Identification of temperature-sensitive neural circuits in mice using c-Fos expression mapping

Area of Science:

• Neuroscience
• Physiology
• Behavioral Science

Background:

• Thermoregulation is crucial for survival.
• Understanding the neural circuits involved is essential for identifying potential therapeutic targets.

Purpose of the Study:

• To map the expression of the inducible transcription factor c-Fos in the mouse brain.
• To identify neural circuits selectively involved in the response to external cold and hot temperatures.
• To investigate the habituation of c-Fos response to repeated thermal exposures.

Main Methods:

• Male C57BL/6J mice were exposed to acute or repeated cold (10°C) or hot (34°C) temperatures.
• Control mice were acclimated to 20°C.
• Immunohistochemical analysis was performed 90 minutes after exposure to quantify c-Fos expression.

Main Results:

• c-Fos expression habituated in the nucleus accumbens and medial cortical amygdala with repeated exposures.
• Consistent c-Fos induction was observed in the hypothalamus, lateral septum, midbrain, dentate gyrus, and thalamus following both acute and repeated thermal exposures.
• The Edinger-Westphal nucleus showed increased c-Fos after acute exposure, with less clear specificity for repeated exposures.

Conclusions:

• The hypothalamus, lateral septum, midbrain, dentate gyrus, and thalamus are key brain regions involved in responding to external temperature changes.
• The study identifies novel brain structures responsive to thermal stimuli, expanding our understanding of thermoregulation.
• Habituation of c-Fos response in certain areas suggests distinct neural pathways for acute versus sustained thermal challenges.