استفاده از حواس پرتی برای تنظیم احساسات: بینش پویایی تتا EEG

Abstract Distraction is a powerful and widely-used emotion regulation strategy. Although distraction regulates emotion sooner than other cognitive strategies (Thiruchselvam, Blechert, Sheppes, Rydstrom, & Gross, 2011), it is not yet clear whether it is capable of blocking the earliest stages of emotion generation. To address this issue, we capitalized on the excellent temporal resolution of EEG by focusing on occipital theta dynamics which were associated with distinct stages of visual processing of emotional stimuli. Individually defined theta band dynamics were extracted from a previously published EEG dataset (Thiruchselvam et al., 2011) in which participants attended to unpleasant (and neutral) images or regulated emotion using distraction and reappraisal. Results revealed two peaks within early theta power increase, both of which were increased by emotional stimuli. Distraction did not affect theta power during an early peak (150–350 ms), but did successfully decrease activity in a second peak (350–550 ms). These results suggest that although distraction acts relatively early in the emotion-generative trajectory, it does not block fast detection of emotional significance. Given that theta dynamics were uncorrelated with Late Positive Potential activity, the present results also encourage researchers to add the occipital theta to the growing toolkit of EEG-based measures of emotion regulation.

1. Introduction Emotion regulation refers to efforts to influence the magnitude or duration of one or more aspects of the emotional response (Gross, 1998, Gross, 2013 and Koole, 2009). One major emotion regulation strategy is distraction, which involves diverting attention away from the emotional stimulus (Sheppes and Gross, 2011). While a key feature of distraction is relatively fast interference with emotion generation (Thiruchselvam et al., 2011), the precise stimulus processing stage at which this occurs is unclear. In the present study, we ask whether distraction is capable of precluding rapid selection of emotional significance at an initial attentional stage, or whether it becomes effective only later (Schupp et al., 2006). To this end, we capitalized on the excellent temporal precision of EEG, focusing in particular on occipital theta correlates of emotional processing (Knyazev et al., 2009, Knyazev, 2007, Lewis, 2005, Womelsdorf et al., 2010 and Zhang et al., 2013).

6. Results 6.1. Descriptive analyses Panel A on Fig. 1 depicts spectral perturbations in different frequencies recorded in this study. The plot reveals expected temporal dynamics whereby an initial power increase in theta, alpha and beta frequencies was followed by power decreases in alpha and beta and a sustained power level in theta and gamma. Panel B indicates that consistent differences between experimental conditions occurred almost exclusively in theta range. Finally, panel C depicts the scalp distribution of theta power revealing that occipital locations exhibited the strongest response. 6.2. Experimental effects on occipital theta perturbations The omnibus results of the mass univariate ANOVA of averaged perturbations are depicted on Fig. 2. Confirming our expectations, the initial theta increase contained two power surges peaking at around 250 ms and 450 ms, with each peak exhibiting different experimental effects. Post-hoc analyses of mean power revealed that the first peak (150–350 ms) was sensitive to valence but remained independent of regulation attempts. Specifically, the power in neutral-attend condition was lower than in negative-reappraise (p < .05), negative-attend (p < .01) and at trend level also in the negative-distract condition (p = .06). Meanwhile, all three conditions with unpleasant images did not differ from each-other (p > .21). On a single-subject level, the difference between neutral-attend and an average of all other conditions was significant at p < .1 for 9 participants (at p < .05 for 5). The three conditions with unpleasant images did not differ from each other for 15 subjects (p > .05). During the second theta peak (350–550 ms), the power recorded in the distraction condition abruptly decreased to the level measured in response to neutral images (p = .73). Both negative-distract and neutral-attend thus differed from negative-reappraise and negative-attend (all p < .05) which continued to be matched to each other (p = .63). The key difference between distraction and other conditions with unpleasant stimuli was significant at p < .1 for 13 participants (at p < .05 for 9). Collectively, these findings revealed that two successive theta peaks, which were both enhanced by emotional content, were differentially sensitive to distraction. In particular, distraction dampened only the second peak. By contrast, reappraisal had no effect on diminishing either peak. This pattern supports our prediction that distraction does not intervene at very early stages of emotional processing, but has a clear effect from approximately 350 ms onwards. Significant experimental effects also emerged within later occipital theta perturbations. As the relative order of experimental conditions was identical in most time windows with significant omnibus effects, power between 1000 and 4000 ms was averaged for the post-hoc analysis. The results indicated that late theta was lower in negative-distract compared to all other conditions (p < .01). The power in the negative-attend condition exceeded neutral-view (p < .05) and, at trend level, also negative-reappraise (p < .10) while the latter two conditions remained indistinguishable (p = .53). On the single subject level, distraction was significantly lower than other negative categories at p < .1 for 13 subjects (p < .05 for 10). Late occipital theta thus continued to be suppressed by distraction, even below the level associated with neutral stimuli. During this period, reappraisal also reduced theta power to the level generated in the neutral condition. 6.3. LPP and theta perturbations LPP amplitudes were re-analyzed in order to explore their covariance with theta dynamics. We first confirmed that the current preprocessing produced dynamics similar to the published study. We then found that temporally overlapping sections of the LPP and theta dynamics were unrelated to each-other. No significant correlations emerged between LPP during the second theta peak (350–550 ms, r = .09, p = 47) nor the late theta window (1000–4000 ms; r = − .09, p = .43). These results suggest that occipital theta dynamics complement the parietal LPP dynamics by providing non-redundant information.