Several studies have advanced on blood testing for Alzheimer's disease using the protein p-tau217, whichis increased seven-fold in AD and accumulates in the brain up to 20 years before symptoms.

Mice with amyloid-beta plaques (indicative of Alzheimer's disease) had impaired synaptic plasticity, until the addition of the "love hormone" oxytocin, which reversed the effects of amyloid-beta.

The breakdown of stored fat is ignited by nerves in the fat tissue, which gets upregulated by the hormone leptin. In mice, the absence of leptin shrinks neurons, which reduces the ability to burn fat.

Age-related hearing loss (presbycusis) is caused mainly by damage to hair cells, the sensory cells of the inner ear; the damage comes from loud noises and may benefit from hair cell regenerative therapy.