Microglial Morphological Complexity in the Piriform Cortex Is Associated with Olfactory Aversion Following Chronic
Kai Clane Belonio1, Zach Fyke2, Eyerusalem S Haile3
1Department of Biological Sciences, University of Illinois Chicago, Chicago, Illinois 60607.
Eneuro
|April 10, 2026
Summary
Chronic stress alters olfactory perception by changing glial cells in the brain. These neuroimmune changes in olfactory regions correlate with increased avoidance of unpleasant odors, potentially linking mood disorders to sensory experience.
Area of Science:
- Neuroscience
- Neuroimmunology
- Sensory Processing
Background:
- Depression is linked to olfactory dysfunction, including anhedonia and heightened aversion to odors.
- Neural mechanisms connecting chronic stress to altered olfactory perception are not well understood.
- Neuroinflammation is implicated in depression-related brain dysfunction, but its role in olfactory processing is unclear.
Purpose of the Study:
- To investigate how chronic stress affects olfactory avoidance behavior and glial cell morphology in olfactory brain regions.
- To explore the relationship between glial plasticity and stress-induced changes in olfactory perception.
Main Methods:
- Utilized the Unpredictable Chronic Mild Stress (UCMS) paradigm in mice.
- Assessed olfactory avoidance behavior using an odorized light/dark box assay.
- Examined microglial morphology and astrocyte density via immunohistochemistry in multiple brain regions.
Main Results:
- UCMS-treated mice exhibited increased avoidance of aversive odorants.
- Chronic stress induced region-specific glial remodeling, including elevated astrocyte counts in the medial amygdala.
- Increased microglial process complexity was observed in the anterior olfactory nucleus and anterior piriform cortex.
- Microglial complexity in the piriform cortex correlated with individual odor avoidance scores.
Conclusions:
- Chronic stress promotes glial plasticity in olfactory sensory and affective networks.
- Glial remodeling, particularly in the piriform cortex, may contribute to stress-related alterations in olfactory perception.
- These findings highlight the neuroimmune basis of sensory-affective integration and its potential role in mood disorders.
More Related Videos
Related Concept Videos
01:03Olfactory Receptors: Location and Structure
14.6K
The process of olfaction, also known as the sense of smell, is a sophisticated chemical response system. The specialized sensory neurons that facilitate this process, known as olfactory receptor neurons, are situated in an upper segment of the nasal cavity, known as the olfactory epithelium. Olfactory sensory neurons are bipolar, with their dendrites extending from the epithelium's apex into the mucus that lines the nasal cavity. Airborne molecules, when inhaled, traverse the olfactory...
14.6K
01:25Olfaction
50.0K
The sense of smell is achieved through the activities of the olfactory system. It starts when an airborne odorant enters the nasal cavity and reaches olfactory epithelium (OE). The OE is protected by a thin layer of mucus, which also serves the purpose of dissolving more complex compounds into simpler chemical odorants. The size of the OE and the density of sensory neurons varies among species; in humans, the OE is only about 9-10 cm2.
The olfactory receptors are embedded in the cilia of the...
The olfactory receptors are embedded in the cilia of the...
50.0K
01:20Physiology of Smell and Olfactory Pathway
14.3K
Humans detect odors with the help of specialized cells located in the upper part of the nasal cavity, called olfactory receptor neurons (ORNs). ORNs possess hair-like structures called cilia, which are receptive to sensations from the inhaled air. When an odorant molecule binds to a specific receptor on the cell of the cilia, it leads to a series of events that ultimately cause the ORN to send electrical signals to the olfactory bulb in the brain through the olfactory nerves.
The olfactory...
The olfactory...
14.3K