Boosting your mood: How exercise and the amygdala dance together

Accumulative evidence has shown that functional heterogeneity exists in subregions of amygdala. Recently, exercise serving as automatic emotion regulation has been observed to induce the altered activation of amygdala associated with mood change. However, the specific role of subregions of amygdala underlying these effects are not fully understood. By using resting-state functional magnetic resonance imaging (rs-fMRI), this study examined whether the subregions of amygdala play distinct roles in mood improvement induced by acute exercise. Participants (n = 76) aged 18-22 were recruited and randomly divided into the exercise group and the control group. The exercise group received a 30-minute intervention with moderate-intensity exercise while the control group completed a reading control task at resting state. Whole-brain rs-fMRI scans were conducted before and after the interventions. Moreover, participants' moods were also assessed using the Positive and Negative Affect Schedule (PANAS) and Abbreviated Profile of Mood States. A mixed-effect model was used to analyze the Group × Time interaction on functional connectivity (FC) seeded from medial amygdala (mAmyg) and lateral amygdala (lAmyg) subregions in each hemisphere. Results revealed that exercise-induced mood improvements were correlated with significant Group × Time interaction effects on FC, showing a notable right-hemispheric predominance. Specifically, enhanced connectivity of the right mAmyg with orbitofrontal cortex, parietal, and cerebellar regions was associated with reduced negative affect and increased self-esteem. Concurrently, enhanced connectivity of the right lAmyg with the orbitofrontal cortex and striatum was linked to a broad spectrum of improvements, including reduced tension and anger, and increased vigor. These findings suggest that acute exercise improves mood via distinct, lateralized neural pathways centered on different amygdala subregions. The mAmyg and lAmyg play complementary roles in automatic emotion regulation, with the right mAmyg modulating affective valence and self-evaluation, while the right lAmyg appears to regulate a broad spectrum of mood states and enhance positive arousal. This work provides a more nuanced neurobiological model for the therapeutic effects of exercise.