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Brain Changes in Fear
This study is currently recruiting patients.
Sponsored by: | National Institute of Mental Health (NIMH) |
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Information provided by: | Warren G Magnuson Clinical Center (CC) |
Purpose
The purpose of this study is to use brain imaging technology to investigate brain changes in people exposed to predictable versus unpredictable unpleasant stimuli. Unpleasant events that can be predicted evoke a response of fear, whereas unpredictable, unpleasant stimuli cause chronic anxiety not associated with a specific event. Information gained from this study may help in the development of more effective treatments for anxiety disorders.
When confronted with fearful events, people eventually develop fear of specific cues that were associated with these events as well as to the environmental context in which the fearful event occurred. Evidence suggests that cued fear and contextual fear model different aspects of anxiety. However, studies that examine the way the brain affects expression of contextual fear have not been conducted. This study will use magnetic resonance imaging (MRI) or Magneto-encephalography (MEG) to compare the brain activity underlying fear brought on by predictable and unpredictable aversive stimuli.
Condition |
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Anxiety Disorders |
MedlinePlus related topics: Anxiety
Study Type: Observational
Study Design: Natural History
Official Title: fMRI Investigation of Explicit Cue and Contextual Fear
Expected Total Enrollment: 114
Study start: October 11, 2002
During fear conditioning in which a phasic explicit (e.g., a light) is repeatedly associated with an aversive unconditioned stimulus (e.g., a shock), the organism develops fear to the explicit cue as well as to the environmental context in which the experiment took place. Experimental evidence suggests that cued fear and contextual fear model different aspects of anxiety. Studies in patients indicated that contextual fear may model an aspect that is especially relevant to anxiety disorders (Grillon et al.,1994, 1998a,b; 1999). However, the neural basis for the expression of contextual fear has not previously been elucidated in human imaging studies.
One important determinant of contextual fear is predictability: contextual fear increases when a treat (e.g., electric shock) is unpredictable, as opposed to when the treat is predictable. The aim of this study is to compare the neural substrates underlying fear evoked by predictable versus unpredictable shocks. Animal studies have indicated that conditioned responses to predictably cued threat and to less explicit threat are separate processes mediated by distinct brain structures. Psychophysiological data suggest that the proposed procedure can differentiate between these two responses. Hence, we anticipate that this procedure will allow us to compare brain correlates of these responses in humans.
Eligibility
Genders Eligible for Study: Both
Accepts Healthy Volunteers
Criteria
Location and Contact Information
More Information
Publications
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