Brain fMRI reactivity to smoking-related images before and during extended smoking abstinence

Abstract

Reactivity to smoking-related cues may play a role in the maintenance of smoking behavior and may change depending on smoking status. Whether smoking cue-related functional MRI (fMRI) reactivity differs between active smoking and extended smoking abstinence states currently is unknown. We used fMRI to measure brain reactivity in response to smoking-related versus neutral images in 13 tobacco-dependent subjects before a smoking cessation attempt and again during extended smoking abstinence (52 +/- 11 days) aided by nicotine replacement therapy. Prequit smoking cue induced fMRI activity patterns paralleled those reported in prior smoking cue reactivity fMRI studies. Greater fMRI activity was detected during extended smoking abstinence than during the pre-quit [corrected] assessment subcortically in the caudate nucleus and cortically in prefrontal (BA 6, 8, 9, 10, 44, 46), [corrected] primary somatosensory (BA 1, 2, 3), temporal (BA 22), [corrected] parietal (BA 5, 7, 40), occipital (BA 17, 18), [corrected] and posterior cingulate (BA 31) cortex. These data suggest that during extended smoking abstinence, fMRI reactivity to smoking versus neutral stimuli persists in brain areas involved in attention, somatosensory processing, motor planning, and conditioned cue responding. In some brain regions, fMRI smoking cue reactivity is increased during extended smoking abstinence in comparison to the prequit state, which may contribute to persisting relapse vulnerability.

Figure 1

Functional MRI Results. Top row: In the pre-quit (scan 1) state, the contrast smoking-related > netural images revealed activation in occipital, medial prefrontal, and posterior cingulate cortex, and in other regions (see Table 1). No activity was detected in the caudate nucleus (cross hair position in all images at Talairach coordinates: (x, y, z) -14, 25, 2). Middle row: During extended smoking abstinence (scan 2), the contrast smoking-related > neutral images revealed activation in the caudate nucleus, prefrontal, parietal, and cingulate cortex, and in other regions (see Table 2). Bottom row: The contrast scan 2 (smoking-related > neutral images) > scan 1 (smoking-related > neutral images) revealed increased reactivity in the caudate nucleus and in other brain regions (Table 3). For all tests: t ≥ 3.1, corrected p < 0.005, cluster sizes noted in tables.