Identifying Decision Making Parameters in Healthy Volunteers and Anxiety Patients
Condition: Anxiety; Healthy Volunteers
MeSH terms: Anxiety Disorders
Study type: Interventional

Summary: 
      Background:

      Research has shown that anxiety affects more than feelings. It also affects behavior.
      Researchers want to learn how the brain and body respond to unexpected threats. They want to
      see if probable pleasant or unpleasant events change decisions.

      Objective:

      To better understand how changes in anxiety are associated with changes in decision-making.

      Eligibility:

      Adults aged 18-50 with generalized anxiety disorder, seasonal affective disorder, or panic
      disorder. Healthy volunteers are also needed.

      Design:

      Participants will be screened under protocol #01-M-0254.

      Participants will complete surveys about their anxiety, risk-taking, and curiosity.

      Participants will complete a computer task. They will be given different choices. They will
      make a choice. They will receive an unpleasant or pleasant stimulus based on their choice.
      They will repeat this task many times.

      Most participants will do the task in the clinic. The unpleasant stimulus will be electric
      shock and acoustic startle. They will receive electric shocks through electrodes placed on
      their arm or fingers. They may hear loud noises through headphones. Their eyeblinks will be
      recorded with electrodes placed under their eye. Their heart rate and skin conductance
      activity will be collected with electrodes as well.

      Some healthy volunteers will do the task during a functional magnetic resonance imaging scan.
      They will lie on a table that slides in and out of a scanner. A coil will be placed over
      their head. The unpleasant stimulus will be electric shock, given as stated above. The
      scanner will record their brain activity. Their breathing and pulse rate will be recorded as
      well.

      Participation will last for 3-4 hours.
    

Detailed description: 
      Study Description:

      This study s goal is to identify parameters of interest in decision making in the context of
      anxiety disorders, using theoretical models in healthy volunteers (HV) and anxiety patients
      (AD). Participants are asked to complete a decision-making task, namely the Multi-armed
      Bandit Task.

      The study will be conducted in the clinic. Participants (HV and AD) are asked to fill out
      questionnaires and complete the Multi-armed Bandit Task. An electric shock is used as the
      aversive stimulus. Monetary reward is used as the reward stimulus. Additionally,
      physiological signals (Heart rate, skin conductance activity, startle) are collected during
      the course of the task. In addition, in a pilot study, participants startle responses for
      varying shock parameters are recorded and analyzed.

      Objectives:

      The primary objective of this study is to use theoretical models in healthy volunteers (HV)
      and patients with an anxiety disorder (AD) to better understand how changes in anxiety are
      associated with changes in decision making. In addition, this study will ascertain whether
      decision making parameters correlate with certain behavioral measures such as trait and state
      anxiety using (i) questionnaires, (ii) physiological measures.

      Endpoints:

      The primary endpoint of this study is a significant difference in model derived parameters
      between experimental manipulations (conditions) and/or population groups. The parameters of
      interest include: 1) Learning Rate, 2) Exploration parameter, 3) Discount rate, 4) Loss
      aversion, 5) Inverse Temperature.

      The secondary endpoints are a significant correlation between functions of model derived
      parameters and behavioral and/or physiological measures of anxiety including:

        1. Questionnaire scores

        2. Startle

        3. Skin conductance
    

Intervention name(s): Multi-arm bandit tasks; Multi-arm bandit tasks
Intervention type(s): Behavioral; Device
Intervention description(s): Part 1 to be completed in the clinic. Subject participation is for one part and is pseudo-randomly.; Part 2 to be completed in the scanner. Subject participation is for one part and is pseudo-randomly.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: fMRI; multi-arm bandit task; anxiety volunteers; Healthy Volunteers