Spontaneous action representation in smokers when watching movie characters smoke

Abstract

Do smokers simulate smoking when they see someone else smoke? For regular smokers, smoking is such a highly practiced motor skill that it often occurs automatically, without conscious awareness. Research on the brain basis of action observation has delineated a frontoparietal network that is commonly recruited when people observe, plan, or imitate actions. Here, we investigated whether this action observation network would be preferentially recruited in smokers when viewing complex smoking cues, such as those occurring in motion pictures. Seventeen right-handed smokers and 17 nonsmokers watched a popular movie while undergoing functional magnetic resonance imaging. Using a natural stimulus, such as a movie, allowed us to keep both smoking and nonsmoking participants naive to the goals of the experiment. Brain activity evoked by movie scenes of smoking was contrasted with nonsmoking control scenes that were matched for frequency and duration. Compared with nonsmokers, smokers showed greater activity in left anterior intraparietal sulcus and inferior frontal gyrus, regions involved in the simulation of contralateral hand-based gestures, when viewing smoking versus control scenes. These results demonstrate that smokers spontaneously represent the action of smoking when viewing others smoke, the consequence of which may make it more difficult to abstain from smoking.

Figures

Figure 1.

Schematic of the study design. Smoking and nonsmoking control scenes were matched for duration and frequency per run.

Figure 2.

A, Brain regions showing a greater blood oxygenation level-dependent signal response during smoking scenes compared with control scenes in all subjects (p < 0.005, uncorrected, cluster extent threshold of 10 contiguous voxels). This parametric map was used to generate unbiased regions of interest to interrogate for an effect of smoking status (i.e., smokers vs nonsmokers). B, The left aIPS and IFG demonstrated greater smoking cue-related activity in smokers compared with nonsmokers. Error bars indicate SEM. IPS, Intraparietal sulcus; LPFC, lateral prefrontal cortex; PFC, prefrontal cortex, PT, pars triangularis.

Figure 3.

Relationship between postscan cigarette craving in smokers and blood oxygenation level-dependent response difference between smoking and control scenes in the dorsal anterior cingulate cortex (r2 = 0.33, p < 0.018; MNI coordinates: 9, 30, 27). Dashed lines indicate the 95% confidence intervals.