Neural correlates of verbal learning in adolescent alcohol and marijuana users - PubMed (original) (raw)

Neural correlates of verbal learning in adolescent alcohol and marijuana users

Alecia Dager Schweinsburg et al. Addiction. 2011 Mar.

Abstract

Aims: Alcohol and marijuana are the most widely used intoxicants among adolescents, yet their potential unique and interactive influences on the developing brain are not well established. Brain regions subserving learning and memory undergo continued maturation during adolescence, and may be particularly susceptible to substance-related neurotoxic damage. In this study, we characterize brain response during verbal learning among adolescent users of alcohol and marijuana.

Design: Participants performed a verbal paired associates encoding task during functional magnetic resonance imaging (fMRI) scanning.

Setting: Adolescent subjects were recruited from local public schools and imaged at a university-based fMRI center.

Participants: Participants were 74 16-18-year-olds, divided into four groups: (i) 22 controls with limited alcohol and marijuana experience, (ii) 16 binge drinkers, (iii) eight marijuana users and (iv) 28 binge drinking marijuana users.

Measurements: Diagnostic interview ensured that all teens were free from neurological or psychiatric disorders; urine toxicology and breathalyzer verified abstinence for 22-28 days before scanning; a verbal paired associates task was administered during fMRI.

Findings: Groups demonstrated no differences in performance on the verbal encoding task, yet exhibited different brain response patterns. A main effect of drinking pointed to decreased inferior frontal but increased dorsal frontal and parietal fMRI response among binge drinkers (corrected P < 0.05). There was no main effect of marijuana use. Binge drinking × marijuana interactions were found in bilateral frontal regions (corrected P < 0.05), where users of either alcohol or marijuana showed greater response than non-users, but users of both substances resembled non-users.

Conclusions: Adolescent substance users demonstrated altered fMRI response relative to non-using controls, yet binge drinking appeared to be associated with more differences in activation than marijuana use. Alcohol and marijuana may have interactive effects that alter these differences, particularly in prefrontal brain regions.

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Conflict of interest statement

Declarations of Interest: None.

Figures

Figure 1

Clusters showing significant main effects for binge drinking (clusters > 1512 μl, corrected p < .05). Orange indicates regions where CON and MJ (non-drinkers; n = 30) showed greater BOLD response during novel encoding than BD and BD+MJ (binge drinkers; n = 44); blue clusters represent regions where BD and BD+MJ showed greater BOLD response during novel encoding than CON and MJ.

Figure 2

Clusters showing significant interactions between binge drinking and marijuana use (_N_=74; clusters >1512 μl, corrected p < .05).

References

1. Johnston LD, O’Malley PM, Bachman JG, Schulenberg JE. Monitoring the Future national results on adolescent drug use: Overview of key findings, 2008. Bethesda, MD: National Institute on Drug Abuse; 2009.
1. Gogtay N, Giedd JN, Lusk L, Hayashi KM, Greenstein D, Vaituzis AC, Nugent TF, 3rd, Herman DH, Clasen LS, Toga AW, Rapoport JL, Thompson PM. Dynamic mapping of human cortical development during childhood through early adulthood. Proc Natl Acad Sci U S A. 2004;101:8174–9. -PMC -PubMed
1. Giedd JN, Blumenthal J, Jeffries NO, Castellanos FX, Liu H, Zijdenbos A, Paus T, Evans AC, Rapoport JL. Brain development during childhood and adolescence: A longitudinal MRI study. Nat Neurosci. 1999;2:861–863. -PubMed
1. Sowell ER, Delis D, Stiles J, Jernigan TL. Improved memory functioning and frontal lobe maturation between childhood and adolescence: a structural MRI study. J Int Neuropsychol Soc. 2001;7:312–22. -PubMed
1. Squire LR, Schacter DL. The neuropsychology of memory. New York: Guilford; 2002.

Neural correlates of verbal learning in adolescent alcohol and marijuana users - PubMed (original) (raw)