Functional MRI of inhibitory processing in abstinent adolescent marijuana users - PubMed (original) (raw)

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Functional MRI of inhibitory processing in abstinent adolescent marijuana users

Susan F Tapert et al. Psychopharmacology (Berl). 2007 Oct.

Abstract

Background: Marijuana intoxication appears to impair response inhibition, but it is unclear if impaired inhibition and associated brain abnormalities persist after prolonged abstinence among adolescent users. We hypothesized that brain activation during a go/no-go task would show persistent abnormalities in adolescent marijuana users after 28 days of abstinence.

Methods: Adolescents with (n = 16) and without (n = 17) histories of marijuana use were compared on blood oxygen level dependent (BOLD) response to a go/no-go task during functional magnetic resonance imaging (fMRI) after 28 days of monitored abstinence. Participants had no neurological problems or Axis I diagnoses other than cannabis abuse/dependence.

Results: Marijuana users did not differ from non-users on task performance but showed more BOLD response than non-users during inhibition trials in right dorsolateral prefrontal, bilateral medial frontal, bilateral inferior and superior parietal lobules, and right occipital gyri, as well as during "go" trials in right prefrontal, insular, and parietal cortices (p < 0.05, clusters > 943 microl). Differences remained significant even after controlling for lifetime and recent alcohol use.

Conclusions: Adolescent marijuana users relative to non-users showed increased brain processing effort during an inhibition task in the presence of similar task performance, even after 28 days of abstinence. Thus, increased brain processing effort to achieve inhibition may predate the onset of regular use or result from it. Future investigations will need to determine whether increased brain processing effort is associated with risk to use.

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Figures

Fig. 1

Fig. 1

Inhibition trial differences in BOLD response contrast between marijuana-using (_n_=16) and non-using (_n_=17) adolescents after 28 days of monitored abstinence. Blue areas show where users had more significantly BOLD response during inhibition (no-go) trials relative to baseline than non-users (p<0.05, clusters >943 μl); no clusters in which users showed significantly less activation than controls were found (see Table 2)

Fig. 2

Fig. 2

Marijuana using adolescents (_n_=16) show more BOLD response (_y_-axis displays fit coefficients) during inhibition trials relative to baseline than control adolescents (_n_=17) in right dorsolateral prefrontal cortex, largely accounted for by users with 1 to 3 years of regular (weekly) marijuana use

References

    1. Achenbach TM, Rescorla LA. Manual for the ASEBA school-age forms & profiles. University of Vermont, Research Center for Children, Youth, and Families; Burlington, VT: 2001.
    1. Adleman NE, Menon V, Blasey CM, White CD, Warsofsky IS, Glover GH, Reiss AL. A developmental fMRI study of the Stroop color-word task. Neuroimage. 2002;16(1):61–75. -PubMed
    1. Anderson KG, Schweinsburg AD, Paulus MP, Brown SA, Tapert SF. Examining personality and alcohol expectancies using fMRI with adolescents. J Stud Alcohol. 2005;66(3):323–331. -PMC -PubMed
    1. APA. Diagnostic and statistical manual of mental disorders. 4. American Psychiatric Association; Washington, DC, USA: 1994.
    1. Bandettini PA, Jesmanowicz A, Wong EC, Hyde JS. Processing strategies for time-course data sets in functional MRI of the human brain. Magn Reson Med. 1993;30:161–173. -PubMed

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