A neuroimaging study involving women with high levels of neuroticism revealed that their brain’s default mode network becomes more active following criticism, but not after they hear praise, compared to the brains of women with average levels of neuroticism. This increase in activity, particularly in the medial prefrontal cortex and the inferior parietal lobule, may indicate a tendency towards rumination. The study was published in the Social Cognitive and Affective Neuroscience.
The default mode network is a network of brain regions that is active when the mind is at rest and not focused on the outside world. It is associated with internal processes such as spontaneous cognition, mind-wandering, thinking about oneself in the past and future, and about relations with others. Its activity can also be indicative of rumination – the tendency to repetitively dwell on distressing thoughts or problems. Rumination may lead to overthinking and a prolonged focus on negative emotions. It can predict the onset or exacerbate symptoms of mental disorders such as depression, anxiety, post-traumatic stress disorder, or eating disorders.
Additionally, the default mode network plays a crucial role in various cognitive functions, including memory consolidation, social processing, and constructing a sense of self. Dysregulation of the default mode network has been implicated in various neurological and psychiatric conditions, including Alzheimer’s disease, depression, and attention deficit hyperactivity disorder (ADHD). The default mode network primarily spans across the medial prefrontal cortex, posterior cingulate cortex, precuneus, and parts of the parietal cortex regions of the brain.
Study author Tina Chou and her colleagues wanted to investigate whether activation patterns of the default mode network differ between individuals who are at a heightened risk for depression, but have not yet developed it. They selected females with high levels of neuroticism to represent this group. Neuroticism is a personality trait that reflects an individual’s tendency to experience negative emotions such as anxiety, fear, and sadness. People high in neuroticism are more prone to emotional instability, mood swings, and a heightened sensitivity to stressors.
The study included 25 women with high neuroticism levels, placing them in the top 20% for this trait, and 28 women with average neuroticism levels. None of the participants had a history of mood or anxiety disorders or were using psychotropic medications. Their average age was 20-21 years, and they had approximately 14 years of education on average.
Participants underwent assessments for neuroticism (using the NEO-FFI) and rumination (using the Ruminative Responses Scale of the Response Styles Questionnaire). They also participated in functional magnetic resonance imaging sessions. During these sessions, they listened to a series of comments, derived from remarks made by mothers of individuals with depression and borderline personality disorder, adapted for the study. These comments, lasting 30 seconds each, were a mix of criticism and praise.
Examples of critical comments include phrases such as “one of the things that bothers me about you is that you’re not very considerate of other people. You can be very self-involved at times. […] It’s all about you and what you need.” Praise comments included phrases such as “one of the things that I really like about you is your sense of humor. It’s not that you’re always telling jokes or anything like that. But you can be really, really funny.” The researchers instructed participants to imagine that those comments were said to them by someone who is really important in their lives.
Results showed that participants high in neuroticism (i.e., at a heightened risk of depression) showed greater activity in two regions of the default mode network compared to females with average neuroticism levels. These areas were medial prefrontal cortex and the inferior parietal lobule. When hearing praises, default mode networks of participants from the two groups reacted similarly. Additionally, activation in the left inferior parietal lobule was associated with rumination in the high neuroticism group, but not in the average neuroticism group.
“Overall, our results suggest that individuals at risk for depression may use a self-referential brain network when preferentially processing negative, rather than positive, information. This form of biased processing is associated with ruminative thoughts and may reflect an underlying neurocognitive vulnerability for later depression. Future treatments targeting the medial prefrontal cortex or the inferior parietal lobule could serve as a preventative intervention for individuals at risk for depression,” the study authors concluded.
The study sheds light on differences in brain responses of individuals with high and average neuroticism. However, it should be noted that neuroticism is not the only risk factor of depression. The control group members could have had other depression risk factors that were not assessed. Additionally, the study samples were small and consisted solely of young adult females. Results on other demographic groups and more diverse samples might not be the same.
The study, “The default mode network and rumination in individuals at risk for depression”, was authored by Tina Chou, Thilo Deckersbach, Darin D. Dougherty, and Jill M. Hooley.