5. Conclusion

The study investigated the neural mechanisms of phosphene using oscillatory transcranial electric stimulations with different polarities and amplitude modulations. Firstly, our results demonstrated that oscillatory electric stimulation can elicit phosphene irrespective of polarity. This finding underscores the importance of dynamic electromagnetic changes in the emergence of visual experiences, supporting the global resonance theory’s proposition that brain oscillation could serve as the foundation of consciousness. Furthermore, we illustrated that neural alignment to AM frequency contributes to phosphene flash rate, and this effect is independent of carrier frequency. This result implies that alignment to external stimulations significantly influences the subjective perception of temporal frequency. Finally, the observation of increased brightness with anodal otDCS and prolonged RT with cathodal otDCS suggests a polarity effect on phosphene quality without interacting with threshold intensity. This discovery implies that current oscillation and polarity may be processed independently, contributing to different aspects of phosphene. In line with our research objectives, the current study provides substantial evidence elucidating the underlying mechanisms of phosphene perception. Our findings in perceptual measurements establish a connection between neural oscillation and subjective visual experiences, opening up new possibilities for future research on prosthesis vision techniques.