Are Neurons Extra Sensitive to Light Energy?
The idea that light can influence the brain isn’t science fiction, it’s science. In recent years, the field of photobiomodulation (PBM) has uncovered how light energy, particularly in the red and near-infrared spectrum, can interact with our cells in surprisingly therapeutic ways. But are neurons, our brain’s most vital and complex cells, especially sensitive to this kind of energy?
What is Photobiomodulation?
Photobiomodulation refers to the use of specific wavelengths of light to stimulate cellular function, most notably through mitochondrial mechanisms. The most common wavelengths used are in the red (600–700 nm) and near-infrared (760–1100 nm) range. These wavelengths penetrate biological tissues and are absorbed by intracellular photoreceptors, particularly cytochrome c oxidase (CCO) in mitochondria, leading to increased ATP production, modulation of reactive oxygen species, and changes in gene expression [1].
Why Neurons Might Be More Sensitive
Neurons are highly metabolically active and rely heavily on mitochondrial function. Since they are post-mitotic and do not easily regenerate, their health is tightly linked to mitochondrial performance. This may explain why they respond especially well to light stimulation.
- High mitochondrial density: Neurons have a large number of mitochondria to support their energy needs, especially in synapses [2].
- Vulnerability to oxidative stress: The brain uses about 20% of the body’s oxygen but comprises only ~2% of its mass. PBM’s ability to regulate redox balance offers potential neuroprotection [3].
- Modulation of neuroinflammation: Light energy has been shown to reduce inflammatory markers and glial activity, both of which affect neuron health [4].
Supporting Evidence
1. Improved Cognitive Function
A randomized controlled trial found that near-infrared PBM applied to the prefrontal cortex improved attention and memory in healthy adults [5].
2. Neuroprotection After Injury
In rodent models of traumatic brain injury, PBM preserved neurons, reduced glial scarring, and stimulated regeneration [6].
3. Functional Imaging Studies
EEG and fMRI studies have shown increased brain activity and connectivity after PBM, suggesting direct effects on neural networks [7].
4. Applications in Neurodegenerative Disorders
Early human studies indicate benefits for Alzheimer’s and Parkinson’s patients, including improved mood, memory, and sleep [8].
Can Light Really Reach the Brain?
The human skull filters out much light, but near-infrared wavelengths, especially in the 810–1070 nm range, can penetrate to the cortex. Studies estimate that enough light reaches cortical tissue to stimulate a biological response, especially when higher-power or pulsed devices are used [9].
Visual Proof: Near-Infrared Light Penetrating the Skull with Vielight Neuro 4
The Vielight Neuro has the deepest penetration in the brain photobiomodulation field. The demonstration video below with a real human skull and the Vielight Neuro clearly demonstrates 810nm light energy with an irradiance of 250 mW/cm2 clearly passing through the skull’s calvaria.
The Vielight Neuro features proprietary Vie-LED technology—highly specialized, custom-engineered LEDs designed to deliver optimal irradiance for brain stimulation without producing excess heat. To ensure safety and efficiency, we’ve intentionally limited the device’s power density to 50% of its maximum potential output. Even still, it features the highest irradiance in the field of brain photobiomodulation according to independent 3rd party tests.
Conclusion
So, are neurons extra sensitive to light energy? Current research strongly suggests yes. Due to their high energy demands and mitochondrial density, neurons are well-positioned to benefit from photobiomodulation. Whether enhancing cognitive performance, protecting against injury, or slowing neurodegeneration, PBM appears to offer a non-invasive, promising method to support Brain wellness.
References
- Hamblin, M.R. (2016). Shining light on the head: Photobiomodulation for brain disorders. BBA Clinical, 6, 113–124. https://doi.org/10.1016/j.bbacli.2016.09.002
- Attwell, D., & Laughlin, S.B. (2001). An energy budget for signaling in the grey matter of the brain. Journal of Cerebral Blood Flow & Metabolism, 21(10), 1133–1145. https://doi.org/10.1097/00004647-200110000-00001
- Sies, H. (2015). Oxidative stress: A concept in redox biology and medicine. Redox Biology, 4, 180–183. https://doi.org/10.1016/j.redox.2015.01.002
- Salehpour, F., et al. (2018). Transcranial Photobiomodulation Therapy: A Novel Method for Neuroenhancement. Journal of Photochemistry and Photobiology B, 183, 47–55. https://doi.org/10.1016/j.jphotobiol.2018.04.007
- Barrett, D.W., & Gonzalez-Lima, F. (2013). Transcranial infrared laser stimulation produces beneficial cognitive and emotional effects in humans. Neuroscience, 230, 13–23. https://doi.org/10.1016/j.neuroscience.2012.11.016
- Xuan, W., et al. (2014). Transcranial low-level laser therapy improves neurological performance in traumatic brain injury in mice. PLOS ONE, 9(1), e86264. https://doi.org/10.1371/journal.pone.0086264
- Tian, F., et al. (2016). Transcranial laser stimulation improves human cerebral oxygenation. Lasers in Surgery and Medicine, 48(4), 343–349. https://doi.org/10.1002/lsm.22470
- Chao, L.L. (2019). Home Photobiomodulation Treatments on Cognitive and Behavioral Function in Dementia. Journal of Alzheimer’s Disease Reports, 3(1), 241–255. https://doi.org/10.3233/ADR-190135
- https://www.vielight.com/blog/irradiance-the-key-to-effective-brain-photobiomodulation/
