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Neuroimaging the Effects of Intravenous Anesthetic on Amygdala Dependent Memory Processes (Amygdala)

This study is ongoing, but not recruiting participants.
Sponsor:
Collaborators:
National Institutes of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Information provided by (Responsible Party):
Weill Medical College of Cornell University
ClinicalTrials.gov Identifier:
NCT00504894
First received: July 19, 2007
Last updated: April 13, 2017
Last verified: April 2017
  Purpose
This study involves 90 healthy volunteers aged between 18 and 50 recruited from the general community. It involves doing a set of simple memory tests while inside a fMRI machine. The subject is given a very low dose of an anesthetic drug intravenously while in the scanner. The subject then sees a sequence of pictures on a screen, and presses a button if they remember seeing the picture before. While this is happening, the scanner will be capturing images that tell us what parts of the brain are active. Hypothesis: patterns of hippocampal and amygdala activation during the encoding and retrieval of memory,as measured by fMRI, will be altered by intravenous anesthetics such that suppression of hippocampal and amygdala activities will be dissociable. This dissociation pattern will be different between the drugs propofol and thiopental.

Condition Intervention Phase
Healthy
Drug: Placebo
Drug: Propofol
Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Participant
Primary Purpose: Other
Official Title: Neuroimaging the Effects of Intravenous Anesthetic on Amygdala Dependent Memory Processes

Resource links provided by NLM:


Further study details as provided by Weill Medical College of Cornell University:

Primary Outcome Measures:
  • New Encoding (Scanner) Task Reaction Time (ms) [ Time Frame: for 90 minutes after the drug/placebo was commenced ]
    The encoding task was performed in the scanner. Subjects viewed a pseudorandom sequence of 160 images, made up of the 40 negative-arousing targets and 40 neutral targets, each presented twice (mean interval between first and second presentations 9.1 images). The task was to indicate with the buttonpress device whether the image they were seeing was being presented for the first time ('new') or whether it had been presented earlier in the sequence ('old'). The sequence was divided into eight blocks of 20 images, with a short break in between blocks. The interstimulus interval was jittered to an average of 12 s (range 6-18 s). Images were presented for 3000 ms and separated by a white fixation cross. For counterbalancing, four versions of the sequence were randomly assigned. The entire encoding task took ∼35 min, after which the drug was stopped and the subject removed from the scanner.


Enrollment: 35
Actual Study Start Date: March 2007
Estimated Study Completion Date: June 2017
Primary Completion Date: December 2015 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Placebo Comparator: Placebo
Placebo given in low dose to gauge subject's responses to visual stimuli.
Drug: Placebo
A low dose given intravenously one time for just under an hour while the subject is shown visually stimulating images in an MRI machine.
Active Comparator: Propofol
Propofol give at 0.90 μgml−1 to gauge subject's responses to visual stimuli.
Drug: Propofol
A low dose of propofol 0.90 μgml−1, given intravenously while the subject is shown visually stimulating images in an MRI machine.

Detailed Description:

Background: Subclinical doses of propofol produce anterograde amnesia, characterized by an early failure of memory consolidation. It is unknown how propofol affects the amygdala-dependent emotional memory system, which modulates consolidation in the hippocampus in response to emotional arousal and neurohumoral stress. We present an event-related functional magnetic resonance imaging study of the effects of propofol on the emotional memory system in human subjects.

Methods: Thirty-five healthy subjectswere randomized to receive propofol, at an estimated brain concentration of 0.90 μgml−1, or placebo. During drug infusion, emotionally arousing and neutral images were presented in a continuous recognition task, while blood-oxygen-level-dependent activation responses were acquired. After a drug-free interval of 2 h, subsequent memory for successfully encoded items was assessed. Imaging analysis was performed using statistical parametric mapping and behavioural analysis using signal detection models.

  Eligibility

Ages Eligible for Study:   18 Years to 50 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • age b/w 18 and 50
  • right-handed
  • minimum of high school education
  • fluent in English
  • normal vocabulary

Exclusion Criteria:

  • any significant medical/psychiatric comorbidity
  • deficit in vision or hearing that would impede the study
  • allergies to any of the study drugs, to soybeans, or eggs.
  • history of head trauma
  • family history of major psychiatric illness
  • body mass index > 30 kg/m2
  • claustrophobia
  • prior exposure to IAPS pictures
  • pregnancy
  • permanent metal objects anywhere in the body
  • a personal/family history of any porphyria
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00504894

Locations
United States, New York
Weill Cornell Medical College
New York, New York, United States, 10065
Sponsors and Collaborators
Weill Medical College of Cornell University
National Institutes of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Investigators
Principal Investigator: Kane Pryor, M.D. Weill Medical College of Cornell University
  More Information

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Weill Medical College of Cornell University
ClinicalTrials.gov Identifier: NCT00504894     History of Changes
Other Study ID Numbers: 0701008933
K08GM083213 ( US NIH Grant/Contract Award Number )
Study First Received: July 19, 2007
Results First Received: February 28, 2017
Last Updated: April 13, 2017
Individual Participant Data  
Plan to Share IPD: No

Keywords provided by Weill Medical College of Cornell University:
N/A healthy volunteers

Additional relevant MeSH terms:
Anesthetics
Propofol
Anesthetics, Intravenous
Central Nervous System Depressants
Physiological Effects of Drugs
Hypnotics and Sedatives
Anesthetics, General

ClinicalTrials.gov processed this record on May 25, 2017