Abstract:

Emotion regulation plays an important role in maintaining mental balance. Automatic emotion regulation is an important aspect of emotion regulation. Previous studies have found that automatic emotion regulation can influence emotional attention bias, and the activation of the left orbitofrontal cortex (OFC) was related to attention allocation to negative emotional stimuli. Although previous studies have provided evidence to the involvement of left OFC in the mechanism of automatic emotion regulation’s influence on attention, little studies provided evidences for this hypothesis by manipulating the activation of left OFC. In order to examine the role of left OFC in attention allocation under automatic emotion regulation, the present study manipulates the cortical excitability by using transcranial direct current stimulation (tDCS). We hypothesized that under the cathodal stimulation condition, the effect of subliminal emotional control words on attention avoidance of fear stimulation was diminished.
Thirty-nine healthy right-handed college students participated in this study. Each participant was settled into cathodal and sham tDCS sessions in random order. After entering the laboratory, the participants completed a state-trait anxiety questionnaire. Then they completed the pre-task, in which emotional control goal was subliminally presented in the beginning of each trial. And fear related dot probe task was adopted in the pre-task. After the task was completed, the participants received tDCS stimulation. A relatively weak current (±1.5 mA) was constantly delivered over the left OFC for 20 min. For the sham tDCS, the stimulation only lasted for 15 sec. After stimulation participants immediately completed the post-task, in which the same task with the pre-task was used. The present study analyzed accuracy and reaction time by a 2 (pre-tesk and post-task) × 2 (tDCS: cathodal, sham)×2 (left-right location consistency of snake picture and target) repeated measures ANOVA.
The results showed that the main effect of location consistency was significant (F(1, 37) = 5.11, p < 0.05, η_p² = 0.12), and the reaction time under the consistent condition was significantly greater than that under the inconsistent condition. The interaction between the location consistency and stimulus conditions was significant, F(1, 37) = 9.78, p < 0.01, η_p ² = 0.21. The simple effect analysis revealed that under the condition of sham stimulation, the reaction time under the consistent condition was greater than that under the inconsistent condition (ps < 0.05). For the cathodal stimulation, there was no significant difference between the reaction time under the consistent condition and the inconsistent condition (p > 0.05). The interaction between the consistency of pre- and post-task, stimulation condition and location consistency was significant, F(1, 37) = 11.41, p < 0.01, η_p² = 0.24. Simple effect analysis showed that under the condition of sham stimulus, the response time under the consistent condition was greater than that under the inconsistent condition (ps < 0.05). Under the cathodal stimulation condition, the response time under the consistent condition was greater than that under the inconsistent condition (p < 0.05), while the response time under the consistent condition was significantly less than that under the inconsistent condition (p < 0.05).
The present study examined the role of left OFC in attention allocation under automatic emotion regulation using subliminal goal priming and dot-probe task. Our findings revealed that after cathodal stimulation, attention avoidance of fear stimuli induced by subliminal control goal priming would be diminished, suggesting that the activation of left OFC influenced emotional attention allocation in automatic emotion regulation.

Key words: automatic emotional regulation, attentional bias, left orbitofrontal cortex (LOFC), transcranial direct current stimulation (tDCS)