Photobiomodulation and the Brain: a New Paradigm
HHS Public Access Author manuscript Author ManuscriptAuthor Manuscript Author J Opt. Author Manuscript Author manuscript; Manuscript Author available in PMC 2018 January 01. Published in final edited form as: J Opt. 2017 January ; 19(1): 013003–. doi:10.1088/2040-8986/19/1/013003. Photobiomodulation and the brain: a new paradigm Madison Hennessy1 and Michael R Hamblin2,3,4 1Briarcliff High School, Briarcliff Manor, NY, USA 2Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA 3Department of Dermatology, Harvard Medical School, Boston, MA, USA 4Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, USA Abstract Transcranial photobiomodulation (PBM) also known as low level laser therapy (tLLLT) relies on the use of red/NIR light to stimulate, preserve and regenerate cells and tissues. The mechanism of action involves photon absorption in the mitochondria (cytochrome c oxidase), and ion channels in cells leading to activation of signaling pathways, up-regulation of transcription factors, and increased expression of protective genes. We have studied PBM for treating traumatic brain injury (TBI) in mice using a NIR laser spot delivered to the head. Mice had improved memory and learning, increased neuroprogenitor cells in the dentate gyrus and subventricular zone, increased BDNF and more synaptogenesis in the cortex. These highly beneficial effects on the brain suggest that the applications of tLLLT are much broader than at first conceived. Other groups have studied stroke (animal models and clinical trials), Alzheimer’s disease, Parkinson’s disease, depression, and cognitive enhancement in healthy subjects. Keywords Transcranial photobiomodulation; low level laser therapy; brain disorders; traumatic brain injury; stroke; Alzheimer’s disease; psychiatric diseases 1 Introduction Light in the visible and near-infrared spectrum makes up the major part of solar radiation and is also provided by artificial light sources.
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