho. The parameter rho is indicative of individuals' subjective preferences for effort. We will test if participants cognitive subjective effort parameters will be significantly different when comparing parameters extracted from pre-fatigue and post-fatigue choices. Effort levels will be expressed as a percentage of each individual's maximum exertion capacity. This will ensure that comparisons can be made between participants.
Mean of physical subjective effort parameters (from behavioral choice data)
Time frame: 1 days
Choice data will be fit to a model of the form u(x) = x\^rho. The parameter rho is indicative of individuals' subjective preferences for effort. We will test if participants physical subjective effort parameters will be significantly different than zero. Effort levels will be expressed as a percentage of each individual's maximum exertion capacity. This will ensure that comparisons can be made between participants.
Differences between physical subjective effort parameters before and after fatigue (from behavioral choice data)
Time frame: 1 day
Choice data will be fit to a model of the form u(x) = x\^rho. The parameter rho is indicative of individuals' subjective preferences for effort. We will test if participants physical subjective effort parameters will be significantly different when comparing parameters extracted from pre-fatigue and post-fatigue choices. Effort levels will be expressed as a percentage of each individual's maximum exertion capacity. This will ensure that comparisons can be made between participants.
Difference between cognitive effort cost parameters between the low and high reward stimuli
Time frame: 1 day
Choice data will be fit to a model of the form u(x) = x\^rho. The parameter rho is indicative of individuals' subjective preferences for effort. We will test if participants subjective effort parameters will be significantly different when comparing parameters extracted from low and high reward stimuli trials. Effort levels will be expressed as a percentage of each individual's maximum exertion capacity. This will ensure that comparisons can be made between participants.
Difference between physical effort cost parameters between the low and high reward stimuli
Time frame: 1 day
Choice data will be fit to a model of the form u(x) = x\^rho. The parameter rho is indicative of individuals' subjective preferences for effort. We will test if participants subjective effort parameters will be significantly different when comparing parameters extracted from low and high reward stimuli trials. Effort levels will be expressed as a percentage of each individual's maximum exertion capacity. This will ensure that comparisons can be made between participants.
Regions of the brain encoding cognitive effort
Time frame: 1 day
We will use a general linear model to examine brain activity that is positively and negatively correlated with chosen cognitive effort value.
Regions of the brain encoding physical effort
Time frame: 1 day
We will use a general linear model to examine brain activity that is positively and negatively correlated with chosen physical effort value.
Regions of the brain encoding changes cognitive effort value following cognitive fatigue
Time frame: 1 day
We will use a general linear model to examine brain activity that is positively and negatively correlated with fatigue-induced changes in cognitive effort value.
Regions of the brain encoding changes physical effort value following physical fatigue
Time frame: 1 day
We will use a general linear model to examine brain activity that is positively and negatively correlated with fatigue-induced changes in physical effort value.
Regions of the brain encoding differences in cognitive effort value resulting from reward-induced changes in motivation
Time frame: 1 day
We will use a general linear model to examine brain activity that is positively and negatively correlated with motivation-induced changes in cognitive effort value.
Regions of the brain encoding differences in physical effort value resulting from reward-induced changes in motivation
Time frame: 1 day
We will use a general linear model to examine brain activity that is positively and negatively correlated with motivation-induced changes in physical effort value.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Right-handed
- Age between 18 and 35 years old - Male or female
- Any ethnicity
Exclusion criteria
- Individuals with a history of any of the following will be excluded from the study:
- Neurological problems such as stroke, head injury, epilepsy, seizures, brain tumors, brain surgery, Parkinson's Disease (self- report)
- Diagnosed history of severe psychiatric disease such as depression, schizophrenia (self-report)
- Metal in the head or eyes
- If they are pregnant or suspect that you may be pregnant
- If they experience discomfort from the MRI scan, such as severe claustrophobia or excessive heating of tattoos
Where
- Baltimore, Maryland
Collaborators
National Institute of Mental Health (NIMH)
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jan 26, 2026 · Source of record for eligibility and locations