Investigating a novel fMRI cannabis cue reactivity task in youth

Abstract

Objective: Adult and adolescent studies suggest increased motivational responses to cannabis cues among regular cannabis users. However, functional magnetic resonance imaging (fMRI) studies have not explored neural activation in response to visual cannabis cues among adolescents in the United States. Gaining a better understanding of the neural circuits related to cue-elicited craving during adolescence may shed light on the neural basis for the development of problematic cannabis use that could ultimately be targeted for interventions.

Methods: 41 non-treatment-seeking youth (ages 17-21; mean age = 18.83; 46.3% female) who reported regular cannabis use underwent fMRI scanning involving a visual cannabis cue task and completed self-report and biological measures. Whole-brain activation was examined for cannabis cues compared to non-cannabis cues, and for active versus passive cannabis cues. Associations between self-reported substance use and task activation were examined.

Results: Cannabis images were identifiable to adolescents and were rated as more rewarding than matched non-cannabis images (p < .05). Greater activation was found for the cannabis cues compared to non-cannabis cues in bilateral posterior cingulate, cuneus, fusiform, precuneus, inferior temporal and parahippocampal gyri, as well as left thalamus, medial frontal and superior frontal gyri. Cue-elicited activation was not significantly associated with self-reported cannabis use (ps > 0.05). No differences were observed for the active versus passive cue contrast.

Conclusions: Cannabis-using youth show more activation to cannabis cues than non-cannabis cues in brain regions underlying incentive salience, reward, and visual attention. This task could be useful for future studies examining neural underpinnings of reward processes in adolescent cannabis users.

Keywords: Cannabis; Cue reactivity; Marijuana; Youth; fMRI.

Fig. 1.

Cannabis cue reactivity paradigm with active and passive cues. BOLD response during cannabis vs. non-cannabis cues was the main contrast of interest. Differences in activation in response to active (e.g., a person consuming cannabis; top left) vs. passive (e.g., cannabis plant; bottom left) cannabis cues were also examined. See Supplement 2 for all 36 cannabis and non-cannabis image pairs.

Fig. 2.

fMRI cannabis cue reactivity paradigm. Each task trial included a fixation cross followed by a cannabis or non-cannabis cue image presentation block, a craving rating period, and a blurred-image presentation.

Fig. 3.

Cannabis cue vs. non-cannabis cue activation. The cannabis vs. non-cannabis cue contrast elicited increased brain activation across 19 clusters (see Table 2). MNI z coordinates are indicated to the left of each slice.