Comparing the benefits of caffeine, naps and placebo on verbal, motor and perceptual memory.

Full Abstract

Caffeine, the world's most common psychoactive substance, is used by approximately 90% of North Americans everyday. Little is known, however, about its benefits for memory. Napping has been shown to increase alertness and promote learning on some memory tasks. We directly compared caffeine (200mg) with napping (60-90min) and placebo on three distinct memory processes: declarative verbal memory, procedural motor skills, and perceptual learning. In the verbal task, recall and recognition for unassociated words were tested after a 7h retention period (with a between-session nap or drug intervention). A second, different, word list was administered post-intervention and memory was tested after a 20min retention period. The non-declarative tasks (finger tapping task (FTT) and texture discrimination task (TDT)) were trained before the intervention and then retested afterwards. Naps enhanced recall of words after a 7h and 20min retention interval relative to both caffeine and placebo. Caffeine significantly impaired motor learning compared to placebo and naps. Napping produced robust perceptual learning compared with placebo; however, naps and caffeine were not significantly different. These findings provide evidence of the limited benefits of caffeine for memory improvement compared with napping. We hypothesize that impairment from caffeine may be restricted to tasks that contain explicit information; whereas strictly implicit learning is less compromised.

Author information

Author/s: Mednick, Sara C (SC); Cai, Denise J (DJ); Kanady, Jennifer (J); Drummond, Sean P A (SP);

Affiliation: University of California, San Diego, Department of Psychiatry and Veterans Affairs San Diego Healthcare System, Research Service, United States. smednick(-atsign-)ucsd.edu

Grants: K01 MH080992-01 (Agency:NIMH NIH HHS) ; K01 MH080992-02 (Agency:NIMH NIH HHS) ; M01 RR00827 (Agency:NCRR NIH HHS) ; R01-AG024506 (Agency:NIA NIH HHS)

Journal and publication information

Publication Type: Comparative Study; Journal Article; Randomized Controlled Trial; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S.

Journal: Behavioural brain research (Behav Brain Res), published in Netherlands. (Language: eng)

Reference: 2008-Nov; vol 193 (issue 1) : pp 79-86

Dates: Created 2008/08/01; Completed 2008/10/21; Revised 2009/11/05;

PMID: 18554731, status: MEDLINE (last retrieval date: 11/6/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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