Effects of Methamphetamine and Fatigue on Long- and Short-Term Memory.
NAVAL AEROSPACE MEDICAL RESEARCH LAB PENSACOLA FL
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We examined the effects of a 10 mg70 kg oral dose of d- methamphetamine HCI on fatigue-related deficits of short- and long-term memory. We used a recognition memory-search task with two memory loads. In one experimental condition, stimuli were committed to long-term memory LTM and performance was rendered automatic by extensive practice with consistently mapped stimuli and responses. In a second condition, the task was organized so that recognition depended on short-term memory STM despite equally extensive practice. After 7680 training trials, 13 subjects performed the task at 90-min intervals in a 13.5-h, sustained-performance session that began at 1930 and ended at 0900. At 0116, seven subjects were administered capsules containing 10 mg70-kg body weight d-methamphetamine HCI, double-blind. The remaining subjects were administered a placebo. Memory-trace strengths and decision speeds declined during the early part of the night in all experimental conditions. The methamphetamine treatment reversed these effects within approximately 2 h of administration. The methamphetamine treatment also reversed an increasing trend in lapse probabilities. The stimulant did not merely produce criterion shifts that led subjects to respond impulsively more rapidly but less accurately. These results suggest that the methamphetamine treatment produced genuine increases in accuracy of recognition and that any criterion shifts that may have occurred were more than compensated for by increased accuracy. Human performance, Sustained operations, SUSOPS, Sustained performance continuous operations, CONOPS, Continuous performance, Stimulant drugs, Methamphetamine, Amphetamine, Sleep deprivation, Sleepiness, Fatigue, Memory, Short-term memory, Long-term memory, Automaticity.
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