Functional Differences in Effortful Control

Study Overview
=================
Brief Summary
-----------------
The purpose of this study was to learn more about the brain circuits involved with effortful control in healthy adult participants. It was planned that the study would enroll 80 participants to a dual task paradigm pilot while undergoing a fMRI scan to assess brain mechanisms that cause the depletion effect. This effect refers to the observation that people perform more poorly on effortful control tasks after they have already performed task requiring effortful control. Then subsequent study participants would be given either methylphenidate (also known as 'Ritalin') which is FDA approved and the most widely-used medication for Attention Deficit Hyperactivity Disorder (ADHD) or a placebo, which is a sugar pill. Each participant would also perform some computer tasks that have been shown in previous studies to require effortful control while undergoing an fMRI (functional Magnetic Resonance Imaging) which takes a special kind of picture of the brain. The study's goal was to learn more about the brain mechanisms by which methylphenidate improves effortful control. After enrolling the first 50 participants, the study assessed whether a depletion effect was observed in the dual task paradigm. It was found that there was not: there was no statistically significant difference in effortful control performance comparing subjects who did and did not perform a prior effortful control task. Because the behavioral manipulation failed, it was determined that the drug manipulation portion of the study was no longer justified. Thus, after enrolling 50 participants to the pilot part of the study, the decision was made to terminate the study without beginning the trial of methylphenidate.

Official Title
-----------------
Functional Differences in Effortful Control

Conditions
-----------------
Healthy

Intervention / Treatment
-----------------
* Behavioral: Dual task paradigm pilot


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Right-handedness Exclusion Criteria: Any clinically significant personal or family history of cardiac problems Any current Axis I psychiatric disorder (diagnosis as verified by the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders-IV) A previous adequate trial with methylphenidate (Ritalin) Currently taking any psychoactive medications Any clinically significant medical condition Any clinically significant neurological problem (seizures, tics, serious head injury) Contraindications to MRI (metal objects in body or claustrophobia) Currently pregnant or lactating Alcohol or substance abuse (current or in the past 2 years) Left-handedness or ambidextrous Liver or kidney disease

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Dual Task Paradigm<br>This arm does not involve any drug intervention, it is an experimental type consisting of 80 subjects to study the dual task paradigm implemented during the fMRI scanning session. 80 subjects will perform the fMRI scan but will not undergo any drug intervention. | Behavioral: Dual task paradigm pilot<br> <br> |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Reaction Time on the Multi-Source Interference Task |  | 3 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Accuracy on the Multi-Source Interference Task | Accuracy is the calculated percentage of correct responses over total trials | 3 hours | 
| Reaction time variability on the Multi-Source Interference Task | Reaction Time Variability is the standard deviation of the trial to trial reaction time distribution (the standard deviation is a unitless quantity) on the Multi-Source Interference Task. | 3 hours | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Methylphenidate, Placebo, functional Magnetic Resonance Imaging (fMRI), Attention Control