Functional MRI of inhibitory processing in abstinent adolescent marijuana users

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.

Neural Correlates of Response Inhibition and Cigarette Smoking in Late Adolescence

“…To ensure that those participants who were heavier smokers in this sample were not actually adults (19-21 years of age), correlation analyses were conducted, and they revealed no association between age and smoking behavior or cumulative exposure We speculate that, although some effects of smoking on the brain may not be evident soon after smoking initiation in adolescence, they may evolve when smoking persists from adolescence through adulthood (Azizian et al, 2010), or when smoking in adolescence increases to levels seen in adulthood. Notably, although studies of adults show strong right-lateralized activation in the IFG during response inhibition, the findings reported here are left lateralized in IFG and bilateral in other frontal regions, possibly reflecting a greater reliance on a more distributed network in immature (Brown et al, 2005;Durston et al, 2006) and patient (Jacobsen et al, 2007;Tapert et al, 2007) than adult samples.…”

The Role of Executive Control in Human Drug Addiction

“…Neuroimaging studies have identified an association between these executive control deficits and dysfunction in prefrontal (particularly dorsolateral and inferior frontal), anterior cingulate, and orbitofrontal regions (Bolla et al 2001(Bolla et al , 2003(Bolla et al , 2004Goldstein et al 2001;Franklin et al 2002;Paulus et al 2002;Kaufman et al 2003;Hester and Garavan 2004;Gruber and Yurgelun-Todd 2005;London et al 2005;Tapert et al 2007;Paulus et al 2008). Individual studies have also identified changes within subcortical (thalamus and basal ganglia), parietal, temporal, and cerebellar regions, although these findings are less consistent.…”

“…It is important to point out that many studies that observe differences in functional brain activity between drug-using groups and matched control participants do not observe a significant difference in executive control performance (Goldstein et al 2001;Tapert et al 2007). Indeed, some studies manipulate task difficulty to ensure equivalent performance between drug users and controls so as to ensure that the differences in brain function observed are not overly influenced by performance differences, or by factors that potentially contribute to performance differences (e.g., fatigue, frustration, effort) (Kaufman et al 2003;Yucel et al 2007b).…”

“…The interpretation of findings from such studies has generally focused on identifying brain regions or brain networks that behave differently in drug users. For example, studies have found that equivalent executive control performance in drug users is typically associated with higher levels of activity within brain regions related to the task (e.g., prefrontal regions; Gruber and Yurgelun-Todd 2005;Tapert et al 2007), or the recruitment of additional analogous brain regions (Desmond et al 2003;Yucel et al 2007b) that suggest compensatory patterns of activity.…”

Asociación diferencial entre el metabolismo regional de la corteza prefrontal y las estructuras límbicas y el tiempo de abstinencia en individuos dependientes de sustancias

“…Barrós-Loscertales et al, 2011;Tapert et al, 2007). De entre las diferentes técnicas utilizadas, el uso de la Tomografía por Emisión de Positrones (PET) en combinación con el trazador 18-Flúor-Desoxi-Glucosa (18FDG) ha demostrado ser una herramienta de gran utilidad en la identificación, localización y cuantificación del consumo de glucosa a nivel cerebral.…”