The Effect of Intravenous Anesthetics on Fear Learning and Memory
Condition: Phobias
Study type: Interventional

Summary: 
      People often develop fearful responses to things, but have no conscious control over the
      fear. This is a basic form of unconscious memory, called "fear conditioning." Intravenous
      anesthetic drugs have remarkable effects on conscious memory, but it is unknown whether they
      have similar effects on these unconscious fear memories.

      To address this question, the investigators will study 114 healthy adult volunteer subjects.
      The subject is given a very low dose of an anesthetic drug intravenously (i.e. through the
      bloodstream). The dose is so low that the subject might not even be able tell if they are
      getting the drug. While they are receiving the drug, the subject will perform a series of
      memory tests and a fear conditioning experiment, which are set up like a very simple computer
      game. To create the "fear response", subjects will occasionally receive a mildly
      uncomfortable shock to their arm. The subject is able to determine the highest level of shock
      that they will receive.

      The investigators are doing this study because the investigators wish to know exactly how the
      drugs affect the way people process fear and emotion. This knowledge might one day be used in
      the treatment of some psychiatric disorders.
    

Detailed description: 
      People often develop fearful responses to things, but have no conscious control over the fear
      (e.g. phobias). This is a basic form of unconscious memory, called "fear conditioning."
      Intravenous anesthetic drugs have remarkable effects on conscious memory, but it is unknown
      whether they have similar effects on these unconscious fear memories.

      To address this question, the investigators will study 114 healthy adult volunteer subjects.
      The subject is given a very low dose of an anesthetic drug intravenously (i.e. through the
      bloodstream). The dose is so low that the subject might not even be able tell if they are
      getting the drug. While they are receiving the drug, the subject will perform a series of
      memory tests and a fear conditioning experiment, which are set up like a very simple computer
      game. To create the "fear response", subjects will occasionally receive a mildly
      uncomfortable shock to their arm. The subject is able to determine the highest level of shock
      that they will receive.

      The investigators are doing this study because the investigators wish to know exactly how the
      drugs affect the way people process fear and emotion. This knowledge might one day be used in
      the treatment of some psychiatric disorders.
    

Intervention name(s): Placebos; Propofol 0.45mcg/mL; Propofol 0.90mcg/mL; Thiopental 1.5mcg/mL; Thiopental 3mcg/mL
Intervention type(s): Drug; Drug; Drug; Drug; Drug
Intervention description(s): IV Saline infusion for 2 hours.; IV Propofol infusion for 2 hours.; IV Propofol infusion for 2 hours.; IV Thiopental 1.5mcg/mL infusion for 2 hours; IV Thiopental 3mcg/mL infusion for 2 hours
Other intervention name(s): Propofol; Propofol; Thiopental; Thiopental
Intervention MeSH terms: Thiopental; Propofol
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Basic Science
Keywords: anesthetic drugs, associative memory, fear