title: No Enhancement of 24-Hour Visuomotor Skill Retention by Post-Practice Caffeine Administration.
abstract: Caffeine is widely consumed throughout the world and appears to indirectly facilitate learning and memory through effects on attention and motivation. Animal work indicates that post-training caffeine administration augments inhibitory avoidance memory, spatial memory, and object memory. In humans, post-training caffeine administration enhances the ability to discern between familiar images and new, similar images. However, the effect of post-training caffeine administration on motor memory has not been examined. Therefore, we tested two groups of low caffeine consumers (average weekly consumption ≤500 mg) in a double-blind, placebo-controlled study involving acquisition of a continuous isometric visuomotor tracking skill. On Day 1, subjects completed 5 blocks (150 repetitions) of training on the continuous isometric visuomotor skill and subsequently ingested either 200 mg of caffeine or placebo. On day 2, subjects completed an additional 5 blocks of training. Day 1 mean performance and performance variability were both similar between groups, suggesting that both groups acquired the motor skill similarly. For mean performance on Day 2, patterns of re-learning, mean performance learning magnitudes, mean performance learning rates, and mean performance retention magnitudes were all similar between groups. For performance variability on Day 2, there was a small trend towards increased variability in the caffeine group during re-learning, but performance variability learning magnitudes and performance variability retention magnitudes did not differ between groups. Because motor skill acquisition can also be conceptualized as a reduction in performance variability, these results suggest that there may be a small negative effect of post-practice caffeine administration on memory of a newly-learned visuomotor skill. Overall, we found no evidence to suggest that post-training caffeine administration enhances 24-hour retention of a newly-learned continuous visuomotor skill, and these results support the notion that memory-enhancing effects of post-training caffeine ingestion may be task-specific.
authors.affiliation: Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa, United States of America.
authors.forename: Sara J
authors.initials: SJ
authors.lastname: Hussain
authors.affiliation: Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa, United States of America.
authors.forename: Kelly J
authors.initials: KJ
authors.lastname: Cole
mesh_terms: D000328:Adult; D002110:Caffeine / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D008297:Male; D009048:Motor Skills / Q000187:drug effects*; D011597:Psychomotor Performance / Q000187:drug effects*; D012890:Sleep / Q000187:drug effects; D055815:Young Adult
chemical_list: D002110:Caffeine