Optogenetic synchronization in excitable media by induced Archimedean spiral.

Abnormal propagation of electrical excitation waves underlies the development of many cardiac arrhythmias. Optogenetics offers a powerful means to precisely manipulate cardiac excitation dynamics. Previous optogenetic control strategies have primarily relied on projecting light patterns that directly mimic wave activity in the studied excitable medium. In this study, we propose a geometry-guided strategy based on synthetic Archimedean spiral line illumination. We demonstrate that this method not only enables effective synchronization of excitation patterns, but also provides a systematic way to study the influence of illumination frequency and wavelength of the projected pattern on synchronization. Our computational analysis is performed in both two- and three-dimensional media using the Bär reaction-diffusion model. We examine both depolarizing and hyperpolarizing modes of optogenetic control, which have previously received very limited attention. Depolarizing illumination achieves synchronization by inducing new wave fronts, whereas hyperpolarizing illumination operates through the formation of dynamic repolarization barriers. Importantly, both mechanisms remain robust under realistic conditions, including optical attenuation and pathological fibrotic remodeling. In summary, this work introduces a biophysically grounded, geometry-driven optogenetic control paradigm for the synchronization and suppression of electrical turbulence in excitable media, laying the foundation for potential future applications in cardiac tissue.