Early Aging Effect on the Function of the Human Central Olfactory System.

Area of Science:

• Neuroscience
• Olfactory research
• Aging studies

Background:

• Smell function significantly declines with age, particularly after the sixth decade.
• Previous research shows reduced central olfactory system activity in seniors, but early aging effects are unknown.

Purpose of the Study:

• To investigate age-related changes in brain activity related to olfaction in healthy adults.
• To examine the correlation between age and olfactory function and brain activity in central olfactory structures.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to study 43 healthy adults aged 22-64.
• Olfaction-related brain activity was measured in response to odor stimulation.
• Correlation analyses were performed between age, smell identification, and brain activity.

Main Results:

• Smell identification function showed a significant negative correlation with age (r = -.32, p = .037).
• Age was negatively correlated with olfaction-related activity in the dorsolateral prefrontal cortex, insular cortex, and orbitofrontal cortex (p < .001).
• No significant age-related correlation was found in the primary olfactory cortex.

Conclusions:

• Age-related functional decline in the central olfactory system begins in early adulthood.
• Secondary and higher-order olfactory brain regions show more prominent age-related decline than the primary olfactory cortex.