Effect of Affective Content on Drug Induced Amnesia of Episodic Memory
Condition: Memory Losses; Amnesia-Memory Loss
MeSH terms: Memory Disorders; Amnesia
Study type: Interventional
Phase: Phase 1

Summary: 
      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.
    

Detailed description: 
      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
    

Intervention name(s): Propofol; Thiopental Sodium; Dexmedetomidine Hydrochloride; Midazolam Hydrochloride; placebo
Intervention type(s): Drug; Drug; Drug; Drug; Drug
Intervention description(s): 1.2ug/ml; 2.0ug/ml; 0.5ng/ml; 60ng/ml; intralipid, saline, saline with multi-Vit solution
Intervention MeSH terms: Midazolam; Dexmedetomidine; Thiopental; Propofol
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Treatment
Keywords: Episodic Memory; Amnesia; Amnesia, Temporary