Transcranial PBM (tPBM), targeting delivery of light energy to the brain, is associated with increased cerebral blood flow, oxygen availability and consumption, adenoside triphophosphate (ATP) production, and improved mitochondrial activity4. More recently, tPBM has demonstrated its value as a treatment for neurological5–10 and neurodegenerative conditions, including Alzheimer’s disease11,12. Thus, tPBM is a form of non-invasive brain stimulation (NIBS). However, compared to the more established forms of NIBS, such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), the concept of the brain being responsive to light stimulation is unfamiliar to many. In recent years, research on the potential efficacy of tPBM has gained momentum13. Research on the effect of PBM on brain cell recovery has shown that, under laboratory conditions, damaged neurons can regrow their neurites with direct exposure to visible red low level lasers14. In an animal study, PBM has been found capable of promoting neurogenesis after ischemic stroke through the proliferation and differentiation of internal neuroprogenitor cells.