Smoking abstinence and depressive symptoms modulate the executive control system during emotional information processing

Abstract

Smoking abstinence disrupts affective and cognitive processes. In this study, functional magnetic resonance imaging (fMRI) was used to investigate the effects of smoking abstinence on emotional information processing. Smokers (n = 17) and non-smokers (n = 18) underwent fMRI while performing an emotional distractor oddball task in which rare targets were presented following negative and neutral task-irrelevant distractors. Smokers completed two sessions: once following 24-hour abstinence and once while satiated. The abstinent versus satiated states were compared by evaluating responses to distractor images and to targets following each distractor valence within frontal executive and limbic brain regions. Regression analyses were done to investigate whether self-reported negative affect influences brain response to images and targets. Exploratory regression analyses examined relations between baseline depressive symptoms and smoking state on brain function. Smoking state affected response to target detection in the right inferior frontal gyrus (IFG). During satiety, activation was greater in response to targets following negative versus neutral distractors; following abstinence, the reverse was observed. Withdrawal-related negative affect was associated with right insula activation to negative images. Finally, depression symptoms were associated with abstinence-induced hypoactive response to negative emotional distractors and task-relevant targets following negative distractors in frontal brain regions. Neural processes related to novelty detection/attention in the right IFG may be disrupted by smoking abstinence and negative stimuli. Reactivity to emotional stimuli and the interfering effects on cognition are moderated by the magnitude of smoking state-dependent negative affect and baseline depressive symptoms.

Figure 1

Each stimulus was presented for 1000 ms with a 200 ms inter-stimulus interval. The interval between distractor stimuli and target stimuli was randomly varied between 5 and 11 seconds in order to minimize distractors serving as predictors of an upcoming target stimulus. Furthermore, 33% of distractors occurred in the absence of a subsequent target. This method eliminated predictability of target onsets when used in conjunction with varying distractor/target SOA. Each run of the EDOT contained 24 negative distractors, 24 neutral distractors and 32 targets with an equal number following each distractor valence.

Figure 2

Smoking condition × emotional valence interaction for task targets Bold response as measured by % signal change to targets following either negative or neutral distractors.

Figure 3

Regression analyses of baseline depression symptoms on brain activation to emotional distractors.

Figure 4

Regression analyses of baseline depression symptoms on brain activation to targets