Testing the Neuroscience of Guided Learning in Depression

Study Overview
=================
Brief Summary
-----------------
Major depression is a prevalent and impairing illness. To better understand the basic science and treatment of depression, the investigators study the behavioral and brain processes associated with learning in depression and how potential disruptions in learning may be repaired. Understanding different methods that change learning may lead to novel treatments that contribute to recovery in people with depression.

Detailed Description
-----------------
Major depressive disorder ranks among the most significant causes of mortality and disability in the world. Recent data from the investigators and others highlight that impairments in reward and loss learning are central to depression, have distinct neural substrates, and improve with successful treatment. Together, these findings suggest an urgent need to delineate the relationships among neural and behavioral learning impairments and depression. Equally important, these insights suggest new targets for treatment such that manipulating the neural and behavioral substrates of learning may facilitate symptom change in depression. To address these issues, the investigators use functional neuroimaging and a computational psychiatry framework to i) systematically characterize the neural and behavioral substrates that attend reward- and loss- learning in depression and ii) assess the degree to which learning in depression responds to two behavioral methods that target learning in different ways. The investigators test the broad hypotheses that i) that depression may be characterized by distinct neural and behavioral disruptions of learning, and ii) these disruptions and associated symptoms may be ameliorated through different methods of guiding learning. Recent advances in computational psychiatry provide a mechanism-based framework within which to understand the nature and trajectory of potential learning impairments in depression and suggest new ways that disrupted learning and associated symptoms may be improved in depression

Official Title
-----------------
Neural Substrates of Reinforcement Learning and Its Training in Major Depression

Conditions
-----------------
Major Depressive Disorder

Intervention / Treatment
-----------------
* Behavioral: Standard Learning
* Behavioral: Guided Learning: Instructed statistics
* Behavioral: Guided Learning: Changing statistics


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: males and females of all ethnicities meet diagnostic criteria for major depression or non-depressed control (assessed by study staff) ages 18-55 fluent in English able to see computer display clearly able to provide informed consent able to follow verbal or written instructions for participants who are referred by a clinician, a letter from that clinician indicating that participation in the study does not constitute an elevated medical or behavioral risk to the participant will be requested. Exclusion Criteria: current pregnancy or menopause claustrophobia MRI contraindications psychotic or bipolar disorder

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 55 Years

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

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

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

Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: No Training<br>Guided learning, standard learning: Repeat administration of standard behavioral learning task | Behavioral: Standard Learning<br>* Participants will complete repeat sessions of a computer-based learning task, and task performance and symptoms will be assessed.<br>|
| Experimental: Instructed Statistics<br>Guided learning, instructed statistics: Repeat administration of behavioral learning task with instructions about task statistics | Behavioral: Guided Learning: Instructed statistics<br>* Participants will complete repeat sessions of a computer-based learning task, and task performance and symptoms will be assessed.<br>|
| Experimental: Not Instructed Statistics<br>Guided learning, changing statistics: Repeat administration of behavioral learning task with changing task statistics | Behavioral: Guided Learning: Changing statistics<br>* Participants will complete repeat sessions of a computer-based learning task, and task performance and symptoms will be assessed.<br>|

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

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Task performance | behavioral measures of learning task performance including accuracy, learning rate | approximately 6 weeks (pre- post- learning task changes and interim time points) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Neuroimaging measures | functional MRI during learning task performance | approximately 6 weeks (pre- post- learning task changes and interim time points) | 
| Symptoms | self-report questionnaires and clinician-obtained symptom measures | approximately 6 weeks (pre- post- learning task changes and interim time points) |