Direct electrophysiological recordings taken at the olfactory mucosa and from cortical responses in the same participants localize where age-related smell loss originates, distinguishing peripheral receptor-level decline from diminished central processing. Olfactory performance is among the earliest measurable markers of neurodegenerative change and a consistent predictor of mortality risk, making the site of failure clinically meaningful. Separating the two levels allows olfactory testing to be interpreted with far greater precision than psychophysical threshold scores alone.
Key Points
- Recordings taken at nasal mucosa and cortex in same participants
- Aging affects peripheral receptor signaling and central processing distinctly
- Olfactory decline precedes clinical neurodegeneration by years
Longevity Analysis
Smell is the only sensory pathway with neurons directly exposed to inhaled air, and its epithelium relies on continuous stem cell turnover — making it an accessible readout of both environmental burden and regenerative capacity. Localizing age-related loss to the receptor surface versus cortical interpretation changes what can be acted upon: mucosal decline points toward inhaled exposures, inflammation, and tissue renewal, while central decline points toward broader neural aging. Olfactory testing earns its place in longevity assessment precisely because it detects change in nervous tissue before cognition registers it.
Original published by Nature - npj Aging, by Yiling Mai.