Neuroimaging the Effects of Intravenous Anesthetic on Amygdala Dependent Memory Processes — Amygdala  

Healthy Clinical Trial

Official title: Neuroimaging the Effects of Intravenous Anesthetic on Amygdala Dependent Memory Processes

Status Terminated

Clinical Trial 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.

Clinical Trial 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. ;

Related Conditions & MeSH terms

• Healthy

• NCT number: NCT00504894
• Study type: Interventional
• Source: Weill Medical College of Cornell University
• Status: Terminated
• Phase: Phase 4
• Start date: March 2007
• Completion date: November 2013