Structured Light Music for Stress Adaptation: The BDNF/TrkB Signaling Axis Mediating Neuroplasticity and HPA Axis Regulation

Background/Objectives: Chronic stress poses a major threat to animal health and welfare, yet current interventions are often invasive, poorly compliant, or lack long-term feasibility. This narrative review synthesizes preclinical mechanistic evidence from mammalian animal models to examine how structured auditory stimulation engages neurotrophic signaling. Structured light music—an auditory stimulus with defined acoustic parameters (e.g., tempo, intensity, and spectral frequency)—has emerged as a promising non-invasive strategy for promoting stress adaptation. However, the molecular mechanism of its effects remains unclear, and systematic analyses linking acoustic features to signaling pathways are scarce. Brain-derived neurotrophic factor (BDNF) and its high-affinity receptor tropomyosin receptor kinase B (TrkB) constitute a central signaling axis regulating neuroplasticity and stress adaptation, suggesting that this pathway may serve as a critical molecular interface linking auditory stimulation to stress-regulatory processes. Methods: In this review, we focus on structured light music stimuli with distinct acoustic characteristics and examine the molecular mechanisms by which they regulate neural plasticity through the BDNF/TrkB pathway. Results: Existing studies have shown that light music is associated with reversal of stress-induced down-regulation of BDNF/TrkB signaling in the hippocampus and prefrontal cortex. This effect is accompanied by enhanced neurogenesis, dendritic spine remodeling, and synaptic protein synthesis, which are linked to the coordinated activation of three downstream pathways: PI3K/Akt, MAPK/ERK and PLCγ. This cascade reaction further correlates with restoration of negative feedback inhibition of the hypothalamic–pituitary–adrenal axis in the hippocampus, reduces the level of glucocorticoids, and alleviates oxidative stress and inflammatory damage. Conclusions: This review proposes that the BDNF/TrkB pathway may serve as a key molecular basis for light music to regulate neural plasticity and achieve systemic anti-stress effects, and provides new ideas for animal welfare management and the formulation of standardized acoustic intervention strategies.