Neutral Picture Stimuli Research Articles

Attentional bias training and cue reactivity in cigarette smokers

Attentional bias for drug-related cues has been associated with drug maintenance and relapse. We investigated whether attentional bias for smoking-related stimuli could be altered using a modified visual probe task in cigarette smokers. We also sought to determine whether changes in attentional bias were associated with changes in subsequent craving and cue reactivity. Male and female (n=54) current smokers (>or=5 cigarettes per day), aged between 18 and 40 years, were recruited from staff and students of the University of Bristol, and from the general population. Participants attended a single test session and completed an attentional training procedure in which they were either trained to attend to smoking-related pictorial stimuli (attend group) or to neutral pictorial stimuli (avoid group). Group allocation was randomized. Following attentional training, participants underwent a smoking cue exposure procedure in which they were exposed to smoking-related stimuli. Subjective measures of mood and craving were taken at baseline and before and after cue exposure. Participants then smoked a cigarette and smoking topography was measured. Attentional training increased attentional bias among participants in the attend group, and decreased attentional bias among those in the avoid group. There were also differences between the attend and avoid groups in post-training changes in craving during exposure to in vivo smoking cues, reflecting greater increases in craving in the attend group, although these effects were observed in males only. These data are the first to show alterations in attentional bias for smoking-related stimuli following a modified visual probe training procedure. Furthermore, post-training group differences in subjective craving suggest potential clinical utility of training procedures, although these effects may operate only in males. Future research should investigate whether multiple training sessions enhance post-training reductions in craving and cue reactivity, and the longer-term persistence of training effects.

Attentional modulation of emotional stimulus processing: An fMRI study using emotional expectancy

We used emotional expectancy to study attentional modulation in the processing of emotional stimuli. During functional magnetic resonance imaging (fMRI), volunteers saw emotional and neutral expectancy cues signaling the subsequent presentation of corresponding emotional or neutral pictorial stimuli. As a control, emotional and neutral pictures were presented without preceding expectancy cue, resulting in a 2 x 2 factorial design with the factors "expectancy" and "emotion." Statistical analysis revealed a significant positive interaction effect between these factors in the medial prefrontal cortex (MPFC, Brodmann area [BA] 9/10), amygdala, and dorsal midbrain. In all these regions, expectancy augmented the neural response to emotional but not to neutral pictures. Time course analysis of raw data suggests that this augmented activation was not preceded by baseline increases in MPFC and amygdala during the period of emotional expectancy. In a post-scanning session, the paradigm was presented for a second time to allow emotional intensity rating. Again, a significant interaction between expectancy and emotion was observed, with intensity ratings specifically enhanced in emotional photographs preceded by expectancy. There was a positive correlation between intensity ratings and blood oxygenation level-dependent (BOLD) signals in the left amygdala. We conclude that specific components of the emotion network show enhanced activation in response to emotional stimuli when these are preceded by expectancy. This enhancement effect is not present in neutral pictures and might parallel accentuated subjective feeling states.

Memory for negatively arousing and neutral pictorial stimuli using a repeated testing paradigm

The relationship between negatively arousing pictorial stimuli and memory was investigated using a repeated testing paradigm. Based on the previous literature, it was assumed that the superior memory for negatively arousing material was due to elaboration. Therefore, we hypothesised that negatively arousing material would produce more hypermnesia than neutral material because of the increased elaboration associated with negatively arousing stimuli. A total of 160 participants viewed negatively arousing or neutral slides for either 1 second or 5 seconds and completed three free recall tests. During the inter-test intervals, participants worked on a filler task or sat quietly. The results showed superior memory for negatively arousing slides over neutral slides, and an increase in memory across tests for the arousal condition but not for the neutral condition. The results did not provide strong support for the elaboration hypothesis.

Emotion, novelty, and the startle reflex: habituation in humans.

Previous research with both animal and human subjects has shown that startle reflex magnitude is potentiated in an aversive stimulus context, relative to responses elicited in a neutral or appetitive context. In the present experiment, the same pleasant, unpleasant, and neutral picture stimuli were repeatedly presented to human subjects. Startle reflex habituation was assessed in each stimulus context and was compared with the habituation patterns of heart rate, electrodermal, and facial corrugator muscle responses. All systems showed initial differentiation among affective picture contents and general habituation over trials. The startle reflex alone, however, continued to differentiate among pleasant, neutral, and unpleasant pictures throughout the presentation series. These results suggest that (a) the startle probe reflex is relatively uninfluenced by stimulus novelty, (b) the startle modulatory circuit (identified with amygdala-reticular connections in animals) varies systematically with affective valence, and (c) the modulatory influence is less subject to habituation than is the obligatory startle pathway or responses in other somatic and autonomic systems.