The Effect of Intravenous Anesthetics on Fear Learning and Memory

NCT ID: NCT00767767

Last Updated: 2019-05-15

Study Results

Results available

Outcome measurements, participant flow, baseline characteristics, and adverse events have been published for this study.

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Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

67 participants

Study Classification

INTERVENTIONAL

Study Start Date

2008-10-31

Study Completion Date

2011-05-31

Brief Summary

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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

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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.

Conditions

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Phobias

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

SINGLE

Participants

Study Groups

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Placebos

Saline Infusion

Group Type PLACEBO_COMPARATOR

Placebos

Intervention Type DRUG

IV Saline infusion for 2 hours.

Propofol 0.45mcg/mL

Anesthetic Drug Infusion

Group Type ACTIVE_COMPARATOR

Propofol 0.45mcg/mL

Intervention Type DRUG

IV Propofol infusion for 2 hours.

Propofol 0.90mcg/mL

Anesthetic Drug Infusion

Group Type ACTIVE_COMPARATOR

Propofol 0.90mcg/mL

Intervention Type DRUG

IV Propofol infusion for 2 hours.

Thiopental 1.5mcg/mL

Anesthetic Drug Infusion

Group Type ACTIVE_COMPARATOR

Thiopental 1.5mcg/mL

Intervention Type DRUG

IV Thiopental 1.5mcg/mL infusion for 2 hours

Thiopental 3mcg/mL

Anesthetic Drug Infusion

Group Type ACTIVE_COMPARATOR

Thiopental 3mcg/mL

Intervention Type DRUG

IV Thiopental 3mcg/mL infusion for 2 hours

Interventions

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Placebos

IV Saline infusion for 2 hours.

Intervention Type DRUG

Propofol 0.45mcg/mL

IV Propofol infusion for 2 hours.

Intervention Type DRUG

Propofol 0.90mcg/mL

IV Propofol infusion for 2 hours.

Intervention Type DRUG

Thiopental 1.5mcg/mL

IV Thiopental 1.5mcg/mL infusion for 2 hours

Intervention Type DRUG

Thiopental 3mcg/mL

IV Thiopental 3mcg/mL infusion for 2 hours

Intervention Type DRUG

Other Intervention Names

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Propofol Propofol Thiopental Thiopental

Eligibility Criteria

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Inclusion Criteria

* age between 18 and 50
* minimum of high school education
* fluent in English
* normal vocabulary

Exclusion Criteria

* any significant medical or psychiatric comorbidity (e.g. asthma, diabetes, hypertension, depression, high anxiety)--subjects must be in excellent health such that they would be classified as American Society of Anesthesiologists Physical Status Class I
* deficit in vision or hearing that would impede the study
* allergies to any of the study drugs, to soybeans, or to eggs
* a history of head trauma
* a family history of major psychiatric illness
* body mass index \> 30 kg/m2
* a recent history of recreational drug use
* prior exposure to the study materials
* pregnancy
* a personal or family history of any porphyria
* failure to exhibit a skin conductance response to deep inspiration
* the ability to read Chinese characters
* assessment by the investigators that the subject may be unable to cooperate or comply with the study requirements.
Minimum Eligible Age

18 Years

Maximum Eligible Age

50 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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National Institutes of Health (NIH)

NIH

Sponsor Role collaborator

National Institute of General Medical Sciences (NIGMS)

NIH

Sponsor Role collaborator

Weill Medical College of Cornell University

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Kane Pryor, MD

Role: PRINCIPAL_INVESTIGATOR

Weill Medical College of Cornell University

Locations

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Weill Cornell Medical College/New York Presbyterian Hospital

New York, New York, United States

Site Status

Countries

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United States

Other Identifiers

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K08GM083213

Identifier Type: NIH

Identifier Source: secondary_id

View Link

0710009434

Identifier Type: -

Identifier Source: org_study_id

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