Amnesia-Memory Loss Clinical Trial
Official title:
Effect of Affective Content on Drug Induced Amnesia of Episodic Memory
The purpose of this research is to understand how some of the drugs commonly used in anesthesia impair memory. We are particularly interested in whether the emotion associated with a memory influences how well these drugs are able to block memory. We are studying four commonly used drugs—propofol, thiopental, midazolam, and dexmedetomidine, all of which may have slightly differing effects. We will also study an inactive substance, called a placebo, that should have no effect. The results of this study will provide information that will be useful in understanding how memory works, how these drugs affect memory, and possibly why some people don't have their memory blocked as easily as others.
The protocol "Effect of Affective Content on Drug Induced Amnesia of Episodic Memory"
investigates the relationship between the ability of affective ('emotional') content to
modulate the formation of episodic memory, and the memory impairment ('amnestic') effects of
several common intravenous anesthetic drugs. Because memory modulation by affective content
appears to be a distinct memory process, the underlying question is whether drugs that
impair memory via different mechanisms will have differing effects on memory modulation.
Specifically, the objectives are: (1) To study the influence of three GABAergic agents
(thiopental, propofol, and midazolam) and one α2-adrenergic agent (dexmedetomidine) on the
ability of affective content to modulate the strength of episodic memory; and (2) To study
whether the subliminal ('consciously imperceptible') presentation of emotional words can
influence memory for visual stimuli shown immediately after the subliminal presentation.
A maximum of eighty volunteers will receive sub-anesthetic doses of one of the four study
drugs, or placebo, while performing a visual continuous recognition task ('CRT') of pictures
with randomly varying affective load. Drug effect on affective modulation of working and
early long-term memory behavior will be examined by analyzing which images are and are not
recognized during the CRT. Drug effect on affective modulation of later long-term memory
will be examined by analyzing which images are recognized several hours after presentation.
In a second experiment, emotive and non-emotive words are subliminally presented immediately
before the presentation of a 'bland' picture. The ability of the subliminally presented word
to influence memory will be examined by analyzing which bland images are recognized several
hours later.
Three hypotheses are tested:
The memory impairment effected by GABAergic drugs will be stronger for memory of emotively
positive images than for memory of emotively negative images
The memory impairment effected by dexmedetomidine will be similar for memory of emotively
positive and negative images
Recognition memory for neutral, non-arousing images will be greater if the image is
immediately preceded by the subliminal presentation of an emotively arousing word than if it
is preceded by an emotively non-arousing word
;
Allocation: Randomized, Endpoint Classification: Pharmacokinetics/Dynamics Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Investigator), Primary Purpose: Treatment