Neuroimaging the Effects of Intravenous Anesthetic on Amygdala Dependent Memory Processes

NCT ID: NCT00504894

Last Updated: 2021-07-15

Basic Information

• Recruitment Status: TERMINATED
• Clinical Phase: PHASE4
• Total Enrollment: 60 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2007-03-31
• Study Completion Date: 2013-11-30

Brief Summary

This study involves 60 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.

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: Sixty healthy subjects were randomized to receive propofol, at an estimated brain concentration of 0.90 μgml-1, thiopental, at an estimated brain concentration of 3.0 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.

Conditions

Healthy

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: OTHER
• Blinding Strategy: SINGLE

Study Groups

Placebo

Placebo given in low dose to gauge subject's responses to visual stimuli.

Group Type: PLACEBO_COMPARATOR

Placebo

Intervention Type: DRUG

A low dose given intravenously one time for just under an hour while the subject is shown visually stimulating images in an MRI machine.

Propofol

Propofol given at 0.90 μgml-1 to gauge subject's responses to visual stimuli.

Group Type: ACTIVE_COMPARATOR

Propofol

Intervention Type: DRUG

A low dose of propofol 0.90 μgml-1, given intravenously while the subject is shown visually stimulating images in an MRI machine.

Thiopental

Thiopental given at 3.0 μgml-1 to gauge subject's responses to visual stimuli.

Group Type: ACTIVE_COMPARATOR

Thiopental

Intervention Type: DRUG

A low dose of thiopental 3.0 μgml-1, given intravenously while the subject is shown visually stimulating images in an MRI machine.

Interventions

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.

Intervention Type: 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.

Intervention Type: DRUG

Thiopental

A low dose of thiopental 3.0 μgml-1, given intravenously while the subject is shown visually stimulating images in an MRI machine.

Intervention Type: DRUG

Eligibility 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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 50 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

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

Responsibility Role: SPONSOR

Principal Investigators

Kane Pryor, M.D.

Role: PRINCIPAL_INVESTIGATOR

Weill Medical College of Cornell University

Locations

Weill Cornell Medical College

New York, New York, United States

Countries

United States

References

Pryor KO, Root JC, Mehta M, Stern E, Pan H, Veselis RA, Silbersweig DA. Effect of propofol on the medial temporal lobe emotional memory system: a functional magnetic resonance imaging study in human subjects. Br J Anaesth. 2015 Jul;115 Suppl 1(Suppl 1):i104-i113. doi: 10.1093/bja/aev038.

Reference Type: DERIVED

PMID: 26174294 (View on PubMed)

Other Identifiers

K08GM083213

Identifier Type: NIH

Identifier Source: secondary_id

View Link

0701008933

Identifier Type: -

Identifier Source: org_study_id