40 Hz Blue LED Relieves the Gamma Oscillations Changes Caused by Traumatic Brain Injury in Rat

Abstract

BackgroundPhotobiomodulation (PBM) using low-level light-emitting diodes (LEDs) can be rapidly applied to various neurological disorders safely and non-invasively.Materials and MethodsForty-eight rats were involved in this study. The traumatic brain injury (TBI) model of rat was set up by a controlled cortical impact (CCI) injury. An 8-channel cortex electrode EEG was fixed to two hemispheres, and gamma oscillations were extracted according to each electrode. A 40 hz blue LED stimulation was set at four points of the frontal and parietal regions for 60 s each, six times per day for 1 week. Modified Neurologic Severity Scores (mNSS) were used to evaluate the level of neurological function.ResultsIn the right-side TBI model, the gamma oscillation decreased in electrodes Fp2, T4, C4, and O2; but significantly increased after 1 week of 40 hz Blue LED intervention. In the left-side TBI model, the gamma oscillation decreased in electrodes Fp1, T3, C3, and O1; and similarly increased after 1 week of 40 hz Blue LED intervention. Both left and right side TBI rats performed significantly better in mNSS after 40 hz Blue LED intervention.ConclusionTBI causes the decrease of gamma oscillations on the injured side of the brain of rats. The 40 hz Blue LED therapy could relieve the gamma oscillation changes caused by TBI and improve the prognosis of TBI.

Gamma frequency entrainment rescues cognitive impairment by decreasing postsynaptic transmission after traumatic brain injury

“…Studies have shown that hippocampal gamma oscillations could be modulated by 40 Hz light flicker and then involved in the process of cognitive ability 10,11,22,23 . Previous study found that gamma oscillations of the injury side after TBI in rats is decreased, and 40 Hz light flicker could attenuate the down‐regulation of gamma oscillation after TBI 24 . Thus, we suspected that gamma oscillations, which could be affected by 40 Hz light flicker, is manipulated and then involved in the process of cognitive ability after TBI treatment in mice.…”

Gamma sensory entrainment for cognitive improvement in neurodegenerative diseases: opportunities and challenges ahead

“…Despite such variability, EEG recordings in mild-TBI patients revealed a significant decrease in synchronization of the low gamma band frequency (25 Hz−40 Hz) across the scalp when compared to healthy controls ( Wang et al, 2017 ). Similarly, a recent study showed decreased gamma power in rat models of TBI in which case 40 Hz visual entrainment by blue LED light could revive gamma power in the injury side of the brain in order to improve overall prognosis ( Yang et al, 2022 ). Therefore, it is highly likely that the propagative nature of sensory entrainment may be suitable for a lesion-diverse condition like TBI, and it could also be remarkably beneficial in terms of scavenging hyper-phosphorylated tau protein and Aβ clusters, thus having significant prognostic value.…”