The role of photobiomodulation in modulating neural activity and brain function: A systematic bibliometric analysis

This systematic bibliometric analysis evaluates the scientific evidence, impact, and trends of photobiomodulation (PBM) for central nervous system (CNS) disorders. Analyzing 150 relevant PubMed-indexed studies (including 46 clinical trials) up to September 2024, we demonstrate PBM's positive effects on the CNS. Key mechanisms include enhanced ATP synthesis, modulated nitric oxide signaling, improved neuronal excitability, suppressed oxidative stress, anti-inflammatory effects, and ion channel modulation. PBM offers therapeutic flexibility: shorter-wavelength, high-irradiance power lasers effectively target deep brain structures, while both modalities suit superficial cortical applications where fine spatial control is nonessential.Crucially, PBM induces long-lasting biological effects, highlighting significant potential for chronic CNS conditions like Alzheimer's disease, Parkinson's disease, and stroke. However, critical challenges hinder translation: optimizing disease-specific wavelengths and light sources (laser vs. LED, continuous vs. pulsed), and establishing standardized, long-term treatment protocols based on robust dose-response relationships. Resolving heterogeneity in parameters (energy density, power, potential thermal effects) is paramount for PBM to become a reliable neuromodulation tool. This analysis provides critical insights for advancing targeted PBM therapies in CNS.