Neuroimaging the Effects of Intravenous Anesthetic on Amygdala Dependent Memory Processes (Amygdala)
|Study Design:||Allocation: Randomized
Intervention Model: Parallel Assignment
Primary Purpose: Other
|Official Title:||Neuroimaging the Effects of Intravenous Anesthetic on Amygdala Dependent Memory Processes|
- 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.
|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)|
Placebo Comparator: Placebo
Placebo given in low dose to gauge subject's responses to visual stimuli.
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.
A low dose of propofol 0.90 μgml−1, given intravenously while the subject is shown visually stimulating images in an MRI machine.
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.
Please refer to this study by its ClinicalTrials.gov identifier: NCT00504894
|United States, New York|
|Weill Cornell Medical College|
|New York, New York, United States, 10065|
|Principal Investigator:||Kane Pryor, M.D.||Weill Medical College of Cornell University|