Olfactory modulation of stress-response neural circuits

Area of Science:

• Neuroscience
• Endocrinology
• Animal Behavior

Background:

• Stress responses are evolutionarily conserved and crucial for survival.
• The hypothalamic corticotropin-releasing hormone neuron (CRHN) axis is a primary endocrine stress pathway.
• Neural circuits relay diverse stressor signals to CRHNs, initiating common hormonal responses.

Purpose of the Study:

• To review neurocircuitry mechanisms controlling CRHNs in response to various stressors.
• To highlight the role of olfactory systems in modulating CRHNs and stress responses.
• To understand how environmental cues, particularly smells, are perceived to regulate stress.

Main Methods:

• Review of existing literature on stress neurocircuits.
• Focus on studies employing retrograde transsynaptic viral tracers.
• Analysis of research investigating olfactory system connections to CRHNs.

Main Results:

• Diverse neural circuits converge on CRHNs to mediate stress responses.
• Olfactory pathways can both excite and suppress CRHN activity.
• Smell perception plays a significant role in initiating stress hormone release.

Conclusions:

• Understanding olfactory control of stress responses provides insight into environmental stress perception.
• Neurocircuitry investigations reveal complex regulation of the stress axis.
• Olfactory cues are critical for animals to adapt and survive environmental changes.