Imagine your brain is a grand symphony, with different sections playing in perfect harmony. Researchers have discovered that rhythmic light flickers can act as conductors, modulating the brain’s oscillations and potentially rescuing them from neurological disorders. A neural network model was developed to investigate the effects of different brain states and various light flicker parameters on thalamocortical oscillations (TCOs). The model generated three distinct oscillatory states – alpha, beta, and gamma – each with its own characteristic frequency. When light flicker stimulation was applied, the degree of entrainment depended on both the brain state and the proximity of the flicker frequency to the endogenous oscillation frequency. Additionally, gamma light flickers were found to accelerate endogenous oscillation while suppressing low-frequency power. Surprisingly, the effects of intensity and duty cycle on entrainment were complex, with high intensity not necessarily correlating with high entrainment possibility. Furthermore, entrainment could be induced more easily with duty cycles below 50%. The study also observed entrainment discontinuity during gamma flicker stimulations with different frequencies due to the network oscillations’ non-linear behavior. These findings advance our understanding of brain entrainment and support potential clinical applications using gamma light flicker to modulate TCOs. Dive into the fascinating research to learn about the symphony of your brain and exciting possibilities for future therapies!

Rhythmic light flickers have emerged as useful tools to modulate cognition and rescue pathological oscillations related to neurological disorders by entrainment. However, a mechanistic understanding of the entrainment for different brain oscillatory states and light flicker parameters is lacking. To address this issue, we proposed a biophysical neural network model for thalamocortical oscillations (TCOs) and explored the stimulation effects depending on the thalamocortical oscillatory states and stimulation parameters (frequency, intensity, and duty cycle) using the proposed model and electrophysiology experiments. The proposed model generated alpha, beta, and gamma oscillatory states (with main oscillation frequences at 9, 25, and 35 Hz, respectively), which were successfully transmitted from the thalamus to the cortex. By applying light flicker stimulation, we found that the entrainment was state-dependent and it was more prone to induce entrainment if the flicker perturbation frequency was closer to the endogenous oscillatory frequency. In addition, endogenous oscillation would be accelerated, whereas low-frequency oscillatory power would be suppressed by gamma (30–50 Hz) flickers. Notably, the effects of intensity and duty cycle on entrainment were complex; a high intensity of light flicker did not mean high entrainment possibility, and duty cycles below 50% could induce entrainment easier than those above 50%. Further, we observed entrainment discontinuity during gamma flicker stimulations with different frequencies, attributable to the non-linear characteristics of the network oscillations. These results provide support for the experimental design and clinical applications of the modulation of TCOs by gamma (30–50 Hz) light flicker.

Read Full Article (External Site)