A Signal Detection Analysis of Olfactory Learning in 12-Month-Old 5xFAD Mice

Area of Science:

• Neuroscience
• Animal Models of Disease

Background:

• Alzheimer's disease (AD) is primarily known for memory deficits.
• Early-stage Alzheimer's disease also involves olfactory dysfunction.
• Investigating olfactory deficits provides insights into early AD pathology.

Purpose of the Study:

• To assess olfactory learning, sensitivity, and response bias in 5xFAD mice, a model for Alzheimer's disease.
• To compare olfactory performance between male and female 5xFAD mice and wildtype controls.
• To utilize signal detection methods to differentiate cognitive from sensory deficits.

Main Methods:

• Operant olfactometer used to test 12-month-old male and female 5xFAD mice and wildtype controls.
• Signal detection analysis applied to measure olfactory sensitivity, learning, and response bias.
• Comparison of olfactory performance metrics between sexes and genotypes.

Main Results:

• 5xFAD mice showed no deficit in odor detection sensitivity.
• Olfactory learning was impaired in 5xFAD mice compared to controls.
• Female 5xFAD mice exhibited worse olfactory learning than males and adopted a more conservative response strategy.

Conclusions:

• Olfactory learning deficits, not detection sensitivity, characterize this Alzheimer's disease mouse model.
• Sex-specific differences in olfactory learning and strategy exist in 5xFAD mice.
• Signal detection analysis is valuable for distinguishing cognitive and sensory impairments in AD models.