Myelin plasticity in a social context

This presentation explores the plasticity of cortical myelin and its relationship to intrinsic brain function and behavioral adaptation, with a particular focus on the social domain. We examine myelin plasticity during adolescence and adulthood, highlighting its role in responding to psychosocial stress and social mental training.

Adolescent Myelin Plasticity and Psychosocial Stress: During adolescence, the brain undergoes substantial remodeling of both structure and function, especially in association regions. This developmental stage coincides with a rise in psychiatric disorders, influenced by genetic and environmental factors. Using myelin-sensitive Magnetic Transfer imaging based on the MPM sequence, we investigated how psychosocial stress impacts myelin plasticity and functional connectivity during this critical period. Our findings show that individuals that are more adaptive to psychosocial stress show increased maturation of myelin in the prefrontal cortex which is associated with greater stability in functional networks. These local changes are accompanied by reconfiguration of both microstructure and functional networks, with strongest reconfigurations in more adaptive individuals. These results underscore the relationship between structural plasticity and behavioral adaptation to psychosocial stressors during adolescence.

Social Mental Training in Adults: In a second study with adults, we examined the effects of social mental training on three functional domains—attention-mindfulness, emotion-motivation, and perspective-taking—over three months on brain microstructure, measured using MP2RAGE, and function. We observed domain-specific functional changes in brain networks linked to attention and interoception. Attention-mindfulness training led to distinct functional changes compared to perspective-taking training, with networks showing stronger functional integration following perspective-taking and stronger segregation following attention-mindfulness training. Moreover, between the three training modules, microstructural alterations, largely reflecting myelination changes, varied spatially across cortical regions and showed depth-specific patterns, suggesting that remodeling processes differ between superior and deep cortical layers. Importantly, these structural and functional changes were associated with behavioral outcomes, demonstrating that brain plasticity persists in adulthood and responds to social environmental demands.

Together, these studies reveal that human brain structure dynamically adapts to shifting social and environmental demands across the lifespan. While plasticity during adolescence is linked to resilience under stress, adult plasticity appears to be shaped by targeted interventions like social mental training. Further research is needed to delineate the timing, duration, and functional implications of these changes at finer spatial and temporal scales.