Brain interleukin asymmetries and paw preference in mice

Area of Science:

• Neuroimmunology
• Brain Lateralization
• Cytokine Signaling

Background:

• The brain's hemispheres exhibit distinct roles in modulating immune responses.
• Cerebral cortex cytokines are implicated in brain lateralization and immune modulation.

Purpose of the Study:

• To investigate the relationship between cerebral cortex cytokine levels and behavioral lateralization.
• To determine if cytokine levels (interleukin-1beta and interleukin-6) differ between brain hemispheres based on paw preference.

Main Methods:

• BALB/c mice were categorized by paw preference (left-pawed, ambidextrous, right-pawed).
• Interleukin-1beta and interleukin-6 levels were measured in both left and right cerebral cortices.
• Mice were treated with either saline or lipopolysaccharide (LPS) to assess cytokine responses under normal and stimulated conditions.

Main Results:

• The right cerebral cortex consistently showed higher basal levels of interleukin-1beta and interleukin-6 compared to the left cortex.
• Significant correlations were observed between cytokine levels in both hemispheres and behavioral lateralization (paw preference scores).
• Specific patterns of cytokine asymmetry were linked to the direction and intensity of paw preference in both saline and LPS-treated mice.

Conclusions:

• Basal levels of interleukin-1beta and interleukin-6 are asymmetrically distributed in the mouse cerebral cortex, favoring the right hemisphere.
• Cytokine levels and their hemispheric distribution are strongly correlated with behavioral lateralization.
• Cytokine asymmetries provide insights into the neuro-immune interactions underlying brain lateralization.