Olfactory sensitivity for aliphatic ketones in squirrel monkeys and pigtail macaques

Area of Science:

• Olfactory neuroscience
• Primate sensory perception
• Animal behavior

Background:

• Olfactory sensitivity varies significantly across species.
• Understanding primate olfactory capabilities is crucial for comparative neuroscience.
• Aliphatic ketones represent a key class of odorants with diverse applications.

Purpose of the Study:

• To assess and compare the olfactory sensitivity of squirrel monkeys and pigtail macaques to aliphatic ketones.
• To investigate the relationship between ketone chemical structure (carbon-chain length, functional group position) and olfactory detection thresholds.
• To evaluate the predictive value of olfactory receptor gene counts and neuroanatomy for olfactory performance.

Main Methods:

• A conditioning paradigm was employed to assess olfactory sensitivity.
• Homologous series of aliphatic 2-ketones, symmetrical ketones, and C7-ketones were tested.
• Olfactory detection thresholds were determined for each species and ketone series.

Main Results:

• Both species demonstrated significant olfactory discrimination of ketones at concentrations below 1 part per million (ppm), with some thresholds below 1 part per billion (ppb).
• Pigtail macaques generally exhibited superior olfactory sensitivity compared to squirrel monkeys for aliphatic ketones.
• A negative correlation was observed between olfactory detection thresholds and carbon-chain length for 2-ketones and symmetrical ketones.

Conclusions:

• Squirrel monkeys and pigtail macaques possess well-developed olfactory sensitivity to aliphatic ketones.
• Olfactory performance is influenced by chemical structure, specifically carbon-chain length.
• Olfactory receptor gene numbers and neuroanatomy are poor predictors of olfactory performance across species.