Microglial morphological complexity in the piriform cortex is associated with olfactory aversion following chronic...

Area of Science:

• Neuroscience
• Neuroimmunology
• Sensory Perception

Background:

• Depression is linked to altered olfactory perception, including aversion to odors.
• Neuroinflammation is implicated in depression, but stress effects on olfactory glial cells are unclear.

Purpose of the Study:

• To investigate how chronic stress affects olfactory avoidance behavior.
• To examine glial cell morphology in olfactory brain regions following chronic stress.

Main Methods:

• Used the Unpredictable Chronic Mild Stress (UCMS) paradigm in mice.
• Assessed olfactory avoidance behavior using an odorized light/dark box assay.
• Analyzed microglial morphology and astrocyte density via immunohistochemistry in olfactory and limbic regions.

Main Results:

• UCMS-treated mice showed increased avoidance of aversive odorants.
• Chronic stress induced region-specific glial remodeling: elevated astrocytes in the medial amygdala.
• Increased microglial complexity was observed in the anterior olfactory nucleus and anterior piriform cortex, correlating with odor avoidance.

Conclusions:

• Chronic stress causes regionally specific glial plasticity in olfactory and affective networks.
• Microglial remodeling in the piriform cortex may underlie stress-related olfactory perception changes.
• Glial plasticity in sensory networks contributes to altered olfactory perception in mood disorders.