Emerging research reveals lithium deficiency in the brain as a pivotal factor in Alzheimer’s disease progression, with novel lithium compounds capable of reversing pathology in mouse models. Complementing this, hypoxia exposure demonstrates protective and restorative effects in Parkinson’s disease mouse models, challenging long-held assumptions about oxygen toxicity in neurodegeneration. Studies also highlight the role of microglia, brain resident immune cells, in prenatal neurogenesis and neurodegenerative disease mitigation via allogeneic transplantation strategies. These advances elucidate complex cellular mechanisms and introduce promising therapeutic avenues in neurodegenerative disorders.