The dynamic relationship of brain-derived neurotrophic factor and oxytocin: Introducing the concept of neurosocial plasticity.

The human brain functions as a highly integrated system. Interconnected cellular and molecular networks within this system process sensory information, cognitive functions, and motor responses. The brain also exhibits a remarkable potential for plasticity-driven adaptive learning and memory. Importantly, neuroplasticity serves as a key mechanism of neuroprotection while also enabling the brain to compensate for injury through adaptive structural remodeling. Understanding the brain as a dynamic system requires examining how its components interact to produce adaptive physiological responses and complex behaviors, such as social interactions. Key molecules, such as brain-derived neurotrophic factor (BDNF) and oxytocin (OT), play pivotal roles in maintaining the brain's dynamic complexity and integrative functioning. In this review, we introduce the concept of "neurosocial plasticity", which refers to the brain's ability to adapt both neural circuitry and social behavior through the dynamic interaction between BDNF and OT. This concept highlights how BDNF-OT interactions may support both neural plasticity and the capacity for adaptive social functioning. We then explore how their co-localization, co-expression, and co-regulation may regulate neural and social plasticity, ultimately shaping the brain's adaptability and the development of social behaviors across various contexts.