Olfactory Development, Part 1: Function, From Fetal Perception to Adult Wine-Tasting

Area of Science:

• Neuroscience
• Developmental Biology
• Otolaryngology

Background:

• Fetal olfactory discrimination of molecules in amniotic fluid emerges after 30 weeks gestation.
• Maternal diet influences fetal olfactory responses.
• Olfactory reflexes are reliable for neonatal testing.

Purpose of the Study:

• To investigate fetal olfactory system development and maturation.
• To highlight the diagnostic utility of olfactory bulb assessment via MRI.
• To underscore the importance of testing cranial nerve 1 in neonates.

Main Methods:

• Magnetic Resonance Imaging (MRI) for olfactory bulb visualization and assessment.
• Clinical examination and neuropathology for diagnosing olfactory bulb malformations.
• Review of fetal neurodevelopmental milestones related to olfaction.

Main Results:

• Olfactory bulbs are reliably visualized by MRI after 30 weeks gestation.
• Hypoplasia or aplasia of olfactory bulbs can be detected prenatally and postnatally.
• Fetal olfactory system maturation, including neuronal differentiation and myelination, is incomplete at term but functional.

Conclusions:

• Fetal olfaction is functional despite incomplete maturation at term.
• Olfactory bulb malformations can be diagnosed using clinical and imaging methods.
• Cranial nerve 1 assessment is crucial in neonates, particularly those with brain malformations or genetic disorders.