Excitable Axonal Domains Adapt to Sensory Deprivation in the Olfactory System

Area of Science:

• Neuroscience
• Cell Biology
• Sensory Systems

Background:

• The axon initial segment (AIS), nodes of Ranvier, and myelin sheath are crucial for neuronal firing and action potential (AP) transmission.
• Olfactory bulb (OB) neurons must reliably transmit signals over long distances for olfactory discrimination.
• The adaptive capacity of myelinated axons in the olfactory system is not well understood.

Purpose of the Study:

• To investigate how mitral cell (MC) axons in the olfactory system adapt to sensory input changes.
• To examine the effects of unilateral olfactory deprivation on axonal morphology, myelination, and physiology in mice.

Main Methods:

• Adult male and female mice underwent unilateral olfactory deprivation.
• Axonal morphology, myelin thickness, and MC spiking patterns were analyzed.
• Physiological changes in MCs and myelination of the lateral olfactory tract (LOT) were assessed.

Main Results:

• Unilateral sensory deprivation induced system-wide adaptations in axonal morphology and myelin thickness.
• MC spiking patterns and APs adapted to sensory deprivation.
• Myelination and MC physiology were altered bilaterally, indicating system-level plasticity.

Conclusions:

• Olfactory system plasticity involves previously unstudied mechanisms affecting myelination and neuronal physiology.
• Adaptations in myelination and MC physiology occur on both deprived and non-deprived sides, suggesting a coordinated system response.
• This study reveals a novel mechanism of neural plasticity in response to altered sensory input.