Hazardous Effects of Light Stimulation in the Central Nervous System

We are continually exposed to various visual stimuli in our contemporary society. Temporal frequency characteristics of the neural response to visual stimuli have been reported: Some temporal stimulation frequencies enhance neural responses and these frequencies are harmonically related, with a greatest common divisor frequency of approximately 6.5 Hz. Such stimuli, especially when high in temporal frequency, sometimes cause unexpected events such as photosensitive seizures. High-temporal-frequency visual stimuli can yield hazardous responses in the central nervous system. The mechanisms by which it does so have begun to be clarified using neuro imaging techniques such as magnetoencephalography. In addition, our knowledge about the relationship between the neural response to the high-temporal-frequency visual stimuli and fatigue in the central nervous system is increasing. Furthermore, the neural mechanisms to cause fatigue in the central nervous system by the visual stimuli has begun to be clarified. In this review, we describe the temporal frequency characteristics of the neural response to visual stimuli and the potential hazardous effects of high-temporal-frequency visual stimuli, particularly focused on the fatigue in the central nervous system.