Neural Correlates of Active Avoidance Learning and Their Interactions With Fear Extinction Mechanisms in PTSD Patients
The University of Texas Health Science Center, Houston
Summary
The purpose of this research study is to study how the brain learns to avoid certain stimuli or situations using an experimental paradigm. The big goal is to measure brain responses and subject's feelings and expectations when they are learning to actively avoid experimental stimuli, and how fear extinction learning and monetary cost can change how and when subjects are to avoid.
Description
This study aims to study the neural correlates of avoidance learning using a recently validated conditioning and active avoidance paradigm (CAAP). The overarching objective is to measure the neural correlates of active avoidance, and how fear extinction learning and monetary cost modulate these avoidance responses. Participants will include healthy controls (HC), trauma-exposed healthy controls (TEHC), and participants with post-traumatic stress disorder (PTSD). Avoidance is common and often hinders the progression and success of extinction-based exposure therapy in PTSD. The data to be gather…
Eligibility
- Age range
- 18–70 years
- Sex
- All
- Healthy volunteers
- Yes
Inclusion Criteria: 1. 18 - 70 years of age 2. Female or Male 3. Inclusion Criteria: PTSD Subjects a. Diagnosis of current PTSD 4. Inclusion Criteria: Trauma-exposed healthy controls (TEHC) 1. SCID diagnosis consistent with no current psychiatric disorders, and no current PTSD 2. History of trauma exposure 5. Inclusion Criteria: Healthy controls (HC) 1. SCID diagnosis consistent with no current psychiatric disorders ("Axis I" disorders). 2. No history of trauma exposure 6. Willing and able to provide informed consent. Exclusion Criteria for ALL subjects: 1. History of neur…
Interventions
- BehavioralFear Conditioning
Participants will be administered increasing intensities of mild electric shock via electrodes connected to the foot. New Biopac stimulators that can deliver higher shock intensity, provided participants agreement will be used to assure adequate conditioning levels. Stimulation is measures in milliamps (mA), and each delivered stimulation will be 0.5 seconds long (500 milliseconds). To colored (blue, red, \& yellow) light stimuli (CS). The light stimulus is followed by a shock or no shock depending on color.
- OtherAvoidance conditioning
Via button pressing. Only one stimulus-CS will enable control over experiencing the shock: the participant can press the button during the first 2 seconds of the light presentation to avoid the shock.
- OtherPavlovian fear extinction learning
After avoidance conditioning, the CS+ associated with avoidance responding appears with no button to press and no shock is administered.
- OtherWillingness to pay to avoid shock
On the next day, participants receive a monetary stipend to use to pay to guarantee that they are not to receive any shocks if they press a button from the CS+. This and all previously described experimental phases noted above will occur inside of the fMRI scanner.
Location
- UTHealth HoustonHouston, Texas