Neural substrates of resisting craving during cigarette cue exposure

Abstract

Background: In cigarette smokers, the most commonly reported areas of brain activation during visual cigarette cue exposure are the prefrontal, anterior cingulate, and visual cortices. We sought to determine changes in brain activity in response to cigarette cues when smokers actively resist craving.

Methods: Forty-two tobacco-dependent smokers underwent functional magnetic resonance imaging, during which they were presented with videotaped cues. Three cue presentation conditions were tested: cigarette cues with subjects allowing themselves to crave (cigarette cue crave), cigarette cues with the instruction to resist craving (cigarette cue resist), and matched neutral cues.

Results: Activation was found in the cigarette cue resist (compared with the cigarette cue crave) condition in the left dorsal anterior cingulate cortex (ACC), posterior cingulate cortex (PCC), and precuneus. Lower magnetic resonance signal for the cigarette cue resist condition was found in the cuneus bilaterally, left lateral occipital gyrus, and right postcentral gyrus. These relative activations and deactivations were more robust when the cigarette cue resist condition was compared with the neutral cue condition.

Conclusions: Suppressing craving during cigarette cue exposure involves activation of limbic (and related) brain regions and deactivation of primary sensory and motor cortices.

Figure 1

Functional MRI findings when cigarette smokers (n = 42) were exposed to cigarette-related cues and allowed themselves to crave (cigarette cue crave condition) compared to the neutral cue condition. The top panel shows higher MR signal for the cigarette cue crave condition in the left cuneus, lingual gyrus, and lateral occipital gyrus, the supramarginal gyrus bilaterally, and the left angular gyrus. The bottom panel shows no voxels with significantly lower MR signal for the cigarette cue crave condition. Scaling for Z scores is presented on the right.

Figure 2

Functional MRI findings when smokers were exposed to cigarette-related cues and resisted craving (cigarette cue resist condition) compared to the neutral cue condition. The top panel shows higher MR signal for the cigarette cue resist condition in the posterior cingulate cortex extending to the precuneus and retrosplenial area bilaterally, the medial aspect of the superior frontal gyrus and anterior cingulate cortex spanning the midline, the left angular gyrus, and the supramarginal gyrus bilaterally. The bottom panel shows lower MR signal for the cigarette cue resist condition in the cuneus and post-central gyri bilaterally, and the right pre-central gyrus.

Figure 3

Functional MRI findings when smokers were exposed to cigarette-related cues and resisted craving (cigarette cue resist condition) compared to cigarette-related cues and allowing craving (cigarette cue crave condition). The top panel shows higher MR signal for the cigarette cue resist condition in the left anterior cingulate cortex, precuneus, and posterior cingulate cortex. The bottom panel shows lower MR signal for the cigarette cue resist condition in the cuneus and lateral occipital gyri bilaterally, left middle temporal gyrus, and right post-central gyrus.

Figure 4

Positive and negative correlations between Urge to Smoke Scale score (craving) and MR signal across all three study conditions. The top panel shows regions with positive correlations, including the medial aspect of the superior frontal gyrus, supramarginal gyrus, precuneus, and inferior frontal gyrus/anterior insula bilaterally, along with the left pre-central gyrus, putamen, and middle frontal gyrus and right lingual gyrus extending to the fusiform gyrus. Negative correlations were found for the cuneus bilaterally; left occipital gyrus, anterior temporal lobe, post-central gyrus, and insula; and right angular gyrus.