MAPT and Alzheimer disease: By comparatively assessing tau aggregates/tangles, neuroinflammation, mitochondrial biogenesis, and histological changes in brain sections of control and treated zebrafish, as well as by analyzing their behavioral responses, the present study shows that (1) the OKA treatment induces AD-like pathology in adult zebrafish, including impaired cognition/memory and (2) a sequential PBM treatment strategy greatly improves the OKA-induced AD pathology.