Brain System Integration and Message Consistent Health Behavior Change

Objective: Modifiable behaviors, including physical activity and sedentary behavior, are important determinants of health, and messages are important tools for influencing these behaviors. Functional neuroimaging research suggests that activity in regions of the brain's default mode and salience systems are independently associated with attending to health promoting messages. However, it remains unclear how these brain systems interact during exposure to persuasive messages and how this interaction relates to subsequent behavior change. Here, we examine how between-person differences in the relative integration between default mode and salience systems while viewing health messages relates to changes in health behavior. Method: Using wrist-worn accelerometers, we logged physical activity in 150 participants (mean age = 33.17 years, 64% women; 43% Black, 37% white, 7% Asian, 5% Hispanic, and 8% other) continuously for an average of 10 days. Participants then viewed health messages encouraging physical activity while undergoing functional MRI (fMRI) and completed an additional month where physical activity was logged and the health messages were reinforced with daily text reminders. Results: Individuals with higher default mode and salience system integration during health message exposure were more likely to decrease their sedentary behavior and increase light physical activity in the month following fMRI than participants with lower brain integration. Conclusions: Interactions between the salience and default mode systems are associated with message receptivity and subsequent behavior change, highlighting the value of expanding the focus from the role of single brain regions in studying health behavior change to larger-scale connectivity.