Electrophysiological evidence of subtle deficits in memory processes in young heavy drinkers and cannabis users
-
1
University of New South Wales, National Drug and Alcohol Research Centre, Australia
Aims: Long-term heavy use of cannabis and alcohol are known to be associated with memory impairments. In this study, we examined whether subtle deficits were observable in young adults using both behavioural measures and ERPs.
Method: Twenty-one regular heavy drinkers, 18 regular cannabis users, and 22 controls aged 18-21 completed a modified verbal learning test (the Rey Auditory Verbal Learning Test) while EEG was recorded. ERPs were calculated for words which were subsequently remembered vs. those which were not remembered, and for presentations of learnt words, previously seen words, and new words in a subsequent recognition test. Principal components analysis was used to increase signal:noise ratio, since the RAVLT typically has too few trials for ERP research.
Results: Relative to controls, heavy drinkers showed (nonsignificant) trends to poorer initial learning and impaired recall after a distractor task; cannabis users also showed the latter effect. In recognition tests, heavy drinkers were less likely to recognise learnt words, while cannabis users were slower to reject previously seen and new words. At encoding, both cannabis users and heavy drinkers showed reductions in the usual P2 recall effect (larger for recalled than not-recalled words) observed in controls. In the recognition test, the parietal old/new effect (~550ms post-stimulus) discriminated between learnt words and previously seen and new words (which did not differ) in controls, but heavy drinkers responded to previously seen words more like learnt words. Cannabis users displayed a reduced frontal N400, reflecting familiarity, to all words, but were mostly like controls.
Conclusions: The study is the first examination of ERPs in the RAVLT in healthy control participants, let alone in substance-using individuals, and represents an important advance in methodology. The results suggest the presence of subtle brain dysfunction associated with encoding and recognition not yet significant enough to cause substantial behavioural differences, and underline the potential for brain dysfunction with early exposure to alcohol and cannabis.
Keywords:
alcohol,
Cannabis,
learning and memory,
recognition memory,
Recall
Conference:
ASP2013 - 23rd Annual meeting of the Australasian Society for Psychophysiology, Wollongong, Australia, 20 Nov - 22 Nov, 2013.
Presentation Type:
Oral Presentation
Topic:
Other...
Citation:
Smith
JL,
Mattick
RP and
Iredale
JM
(2013). Electrophysiological evidence of subtle deficits in memory processes in young heavy drinkers and cannabis users.
Conference Abstract:
ASP2013 - 23rd Annual meeting of the Australasian Society for Psychophysiology.
doi: 10.3389/conf.fnhum.2013.213.00051
Copyright:
The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers.
They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.
The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.
Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.
For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.
Received:
09 Oct 2013;
Published Online:
05 Nov 2013.
*
Correspondence:
Dr. Janette L Smith, University of New South Wales, National Drug and Alcohol Research Centre, Sydney, 2052, NSW, Australia, janette.smith@unsw.edu.au