Photobiomodulation for the aging brain.

Longevity is one of the great triumphs of humanity. Worldwide, the elderly is the fastest growing segment of the population. As a consequence, the number of cases of age-related cognitive decline and neurological diseases associated with aging, such as Alzheimer's and Parkinson's, has been increasing. Among the non-pharmacological interventions studied for the treatment or prevention of age-related neurocognitive impairment, photobiomodulation (PBM) has gained prominence for its beneficial effects on brain functions relevant to aging brains. In animal models, the neuroprotective and neuromodulatory capacity of PBM has been observed. Studies using both animals and humans have shown promising metabolic and hemodynamic effects of PBM on the brain, such as improved mitochondrial and vascular functions. Studies in humans have shown that PBM can improve electrophysiological activity and cognitive functions such as attention, learning, memory and mood in older people. In this paper we will review the main brain effects of PBM during aging, discuss its mechanisms of action relevant to the aging brain, and call for more controlled studies in older populations.