Brain-imaging research suggests that suppressing or reappraising emotions may not produce the straightforward neural changes scientists expect. An analysis of 40 functional MRI datasets found that the relevant effect was small and difficult to detect, while differences between brain scans, questionnaires, and task-based assessments showed little consistency. The findings also raise questions about how the timing of emotional and decision-making activity affects the results.
The amygdala is a structure deep in the brain that is active when people respond emotionally to events, among many other situations. It might therefore seem reasonable to expect amygdala activity to decrease when people try to suppress their emotions. To test that expectation, the research team examined brain activity using 40 functional MRI datasets, a sample large enough to reveal relatively small effects.
That larger dataset was important because the effect was difficult to detect. “The effect size was relatively small. To detect this effect size with 80 percent statistical power, one study would need to examine 1,105 participants,” the researchers noted. They added that few fMRI studies have access to such a large number of participants.
An even greater challenge emerged when the researchers compared differences between individuals in the MRI data with differences in questionnaire responses and task-based assessments. The variation across the different types of measurements was poorly correlated, suggesting that they did not consistently capture the same aspects of emotion regulation.
Credit: Cicorello et al.
A timing issue?
When the researchers examined activity in brain regions involved in high-level decision-making, another possibility emerged. If people can reappraise emotional cues, those regions might be expected to become more active because they help support the reappraisal process.
However, the fMRI data did not show that pattern. Instead, activity in the amygdala was correlated with activity elsewhere in the brain. When the amygdala was more active, indicating a stronger emotional response, the decision-making regions were also more active. Conversely, when emotional responses appeared to be suppressed, the brain’s reasoning centers were less active as well.
Source: arstechnica.com